canine impactions

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CANINE IMPACTIONS

Presented by: Dr. Naveen Sharma

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Contents• Introduction• Incidence • Maxillary canine• Classification• Etiology• Diagnosis• Complication of untreated impacted canine• Treatment options• Methods of Creating Space • Surgical Exposure of impacted canine• Attachments For canine • Traction • Impacted tooth and Periodontium• Retention• Success & duration• Time to extract canine• Mandibular canines• Impacted canines in adults• Conclusion

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The treatment of impacted teeth has caught the imagination of many in

dental profession. However, the orthodontic / surgical modality has achieved

the most satisfactory result in long-term.

Mandibular third molar Maxillary canine mandibular second premolar.

Canine playing an important role in esthetics, being corner

tooth of mouth and function deserves special attention for its impaction to

be properly diagnosed and managed.

Introduction

When can a tooth considered to be impacted?

Gron A M (1962) Prediction of tooth emergence. J Dent Res 41: 573-85

Under normal conditions, tooth erupts with a developing root and with approximately ¾ of its final root length.

Hence in simple terms, a tooth can be considered impacted if its root is completed but still has not erupted

Applying this concept to maxillary and mandibular canines , they generallyhave their ¾ root completed by 11-12 yrs and 9-10 yrs respectively.

According to Shafer, Hine and Levy,

Impacted teeth are those which are prevented from

erupting by some physical barrier in the eruption path.

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Incidence

Dachi and Howell reported that the incidence of maxillary canine impaction is 0.92%, and mandibular canine

impaction is 0.35%

Asians present more of buccal canine impactions.

Impactions are twice as common in females (1.17%) as in males (0.51%).

Of all patients with maxillary impacted canines, it is estimated that 8% have bilateral impactions.

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Normal development of maxillary canine

3 yrs 5 yrs 6.5 yrs8

Normal development of maxillary canine

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Etiology • Generalized causesEndocrine deficiencies, Febrile diseases, and Irradiation.• Localized factors(a) tooth size-arch length discrepancies, (b) prolonged retention or early loss of the deciduous

canine, (c) abnormal position of the tooth bud, (d) the presence of an alveolar cleft,(e) ankylosis, (f ) cystic or neoplastic formation, (g) dilaceration of the root, (h) iatrogenic origin and (i) idiopathic condition with no apparent cause

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Theories put forth for maxillary canine impactions

Long path of eruption

Early days of Broadbent in 1940

Most common reason been given

Tooth had much to travel from floor of orbit to oral cavity, hence had greater chances of “losing its way”

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Crowding

Developmental position of lateral incisor and 1st PM is palatal to line of arch

Hitchson A D (1956) Impacted maxillary canine. Br Dent J 100: 1-1212


Non-resorption of root of deciduous teeth

Spontaneous eruption of previously impacted canines, following extraction of deciduous canine

Clinical evidence – presence and advancing eruption of the permanent tooth provides a stimulus for

resorption, and a portion of root distant from unerupted permanent tooth may be unaffected by the

process

Lappin M M (1951) Practical management of impacted maxillary canine. AJODO 37:769-78

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Trauma

• May cause movement of lateral incisor

• By conduction, movement of canine bud itself

• Shortness of lateral incisor root, whose development ceased as a result of trauma

Trauma as a possible etiologic factor for maxillary canine impaction. Brin et al: AJODO 1993;104:132-7

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Presence of chronic irritation

Favorable spontaneous eruption of severely displaced maxillary canines with associated follicular disturbance. Fearne J: BJO 1988 ;15 : 93-8

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Peg laterals

Small lateral incisors were found to be 8 times more frequent and peg laterals 9 times more frequent in

palatal impacted canine cases as compared with normal population.

Anomalous small and peg shaped laterals develop much later than normal laterals.

Incidence of anomalous lateral incisors in relation to palatal displaced canines;Becker et al, AO 1981; 51: 24-9

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Relationship of canine to late developing peg laterals

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Guidance theory of MillerPrevalence of impacted canines to be high with

congenitally missing lateral incisors

Permanent canines lacks the normal guidance provided by the distal aspect of lateral

incisors

Influence of congenitally missing teeth on eruption of upper canine. Miller B H; Dent Pract Dent Rec; 1963, 13: 497-504

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Heredity

Prevalence of small peg shaped and missing lateral incisors, late developing dentitions and other missing teeth among close relatives was very high in

addition to palatally impacted canines.

Familial trends in palatal canines, anomalous lateral incisors and related phenomenon.Zilberman et al; EJO 1990; 12: 135-9

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Complications of untreated impacted canines

A) Morbidity of deciduous canine

Root is resorbed and small leading to eventual mobility and shedding.

High susceptibility to caries.

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B) Cystic change

Loss of vitality of dec. canine

Periapical pathology

Communicates with follicular sac of perm. Canine

Enlargement of follicular sac

Cystic change

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C) Permanent canine

crown resorption

Degeneration of REE

Direct contact of bone and enamel

Osteoclastic activity

Replacement resorption22


D) Resorption of roots

of adjacent teeth

Onset is rapid and its

conduct aggressive

Resorbed lateral incisors adjacent to impacted canines have normal crown size. Brin et al; AJODO 1993; 104: 60-6

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Diagnosis

• Inspection

• Palpation

• Radiography

Orthodontic treatment of impacted teeth; Adrian Becker; 1st ed.24

Inspection • Non-appearance of permanent canine clinically by its eruption

age.• Presence of antimere. • Presence of anterior spacing for a long period• Persistent median diastema• Abnormal morphology of lateral incisor or presence of peg

laterals• Improper angulations of adjacent teeth

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Palpation

• Bulge of per. canine could be palpated buccally above the deciduous canine 2-3 yrs before its eruption

• It should be palpated deep above attached gingiva in the sulcus where mucosa reflects

• Deciduous canine should be checked for mobility

• Palpation should be done in abnormal locations after getting clue from inspection

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Periapical

Mandibular arch

Max. ant. occlusal True vertex/occlusal

OPG Lateral ceph

Extraoral

I. Qualitative radiographs

Maxillary arch Occlusal

PA view

Parallax method Radiographic views at right angle C T scanning

II. 3-D localisation

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Periapical viewFirst simplest and most informative view

Advantages1) Root development, pattern and

integrity2) Crown resorption 3) Root resorption of adjacent tooth4) Minimum of surrounding tissue is

exposed which increase accuracy and resolution.

5) Minimal radiation exposure

Disadvantage1) 2D picture of 3D object2) Cannot determine bucco-lingual

posn of tooth & vertical position of impacted tooth. 28

Occlusal Radiograph

Maxillary anterior occlusal

Does not show exact cross section

of anterior teeth making it difficult to

find bucco-lingual position of impacted teeth

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Occlusal Radiograph

Maxillary true (vertex) occlusal

X-ray beam runs parallel to long axisof incisors.

Possible to get cross section of anteriors.Allows for bucco-lingual position of

impacted canines.

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Occlusal RadiographMaxillary true (vertex) occlusal

Ong’s projection

Alternative technique to vertex/true occlusal view Ong: AJO-DO, Volume 1994 Dec (621 - 626)

Extra-oral technique for vertex occlusal view,To increase clarity and reduce exposure due to

use of intensifying screen

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Occlusal RadiographMandibular occlusal

900 to OP – cross-section of PM, molar region

1100 to OP – cross-section of incisor region

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Lateral cephalogram

Periapical views can be misleading to determine vertical position of canine

A lateral cephalogram gives a accurate location of canine in vertical and saggittal plane

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OPG

• When mesio distal width of canine crown was 1.5 times larger (i.e. 15% larger) than the adjacent central incisor, then the canine is palatally placed

• This is only true in cases where canine should not be at a higher level

Reliability of a method for localisation of displaced maxillary canines using a single panoramic radiograph. Chaushu et al; clin orthod res 1999; 2: 194-9

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Tube shift technique or Clarke technique (PARALLAX METHOD)

Mesial angulation Normal angulation Distal angulation

Given by CLARK in 1909Based on binocular principle

Disadvantage: In cases when canine is highly placed, and Periapical film shows no superimposition of canine with the roots of erupted tooth or when superimposition is only in the periapical region the result may be

misleading.

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Vertical tube shift method

Left canine is highly placed in OPG.

In IOPA left canine moves towards apical 1/3 of lateral incisor.

Left canine is labially placed, as it moves in opp. direction of tube shift.

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Radiographic views at right angles

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Radiographic views at right angles

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CT Scan

The above mentioned plain film methods are inadequate in fully describing 3D location and relationship to adjacent structures particularly in B-L plane

and relation to adjacent teeth roots

These shortcomings are taken care of by CT scan and newly introduced

CBCT.

Disadvantage:

1) Expensive.

2) Increased Radiation Exposure than any other method

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3D analysis of impacted canines using volumetric analysis. Walker et al; AJODO 2005; 125: 418-23 40

Rapid prototyping

• A new method for diagnosis and treatment planning of maxillary canine impaction.

Rapid prototyping as a tool for diagnosis and treatment planning for maxillary canine impactionJorge Faber, Patrícia Medeiros Berto, and Marcelo Quaresma, AJODO 2006;129:583-9

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Rapid prototyping

Rapid prototyping as a tool for diagnosis and treatment planning for maxillary canine impactionJorge Faber, Patrícia Medeiros Berto, and Marcelo Quaresma, AJODO 2006;129:583-9

CLASSIFICATION OF IMPACTED CANINE

Impacted canine

Maxillary canine Mandibular canine

Buccal Palatal LingualBuccal

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Classification of palatally impacted canine

Based on two variables:

(1) Transverse relationship of the crown of the tooth to the line of dental arch which may be

(a) Close

(b) Distant ( nearer the midline)

(2) Height of the crown of the teeth in relation to the occlusal plane which may be

(a) High

(b) Low

Group 1 - Proximity to the line of arch – close.

- Position in the maxilla – low.

Group 2 - Proximity to the line of arch – close.

- Position in the maxilla – forward , low &

mesial to the lateral incisor root.

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• Group 3 - Proximity to the line of arch –close. - Position in the maxilla – high.

• Group 4 - Proximity to the line of arch -distant.- Position in the maxilla – high.

Group 5 - Canine root apex mesial to that of

lateral incisor or distal to that of first premolar.

Group 6 - Erupting in the line of arch in place and

resorbing the roots of incisors.

TREATMENT ALTERNATIVES

1. No treatment, if the patient does not desire it. Since the

long term prognosis of deciduous canine is poor as its root

may eventually resorb , it should be periodically evaluated.

2. Auto transplantation of the canine.

3. Extraction of impacted canine and moving premolar in its

position.

4. Extraction of the canine & posterior segmental osteotomy

to move the buccal segment mesially to close the residual

space.

TREATMENT ALTERNATIVES

5. Prosthetic replacement of the canine, not amendable

for juvenile cases.

6. Most desirable approach is surgical exposure of the

canine followed by orthodontic treatment .

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General steps of mechanotherapy

• Leveling and alignment of the erupted teeth

• Creating enough space for the impacted canine and maintaining it

• Conversion of the arch into a rigid anchorage unit

• Surgical exposure of the crown of the impacted canine and attachment bonding

• Application of low force (60 gms) traction from rigid anchorage unit

• Final detailing

• Retention

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Methods of Creating SpaceOne of the primary objective of

orthodontic treatment of impacted canine is the creation of space in the dental arch for the impacted tooth alignment.

A) Existing incisor space:

Becker showed incisor spacing was due to failure of completion of ugly duckling stage of development. During final stage these

existing space will be closed by mesial movement of lateral incisor.

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Methods of Creating Space

B) Improving Arch form:

The achievement of good arch form is an important initial goal in the maxillary arch in

non extraction cases. Maxillary canine erupt more buccally to deciduous canine

and slightly buccally to premolar and lateral

incisors. So improving arch form after extraction of

deciduous canine will add 2-3 mm of space.

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C) Increasing arch length:

In mild crowding cases distalization of molar is recommended which

increases the arch

length.

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E ) Extraction as means of prevention(Mixed dentition period)

a) Deciduous Canine

Erickson and Kurol concluded that patient with age of 10-13 years preferably with delayed dental age,

palatal displacement of canine with apex confirmed in line of arch requires extraction of deciduous canine for good prognosis for eruption

of permanent canine.

Canine impaction identified early with panoramic radiographs.Lindauer et al, AJODO 1992;123:91-7

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b) First premolar

I) Crowding of maxillary arch

II) Bimaxillary Protrusion

III) Class II Relation

c) Lateral incisor

Peg shaped or severely malformed lateral incisor (Dens

invaginatus) can be extracted instead of healthy premolars.

d) Central incisor

When there is advanced resorption of central incisor roots

more than 2\3rd and canine erupting in a line close to the long axis of

the incisor, extraction of incisor is indicated.

E ) Extraction as means of prevention

(Mixed dentition period)

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Anchorage consideration and space maintenance

• Use of full dimension stainless steel rectangular wire in edgewise brackets

• Use of 0.022 / 0.020 wires with uprighting springs or torquing springs to act as brakes if necessary in Beggs and Tip-edge appliance.

Steel tubing – added rigidity and hygieneDeactivated niti coil spring 56

• The microscrew should be placed in the labial cortical alveolar bone, at an angle of 10-20° to the bone surface and as parallel to the tooth's long axis as possible.

• This keeps the apex of the microscrew on the buccal side and reduces the likelihood of its contacting the root.

• The head of the microscrew should be located as incisally as possible to maximize the vertical component of force,

Micro-Implant Anchorage for Forced Eruption of Impacted CaninesPARK et al, JCO 2004; 38; 297-302.

Micro-Implant Anchorage

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Micro-Implant Anchorage


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• In lingual treatment, the smaller arches that are required for the shorter interbracket distances and smaller bracket slots may not be able to resist distortion.

• The impacted canine needs to pass over the archwire during buccal movement.

• These considerations make skeletal anchorage for eruption of impacted canines even more appealing in lingual orthodontics than in labial appliance treatment.

MICRO-IMPLANT ANCHORAGE AND LINGUAL APPLIANCE


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Surgical exposure to allow natural eruption to occur

• Most useful when the canine has a correct axial inclination and does not need to be uprighted during its eruption.

• Clark recommended that a polycarbonate crown be placed over the impacted tooth after its surgical exposure.

• The crown should be made long enough to extend through a window cut in the palatal tissue.

• Often, 6 months to 1 year may elapse before the impacted tooth has erupted sufficiently to permit removal of the polycarbonate crown and its replacement with an orthodontic attachment.

• If the tooth fails to erupt, Clark recommends the removal of any cicatricial tissue surrounding the crown.

MAIN DISADVANTAGES • The spontaneous but slow canine eruption, the increased

treatment time, and the inability to influence the path of eruption of the impacted canine

Clark D. The management of impacted canines: free physiologic eruption. J Am Dent Assoc 1971;82:836-40.

TYPES OF FLAPS FOR IMPACTED CANINE

Buccally accessible impacted teeth

• A circular incision

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Apically repositioned surgical flap Full flap closure

Uncovering labially impacted teeth: apically positioned flap and closed eruption technique.Vermette et al; AO 1995; 65: 23-32.


62Maintaining ideal tooth-gingiva relationship when exposing and aligning an impacted tooth.Wong-Lee et al; 1985 BJO; 12: 189-92

Palatal Impaction

• Partial

• Full flap closure


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Two approaches are generally recommended in regard to the timing

of placing the attachmentTWO-STEP APPROACH.First, the canine is surgically uncovered and the area is packed with a surgical

dressing to avoid the filling in of tissues around the tooth.After wound healing, within 3 to 8 weeks, the pack is removed, and an attachment is

placed on the impacted tooth.

ONE-STEP APPROACHThe attachment is placed on the tooth at the time of surgical exposure The tissues over the attachment should be excised, and a periodontal pack should be

placed. The pack will minimize patient discomfort and prevent the granulation tissues from

covering the attachment before the clinician is ready to apply traction forces on the impacted tooth.

This approach is particularly recommended for palatally impacted teeth. One of the important advantages of such an approach is that when the force is

applied to• the impacted tooth, the clinician is able to visualize the crown of the tooth and

to have better control over the direction of tooth movement. • This will avoid moving the impacted tooth into the roots of the neighboring

teeth.

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Attachments For caninea) Lasso wire – Shapira and Kuftinec

1) Poor control over direction of extrusion

2) Risk of external root resorption near CEJ

3) Risk of alveolar crestal bone loss and loss of attachment epithelium

b) Bands -- Vonder Heydt

1) Requires Extensive bone removal

c) Cast canine caps -- Lewis, Dewel

1) Requires extensive crown preparation

AO 1981; 51: 203-7

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Attachments For canine

d) Threaded pins – Becker and

Zilberman

1) Chances for non vitality of the

tooth

2) Needs restoration of the tooth

at the end of treatment

e) Direct Bonding -- Jacoby,

Nielson

1) Easy to perform

2) More reliable method

AJODO 1978; 74: 422-9 Twin bracket Eyelet

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(f) Elastic ties and modules

Advantages

- Application of light forces

- Good range of action

- Easier to tie

Disadvantages

- Tends to loosen

- High degree of force decay

Attachments for canine

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Attachments For canine

g) Magnets

Developmental stage. Greatest disadvantage is

corrosion.

Method is clumsy and inconvenient

Treatment of an impacted canine with magnets. Darendelier et al; JCO 1994;28:639-43

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FORCE GENERATING DEVICES

Alignment of Impacted Canines with Cantilevers and Box Loops; Surendra Patel ;

JCO 1999 volume 33 : 2 : 82-85

Cantilever

1. Initial extrusion mechanics with a cantilever.

2. Use of a box loop to continue canine extrusion and to make 1st- and 2nd-order corrections.

3. Incorporation of the canine into a continuous archwire for finishing.

TMA BOX LOOP

• TMA .017 X .025 wire used.

• Produce saggittal and transverse corrections while continuing vertical

eruption.

Alignment of Impacted Canines with Cantilevers and Box Loops; Surendra Patel ;

JCO 1999 volume 33 : 2 : 82-85


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Cantilevers


Cantilever Mechanics for Treatment of Impacted CaninesFISCHER et al; JCO NOVEMBER 2000

Buccal impaction0.017 x 0.025 TMA

Palatal impaction0.016 x 0.025 TMA

NICKEL TITANIUM CLOSED-COIL SPRING

• 0.009”X 0.041” spring

• Provides 80 gm of force when stretched to twice its resting

length

TECHNIQUE CLINIC Nickel Titanium Closed-Coil Spring for Extrusion of Impacted Canines; LORING L. ROSS; JCO1999; VOLUME 33 : NUMBER 2 : PAGES (99-100)


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THE MONKEY HOOK

It is a simple auxiliary with an open loop on each end for the attachment of intra oral elastic or elastomeric chain or for connecting to a bondable loop button.

The Monkey Hook: An Auxiliary for Impacted, Rotated, and Displaced Teeth.

S. JAY BOWMAN et al; JCO 2002 July


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Alternative is forming a coil on the place where canine should lie at the end of rx andApplying traction using monkey loop

Application of force in differentplanes possible with monkey loop Application of traction from lower jaw

The Monkey Hook: An Auxiliary for Impacted, Rotated, and Displaced Teeth.

S. JAY BOWMAN et al; JCO 2002 July

THE MONKEY HOOK

AUSTRALIAN HELICAL ARCHWIRE

•Made in special plus .016” arch wire

•Force should not exceed 200 gm

• Activation by twisting the steel

ligature wire every two weeks

Eruption of impacted canines with an australian helical archwire

Hauser et al; JCO sep 2000


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Two Stage Traction

Palatally impacted canine

When crown of canine is more palatally displaced,surgery on the buccal side needs to become more radical,rendering a palatal; approach preferable.

Usually palatally impacted tooth is guided to occlusion in two stages.

I) Guiding tooth to oral environment

II) Guiding tooth to line of arch

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Guiding Tooth To Oral Environment

1) Active palatal arch (Becker 1978)

It consist of fine 0.020 inch removable palatal arch

wire carrying an omega loop on each side. End of the wire

is double-ended for Frictionless fit in lingual sheath. It is

activated by elevating downward activated palatal arch

wire and hooking the pigtail ligature around it.

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2) Ballista Spring (Jacoby 1979)

It is made of rectangular wires. It proceeds forward until it is opposite to canine space and bent vertically

downwards and terminate into a small loop.With slight finger pressure ,spring is tied to pigtail ligature. By this it

provide an extrusive force for the canine to erupt. 80


3) Light Auxiliary Labial Arch (Kornhauser1996)

It is made up of 0.014 inch round SS wire with vertical

loops in the area of impacted canine on both sides. This

loop has a small helix. This wire is tied with the basal arch

wire in piggyback fashion. If basal arch wire is not used it

will leads to extrusion of adjacent tooth and cause

alteration of occlusal plane .

THE K- 9 SPRING

• Made in 0.017”X 0.025”TMA wire

• Simple in design

• Low cost

• No patient compliance

• Light continuous eruptive and distalizing forces

The K-9 Spring for Alignment of Impacted CaninesVarun Kalra; JCO Oct 2000


MANDIBULAR ACHORAGE

•Lingual arch is fabricated with 0.036 inch SS wire

•Vertical hooks (5-6mm in length)

•Elastic force should not exceed 40-60 gm

•confirmation of ankylosis of the impacted tooth is suspected •in cases where the maxillary arch is unsuitable for providing anchorage.

Management of impacted maxillary canines using mandibular anchorage

Pramod K. Sinha, and Ram S. Nanda; AJODO March 1999


Samarium cobalt magnet coated with thermoplastic material (Eurcodur).

Communication of the impacted tooth with the oral cavity can cause periodontal tissue damage.

the continuous force applied to the palatal mucosa by a ligature wire can be quite painful, especially after activations.

treatment is less traumatic and poses less risk of infection than conventional orthodontic methods

MAGNETS

Case Report :Treatment of an Impacted Canine with MagnetsM. ALI DARENDELILER, MARC FRIEDLI, JCO 1994; Nov(639 - 643).


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Deep infraosseous impacted canines.

Technique allows for orthodontic traction

of the impacted tooth to the center

of the alveolar ridge.

Creates the natural path of eruption.

Tunnel traction of infraosseous impacted maxillary canines –Tunnel traction of infraosseous impacted maxillary canines. A three-year periodontal follow-up. Crescini et al. AJO-DO, Volume 1994 Jan (61 - 72):

Tunnel traction

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Tunnel traction

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Corticotomy-assisted Exposure of Palatally Impacted Canines

Orthodontic Treatment Acceleration with Corticotomy-assisted Exposure of Palatally Impacted Canines A Preliminary StudyT. J. Fischer. Angle Orthodontist, Vol 77, No 3, 2007

CONCLUSIONS• The results demonstrated that under the same conditions the corticotomy-assisted approach produced faster tooth movement in all six patients.• Additionally, this surgical procedure did not produce any significant difference in the periodontal health of the canine.

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If the root apex of canine is mesial to lateral incisor or distal to premolar , tooth is considered as TRANSPOSED.

I) Incomplete transposition: Roots will be in line of arch in its position and crown tipped due to path of eruption. (uprighting of tooth will align the tooth in arch).

II) Complete transposition: Both crown and root together will be completely interchanged.

Canine transposition

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TREATMENT OPTIONS

•To resolve the transposition to ideal relationship

•To align the transposed canine where it is erupting

•Use canine for auto transplantation into prepared socket

in ideal site

•To extract severely displaced canine, lateral incisor or

premolar depending upon prognosis


89Maxillary Canine—First Premolar Transposition. Restoring Normal Tooth Order With Segmented MechanicsFilho et al. Angle Orthodontist, Vol 77, No 1, 2007


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Auto transplantation

Transalveolar transplantation of maxillary caninesSagne, Lennartsson, and Thilander; AJO-DO Volume 1986 Aug (149 - 157)

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1. Patient's ability to cooperate is critical.2. Procedure is best performed when the root length of the transplant is

between one half and three fourths complete.3. The recipient site must be healthy and of adequate size to receive the

transplant; it is important that the recipient site be prepared before the transplant is made available.

4. Tremendous care must be exercised not to insult the root surface; wherever possible, the transplant should be handled only by its crown.

5. The length of time from removal to reinsertion should be minimal; ideally, this is a nonstop relocation. Desiccation of the periodontal ligament can cause resorption, ankylosis, and failure.

6. Circumdental ligation with metallic sutures is contraindicated.7. Soft-tissue reproximation and ligation with silk sutures constitute a

preferred form of fixation during the first ten days.8. Further stabilization can be employed through direct bonding, if

necessary, for from 10 days to 6 weeks . After this time the tooth should be treated like any other tooth of similar developmental stage.

9. The chance of a favorable prognosis for a properly prepared autogenic dental transplant can approach 100 percent.

AJO-DO Volume 1980 Feb (146 - 162): Autogenic tooth transplantation - Northway

Auto transplantation Dentigerous Cyst

Dentigerous cyst may inhibit the eruption of the involved canine.

Treatment:• Marsupialization is the procedure consists of fenestrating the outer

wall of the cyst, and relieving the intracystic pressure.

• With this early decompression, the size of the cavity slowly

decreases, enabling the surrounding bone to regenerate around the

impacted tooth, which eventually erupt the tooth into the dental arch.

• No traction should be applied until bone regenerates to an acceptable

level, as the periodontal apparatus of such a tooth is weak and will lead

to compromised long term prognosis

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Success rate and duration of treatment

• Younger patients required a longer treatment.

• The younger the patient, the more severely impacted the canine.

• If the canine was impacted less than 14 mm from the occlusal plane, treatment duration averaged 23.8 months;

• If the canine was impacted more than 14 mm from the occlusal plane, treatment duration averaged 31.1 months.

Factors that relate to treatment duration for patients with palatally impacted maxillary canines. Jeffrey A. Stewart (AJODO 2001;119:216-25)

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• The success rate among the adults was 69.5% compared with 100% among the younger controls

• The adults showed significant increase in the duration and number of treatment visits required for resolving the canine impaction, in both the simpler and the more difficult cases.

• It was concluded that the prognosis for successful orthodontic resolution of an impacted canine worsens with age.


Success rate and duration of orthodontic treatment for adult patients with palatally impacted maxillary canines. Adrian Becker, AJODO 2003;124:509-14

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A rough prediction can be made for number of visits required:

● Patients aged more than 25 years require remarkably longer treatments than younger patients (30 additional visits on average).

● The canines with cusp tips farther from the occlusal plane require longer treatments: 1 additional visit was required if the distance increased by 0.63 mm in the panoramic radiograph.

● The canines with cusp tips located mesially to the axes of the lateral incisors required 10 more visits than the distally located canines on average.

Factors associated with the duration of forced eruption of impacted maxillary canines:A retrospective study. Zuccati et al, AJODO 2006;130:349-56


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Impacted Canines And Root Resorption Of Incisors

• Resorption of roots stops when canine impaction has been solved.

• Subsequent orthodontic movement of resorption affected teeth does not generate further resorption.

• Incisors with severely resorbed roots have high survival rate.

• Teeth remain vital, and retain their color, and appearance.

• Teeth show very low degree of mobility and an improvement in periodontal bone support following post treatment retention.

• Splinting is not usually necessary. Long-term follow-up of severely resorbed maxillary incisors after resolution of an etiologically associated impacted canine. Adrian Becker; AJODO 2005;127:650-4

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Impacted canine and Periodontium

1. Labially impacted maxillary anterior teeth uncovered with an apically positioned flap technique have more unaesthetic sequalae than those uncovered with a closed-eruption technique.

2. Negative esthetic effects, such as increased clinical crown length, increased width of attached tissue, gingival scarring, and intrusive relapse were evident in the teeth treated with an apically positioned flap.

Uncovering labially impacted teeth: apically positioned flap and closed-eruption techniques Vermette et al; Angle Orthodontist 1995 No. 1, 23 - 33:

Apically positioned flap vs closed eruption

Surgical exposure, orthodontic movement, and final tooth position as factors inperiodontal breakdown of treated palatally impacted canines. Kohavi et al; AJODO 1984;85:72-7.

Impacted canine and Periodontium

Bone support levels graph – dark (untreated)

X1 – min surgery with primary closureXh – follicular sac removed till CEJ

M1 – tipping, extrusion, rotation movements onlyMh – root uprighting & torquing movements

Evaluation of post treatment alignment by Becker et al

• Incidence of rotations and spacing

1. Impacted side - 17.4%

2. Control side - 8.7%

• Ideal alignment on control side is twice as often as the impacted side.

Retention considerations

Impacted maxillary canines: A review; Samir E. Bishara; AJODO 1992;101:159-71

To minimize rotational relapse, options available are

1. Fiberotomy

2. Bonded fixed retainer

Clark’s suggestion for palatally impacted canine: Lingual drifting

can be prevented by removal of half moon- shaped wedge of

tissue from lingual aspect of canine.

Retention considerations


101

Buccally impacted maxillary canines

• Primary etiology is crowding

• Fournier et al suggest that labially impacted teeth with a favorable vertical position may be treated initially by surgical exposure but without the application of a traction force.

• He believes that in younger patients the tooth will erupt on its own after surgical exposure, whereas in older patients traction is almost always indicated.

• The attached gingiva could be made available through an apically repositioned flap, a laterally repositioned pedicle graft, or, when necessary, a free gingival graft.


When to extract impacted canines?

(1) If it is ankylosed and cannot be transplanted, (2) if it is undergoing external or internal root

resorption, (3) if its root is severely dilacerated, (4) if the impaction is severe (e.g., the canine is lodged

between the roots of the central and lateral incisors and orthodontic movement will jeopardize these teeth)

(5)If the occlusion is acceptable, with the first premolar in the position of the canine and with an otherwise functional occlusion with well-aligned teeth

(6) if there are pathologic changes (e.g., cystic formation, infection), and the patient does not desire orthodontic treatment.


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18

103

Canine vs. premolar extraction• The prognosis for the successful exposure and

guidance of the canine to its proper position in the dental arch is often guarded.

• This is because the canine may be ankylosed, undergo resorption, or become nonvital.

• If the overall orthodontic treatment plan involves the removal of premolars, it is advisable to postpone their extractions until the canine is surgically exposed and orthodontic forces are applied.

• This is done to ensure the feasibility of moving the impacted tooth before extracting a workable replacement.


Mandibular canines

• Not much is present in literature about mandibular canines as its occurrence is a rare condition.

• For lingually placed canine, attachment has to be bonded on buccal surface only, buccal surgical exposure preferred.

• Treatment principles are same as followed during maxillary canines, keeping the final prognosis in mind

105

Canine impactions in adults

Aesthetic consideration is an added point

to be considered in adult Rx of

impacted canines.

Removable prosthesis

Buccal wire with a pontic

Bonded pontic to adjacent teeth106

ConclusionThe management of the severely impacted canine is

often a complex undertakingand requires the joint expertise of a number of

clinicians. It is important that these clinicians

communicate with each other to provide the patient with an optimal treatment plan based on

scientific rational.

107

Thank You

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1

CEPHALOMETRICS


CONTENTS

• HISTORY

• TECHNICAL ASPECTS

• TRACING TECHNIQUE

• CEPHALOMETRIC LANDMARKS

• CEPHALOMETRIC ANALYSIS

• APPLICATION OF CEPHALOMETRICS

• ERRORS OF CEPHALOMETRIC MEASUREMENTS

• METHODS OF CONTROLLING ERRORS

• STANDARDIZATION OF IMAGE GEOMETRY

• LIMITATIONS OF CEPHALOMETRICS

• DIGITAL CEPHALOMETRY

• CONCLUSION

HISTORYHistory prior to the advent of radiography begins with the attempts of the scientists to classify the human physiques.

Basically it stems from the history of Anthropometry.

Human forms have been measured for many reasons

1.To aid self portrayal in

- sculpture

- drawing

- painting

2. To test the relation of physique to health, temperament and behavioral traits.

Radiographic cephalometry- Alexander Jacobson

Vitruvivous pollio

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2

History of Cephalometric

Radiography

• In 1895, Prof. Wilhelm Conrad Roentgen made a remarkable contribution to science with the discovery of x-rays.

• On December 28, 1895 he submitted a paper “On A New Kind of Rays, A Preliminary Communication” to the Wurzburg Physical Medical Society.

• Prof. Wilhem Koening & Dr. Otto Walkhoffsimultaneously made the first dental radiograph in 1896.

• Van Loon;

- First to introduce Cephalometrics to orthodontics.

- He applied anthropometric procedures in analyzing facial growth by making plaster casts of face in to which he inserted oriented casts of the dentition.

• Hellman in 1920s used cephalometric techniques and described their value.

• The first x- ray pictures of skull in the standard lateral view were taken by A.J.Pacini & Carrera in 1922.

• Pacini received a research award from the American Roentgen Ray Society for a thesis entitled “Roentgen Ray Anthropometry of the Skull”.

• Pacini;

Introduced a teleroentgenographictechnique for standardized lateral head radiography which proved to be of tremendous use in cephalometry, as well as in measuring growth and dev of face.

• Atkinson in 1922 advocated the use of roentgenograms in locating the ‘key ridge’ and the soft tissue relations to the face and the jaws.

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3

• In 1923 Mc Cowen used profile roentgenograms for orthodontic purposes to visualize the relationship between the hard and soft tissues and to note changes in profile which occur during treatment.

• In 1931 cephalometric radiography came to full function when B. Holly Broadbent in USApublished methods to obtain standardized head radiographs in the Angle Orthodontist (A new X ray tech & its application to orthodontia).

• H. Hofrath simultaneously published the same in Fortschritte der Orthodontie in Germany.

• The interesting fact is that Broadbent was an Orthodontist, whereas Hofrath was a Prosthodontist.

• This development enabled orthodontists to capture the field of cephalometry from the anatomists and anthropologists.

Broadbent’s contribution

1. Broadbent’s interest in craniofacial growth began with his orthodontic education under E.H. Angle in 1920.

2. He continued to pursue that interest along with his orthodontic practice, working with a leading anatomist J.Wingate Todd

3. During 1920’s he refined the craniostat in tocraniometer.

4. That proved to be the first step in the evolution of craniostat in to a radiographic cephalostat.

5. He published methods to obtain standardized head radiographs in the Angle Orthodontist(1931) (A new X-ray tech & its application to orthodontia).

• The diagnosing dental deformities by means of planes & angles was first proposed in 1922 by Paul Simon in his book, “Fundamental Principles of a Systematic Diagnosis of Dental Anomalies”.

• Although his “Law of the Canines” was later disproved by Broadbent, his theories stimulated Broadbent to apply the principles of craniometry to living subjects.

• Hofrath’s technique differed from Broadbent’s in that the path of the central ray was not fixed in relation to the head.

• In 1937, using serial records of twins; Broadbent showed how growth – or its lack –was the greatest limiting factor in clinical success.

• In 1943 he stipulated that eruption of the third molars had no ill effect on the denture, particularly the lower incisors.

• Brodie, in a landmark study, corroborated Broadbent’s contention that the growth patternof the normal child’s face develops in an orderly downward and forward fashion and that the pattern, once attained at an early age, did not change.

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4

Thompson and Brodie in a report on the rest position of the mandible, concluded that:

• The morphogenetic pattern of the head was established at a very early age and did not change.

• The presence or absence of teeth has little bearing on the form or the rest position of the mandible.

• Vertical facial proportions are constant throughout life.

• Margolis (1943) wrote on the relationship between the inclination of the lower incisor and the incisor-mandibular plane angle.

• In 1947 Margolis contributed his maxillo-facial triangle.

THE TECHNICAL

ASPECTS

The basic components of the equipment for producing the lateral cephalogram are:

1. An X-ray apparatus

2. An image receptor system

3. A cephalostat

Oral Radiology, Principles and interpretation- White and Pharoah (5th edition)

THE X- RAY APPARATUS

The three basic elements that generate that X-ray are:

A. Cathode

B. Anode

C. The electrical power supply.


CATHODE

• Tungsten filamentsurrounded by a molybednum focusing cup.

• Connected to a low voltage & high voltage circuit.

• A step down transformersupplies the low voltage circuit with 10V and a high current to heat the filament un till the electrons are emitted.


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5

STEP UP TRANSFORMER

• Supplies the high voltage circuit with 65-90kV.

• Differential potential accelerates the electrons.

• The electron beam is directed by the focusing cup to strike a small target in the anode called focal spot.


ANODE

• Small tungsten block embedded in the copper stem, which stops the accelerated electrons whose kinetic energy causes the production of photons.

• Less then 1% is converted to photons, rest is converted to heat.

• Although tungsten is a high molecular substance, its thermal resistance is unable to withstand the heat.


THE IMAGE RECEPTOR SYSTEM

It records the final product of X-Rays after they pass through the subject. The extraoral projection like the lateral cephalometric technique, requires a complex image receptor system that consists of :

1. Extraoral film

2. Intensifying screen

3. A cassette

4. A grid & a soft tissue shield

THE CEPHALOSTAT

Ear rod

forehead clamp

1.Ear rod2.Forehead clamp3.Infra orbital pointer4.Cassette holder

Cassette holder


X-Ray Source position

• It is positioned 5 feet(152.4cm) from the subject’s midsagittal plane.

Film position

To minimize variations in magnification from patient to patient& to obtain consistent measurements on the patient over time, a distance of 15cm is often used.


15"60"

Source Plane

X-ray Source

Patient in Head Positioning

Device

Mid-Sagittal Plane

Film Plane

X-ray Film in

Cassette

152.4 cms

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6

PATIENT POSITIONING;

• It is based on the same principles that described by the Broadbent.

• The patients head is fixed by the two ear rods.

• The head which is centered in the cephalostat, is oriented with the Frankfurt plane parallel to the floor & the midsagittal plane vertical & parallel to the cassette.

Ear rod

LATERAL CEPHALOGRAM


• The standardized Frankfurt plane is achieved by placing the infraorbital pointer at the patients orbit and then adjusting the head vertically until the infraorbital pointer & the two ear rods are at the same levels.

• The upper part of the face is supported by the forehead clamp, positioned at the nasion.

Ear rod

forehead clampcassette


• Identical to that of lateral ceph except that the Patient is facing the film.

• Patient mid saggital plane is perpendicular to the film plane.

• FH plane is horizontal.

• Canthomeatal line directed upward by 100.

PATIENT POSITIONING;

PA CEPHALOMETRIC

RADIOGRAPH


Shortcomings of the

Frankfurt horizontal

plane

• Some individuals show a variation of their FH

plane to the true horizontal to an extent of 10°.

• The landmarks to locate the FH plane on a cephalogram, orbitale & porion, are difficult to locate accurately on the radiographs.

Am J Phys. Anthropol. 16: 1956

• An alternative to overcome this was to use a functionally derived NHP.According to Morrees & Kean.

• It was obtained by the patient standing up & looking directly into the reflection of his/her eyes in a mirror directly ahead in the middle of the cephalostat.

• To record the NHP,the ear rods are not used for locking the patient head into a fixed position but serve to place the midsagittal plane at a fixed distance from the film plane.

Am J Phys. Anthropol. 16: 1956

TRACING TECHNIQUE

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7

Tracing supplies and

equipments

• A lateral cephalogram

• Acetate matte tracing paper(.003 inches

thick, 8×10 inches)

• A sharp 3H drawing pencil or a very fine tipped pen

• Masking tape

• A few sheets of cardboard (preferably black) and a hollow cardboard tube.


• A protractor and tooth symbol tracingtemplate for drawing the teeth. Also templates for tracing the outlines of ear rods.

• Dental casts trimmed to maximum intercuspation of the teeth in occlusion.

• Viewbox (variable rheostat desirable but not essential).

• Pencil sharpener and a eraser.


Tracing of a Cephalogram

• Thorough familiarity with the gross anatomy is required before the tracing.

• By convention the bilateral structures (eg, the rami and inferior borders of the mandible) are first traced independently. An average is then drawn by visual approximation, which is represented by a broken line.

Radiographic cephalometry- Alexander Jacobson Radiographic cephalometry- Alexander Jacobson

General considerations for

the tracing

• Start by placing the cephalogram on the viewbox with the patient’s image facing towards the right.

• Tape the four corners of the radiograph to the viewbox.

• Draw three crosses on the radiographs, two within the cranium and one over the area of the cervical vertebrae (registration crosses).


• Place the matte acetate film over the radiograph and tape it securely.

• After firmly affixing the acetate film, trace the three registration crosses.

• Print the pt name, record number, age in years and months, the date on which the cephalogram was taken and your name on the bottom left corner of the acetate film.

• Begin tracing using smooth continuous pressure.


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8

Stepwise tracing technique

1. Tracing the soft tissue profile, external cranium and the vertebrae,

2. Tracing the cranial base, internal border of the cranium, frontal sinus and the ear rods,

3. Maxilla and related structures including the nasal bone and pterygomaxillary fissure,

4. The mandible.


CEPHALOMETRIC

LANDMARKS

A landmark is a point which serves as a guide for measurement or construction of planes. They are divided into two types:

1. Anatomic: These represent actual anatomic structure of the skull.

2. Constructed: These have been constructed or obtained secondarily from anatomic structures in the cephalogram.


Requisites for a landmark

• Landmark should be easily seen on the roentegenogram, be uniform in outline, and easily reproducible.

• Lines and planes should have significant relationship to the growth vectors of specific areas.

• Landmark should permit valid quantitative measurement of lines and angles.


• Measurement should have significant relation to the information sought.

• Measurements should be amenable to statistical analysis but should preferably not require extensive specialized training in statistical methods.

• Following is the list of most commonly used Cephalometric landmarks.


LATERAL CEPHALOGRAM

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9

Point A revisited – Jacobson- AJO 1980

Point A cannot be accurately identified in all cephalometric

radiographs.. In instances where this landmark is not clearly

discernible, an alternative means of estimating the anterior extremity

of the maxillary base is shown.

Procedure;

A point plotted 3.0 mm. labial to a point between the upper third and

lower two thirds of the long axis of the root of the maxillary central

incisor was found to be a suitable point - (estimated point A) through

which to draw the NAE line and one which most closely approximates

the true NA plane.

3mm

Cephalometric planes

1. Are derived from at least 2 or 3 landmarks

2. Are used for;

- measurements,

- separation of anatomic divisions,

- definition of anatomic structures of relating parts of the face to one another.

The various cephalometric planes used are:

1. Horizontal planes

2. Vertical planes

Sella-Nasion

plane:

Frankfurt

Horizontal

plane: (The name is given in the conference of anthropology,held at Frankfurt in1985)

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10

Basion-Nasion

plane

Palatal plane

Occlusal

plane

Mandibular

plane:

1.Salzmann took lower border of the mand.

2. Go – Me- Mc Namara- Rakosi- COGS

3. Go – Gn- Steiners’s

Vertical

planes;

• Facial plane• Ramal plane• Y- Axis• NA• NB

CEPHALOMETRIC ANALYSIS

Principle of Cephalometric

analysis

• The goal is to compare the patient with a normal reference group, so that differences between the patient’s actual dentofacial relationships and those expected for his/her racial or ethnic groups are revealed.

• First popularized after world war-II in the form of Down’s analysis.

• The standards developed for the Down’s analysis are still useful but have been largely replaced by newer standards, based on less rigidly selected groups.

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11

Two basic ways to approach

this goals are:

• Use of selected linear and angularmeasurements to establish the appropriate comparisons.

eg; Down’s analysis.

• Template method: Express the normative data graphically and to compare the patient’s dentofacial form directly.

MEASUREMENT ANALYSIS

HARD TISSUE ANALYSIS

• DOWN’S• TWEED’S• WITS APPRAISAL• STEINER’S• Mc NAMARA’S• RAKOSI’S• SCHWARZ• COGS

SOFT TISSUE

ANALYSIS

• HOLDAWAY’S

• ARNETT

- FH plane is used as the reference plane.

- It was based on the study of 25 white subjects who had good occlusion and proportional facial skeleton.

- This analysis indicates whether the dysplasia is in the facial skeleton or in the dentition or both.

DOWN’S ANALYSIS TWEED’S ANALYSIS

Tweed used three planes to establish a diagnostic triangle, the three planes used in this analysis are:

1. Frankfurt horizontal plane

2. Mandibular plane

3. Long axis of lower incisor

TWEED’S

TRIANGLEThe values of the angles according to Tweed’s finding are as follows:

1. FMA = 25°

2. FMIA = 65°

3. IMPA = 90°

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12

STEINER’S ANALYSIS

Developed by Cecil.C.Steiner in the 1950’s can be considered the first of the modern cephalometric analysis for two reasons:

1. It displayed measurements in a way that emphasized not just the individual measurements but their interrelationship into a pattern.

2. Specific guide for use of cephalometric measurements in treatment planning.

AJO DO-1959

Steiner analysis

• Skeletal analysis

• Dental analysis

• Soft tissue analysis

AJO DO-1959

SNA: 820SKELETAL

AJO DO-1959

SNB: 800SKELETAL

AJO DO-1959

ANB: 20SKELETAL

AJO DO-1959

OP-SN: 140SKELETAL

AJO DO-1959

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13

MP-SN: 320SKELETAL

AJO DO-1959

UI-NA= 220

UI-NA= 4mm

DENTAL

NA

AJO DO-1959

LI-NB = 250

LI-NB = 4mm

DENTAL

NB

AJO DO-1959

INTERINCISAL

ANGLE: 1300

DENTAL

AJO DO-1959

SOFT TISSUE ANALYSIS

STEINER’S

S-LINE

AJO DO-1959

The mean values for Steiner’s analysis

are as follows:

SNA 82°

SNB 80°

ANB 2°

SND 76°

Upper incisor to NA 22°

Upper incisor to NA 4mm

Lower incisor to NB 25°

Lower incisor to NB 4mm

interincisal angle 130°

MP to SN 32°

.

14

McNAMARA ANALYSIS

Divided craniofacial skeletal complex into 5 major sections;

1. Maxilla to cranial base.

2. Maxilla to mandible.

3. Mandible to cranial base.

4. Dentition.

5. Airway.

NASOLABIAL

ANGLE: 1020

MAX TO CRANIAL BASESOFT TISSUE

EVALUATION

Pt A-N

Perpendicular:

1.mixed dentition=

0mm

2.adult= 1mm

MAX TO CRANIAL BASEHARD TISSUE

EVALUATION

1. EFF MAX LENGTH

MAX TO MANDIBLE

91

117

ANTEROPOSTERIOR

2.EFF MAND LENGTH

Ans-Me

VERTICAL MAX TO MANDIBLE

Mand plane

angle

MP-FH: 220

SKELETAL

AJO DO-1959

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15

Facial axis

angle= 900

SKELETAL

AJO DO-1959

900- obtained Pog-N Perpen

1. mixed dent

(6-8mm)

2.female=(-4-0)

3.males =(+/-2)

MANDIBLE TO CRANIAL BASE

MAX INCISOR

POSITION

DENTITION

4-6mm

MAND INCISOR

POSITION

DENTITION

1-3mm

Upper pharynx=15-20mm

Lower pharynx=11-14mm

AIRWAYWITS APPRAISAL

• Indicates antero-posterior disharmonies of the jaws.

• It’s a linear measurement, not an analysis

• Was developed as a shortcoming to ANB.

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16

Shortcomings

of ANB

AO-BO

1. Sk Cl-I ; BO 1mm front of AO2. Sk Cl-II; BO is behind AO3. Sk Cl-III; BO is ahead of AO

DRAWBACKS;

1.Value varies with occ plane.2.Value varies with dist betw points A and B3.OP is not the actual plane and the left and the

right side do not always coinside in a lateral ceph

RAKOSI JARABAK’S ANALYSIS

1. Cephalometric radiography; Thomas Rakosi.

Saddle Angle

1230+/-5


ARTICULAR ANGLE

1430+/- 6


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17

GONIAL ANGLE

Gonial angle

=1280+/-7

U=52-55

l=72-75


SUM OF POST ANGLES

396+/-60


MAND PLANE ANGLE

MP-SN=320


ANGLE OF INCLINATION

850


Pn-OP

750


Pn-MP

650


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18

BASAL PLANE ANGLE

250


Ant-Post face Ht

62-65%


Inter-Incisal

1350


UI-SN

1020+/-2


UI-PP

700+/-5


LI-MP

900 +/-3


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19

CEPHALOMETRICS FOR

ORTHOGNATHIC SURGERY

1. Cephalometric analysis specially designed for the patient who requires maxillofacial surgery.

2. Landmarks and measurements were made which could be altered by common surgical process.

J Oral Surgery:vol-36, April 1978

3.The comprehensive appraisal includes all of the facial bones and a cranial base reference.

4. Rectilinear measurements can be readily transferred to a study cast for mock surgery.

5. Critical facial skeletal components are examined.

6. Standards and static's are available for variations in age and sex.

7. Systematised approach to measurements that can be computerised.

8. COGS appraisal describes dental, skeletal and soft tissue variations.

J Oral Surgery:vol-36, April 1978

1.Ar-Ptm

2.Ptm-N

J Oral Surgery:vol-36,April 1978

CRANIAL BASE

Ar-Ptm

Ar-N

Ptm-N

HP

1.N-A-Pg(ANGLE)

2.N-A (ll-HP)

3.N-B (ll-HP)

4.N-Pg(ll-HP)


HORIZONTAL(SKELETAL)

HP

1.N-A-Pg(ANGLE)

2.N-A (ll-HP)

3.N-B (ll-HP)

4.N-Pg(ll-HP)


HORIZONTAL(SKELETAL)

HP

1.N-ANS(PER-HP)

2.ANS-Gn(PER-HP)

3.PNS-N(PER-HP)

4.MP-HP(ANGLE)

5.UI-NF(PER-NF)

6.U6-NF(PER-NF)

7.LI-NF(PER-NF)

8.L6-NF(PER-NF)


VERTICAL(SKELETAL,DENTAL)

HP

N-ANS

ANS-Gn

PNS-N

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20

1.N-ANS(PER-HP)

2.ANS-Gn(PER-HP)

3.PNS-N(PER-HP)

4.MP-HP(ANGLE)

5.UI-NF(PER-NF)

6.U6-NF(PER-NF)

7.LI-NF(PER-NF)

8.L6-NF(PER-NF)


VERTICAL(SKELETAL,DENTAL)

HP

1.PNS-ANS(II-HP)

2.Ar-Go (LINEAR)

3.Go-Pg (LINEAR)

4.B-Pg (II-MP)

5.Ar-Go-Gn(ANGLE)


MAX & MAND

HP

1.PNS-ANS(II-HP)

2.Ar-Go (LINEAR)

3.Go-Pg (LINEAR)

4.B-Pg (II-MP)

5.Ar-Go-Gn(ANGLE)


HP

MAX & MAND

1.U OP-HP(ANGLE)

2.L OP-HP(ANGLE)

3.A-B (II-OP)

4.UI-NF(ANGLE)

5.LI-MP(ANGLE)


DENTAL

HP

1.U OP-HP(ANGLE)

2.L OP-HP(ANGLE)

3.A-B (II-OP)

4.UI-NF(ANGLE)

5.LI-MP(ANGLE)


HP

DENTAL

1.U OP-HP(ANGLE)

2.L OP-HP(ANGLE)

3.A-B (II-OP)

4.UI-NF(ANGLE)

5.LI-MP(ANGLE)


HP

DENTAL

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21

THE HOLDAWAY SOFT-TISSUE

ANALYSIS

• The analysis outlines the parameters of soft tissue balance.

• Consists of 11 measurements.

Facial angle

(900)

Upper lip

curvature;2.5mm

Skeletal

convexity at

point A;+/-2mm

H-angle; 7-150

Nose tip to H-

line; 12mm max

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22

Upper sulcus

depth;5mm

Lower sulcus

depth;15mm

Lower lip to H-

line; 5mm

Upper lip

thickness; 15mm

Upper lip stain;

within 1mm

Soft tissue chin

thickness; 10-12mm

TEMPLATE ANALYSIS

• In the early years of cephalometric analysis, it was recognized that representing the norm in graphical form might make it easier to recognize a pattern of relationship.

• In recent years, direct comparisons of patients with templates derived from the various growth studies has become a reliable method of analysis.

- One of the objectives of any analytic approach is to reduce the practically infinite set of possible cephalometric measurement to a manageably small group that can be compared to the norms and thereby provide useful information.

- From the beginning it was recognized that the measurements for comparison with the norms should have several characteristics.

The following were specifically desired:

1. The measurements should be useful clinically in differentiating patients with skeletal and dental characteristics of malocclusion.

2. The measurement should not be affected by the size of patient:.

3. The measurement should be affected minimally by the age of the patient.

What is a template?

Any individual cephalometric tracing can be represented as a series of coordinate points (x,y) on an grid. Similarly the cephalometric data from any group also could be represented graphically by calculating the average coordinates of each landmark point, and then connecting the points. The resultant average or composite tracing often is referred to as a “template”.

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23

Male and Female diagnostic templates At present two forms of the

templates are currently

available:

• Schematic template (Michigan, Burlington): These show the changing position of selected landmarks with age on a single template.

• Anatomically complete template

(Broadbent-Bolton, Alabama): These are a different ones for each age.

Selecting of a template

for analysis

The first step in template analysis is to pick the correct template from the set of age different ones that represent the reference data. Two things that have to be kept in mind are:

• The patient’s physical size

• Developmental age.

The best thing to do is to select the reference template considering the length of the anterior cranial base, which should be same for the patient and the template.

After this we move forward or backwards in the template age if the patient is developmentally quite advanced or retarded.

Doing analysis using a

template

It is based on a series of superimpositions of the template over a tracing of the patient being analyzed. The sequence of superimpositions follows:

1. Cranial base superimpositions:

- This allows the relationship of the maxilla and mandible to the cranium to be calculated.

- Superimposition being done on SN-plane, registering the patient’s tracing at nasion rather than sella if there is a difference in the anterior cranial base length.

- With the cranial base registered, the anteroposterior and vertical position of the maxilla and mandible can be observed.

- ANS, ptA for the anterior maxilla, PNS for the posterior maxilla.

- PtB, Pog and Gn for the anterior mandible and Go for the posterior mandible are looked for.

Eg; 11yr old pat with mand showing age of 6yrs.

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24

2. Regional superimposition:

- The (second) superimposition is on the

maxilla to evaluate the relationship of the maxillary dentition to the maxilla. Template makes the vertical evaluation of the teeth possible which is not possible with the measurement approach.

- The (third) superimposition is on the mandible same as that of maxilla

Advantages of the template

analysis

• It allows the easy use of the age related samples,

• It quickly provides an overall appraisal of the way in which the patient’s dentofacial structures are related unlike the measurement approach in which the focus sometimes shifts to acquiring the numbers themselves.

APPLICATIONS OF

CEPHALOMETRICS

Application of cephalometrics

• For gross inspection

• To describe morphology and growth

• To diagnose anomalies

• To forecast future relationships

• To plan treatment

• To evaluate treatment results

ERRORS OF CEPHALOMETRIC

MEASUREMENTS

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25

ERRORS OF CEPHALOMETRIC

MEASUREMENTS

These are grossly divided into three heads :

1. Radiographic projection errors

2. Errors within the measuring system

3. Errors in landmark identification.

A.RADIOGRAPHIC PROJECTION

ERRORS;

Occurs during the recording procedure, the

object as imaged on a conventional

radiographic film is subject to magnification

and distortion.

1.MAGNIFICATION:

• Magnification occurs because the X ray beams are not parallel

with all points of the object to be examined.

• The magnitude of the enlargement is related to the distances

between the focus, the object, and the film.

- The use of the long focus-object and the short object-film

distances has been recommended in order to minimize such

projection errors.

- Although long focus objects distances are preferable, a focus-film

distance of more than 280 cms does not significantly alter the

magnitude of the projection error.

EFFECT OF FOCUS FILM DISTANCE ON

RADIOGRAPHIC MAGNIFICATION

EFFECT ON OBJECT FILM DISTANCE ON

RADIOGRAPHIC MAGNIFICATION AND SHARPNESS 2.DISTORTION:Distortion occurs because of different

magnifications between different planes.

Although most of the landmarks used in cephalometric analyses are located within the mid Sagittal plane, some landmarks and many structures that are useful for superimposition are affected by distortion, owing to their location in a different field of depth.

In this instance both linear and angular measurements will be affected.

.

26

3. DIRECTIONS OF POSSIBLE

MISALIGNMENTS OF THE HEAD

Z-Vertical axisX-Transverse axisY-PA axis

a.Furthermore landmarks and planes not located in the midsagittal plane are usually bilateral giving a dual image on the radiograph.

b.The problem of locating bilateral structures can somewhat be compensated by recording the midpoints between these structures.

Bilateral structures in the symmetric head position do not superimpose in a lateral cephalogram !!

- The fan shaped X-ray beam expands as it passes thus causing a divergence between the images of all bilateral structures except those along the central beam

4.BILATERAL STRUCTURES

- In order to control errors during radiographic projection, the

relationship between the X ray target, the head holder and the

film must be fixed.

- The metal markers in the ear rods must be aligned and its good

practice to include a metal scale of known length to provide

permanent evidence of the enlargement of each film.

- For special research purposes, projection errors can be reduced

by a combination of stereo head films and the use of osseous

implants.

B.ERRORS WITHIN THE MEASURING

SYSTEM:

The development of computerized equipment for electronic

sampling of landmarks has greatly speeded up data collection

and processing and has reduced the potential for human

measuring errors.

The errors with a digitizer has two components:

• The error of the digitizing system

• The precision with which a marked point on the film or tracing

can be identified.

- An accuracy of .1mm is desirable without any distortion over

the surface of the digitizer.

Erickson and Solow (1981) have described specific procedures for

testing and correcting the digitizers before any routine use in

cephalometric research.

Errors of scaling can be corrected by setting switches in the control

unit of the digitizer or by scaling the incoming x-y coordinates by a

software programme.

Non-linearlities can be corrected by including certain matrices in the

software programme .

If these requirements are met , the measurements are more reliable

than those obtained by any manual device owing to the superior

accuracy of the digitizer.

C.ERRORS IN LANDMARK

IDENTIFICATION:

The major source of error in cephalometric has been

landmark identification.

The factors involved are:

• The quality of the radiographic image,

• The precision of the landmark definition and the

reproducibility of landmark location,

• The operator and registration procedure.

.

27

1.THE QUALITY OF THE RADIOGRAPHIC IMAGE

a. Expressed in terms of sharpness/blur and contrast and

noise.

b. Sharpness is related to blur and contrast

c. Blur is the distance of optical density change between

the boundaries of a structure and its surroundings.

3 types of unsharpness1. Geometric unsharpness2. Motion unsharpness3. Receptor unsharpness

Geometric unsharpness

Is directly related to the size of the focal spot and the focus

film distance.

Receptor unsharpness

•Depends on the physical properties of the film and the

intensifying screen

Eg; Combinations of fast films and rare earth intensifying

screen have reduced the exposure required, but produces

images with poorer definition.

Motion unsharpness

• Movement of the tube, object or the film during exposure

results in image blur.

- By increasing the current it is possible to reduce the

exposure time and thus reduce the effect of movements,

- Blur from scattered radiation can be reduced by using a

grid at the image receptor end.

2.PRECISION OF THE LANDMARK DEFINITION AND

THE REPRODUCIBILITY OF LANDMARK LOCATION

A clear unambiguous definition of cephalometric landmarks chosen

is of utmost importance for cephalometric reliability.

• The reference plane to which they are related should accompany

definitions of landmarks.

• Conditions required to record some landmarks should not be

unspecified or ambiguous.

(EG: lips in repose/ centric occlusion/ head posture)

• Some landmarks can be more reliably located than others.

• Geometrically constructed landmarks and landmarks identified

as points of change between concavity and convexity are quite

unreliable.

•The radiographic complexity of the region also lays an

important role making some landmarks more difficult to

identify.

The most reliably identified landmarks are; (According to

Miethke)

1.Incision superior incisal and

2.incision inferior incisal.

Landmarks difficult to identify are;

1.Anatomical porion and

2.Landmarks on the condyle.

3.The cusps of the posterior teeth or the lower incisor apex.

Baumrind and Franz (1971) pointed out that, the impact

that errors in landmark location have on angular and

linear measurements is a function of three variables:

1. The absolute magnitude of the error in landmark location.

2. The relative magnitude or the linear distance between the landmarks considered for that angular or linear measurement.

3. The direction from which the line connecting the landmarks intercepts the envelops of the error

.

28

The envelope is the pattern of total error distribution.

Since cephalometric landmarks have a non-circular

envelope of error, the average error introduced in linear

measurements will be greater if the line segment

connecting them to another point intersects the wider

part of the envelope.

•Errors in landmark identification can be reduced if measurements

are replicated and their values averaged.

•Consecutive evaluation of one cephalogram at random showed that

the localization of a landmark is more exact the second time that at

the first judgment. (Miethke 1989)

•The more the replications the smaller the impact of random error on

the total error becomes. There is however a practical limit for the

repeated assessment .

•Even for the purpose of scientific research if cross sectional or serial

measurements from two groups must be compared, duplicate

measurements are sufficient.

3. THE OPERATOR AND REGISTRATION

PROCEDURE

The operator’s alertness , training and his or her working conditions

affect the magnitude of the cephalometric error. In cephalometric

studies therefore the error level specific to the operator must be

established if any meaningful conclusions can be drawn from the

data.

The most important contribution to improvement in landmark

identification are experiences and calibration. In studies that

compare two groups of radiographs ,the operator can introduce

different types of error or bias.

One type of operators bias is the operators variability which

involves both

inter observer variability (disagreement between observers for

the identification of a particular landmark) and

intra observer variability ( the disagreement within the same

observer over time due to changes in his or her identification

procedure)

A good method to reduce this error consists of calibration and

periodic recalibration tests to establish confidence limits of

reproducibility for each observer

Another kind of error can be introduced because of

unconscious expectations of the operator when assessing

the outcome of the scientific research (that is the outcome

of different treatment results)

Randomization of record measurements or double blind

experimental designs can be used for reducing such bias

When serial records are being analyzed it has been suggested

that all the records of one patient should be traced on the

same occasion.

This minimizes the error variance within individual

observers although it increases the risk of bias.

.

29

METHODS OF CONTROLLING ERRORS

A.Taking the radiographs;

• The relationships of x-ray target, head holder, and film must be

fixed. The metal markers in the ear rods must be aligned, and it is

good practice to include a metal scale of known length at the

midsagittal plane to provide permanent evidence of the

enlargement of each radiograph.

2. Every effort must be made to

obtain films of high quality as

described in the standard texts.

3. Use of an aluminum wedge to

improve the definition of the soft

tissues and anterior bony

structures

4. Fast films and rare-earth intensifying screens reduce the exposure

greatly but give poorer definition than slower films and high-

definition screens.

5. Nevertheless, exposure reduction is of primary importance and

attention should be directed to obtaining the best screen/film

combination.

6. Minor distortions can arise if the film is not flat, because the

cassette does not support it adequately. This can be checked by

exposing a test grid which will reveal any serious lack of flatness

of the film.

B. Landmark identification;

1. Tracings should be made on good-quality drafting paper which

does not obscure any details.

2. The most important contributions to improvement in landmark

identification are experience and calibration.

3. Before any major study is undertaken, particularly if more than

one measurer is involved, calibration is of the greatest importance.

C. Experimental design;

• As they are collected, measurements should be checked for "wild"

values.

• This can be done against previously published standards as the

study progresses or against the measurements of the study itself

after it has been completed.

• Measurements more than 3 standard deviations away from the mean

may, indeed, be expressions of normal variation, but often they will

be the result of incorrect identification of a point or misreading of

an instrument.

• Random errors are reduced if measurements are replicated and

averaged. If this is to be done, it is the tracings which should be

replicated, not the measurements of tracings, because the greatest

errors may arise in point identification rather than in measurement.

5. The procedure is much less tedious if radiographs are digitized

directly.

6. Baumrind and Millersuggested that tracings should be repeated

four times, which will halve the random error, but this is too

arduous for all but gives the most exacting investigations.

7. An important way of controlling systematic errors is to randomize

the order in which the records are measured.

Thus, for example, if two groups of cases are being compared,

they should be traced in random order and, if possible, in a way

that prevents the measurer from knowing to which group any

record belongs.

STANDARDIZATION OF IMAGE

GEOMETRY

The early cephalometrists recognized the importance of standardized

head position if cephalograms were to be measures consistently.

All conventional cephalometric analyses are based on the assumptions

of standardized and fixed distances between the anode object and film.

If they are met, valid comparison can be made between images

generated on different cephalostats. If they are not maintained

comparisons cannot be made even if they are two radiographs from the

same machine.

.

30

Another gap in the conventions is the direction in which the

patient is facing.

In the USA the left side of the face is positioned closer to the

film while in Europe the right side of the face is closer to the

film.

Obviously either convention is acceptable but care should be

taken not to mix conventions in the same subject.

It should be kept in mind that the side closer to the film will

appear larger.

Any image acquired with the ear rods disengaged will be

subject to increased measurement errors, because the central

beam will inevitably deviate from the porion-porion axis.

LIMITATIONS OF RADIOGRAPHIC

CEPHALOMETRY

1. It gives two dimensional view of a three dimensional object.

2. The reliability of cephalometrics is not always accurate.

3. Standardization of analytical procedures are difficult. 4. Growth pattern not taken into consideration5. Mean values are based on different population6. Form and functions not taken into consideration

The manual technique of tracing a cephalogram is time consuming

and tedious.

In comparison computerized cephalometry is very fast and takes

just 10% of the time a manual tracing requires.

Due to direct digitization of the landmarks the process removes

human errors except those of landmark identification.

In addition to speed computerized cephalometry also facilitates

the use of double digitization of landmarks thus significantly

increasing the reliability of the analysis.

COMPUTERISED CEPHALOMETRIC

SYSTEMS:

Other benefits of this method include:

•Easy storage and retrieval of cephalometric values and tracings

•Intergration of the cephalometric registrations within an office

management computerized sytem.

•Combinationof the cephalometric data with patients files photos and

dental casts.

Three possible approaches may be used to perform a cephalometric

analysis.

1. The most common method is by manually placing a sheet of

acetate over the cephalometric radiograph, tracing salient

features, identifying landmarks, and measuring distances and

angles between landmark locations.

2. Another approach is computer aided. Landmarks are located

manually while these locations are digitized into a computer

system. The computer then completes the cephalometric

analysis.

3. The third approach is completely automated. The cephalometric

radiograph is scanned into the computer. The computer

automatically locates landmarks and performs the

cephalometric analysis.

(Rudolph, Sinclair,AJO 1998)

Currently, several commercially available systems can perform

basic cephalometric analysis tasks.

The user locates landmarks manually with a mouse cursor on

the display monitor on some systems. Other systems digitize

landmark locations on a digitizing pad. In either case a

computer algorithm performs a cephalometric analysis by

calculating distances and angles between landmark locations.

In addition, the algorithm connects these landmarks with line

segments to produce a tracing. Some systems are capable of

moving the tissues to simulate treatment effects, growth

effects, and surgical prediction. Finally, some of these systems

also are able to produce a time series of images using landmark

locations, not superimposition contours, to register images.

.

31

Generally, these systems do not save time, are expensive, and

require technical training. The accuracy of these computer-

aided programs has been demonstrated to be similar to that of

manual digitization, and because manual landmark

identification programs require subjective user point

identification, they are limited in scope.

In addition, the number of landmarks required are high; this

tends to negate any time saved using this method. Although

the analysis uses a computer, the process of manual point

digitization can be time-consuming and error-prone.

Automatic Landmark Identification

A third approach to cephalometric

analysis is completely automated. The

cephalometric image is scanned into a

computer and both landmark

identification and cephalometric

analysis are automated.

The process has the potential to

increase accuracy, provide more

efficient use of clinicians' time, and

improve our ability to correctly

diagnose orthodontic problems.

Additionally, this process may provide mathematical descriptions

of landmark locations that could be applied to new ways of

evaluating cephalometric radiographs to derive clinically important

information.

Digitized cephalometry

– Dentofacial planner

– Quick ceph image

– Por dios

– Digigraph

– Rocky mountain orthodontics – JIFFY orthodontic evaluation

– Prescription planner.

DIGITAL RADIOGRAPHY

• A digital image is a matrix of square pieces or picture elements (pixels), that form a mosaic pattern from wherein original image can be reconstructed for visual display.

Analog Image Digital Image

• 1) Conventional radiographic 1) a) Light sensitive Image elements to record

the image.b) Shades of gray to

display the Image

• 2) Silver halide grain 2) Light sensitive elements

• 3) Randomly dispersed 3) Regular grid of rows and Columns

• 4) Continuous Spectrum 4) Numeric and Discrete.

PIXELS AND VOXELS

• Pixel

2-D Digital Images – Composed of Picture elements.

• Voxel

3-D Digital Images – Composed of volume elements.

PRODUCTION OF DIGITAL IMAGE

Analog to Digital conversion (ADC).

• Sampling - Small range of voltage values grouped together.

• Quantization - Every sampled signal is assigned a value. Pixels are arranged in proper locations and given a shade of gray corresponding to quantization

number.

Advantages;

• It is very fast.• It is only necessary to digitise the points directly on

the cephalogram and calculations are done in seconds.

• It removes human error• Facilitates use of double digitisation of landmarks,

thus increasing reliability.• Easy storage and retrieval of values.• Simultaneous demonstration of anatomical

structures of different thickness--i.e., bone and soft tissues--and its lower exposure dose make digital radiography the diagnostic procedure of choice in cephalometrics.

• Filmless imaging.• Patient education.• Better treatment planning.

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32

CONCLUSION

• Roentgenographic cephalometrics although a major one-is one of many approaches and considerations in the diagnosis and treatment of an orthodontic patient.

• A roentgenographic cephalometric analysis is essentially a technique to be used as aguide in the diagnosis of a case of malocclusion.

• Although innumerable controversies exist in the field of cephalometrics, it is still a very significant & effective diagnostic tool.

A knowledge of what we have done and not done &, particularly, what we have not done, moulds and crystallizes our treatment philosophy & conditions it for better service for those who come to us. Thus making cephalometrics indispensable in clinical practice.

1. Radiographic cephalometry- Alexander Jacobson2. Oral Radiology, Principles and interpretation-

White and Pharoah (5th edition)3. Orthodontic cephalometry; Athanasios.4. Cephalometric radiography; Thomas Rakosi.5. Moores and Kean; NHP; Am J Phys. Anthropol. 16:

19566. Point A revisited – Jacobson- AJO 19807. Cecile Steiner-AO-1959, vol;29, no;18. Cecile Steiner- cephalometrics for you and

me;AJO DO-1953, vol 39.9. Soft tissue cephalometric analysis: AJODO-1999:

116.10. Cephalometrics for orthognathic surgery: JOS;vol

36; April 1978

REFERENCE

11. A frontal asymmetric analysis: JCO/July 1987

12. A cephalometric analysis based on NHP: JCO 1998; vol 1991, March.

13. Downs. W . F :analysis of dentofacial profile, angle orthod. Vol 26; 1956

14. McNamara;’ a method of cephalometric evaluation; AJODO. 86; 1984

15. Orthodontics in 3 millennia. Chapter 8;AJODO 2006; 129.

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1

Changing concepts of Attritional

occlusion

Dr.P.R.Begg


Preview :

Oldness of the idea regarding Attritional occlusion.

Stone age man’s dentition

Characteristics of Attritional occlusion

Correlative studies

Relevance of Begg’s hypothesis to the present day

Present view regarding Attritional occlusion.

Oldness of the idea of attritional

occlusion.

Sim Wallace (1904)

Introduced the “disuse” idea.

Efficient masticatory organ

Importance of chewing

Unnecessary blame on heredity

Brain vs. osseous structures

Campbell T.D. (1925)

Compared the quality and methods of preparation of food b/w native and present day aboriginals.

Crude methods of preparation of food required a very vigorous masticatory effort which led to a very efficient and perfect dentition.

Dental diseases limited to individuals of advanced years due to refinements in food.

Klatsky and Fisher (1953)

Reintroduced the idea of SimWallace.

Malocclusion – Disease of civilization.

Re-examined 3 basic factors :

1. Heredity -- x

2. Environment -- x

3. Function -- √

Undue importance on nutritional aspects of diet rather than on food texture.

.

2

Stone age mans dentition

Dr.P.R.Begg (1954)

Termed as Attritional occlusion

Concept based on studies on Australian aboriginals.

Their teeth exhibited :

1. Extensive occlusal and interproximal wear.

2. Lack of caries, pdl disease, crowding.

He considered the above as normal and civilised man’s unworn dentition and related problems as abnormal.

Anatomically correct occlusion

Correct occlusion – Based on continual

change.

2 important factors :

Position of teeth in jaw bones.

- continual mesial migration and vertical eruption which compensate for tooth attrition.

Anatomy of teeth.

- changing anatomy, dependent upon attrition.

Stone age mans dentition

When stone age man’s decidous incisors erupt, his hard, coarse, fibrous, gritty food immediately commences the process of interproximal reduction and occlusal attrition.

Prerequisite – excess of tooth substance.

As attrition occurs upper and lower decidous incisors assume an edge to edge overbite

.

3

Decrease in the overall M-D length of the deciduous dental arches.

i.e. the permanent molars erupt further mesially in the jaws than in civilized man.

Begg’s view on Angle’s classification.

As the permanent teeth erupt the process of attrition is continous.

Permanent incisors erupt in an overbite similar to that of civilised man but soon assume an edge to edge bite.

i.e. lower incisors

- more prominent.

- curve of spee flat mesiodistally.

Also , during the transition to an edge to edge bite :

-- canines, premolars and 2nd molars wear interproximally and occlusally but maintain contact by mesial migration.

-- provides adequate space for erupting canines, 2nd molars and 3rd molars.

.

4

Begg (1930’s)

Aim:

To evaluate the amount of reduction in size of the lower dental arch prior to the eruption of lower 3rd molars.

Measurements done on aboriginal skulls collected from the south australian museum using a boley guage in millimeters.

Mandibles separated into 2 sets.

Results

Difference b/w the 2 sets of measurements

-- 5.28 mm x 2 = 10.56 mm

Maxilla : 1mm less than mandible.

The above figure according to Begg is an underestimation as canines, PM’s and 2nd

molars have just erupted

with aid of “restoration” pencil drawing the estimated reduction in arch width –14.7mm

Four degrees of tooth wear (Broca)

First stage : enamel worn without exposure of dentin

Second stage : cusps worn down and dentine exposed

Third stage : appreciable amount of crown worn away

Fourth stage : wear extended to the neck of the tooth

Disagrees with :

-- Strang, Huckaba

-- Anthropologists

-- G.V.Black, E.H.Angle and others

Concludes that textbook normal occlusion develops only in those individuals who have too small an amount of tooth substance.

Characteristics of attritional occlusion

( Evidence in favour of attritional occlusion )

Edge to edge anterior overbite

Gingival recession and vertical eruption

Caries and periodontal disease

Eruption of first permanent molars

Anatomy of TMJ

Proximal wear

Eruption of 3rd molars

Change in the curve of Wilson

Reason for Cusps of Carabelli

Secondary dentin and Pulpal pain

Low incidence of malocclusions with tooth crowding.

.

5

Edge to edge anterior overbite Gingival recession and vertical eruption

Caries and periodontal disease Eruption of first permanent molars

Anatomy of TMJ

Shallow glenoid fossa

Low eminentia articularis

Flattened condylar head

Deep fossa

Round condylar head

Proximal wear

.

6

Eruption of 3rd molars

Change in the curve of Wilson

+ Reason for Cusps of Carabelli

Secondary dentin and Pulpal pain X-Occlusion (M.J.Barret)

Variation of clinical procedures based

on the tenents of attritional occlusion

Extractions are rational based on a sound etiological basis as it simulates the extensive M-D attrition in SAM.

If tooth material excess is mild Ist PM extraction suffices and if its grossly excess 8 teeth extractions are needed

Opening of the bite to edge to edge position in stage 1

Retraction of upper incisors to edge to edge position in stage 1

Mesial movement of posterior teeth in general in stage 2.

Evaluation of Australian aboriginals

(Corrucini et.al)

Aim: To evaluate the Begg hypothesis.

Method :A collection of dental casts from the Yuendumu settlement situated 285km northwest of Alice Springs in the northern territory of Australia.

Established in 1946 to provide a central area for provisioning aboriginals who had left their tribal areas

.

7

Study consisted of 4 groups :

1. Older generation – born before 1937 (48)

2. Younger generation – post 1937 (48)

3. Aboriginal skulls – south aus.museum (48)

4. Haasts Bluff cast collection (35)

Each occlusal variable was statistically evaluated.

The younger vs. older contrast was given primary interest as it explained the effect of civilization.

Results

Summarized findings of Yuendumu study:

- No occluso-incisal attrition observed in Yuendumu subjects.

- Leeway space could not be co-related to crowding

- The overall size of teeth did not correlate to crowding as the size of teeth of normal and malocclusion subjects being identical.

Examination of dental crowding and its

relationship to tooth size and arch dimension

Howe , Mcnamara

To examine the extent to which tooth size and jaw size contribute dental crowding.

Conditions predispose crowding:

1. Excessively large teeth

2. Small bases

3. Combination

Materials and methods

104 subjects – maxillary and mandibular casts

2 groups:

-- Non-crowded group

-- Crowded group

Measurements :

- M-D tooth diameters

- Arch width

- Arch perimeter

.

8

Conclusion

-- subjects with dental crowding were more likely to have smaller dental arch measurement than subjects without crowding

-- treatment could be directed towards

1. Reduction of tooth mass

2. Dental arch expansion

3. Combination of both

Reassesment of Begg’s study

2 studies done by Dawes, at university of Adelaide in 1987 and other by Corrucini in 1990 showed a greater variance with the results obtained by Begg.

Studies on Attritional occlusion similar to begg have not been able to relate with the value of 10.56mm. Their estimate ranged from 20-40% of begg’s value.

-- Murphy, Beyron 1964

-- Fishman 1976

-- Dawes 1987

-- Corrucini, Kaul 1990

Dawes points a discrepancy b/w the measurements of Campbell and Begg. If Begg were to use Campbell's measurements the value would have been 7.24 instead of 10.56.

His measurements on skulls with and without attrition were identical.

Major evidence against Begg’s Hypothesis was the longitudinal study on Yuendumu aboriginals. Results were in contrast to the cross-sectional approach of Begg.

Relevance of attritional occlusion to the present day

Attrition does occur in SAM but certainly less than 14.7 mm

The role of diet, attrition and mesio-occlusal migration are biologically valid explanations in accounting for malocclusion.

Mesio occlusal migration in modern man is predicted on good tooth contacts and when a loss of tooth occurs the teeth distal to the site of loss move mesially.

Present day concept

Etiology of malocclusion :

-- Attritional occlusion – X

-- Multifactorial

-- Corrucini view

.

9

Extractions necessary but based on analysis.

Late lower incisor crowding

Functional occlusion and incisal guidance

References:

Begg orthodontic theory and technique

-- Begg and kesling.

Stone age man’s dentition

-- Dr.P.R.Begg :AJO 1954

How anthropology informs the orthodontic diagnosis of malocclusion’s causes

-- Robert S.Corruccini

Contemporary orthodontics

-- W.Profitt

www.cyberdontic.com/SlideFrm2.htm

.

1

“Contributions of Dr. T. M. Graber to

Orthodontics”

1917-20071


Dr Thomas M. “Tom” Graber,

known internationally as an

orthodontist, researcher, and dental

educator.

2

Introduction and Brief History of Dr.T.M.Graber

3

Born in St Louis on May 27, 1917.

Was a chemical engineer when he was 13.

Earned a DMD degree in dentistry (Washington University,

1940), an MSD in orthodontics (Northwestern University,

1946), and a PhD in anatomy (Northwestern University,

1950)

He served as a captain in the United States Army Dental

Corps from 1941 to 1945.

Unlikely spiritual connection between a world-

famous orthodontist who fought against the

Germans during World War II.4

• He was on the faculty of Northwestern University from 1946 to 1958; at the University of Chicago from 1969 to 1982, where he was head of the Section of Orthodontics; and at the University of Illinois at Chicago College of Dentistry from 1994 until his death.

• He also served as a visiting professor on the faculties of the University of Michigan, The University of Freiburg, Germany, and the University of Gothenburg, Sweden.

5

A pioneer in orthodontics and craniofacial biology, Dr.Graber did research on

Craniofacial anomalies

Cleft palate, cleft lip

Temporomandibular joint anatomy and disturbances

Orthopedic growth guidance of the dentofacial complex and

The use of magnetic forces in orthodontics and dentofacial orthopedics.

His 60 years of research have added to our knowledge in these fields and changed the way they are taught around the world. 6

.

2

❖ He gave more than 475 continuing educationcourses around the world and was on the American Association of Orthodontists Annual Session program more than any other person in AAO history.

❖ Beginning in 1951, he made annual lecture tours to universities, departments and medical and dental societies around the world.

❖ He wrote 28 books on orthodontics and dental anatomy and contributed chapters to 20 other books.

❖ He wrote more than 175 scientific articles in refereed dental and medical journals, not to mention hundreds of book and journal article reviews and abstracts.

7

➢Dr Graber’s contributions to organized orthodontics and orthodontic education were unsurpassed. He served on the AAO Council on Orthodontic Education from 1962 to 1973.

➢Founded the Audiovisual Council of the AAO in 1962

➢Was general chairman of the AAO Annual Session twice.

➢Founded the Kenilworth Dental Research Foundation.

➢Was director of Continuing Education for the G. V. Black Institute since 1967.

8

➢Was director of Dental Continuing Education for the University of Chicago Center for Continuing Education from 1971 to 1981

➢Founded the Northwestern University Cleft Lip and Palate Institute and the Orthodontic Section at the University of Chicago Medical School.

➢Was a founding member of the Illinois Society of Orthodontists, and

➢Was a former president of the Chicago Society of Orthodontists, the Midwest Component of the Edward H. Angle Society, and the Illinois Society of Orthodontists.

9

He received honorary doctoral degrees from;

❑ University of Gothenburg, Sweden, 1989

❑Washington University, St Louis, 1991

❑ University of Michigan, 1994

❑Kunming Medical University, China, 1996, and

❑ Aristotle University of Thessaloniki, Greece, 2005.

“His honorary degrees from Washington University and the University of Michigan were the first and only ones ever given to a dentist”

10

▪ Dr Graber received awards

too numerous to list.

▪ He was quite proud to be the first non-Japanese

person to be inducted as a member of the Japan

Orthodontic Society in 1997, and he received the

Emperor of Japan’s Order of the Sacred Treasure,

the highest Japanese award ever bestowed upon a

noncitizen of Japan, in 2003.

11

• Active in his community, Dr Graber was a

member of the Sons of the American

Revolution, and had been a leader in the Boy

Scouts of America.

• He was a generous philanthropist, having

endowed a professorship at the University of

Michigan

12

.

3

He is survived by his wife of 66 years,

Dr Doris Graber; sons Dr Lee W.Graber,

Dr Thomas W. Graber, Jack D. Graber, and

Dr Jim M. Graber; daughter Dr Susan Graber;

and 14 grandchildren.

13

Dr. T. M. Graber, died in his home

among family members on June 26, 2007.

He was 90. 14

Graber’s contribution

15

Occlusion.

Diagnosis.

Craniofacial anomalies.

Cleft palate, cleft lip.

Temporo-mandibular joint anatomy and disturbances.

Orthopedic growth guidance of the dentofacial complex.

The use of magnetic forces in orthodontics and dentofacial orthopedics.

Extractions.

Root resorption & expansion.

16

Physiology of Occlusion

17

Normal Occlusion

- T.M. Graber (DCNA, 1968)

In this paper, Dr. Graber states that any definition of normal occlusion cannot be static and merely descriptive of tooth relationships. Normal occlusion involves not only the teeth, but also the investing tissues, the contiguous and motivating musculature, curve of Spee, inter-occlusal clearance, and the TMJ morphology and function.

18

.

4

❑He has organized the historical progress in the

development of current concepts of occlusion into

three periods:

- fictional period (before 1900)

- hypothetical period (1900-1930)

- factual period (1930 – present).

19

FICTIONAL PERIOD.

• Concepts were developed from inductive analysis.

• Terminology was loose and reflected the personal preferences of the authors.

• Authors talked about dental antagonisms, “meeting” or “gliding” of teeth.

• Good descriptions of the morphologic nature of individual teeth existed, but an appreciation of the functioning dentition as a whole was lacking.

20

HYPOTHETICAL PERIOD.

It was E.H. Angle who organized the existing

concepts of occlusion at the time and formulated

definite principles of diagnosis in treatment.

• He gave the ‘key of occlusion’ based on the position of the upper first molar.

• Angle described normal occlusion using a skull which he called ‘Old Glory’. Old Glory

21

• Calvin Case developed the concept of “apical base”. He also called attention to the effect of the nose and chin button on the profile.

• In 1908, Bennett suggested the functional analysis or the dynamic approach to occlusion for the first time.

He noted that the mandible had a resting position (depended on musculature) and a functional position (depended on the teeth in maximum contact).

22

FACTUAL PERIOD.

• With the introduction of biometric procedures and scientific methodology, this period saw a trend toward the dynamic and a de-emphasis on the static.

• In 1931, B. Holly Broadbent introduced radiographic cephalometry.

• Occlusion now meant inter-digitations of teeth, plus the influence of the musculature as well as that of the

temporo-mandibular joint.

23

The developing occlusion – Orthodontic considerations for the handicapped.

- Owen, Graber (DCNA, 1974).

• The authors state that the nature and severity of the

handicap in a child may totally dominate the dental

diagnostic and treatment considerations.

• They have described the type of care to be rendered

according to the severity of the handicap;

- mild

- moderate

- severe.24

.

5

• Timing, case selection and management are the main factors in treating or not treating the handicapped patient.

• It is important to weigh the possible benefits to the child with the individual’s physical and dental status as affected by his ability to comprehend and cope with orthodontic procedures.

25

The “three M’s”: Muscles, malformation and malocclusion.

- T.M. Graber (AJO, 1963)

• In this classic article, Dr. Graber has analysed

muscles and their relationship to structural

configuration in Class I, Class II, and Class III

malocclusions.

• “Whenever there is a struggle between muscle and

bone, bone yields." Muscle function can be adaptive

to morphogenetic pattern.

26

• A change in muscle function can initiate morphologic variation in the normal configuration of the teeth and supporting bone, or it can enhance an already existing malocclusion.

• In the latter instance, the inherent structural mal-relationship calls for compensatory or adaptive muscle activity to perform the daily functions.

• The structural abnormality is increased by compensatory muscle activity to the extent that a balance is reached between pattern, environment, and physiology.

27

• It is imperative that the orthodontist appraise

muscle activity and that he conduct his

orthodontic therapy in such a manner that the

finished result reflects a balance between the

structural changes obtained and the functional

forces acting on the teeth and investing tissues at

that time.

28

EXTRACTIONS

29

SERIAL EXTRACTION

-Graber. T . M, AJODO (1971; VOL-60;NO6)

• Serial extraction is a guided, progressive removal

of deciduous teeth ahead of the time they would

normally be shed, to enlist the fundamental

phenomena of adaptability and adjustment.

30

.

6

DIAGNOSTIC DISCIPLINE

➢Complete diagnostic records

- Study models, undistorted periapical rad,

panoramic rad, cephalometric rad.

➢Calipers and fine-line dividers can be used to

measure the width of the teeth.

31

Stages in extraction therapy

A. Removal of deciduous canines;

1. To permit the eruption & optimal alignment of

lateral incisors.

2. Improve the position of the central incisors

3. Prevent the lingual eruption of lateral incisors.

4. If nature has not already exfoliated deciduous

canines or has exfoliated only one of them, these

teeth are removed between the age of 8-9 yrs in

patients with average developmental pattern.32

B. Removal of first deciduous molars :

To accelerate the eruption of 1st premolars

ahead of canines, if at all possible.

1. One must consider enucleating the unerupted 1st

premolars to obtain the optimal benefits of serial

extraction.

2. Extraction of 2nd deciduous molar when canines

have erupted prior to 1st premolar.

3. 1st deciduous molars are extracted approx 12

months after the deciduous canines. (9-10 yrs)

33

4. Timing is not so critical for removal of the 1st

deciduous molars.

5. Some prefer to extract remaining deciduous

canines & 1st deciduous molars at the same time.

34

C. Removal of the erupting first premolars.

The purpose of this is to permit the canine to

drop distally into the spaces created by the

extraction.

1. Important considerations

- All diagnostic criteria must be evaluated.

- status of developing 3rd molar.

➢ If the procedure had been carried out correctly

and the timing had been right, this is the most

rewarding experience.

35

➢ If the decision has been definitely made that it is

necessary to remove the 1st premolar, the sooner it

is done better the better is the self adjustments.

36

.

7

37

The role of upper second molar extraction in

orthodontic treatment.


In Class II treatment, the greatest change

produced by the orthodontic appliances is in the

maxilla.

Distal adjustment of tooth position in the maxilla

alone, or in conjunction with mandibular growth, is

the basis for correction.

38

❑ If space required for the tooth adjustment is gained in the second molar area, only as much space as required need be used, with the subsequent mesio-vertical eruption of the maxillary third molars filling the gap.

❑ Maxillary 2nd molar removal expedites correction of Class II/1 malocclusion, provided that:

▪ There is excessive labial inclination of the maxillary incisors, with no spacing.

▪ Overbite is minimal.

▪ 3rd molars are present in the maxilla, in good position and of proper shape.

39

❑ The cases offering the poorest prognosis for

maxillary 2nd molar extraction are;

- severe basal dysplasia with vertically inclined maxillary

incisors

- no spacing, and

- severe overbite.

40

Maxillary second molar extraction in Class II

malocclusion.


➢ In this paper, Dr. Graber has again dwelled upon the removal of upper 2nd molars as a therapeutic means for correction of Class II malocclusion.

➢He recommends the extraction of maxillary 2nd

molars in those instances in which there are good maxillary 3rd molars and where there is a significant Class II/1 malocclusion and involvement of all 4 tissue systems – teeth, bone, muscle and nerve.

41

➢A fixed lingual arch is used to prevent the

mandibular 2nd molars from over-erupting.

➢Minimum mechanotherapy is required, wrt. to

appliances and duration of treatment.

➢The results appear to be stable over a long period

of time.

➢The iatrogenic reaction is minimal or non-existent.

42

.

8

Orthopedic appliances

43

Extraoral force – facts and fallacies.


• Dr. Graber studied 150 cases of Class II div-1 malocclusion treated with extraoral force using the same type of appliance.

• The appliance consisted of molar bands, an .045 inch stainless steel labial arch wire with vertical spring loops at the lateral-canine embrasure to receive the cervical gear. This was a metal tube with a continuous spring inside to provide distal motivating force.

44

He concluded that:

• Class II div-1 malocclusions are amenable to correction by the use of extra oral force. Marked improvement in the basal relations can be obtained.

• Overbite and over jet problems can be helped greatly.

• Coordination of treatment with the pubertal growth spurt ensures a greater likelihood of success [ 10-12 yrs. in girls; 12-17 yrs. in boys].

45

▪ Certain untoward sequelae may be seen in the use of

extraoral force. These include:

✓incomplete correction of tooth mal-relationship,

✓excessive distal tipping of maxillary 1st molars,

✓possible impaction of maxillary 2nd or 3rd molars,

✓possible excessive lingual tipping of maxillary

incisors.

✓possible unilateral response in correction of Class

II relationship, and

✓difficulty in the control of excessive overbite.

46

Dentofacial orthopedics vs. Orthodontics.- Graber, Chung, Aoba (JADA,1967)

• In this paper, the authors have reported that

orthopedic therapeutic measures with heavy and

interrupted force against the bone may be used

successfully in orthodontics.

• Greater use of this type of extraoral force is

recommended because of its superior ability to

correct basal jaw antero-posterior mal-relationships.

47

• In addition, there is greater stability, a lower percentage of tooth extractions, minimal use of intraoral appliances, less attendant orthogenic damage (decalcification, root resorption), minimal chair time, and longer intervals between appointments.

• An occipital base of anchorage is more satisfactory for correction of Class III mandibular prognathism.

• In cases of open bite, the direction of restrictive force must be as vertical as the design of the cranial cap will permit.

• In Class II/1 malocclusion, a cervical source of anchorage is satisfactory.

48

.

9

Heavy intermittent cervical traction in Class

II treatment: A longitudinal cephalometric

assessment.

- Mills, Holman, Graber (AJO, 1978)

• Investigated the changes brought about in the dentofacial complex as a result of the use of heavy cervical traction forces applied intermittently in the maxilla in growing Class II/1 patients, and compared with untreated controls.

49

Their findings showed that there was:

• A stable reduction in the ANB.

• ANS did not move downward during treatment; no significant tipping of PP occurred.

• Less forward progress of pt. B and Pog occurred in treated group. Thus, SNB was constant.

• Mandible was rotated downward and backward – slight increase in SN-MP angle.

• Significant decrease in overbite occurred during treatment.

• UI-SN decreased during treatment, but increased during follow-up.

50

• Treatment had marked withholding effect on normal downward and forward eruption of maxillary 1st molars. However, in post-treatment period, these teeth erupted more than in controls, losing some of the treatment effect.

• Distal tipping of upper molars occurred during treatment, but relapsed after appliance removal.

• Distal uprighting of lower molars and incisors occurred during treatment. Molar position was stable, but incisors relapsed following treatment.

• Sagittal arch length decreased significantly during treatment. This effect was stable.

51

• Both the Downs OP and functional OP tipped

downward anteriorly as a result of treatment, and

relapsed insignificantly following treatment.

• Anterior facial height increased more than

normally as a result of treatment. Most of this

change took place in the lower facial height.

52

The effectiveness of protraction face mask

therapy: A meta-analysis

- Kim, Viana, Graber, Omerza & BeGole (AJODO, 1999)

• This study examined the effectiveness of maxillary protraction with orthopedic appliances in Class III patients. A meta-analysis of relevant literature was performed to determine whether a consensus exists regarding controversial issues such as the timing of treatment and the use of adjunctive intraoral appliances.

53

The results showed that there was:

• No distinct difference between the palatal expansion group and non-expansion group except for 1 variable, upper incisor angulations, which increased to a greater degree in the nonexpansion group. This finding implies that more skeletal effect and less dental change are produced in the expansion appliance group.

54

.

10

• Examination of the effects of age revealed greater treatment changes in the younger group.

• Results indicate that protraction face mask therapy is effective in patients who are growing, but to a lesser degree in patients who are older than 10 years of age, and that protraction in combination with an initial period of expansion may provide more significant skeletal effects.

55

Craniofacial features of patients with Class

III abnormalities: Growth-related changes

and effects of short-term and long-term

chincup therapy.

- Deguchi, Kuroda, Minoshima &

Graber (AJODO, 2002)

• The craniofacial features of patients with Class III abnormalities, including growth-related changes and effects of short-term and long-term chincup therapy, were studied.

56

• Twenty female subjects were treated with

chincups and an orthopedic force of 500 g for 31

months (short-term treatment group). Another 36

female patients were treated with chincups and a

force of 250 to 300 g for 86 months (long-term

treatment group).

• Cross-sectional lateral films of 562 skeletal Class

III girls served as controls.

57

Their results showed that:

• Short-term treatment resulted in a slight improvement in ANBangle and Wits appraisal, while long-term treatment resulted in a significant improvement in ANB angle and Wits appraisal.

• Such treatment also resulted in a significant inhibition of the growth of the ramus (2.2 mm) and body length (3.6 mm) of the mandible, a backward rotation of the mandible, and a reduction (8.2°) of the gonial angle.

• However, there was no alteration of any parameter of the maxilla and the cranial base, except the length of S-N and N-S-Ar in the long-term treatment group.

58

Long-term application of chincup force

alters the morphology of the dolichofacial

Class III mandible.

- Deguchi, Kuroda, Hunt &

Graber (AJODO, 1999)

• Investigated the immediate and long-term effects of prolonged use (mean, 7 years 2 months) of chincup appliances in subjects with dolichofacial Class III mandibles.

• 36 female subjects with severe skeletal Class III malocclusions, associated with large gonial angles, were studied.

59

• At posttreatment (T1, 65 months duration) and postretention (T2, 56 months after T1), Ar-Me and Wits appraisal cephalometric parameters were significantly different between patients and control subjects (n = 230).

• The Go-Me parameter in treated subjects was longer than that of the controls at T0 but became significantly shorter at T2.

• Ar-Go parameter increased less than the controls at T2.

• Results indicate that long-term use of the chincup appliance (>5 years) is effective in subjects with severe skeletal Class III abnormality.

60

.

11

Growth Modification of the Rabbit Mandible

Using Therapeutic Ultrasound: Is it Possible

to Enhance Functional Appliance Results?

- El-Bialy, El-Shamy, Graber (AO, 2003)

• The objective of this study was to evaluate the effect

of therapeutic US on condylar and mandibular growth

in the rabbit model.

61

• Eight growing New Zealand male rabbits were chosen for this study.

• They received therapeutic US on one side of the mandible for 20 minutes/day for four weeks.

• Anthropometrical and histological evaluations revealed that US enhances mandibular growth by condylar endochondreal bone growth and consequently mandibular ramus growth.

• It thus increases the mandibular condylar, ramal, and total mandibular heights in growing rabbits.

62

Rare earth magnets

63

Graber described the potential for the clinical utilization of rare earth magnets for the following purposes:

• Space control (space closure/opening).

• Open bite therapy (intrusion of posterior teeth).

• Palatal expansion.

• Growth guidance (functional appliances).

• Dis-impaction of canines and molars.

64

Rare earth magnets and impaction

- Vardimon, Graber, Drescher & Bourauel (AJO 1991)

• Introduced a new, magnetic attraction system, with a magnetic bracket bonded to an impacted tooth and an intraoral magnet linked to a Hawley type retainer for stimulating the natural eruption of an impacted tooth into the oral cavity.

65

• The magnetic system consisted of a magnetic bracket and an intraoral magnet.

• A miniaturized prism-shaped Nd2Fe14B magnetic alloy in an unmagnetized form was ground down (width= 2.20 mm ×height = 2.59 mm × depth = 2.02 mm) to fit into an enlarged intrabracket space, i.e., into the space created between two machined down tie wings of a twin bracket.

66

A. Modified twin bracket

to receive a nonmagnetized

prism-shaped magnet.

.

12

• Vertical and horizontal magnetic brackets were

designed, with the magnetic axis magnetized parallel

and perpendicular to the base of the bracket,

respectively.

• The vertical type is used for impacted incisors and

canines.

67

B, Vertical magnetic bracket,

with the magnetic axis (arrow)

oriented parallel to the base

of the bracket.

• Horizontal magnetic bracket is applied for impacted premolars

and molars.

• Horizontal magnetic

• bracket, with the magnetic axis (arrow) oriented

perpendicular to the base of the bracket.

68

C, Horizontal magnetic bracket,

with the magnetic axis (arrow)

oriented perpendicular to the

base of the bracket.D, An edgewise slot installed

in a magnetic piece.

E, Edgewise magnetic bracket,

the magnetic axis can be oriented

(as in B or C) in both vertical

and horizontal directions.69 70

An intraoral magnet

attached

to a Hawley’s retainer.

▪ The system operated at an attractive force level of 0.2 to

0.5 N.

▪ Adjustment was accomplished by temporarily interposing

a magnetic spacer between the two magnetic units.

▪ No side effects were observed in this restricted number of

treated cases, and treatment time was reduced.

▪ The study recommends the application of magnets in the

treatment of impaction on the grounds of less invasive

surgical procedure, effective attractive forces at short

distances, and controlled spatial guidance.

71

Magnetic versus mechanical expansion with

different force thresholds and points of force

application.

- Vardimon, Graber, Voss & Verrusio (AJODO, 1987)

• Studied the effects of force magnitude (high vs. low) and point of force application (tooth vs. direct palatal endosseous pins) on palatal expansion treatment in 4 Macaca fascicularis monkeys.

72

.

13

Animal 1(IS) : animal with indirect screw

• Received an upper acrylic appliance with an expansion screw.

• The appliance was bonded bilaterally from canine to 1st molar.

• Thus, high forces (2033gms.) were transmitted indirectly to the mid-palatal suture via the abutment teeth.

73

Animal 2 (IM) : animal with indirect magnets.

• Received similar appliance with two permanent

rare earth repulsive magnets in the configuration.

• The appliance was bonded to the abutment teeth

(canine and 1st molar).

• It transmitted low forces (258 gms.) indirectly to

the mid-palatal suture.

74

Sliding (A) and stationary (B) acrylic housings to receive the magnets.

(C) Acrylic occlusal extensions to be bonded to dental arch.

(D) Horizontal tubes to receive the U-shaped bars (E)

Vertical holes (F) to retain the reactivation holders (G)

Teflon rings (H) to serve as barriers in the rectivation process.

Animal 2 (IM)

75

76

Animal 3 (DM) : animal with direct rare earth magnet.

• Received a magnetic unit linked to a plate attached to the palate via 4 endosseous pins .

• It transmitted low forces (258 gms.) directly to the palatal shelves.

Animal 4 (control) : received a passive sham appliance bonded to abutment teeth.

77

Animal 3 (DM)

78

.

14

• Stainless steel wire markers were bonded along the long

axis of the buccal crown surfaces of the upper canines (3)

and first molars.

• Tantalum implants (nonmagnetic) were inserted in the

bone bilaterally on each side of the facial sutures:

- Pm, premaxillary;

- P, palatal (maxilla);

- KR, key ridge (infrazygomatic ridge);

- IO, infraorbital;

- ZT, zygomaticotemporal;

- TZ, temporalzygomatic;

- ZF, zygomaticofrontal;

- FZ, frontozygomatic;

- FM, frontomaxillary; and

- F, frontal. 79


• Treatment time was longer in the low force,

magnetically induced appliances groups – 33 days in

IS, 135 days in IM and 95 days in DM groups.

• In animal IS, a diastema developed between the

incisors and the force was directed supero-laterally

and then trans-medially, thus causing fractures in the

nasal complex and other iatrogenic sequelae.

80

• In the magnetically-induced appliances, the force

radiated supero-laterally, dissipating in the

zygomatico-frontal suture, and the overjet

significantly increased due to marked widening of

incisive and transverse sutures.

• The palatally pinned magnetic appliance produced

bodily tooth movement, the greatest increase in inter-

molar distance, and a superior positioning of the

maxillo-palatine region.

81

• Their results suggested reduction of conventional

forces for palatal expansion by up to eightfold,

through the use of rare earth magnets.

• Thus the elimination of potential iatrogenic squeal

in the form of uncontrolled force levels.

82

Stability of magnetic vs. mechanical palatal

expansion

- Vardimon, Graber & Voss (EJO, 1989)

• Spatial stability following palatal expansion (PE) treatment was studied longitudinally on 8 Macaca fascicularis monkeys.

• The sample was divided into short-term and long-term groups.

83

The 4 animals in each group received:

(1) An indirect screw (IS) PE appliance [F=2035g].

(2) An indirect magnetic (IM) PE appliance [F=258g and 360 g].

(3) A direct magnetic (DM) PE appliance [F=258g and 360g].

(4) A sham appliance.

Direct force transmission was via pinning to the palatal shelves, indirect transmission was via abutment teeth.

84

.

15

This study indicated that:

• Transverse stability was greatest in the skeletally borne appliance.

• Inter-canine distance relapse was 53% for IS and 23% for DM groups.

• Inter-molar expansion was more stable than inter-canine expansion due to selective activity of circum-maxillary sutures and root configuration.

• Sagittal advancement and vertical superior translation were greater in the magnetic appliances with low force PE regimen.

• Clinical implication – low force palatal expansion regimen can be of substantial benefit in young skeletal Class III patients with transverse maxillary deficiency.

85

Magnetic strength and corrosion

of rare earth magnets- Ahmad, Drummond, Graber, BeGole (AJODO, 2006)

• Evaluated several magnet coatings and their effects on magnetic flux density.

• 60 neodymium-iron-boron magnets were divided into 6 equal groups—polytetrafluoroethylene-coated (PTFE), parylene-coated, and noncoated.

• They were subjected to 4 weeks of aging in saline solution, ball milling, and corrosion testing.

86

Their results showed ;

• A significant decrease in magnet flux density after applying a protective layer of parylene, whereas a slight decrease was found after applying a protective layer of PTFE.

• After 4 weeks of aging, the coated magnets were superior to the non-coated magnets in retaining magnetism.

• The corrosion-behaviour test showed no significant difference between the 2 types of coated magnets, and considerable amounts of iron-leached ions were seen in all groups.

87

The authors concluded that throughout the

processes of coating, soaking, ball milling, and

corrosion testing, PTFE was a better coating

material than parylene for preserving magnet flux

density. However, corrosion testing showed

significant metal leaching in all groups.

88

Functional orthopedic magnetic appliance

(FOMA) II-Modus operandi

- Vardimon, Stutzmann, Graber, Voss, Petrovic

(AJODO, 1989)

• Introduced a new functional appliance (FA) to correct

Class II dentoskeletal malocclusions.

• The FOMA II uses upper and lower attracting

magnets (Nd2Fe14B) to constrain the lower jaw in an

advanced sagittal posture.

89

• In vitro, a special gauge

transducer measured the

magnetic attractive path

and forces.

Assembly for measuring the

attractive path of vertico-

sagittally displaced magnets.

90

.

16

• In vivo, 13 prepubertal female Macaca fascicularis monkeys received facial implants and were treated for 4 months with the following appliances:

✓Conventional Functional appliance (4 subjects)

✓ FOMA II (5 subjects)

✓Combined FOMA II + FA (2 subjects)

✓ Sham (control) appliance (2 subjects).

91

A. The FOMA II consisted of

upper and lower magnetic

plates.

• Buccal (solid line) and lingual

(dashed line) 0.035-inch

stainless steel arch wires

formed the metal substructure.

• The two arch wires were linked

together by acrylic overlaying

the incisor and molar crowns.

• The FOMA II was designed

with a magnetic inclined plane

(25°).

92

B. The conventional FA

(feedback plates) guided

the mandible to a forward

position by using a

slanted guide bar

attached to the upper

plate and a lower oblique

plane of the lower plate.

93

C. The combined FOMA II +

FA appliance consisted of

a labial magnetic unit and

a lingual prong system.

94

D. The sham appliance with

its passive upper and

lower plates.

95

The in vitro results showed the following:

• Vertico-sagittally displaced upper and lower magnets attracted ultimately along an oblique line with a terminal horizontal slide to become fully superimposed.

• The functional performance improved when the magnetic interface acted as a magnetic inclined plane.

• The magnetic force was able to guide and constrain the mandible toward the constructive protrusive closure position.

96

.

17

The in vivo results demonstrated the following:

• Functional performance increased in FOMA II (22%) and in the combined FOMA II + FA (2-8%) over the conventional FA.

• Mandibular length increased significantly in the treated animals over the-control animals.

• Incisor proclination was lower in magnetic appliances than in the conventional FA.

• Mandibular elongation and condylar posterior inclination resulted from posterosuperior endochondral growth and by bony remodeling of the condylar neck.

• No anterior displacement of the postglenoid spine nor the articular eminence was found.

97

The Functional orthopedic magnetic

appliance (FOMA) III

- Vardimon AD, Graber TM, Voss LR, Muller (AJODO, 1990)

• Developed an intraoral intermaxillary appliance for

the treatment of Class III malocclusions that exhibit

mid-face sagittal deficiency with or without

mandibular excess.

98

• The FOMA III consists of upper and lower acrylic plates with a permanent magnet incorporated into each plate.

• The upper magnet is linked to a retraction screw and is retracted periodically (e.g., monthly) to stimulate maxillary advancement and mandibular retardation.

99

• The upper plate of a FOMA III consists of a 0.031-inch stainless steel arch wire forming the metal substructure. The arch wire bypasses the premolar-canine segment to permit eruption and crosses the occlusal plane at the M1-M2 embrasure (a).

• The upper magnetic housing (b) is linked to a retraction screw (c).

100

• The magnetic unit (b + c) is positioned along the mid-palatal line.

• The screw housing is linked to the plate at the M1-M2 level (d).

101

• Two guiding bars (e), attached to the plate (lingually to the central incisors and laterally to the screw housing), restrains the magnetic unit from vertical deflection via guiding tubes (f).

102

.

18

Upper plate of a FOMA III in an

experimental animal.

103

The attractive mode neodymium magnets used in their

study produced a horizontal force of 98 gm and a

vertical force of 371 gm.

• The ratio of horizontal to vertical force vectors is dictated by inclination of magnetic interface in the sagittal plane.

• The more perpendicular the magnetic interface is to the occlusal plane (sin 90° = 1), the greater is the horizontal force vector.

104

The interaction between sutural and condylar

growth sites appeared biphasic, characterized by

an immediate and rapid excitation of the circum-

maxillary sutures followed by a delayed and slow

suppression of the condylar cartilage.

105

Maxilla:

1. The target area of the protractive force was found to be localized in the pterygomaxillary fissure.

2. Three dimensionally, the separation of the sutures at the PMF was found to diminish in infero-superior and latero-medial directions.

Mandible:

The fact that no pathologic change was found in the condylar cartilage encourages a long-term use of the FOMA III appliance, initiating treatment at an early skeletal age.

106

• A later radiographic and histologic study by

Vardimon, Graber et al (AJODO 1994), again on 9

Macaca fascicularis monkeys who were treated for

4 months with FOMA III revealed the following

data:

1. The growth pattern of the cranial base (saddle

angle) was not altered.

2. Midfacial protraction occured along a recumbent

hyperbolic curve with a horizontal maxillary

displacement and an anterosuperior premaxillary

rotation.

107

3. Cumulative protraction of the maxillary complex was initiated at the pterygomaxillary fissure with an additional contribution provided by other circummaxillary sutures (zygomaticomaxillary s., transverse s., premaxillary s.)

4. Inhibition of mandibular length was minimal, but a tendency toward a vertical condylar growth pattern was observed.

108

.

19

Root resorption

109

Determinants controlling iatrogenic

external root resorption and repair

during and after palatal expansion.- Vardimon, Graber, Voss, Lenke (AO, 1991)

• In this study, the mechanisms controlling external root resorption (ERR) and repair were studied on 8 Macaca fascicularis monkeys.

• The animals were treated with jackscrew, magnetic and sham palatal expansion screws. They were divided into short- and long-term groups.

110

• SEM morphometric analysis found major evidence of

ERR in the tooth-borne jackscrew appliance, in the

long-term group, in the maxillary premolars, on the

buccal and furcation root surfaces, on the mesio-

buccal root and in the apical zone.

• Correspondingly, the ERR mechanism is controlled

by impulse (F. Δt) and the critical barrier of the PDL

as primary determinants and by the environment

density as the secondary determinant.

111

• ERR is initially regulated by the force component

of the impulse and, with increased duration, by the

time component.

• The impairment/repair dynamics were found to be

dominated by 3 principles: ERR level of

irreversibility, delayed resorption response and

jiggling.

112

Results

1. Teeth

- Multirooted teeth were

substantially more

susceptible to ERR than

single rooted teeth

113

2. Surfaces

- The buccal root surface

and the furcation surface

showed distinguishable

ERR destruction

114

.

20

3. Single roots of multirooted teeth

- The mesiobuccal (MB) root always exhibited the highest ERR assault

followed by the distobuccal (DB) and the palatal (P) roots for the buccal

surface and the palatal and distobuccal roots for the palatal surface

115

4. Root zones

• The apical root zone was the most disturbed vertical root

region followed by the midroot and cervical root zones

116

5. Short-term vs. long-term

• An increase in the buccal ERR indices from the short-term

group to the long-term group was recorded for both

indirect appliances

• In contrast, the direct magnetic subjects showed a recovery

, suggesting that only low ERR impairments (cementum

defects) are repairable

117

Repair of orthodontically induced root

resorption by ultrasound in humans.

- El-Baily, El-Shamy & Graber (AJODO, 2004)

• This study evaluated the effect of low-intensity pulsed ultrasound (LIPUS) on the healing process of orthodontically induced tooth-root resorption in humans.

• 12 orthodontic patients who were seeking orthodontic treatment that necessitated extracting the first premolars before mechanotherapy participated in this study.

118

• For each patient, buccally activated springs were used to tip the maxillary first premolars buccally, with an initial force level of 50 g.

• A short period of LIPUS was applied to 1 side of each patient’s mouth, with the other side used as a control.

• After 4 weeks, the experimental premolars of all patients were extracted, and the premolars of 6 patients were studied by scanning electron microscopy (SEM); the premolars of the other 6 patients were studied histologically.

119

• The SEM study showed a statistically significant

decrease in the areas of resorption and the number of

resorption lacunae in the LIPUS-exposed premolars.

• Histologic examination showed healing of the

resorbed root surface by hypercementosis.

• The results of this study provide a non-invasive

method for reducing root resorption in humans.

120

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21

Repair process of external root resorption

subsequent to palatal expansion treatment.

- Vardimon, Graber & Pitaru (AJODO, 1993)

• The repair process of external root resorption (ERR) and the role of retention mechanics in enhancing ERR repair were studied on eight Macaca fascicularismonkeys that were divided equally into short- and long-term groups. 6 monkeys received palatal expansion appliances, and 2 received sham appliances.

121

• The short-term group received active treatment.

• The long-term group received additional retention (4

months) and relapse (2 months) treatment periods

with biweekly injections of individual vital dye per

phase, i.e., procion red H-8B and violet H-3R (80

mg/kg B.W.), respectively.

122


• The short-term group demonstrated penetrated resorption with pulp exposure at sites with initial deficiency of the protecting odontoblastic layer (apical zone, nutrition canal).

• The long-term group showed two forms of ERR repair:

(1) Nonfunctional retarded repair cementum, comprised of overlapped incremental lines and deprived of extrinsic fibers, was delineated in severe pulp exposure.

123

The pulp/dentin complex showed intense incorporation

of procion dye in the dentinal tubuli, conceivably

related to a defense response in the form of sclerotic

dentin.

(2) Functional rapid repair cementum, comprised of

discriminated incremental lines mainly of mixed

cellular cementum, with a consistent pattern of five

sequential phases: the lag phase (14 to 28 days), the

incipient phase (14 days), the peak phase (14 to 28

days), the steady phase (42 to 56 days) and the

retreating phase (70 days).

124

Sharpey's fibers at functional ERR sites were scarce, never emerging from the dentinocemental junction, and not developing into principal fibers.

The pulp/dentin complex showed an increase in pulp stones but no formation of tertiary dentin. The apical area responded by hypercementosis in the form of apical occlusion and a displaced pulp canal.

125

Other contributions

126

.

22

A cephalometric analysis of the

developmental pattern and facial

morphology in cleft palate.

- T.M. Graber (AO, 1949)

• 33 cleft palate patients (22 males, 11 females) were studied cephalometrically.

It was found that:

• The maxilla in CLP cases is deficient in antero-posterior, lateral, as well as vertical growth.

127

• There is an abnormally large contribution of upper face height to total face height when the teeth are in occlusion, due to vertical maxillary deficiency.

• There is markedly larger inter-maxillary clearance or freeway space in CP individuals when compared to normals. This suggests that while there is a bony insufficiency, the general musculature attempts to maintain a normal developmental pattern and relation of parts.

• Mandibular growth on the whole appears normal. Values taken with the teeth in occlusion indicate overclosure.

128

• There is excessive lingual axial inclination of the lower incisors to the mandibular plane.

• The maxillary 1st molar tends towards a distal position with reference to craniometric measurements outside the maxilla.

• Surgical correction can limit the growth potential of the maxillary denture.

• The clinical results of orthodontic treatment, while improving the tooth to tooth relationship in some cases, does not necessarily stimulate basal bone development. Therapeutic results are often unstable and have to be maintained indefinitely.

129

A functional study of the palatal and

pharyngeal structures.

- Graber, Bzoch, Aoba (AO, 1959)

• Using high speed roentgenographic equipment, the

soft tissue morphology of normal subjects was

studied during the instant of production of various

consonant sounds (p, b, f, w, m).

• Biometric analysis was made.

130

Following conclusions were drawn:

• Soft palate increases significantly in length from the

rest to functional position.

• The greatest extent of the upward and backward

movement of the palate takes place at the midpoint of

the posterior superior surface of the palate

(mean=16mm.).

• The velopharyngeal valve is consistently closed for

all the consonant sounds during normal speech

production.

131

• Slight anterior movement of the posterior

pharyngeal wall is seen in 50% of normal cases.

The authors concluded that the orthodontist, as well

as the prosthodontist and speech therapist, should

profit from a better appreciation of normal speech

physiology.

132

.

23

Postmortems in post-treatment

adjustment.


• In this classic article, Dr. Graber stresses the need for a

longer period of orthodontic management in many cases.

• He says that, with the orthodontists’ dependence on

pattern and growth and development, it is essential to

keep patients under observation longer and observe the

status of the stomatognathic system in its biologic

continuum.

133

Orthosurgical teamwork.

- Olson, Mincey & Graber (JADA, 1975)

• Using the examples of 6 patients with different malocclusions, the authors have reported on the combined orthodontic-surgical approach towards treatment.

• They state that surgery and orthodontics can separately, but surely better in combination, correct a variety of developmental jaw deformities, whether they are hereditory or traumatic in origin.

134

• The patient is best served by this teamwork, not only during the actual mechanical and operative phases, but also during the initial diagnostic and treatment planning phases, which are every bit as important.

• Proper diagnosis requires a thorough knowledge of growth and development, of cephalometric analysis, of occlusion and proper jaw relationships, and of surgical and orthodontic techniques to correct these deformities.

• Here, the orthodontist, because of his training and experience in these aspects, can be invaluable to the surgeon.

135 136

• A series of orthognathic cases illustrates the

potential service that is available to the young and

the adult patient.

• Patients have problems that are not within the

therapeutic possibilities of the orthodontist alone.

• Surgical procedures in combination with

orthodontics and prosthetics, have now achieved a

level of sophistication that permits correction of

almost any type of the facial deformity quickly,

with minimum pain, and relative few unfavorable

sequelae

137

Post-pharyngeal lymphoid tissue in

Angle Class I and Class II malocclusions.

- Sosa, Graber & Muller (AJO, 1982)

• Studied the relationship between the adenoid tissue and type of malocclusion.

• Xeroradiographic lateral cephalograms were made of 80 Class I and 64 Class II/1 malocclusions.

• The epipharyngeal lymphoid tissue, nasopharyngeal airway, nasopharynx and certain cephalometric landmarks were measured.

138

.

24


• There is no clear-cut relationship between either Class I or Class II/1 malocclusions and the total nasopharyngeal area.

• Sexual dimorphism was seen:

- Class I males: widening of antero-posterior dimension of nasopharynx is associated with anterior rotation of the mandible, longer maxillas, larger SNB angles, opening of cranial base angle, and increased distance from sella to PNS. Thus, these patients have more anteriorly positioned maxilla and mandible.

139

- No association was present at all for Class II/1

males.

- Class II/1 females: larger nasopharyngeal area is

associated with longer maxillae and smaller

palatal plane angles, and anterior rotation of

mandible.

140

Orthodontics and temporomandibular

disorder: A meta-analysis.

- Kim, Graber & Viana (AJODO, 2002)

• In this meta-analysis, the relationship between traditional orthodontic treatment, including the specific type of appliance used and whether extractions were performed, and the prevalence of temporomandibular disorders (TMD) was investigated.

• Their data indicated that traditional orthodontic treatment did not increase the prevalence of TMD.

141

CONCLUSION

142

Dr. Thomas M. Graber was certainly a pioneer

amongst men. His complete devotion and love for the

specialty of orthodontics is reflected in his extensive

works on a myriad of topics, spanning over a period

of nearly six decades.

143

• As Dr. Graber’s family friend and colleague Dr. Jim McNamara noted, “Tom’s energy and enthusiasm for our profession make him a wonderful role model for future generations of orthodontists.”

• The passing of Dr. Thomas M. Graber marks the end of an era in orthodontics.

144

http://web.auth.gr/dent/ortho/news/imgs/Image47.jpg

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25

EVEN WHEN STARS DIE, THEIR GLOW

PERSISTS …

145 146

147

REFERENCES

1. Alexander D. Vardimon AD, Graber TM, Drescher D, Bourauel C. Rare earth magnets and impaction. Am J Orthod Dentofac Orthop. 1991; 100: 494-512.

2. Ahmad KA, Drummond JL, Graber TM, BeGole E. Magnetic strength and corrosion of rare earth magnets. Am J Orthod Dentofacial Orthop 2006;130:275 e11-15.

3. Vardimon AD, Graber TM, Voss LR, Verrusio E. Magnetic versus mechanical expansion with different force thresholds and points of application. Am J Orthod Dentofacial Orthop 1987;92: 455-66.

4. Vardimon AD, Graber TM, Drescher D, Bourauel C. Rare earth magnets and impaction. Am J Orthod Dentofacial Orthop 1991; 100:494-512.

5. Graber TM. Ch. 4 - Current status of magnetic forces in orthodontics (Biomechanics in clinical orthodontics) W.B. Saunders Co. 1997.

6. Vardimon AD, Stutzmann JJ, Graber TM, Voss LR, Petrovic AG. Functional orthopedic magnetic appliance (FOMA) II-Modus operandi. Am J Orthod Dentofac Orthop 1989;95:371-87.

148

7. Vardimon AD, Graber TM, Voss LR, Muller TP. Functional orthopedic magnetic appliance (FOMA) III-Modus operandi. Am J Orthod Dentofac Orthop.1990; 97(2): 135-48.

8. Vardimon AD, Graber TM, Stutzman J, Voss L, Petrovic AG. Reaction of the pterygomaxillary fissure and the condylar cartilage to intermaxillary Class III magnetic mechanics. Am J Orthod Dentofac Orthop 1994;105:401-13.

9. Graber TM. Notes and comments. Dental Abstracts 1976; 21(12): 712-13.

10. Vardimon AD, Graber TM, Voss LR. Stability of magnetic vs. mechanical palatal expansion. Eur. J Orthod. 1989; 11(2): 107-15.

11. Graber TM. Normal occlusion. Dent Clin North Am. 1968; Jul.: 273-90.

12. Owen D, Graber TM. The developing occlusion – orthodontic considerations for the handicapped. Dent Clin North Am. 1974; 18(3): 711-21.

13. Olson RE, Mincey DL, Graber TM. Orthosurgical teamwork. J Am Dent Assoc. 1975; 90: 998-1011.

14. Graber TM. The role of upper second molar extraction in orthodontic treatment.Am J Orthod. 1955; 41: 354-361.

15. Graber TM. Maxillary second molar extraction in Class II malocclusion. Am J Orthod. 1969; 56(4): 331-53.

149

16. Graber TM. Extraoral force – facts and fallacies. Am J Orthod. 1955;

41: 490-505.

17. Graber TM. Postmortems in post-treatment adjustment. Am J Orthod.

1966; 52(5): 331-52.

18. Graber TM. Serial extraction: A continuous diagnostic and decisional

process. Am J Orthod. 1971; 60(6): 541-75.

19. Graber TM, Chung DDB, Aoba JT. Dentofacial orthopedics vs. orthodontics. J Am Dent Assoc. 1967; 75: 1145-66.

20. Mills CM, Holman RG, Graber TM. Heavy intermittent cervical traction in Class II treatment: A longitudinal cephalometric assessment. Am J Orthod. 1978; 74(4): 361-79.

21. Graber TM. Pride in orthodontics. Am J Orthod Dentofac Orthop. 2000 May;117(5):618-20.

22. El-Bialy T, El-Shamy I, Graber TM. Growth modification of the rabbit mandible using therapeutic ultrasound: is it possible to enhance functional appliance results? Angle Orthod. 2003; 73:631–639.

23. Graber TM, Bzoch KR, Aoba T. A functional study of the palatal and pharyngeal structures. Angle Orthod. 1959; 29(1): 30-40.

150

• 24. Graber TM. A cephalometric analysis of the developmental pattern and facial morphology in cleft palate. Angle Orthod. 1949; 19(2): 91-100.

25. Kim JH, Viana MAG, Graber TM, Omerza FF, BeGole EA. The effectiveness of protraction face mask therapy: A meta-analysis. Am J Orthod Dentofac Orthop 1999;115:675-85.

26. Deguchi T, Kuroda T, Minoshima Y, Graber TM. Craniofacial features of patients with Class III abnormalities: Growth-related changes and effects of short-term and long-term chincup therapy. Am J Orthod Dentofacial Orthop 2002;121:84-92

27. Deguchi T, Kuroda T, Hunt NP, Graber TM. Long-term application of

chincup force alters the morphology of the dolichofacial Class III

mandible. Am J Orthod Dentofacial Orthop 1999;116:610-5.

28. Kim MR, Graber TM, Viana MA. Orthodontics and temporomandibular

disorder: A meta-analysis. Am J Orthod Dentofacial Orthop

2002;121:438–46.

.

26

151

29. Vardimon AD, Graber TM, Voss LR, Lenke J. Determinants controlling iatrogenic

external root resorption and repair during and after palatal expansion.

Angle Orthod. 1991; 61(2): 113-22.

30. El-Bialy T, El-Shamy I, Graber TM. Repair of orthodontically induced root

resorption by ultrasound in humans. Am J Orthod Dentofacial Orthop

2004;126:186-93.

31. Vardimon AD, Graber TM, Pitaru S. Repair process of external root resorption subsequent to palatal expansion treatment. Am J Orthod Dentofac Orthop 1993;103:120-30.

32. Graber TM. The “three M’s”: Muscles, malformation and malocclusion. Am J Orthod. 1963; 49(6): 418-50.

152

• Graber TM. Occlusal splints (Letter to Editor). J Am Dent Assoc. 1980; 100: 171a.

• Graber TM. Books for the dentist. J Am Dent Assoc. 1974; 88: 1322-42.

• Graber TM. On thumbsucking (Letter to Editor). J Am Dent Assoc. 1970; 81: 805.

• Graber TM. An orthodontic perspective after 75 years. Am J Orthod. 1976; 69(5): 572-83.

• Graber TM. Auxiliary personnel – pillars of practice procedure. Am J Orthod. 1965; 51(6): 412-36.

.

1

DIGITAL IMAGING INORTHODONTICS


.

.

DR.ASHWIN GEORGE, M.D.S, Dip N.B,

RAGAS DENTAL COLLEGE,

CHENNAI

Normal X-ray Digital X-ray

Silver halide grains in x-ray

films perceived as different

shades of gray by the

human eye due to varying

densities

Silver halide grains are

replaced by small light-

sensitive electronic

sensors which produce an

electric signal depending

on the voltage recorded

by the sensor

(this analog electronic signal is converted into a digital signal by a capture

card [frame grabber] and represented by shades of gray ranging from

values 0 to 255)

PRINCIPLES OF DIGITAL IMAGING

CONVENTIONAL(ANALOG)

DIGITAL

CEPHALOGRAM

CONVENTIONAL DIGITAL

OPG INDIRECT DIRECT

a) Scanner

b) Phosphor plate

a) Charged Coupled Device (CCD)

b) Complementary metal oxide

semiconductor (CMOS)

METHODS OF IMAGE ACQUISITION

.

2

SCINTILLATOR

- converts x-radiation to photons

(light)

FIBRE OPTIC LAYER

- conducts photons to CCD

- stops x-radiation

CCD

- converts photons to electrons

(charge)

ELECTRONIC CIRCUIT

- amplifies the signal

- converts the analog signal to digital

DIGITAL IMAGING THROUGH CCD

✓ Dose reduction

✓ Image prediction

✓ Reduced overall time

✓ Measurements [Digital Calipers]

✓ 3-D Reconstruction

✓ Contrast enhancement

✓ Storage

✓ Teleradiology

✓ Environmentally Friendly

DISADVANTAGES

► Cost

► Reduced Sensor Dimension

► Cross-Infection Control

ADVANTAGES

DIGITAL IMAGING

There are five basic techniques for producing

digital models:

1) Stereophotogrammetry

2) Laser scanning

3) Destructive imaging

4) White light scanning

5) CT scanningStereo pairs of images are captured from two converging

cameras and three dimensional reconstruction occurs in

only those areas that are visible to both cameras

A new Laser scan based approach callede-models was developed to improve the accuracy and efficiency of orthodontic diagnosis, treatment planning, and bracket placement.

➢ Pointing and clicking with the mouse can easily measure Bolton

discrepancies and arch length tooth size discrepancies.

USES

Using the e-model software,

the clinician can move, rotate,

or zoom in on the model and

make measurements in any

plane or orientation.

DIGITAL MODELS

The orthodontist sends the impression and bite registration to

GeoDigm/OrthoCAD. E-models are constructed through proprietary laser

scanning process

.

3

One of the latest

innovations in 3D digital treatment planning called E-plan, which simulates multiple treatment options.

In addition, the software

has an articulation

feature that enables the

clinician to identify

centric occlusion and

point of initial contact. ONE CAN CHOOSE PREFERRED BRACKETS, WIRES

FROM THE AVAILABLE STRAIGHT WIRE SYSTEM

INCISORS AND MOLARS ARE REPOSITIONED

AS REQUIRED

VIRTUAL SET UP

MAXILLARY AND MANDIBULAR

TEETH CAN BE SLID

INTO THEIR PROPER POSITIONS

ALSO ONE CAN CORRECT THE

BRACKET POSITIONS FOR

BETTER INTER AND INTRAARCH

RELATIONSHIPS EXTRACTIONS WITH RESULTANT

SPACE CAN BE MANIPULATED

MANUALLY OR

AUTOMATICALLY

BRACKET PLACEMENT USING

OrthoCAD SOFTWARE

(Wand with miniature video

camera, LED and tip)

Viewing the teeth on monitor

screen with the wand and

temporarily setting the

bracket on the tooth

Initial bracket placement

Adjusting to the correct position Final correct bracket placement

ORTHOCAD BRACKET PLACEMENT

.

4

ADVANTAGES OF ORTHOCAD BRACKET PLACEMENT

1) Consistent, accurate bracket placement

2) Expresses the full potential of the appliance

3) Yields better treatment outcome

4) Shorter treatment time

5) Allows to compare multiple treatment scenarios"virtual bracket placement"

and selection of the

arch wire sequence and progression

Wire bending robot

Producing arch wires

OraScanner -a light-based

imaging device Diagnosis and

treatment planning

Obtaining a

Virtual model

SURE SMILE TECHNOLOGY

PRETREATMENT RADIOGRAPHS

AND IMPRESSIONS SENT TO

INVISALIGN LABORATORIES

IMPRESSIONS ARE CONVERTED

TO PLASTER MODELS AND

CHECKED FOR QUALITY

INVISALIGNERS

MODELS ARE COATED WITH

PROTECTIVE

SHELLS AND ENCASED IN A MIXTURE

OF RESIN AND HARDENER

AFTER CHEMICAL CURING, BLOCKS OF

HARDENED RESIN WITH PLASTER

MODELS ARE OBTAINED

EACH TRAY IS PLACED IN A

DESTRUCTIVE SCANNING

MACHINE

STEREO LITHOGRAPHIC

MACHINE

INVISALIGN CUTTERTRIMMING

OF INVISALIGN

DESTRUCTIVE

SCANNING

GENERATED 3-D

MODEL

Use of INVISALIGN appliance

in the treatment of moderate crowding

.

5

ADVANTAGES OF INVISALIGN➢ Improved esthetics

➢ Ability to remove the appliance

DISADVANTAGES➢ All permanent teeth should be fully erupted

➢ It does not allow for continued eruption of teeth or dental arch

changes during growth

➢ Major restorative work should be performed before the

commencement of treatment

➢ Treatment plan cannot be changed once the appliance series has

begun

➢ Only crown position is displayed in the computer

➢ Inability to integrate hard and soft tissues

➢ It is expensive

COMPUTERIZED SURGICAL

PREDICTION IMAGING

“A useful indicator of

potential treatment

outcomes with different

techniques & the

orthodontist’s ability to

achieve them”

The software superimposes the patients lateral

photograph onto the lateral cephalogram to a proportionate

scale.

When the computerized predictions are made, the

patient can now have an idea of his / her probable facial

appearance after the planned treatment.

Pre treatment Computer prediction

VIDEO IMAGING & PREDICTION ADVANTAGES

→ Stored in computer memory

and recalled easily

→ Several alternative

predictions possible much more

rapidly

→ Enhancement of the doctor-

patient communication

→ Promotes greater

understanding and satisfaction

with the outcome, as long as the

patient recognizes that the

DISADVANTAGES

→ Software design

dependent and technique

sensitive

→ Expensive

→ Poor soft tissue

definition in particular

areas

Prediction is only a goal and not a guarantee

Pt –A Age: 24/M

Diagnosis: Skeletal Class III

Hypoplastic Maxilla and Prognathic Mandible

Pre-Treatment Profile

.

6

Pre-Surgical after Dentoalveolar Decompensation

Manual Prediction

(Cut and Paste Method) Maxillary Advancement – 4 mm

Mandibular setback - 4mm

Soft tissue changes associated with

treatment

MAXILLARY ADVANCEMENT

Nose : Slight elevation of tip

Base of upper Lip : protracted by 1 mm

Upper Lip : protracted by 2.8 mm

and shortens by 1.5 mm

MANDIBULAR SETBACK:

Chin retracted by 4 mm

Lower Lip by 2.8 mm

Pre-Surgical

Manual Superimposition

Comparison between Manual and Computerized Prediction

Pre Surgical

Computer Superimposition

Computer SuperimpositionManual Superimposition

•1•2

•3

•4

•5

•1•2•3

•4

•5

C:\ss.pat

Pre- Surgical Computer Prediction Actual Post

Treatment

DENTOFACIAL PLANNER

PLUSDFP WINDOWS 98 Platform

DOLPHIN IMAGING DI WINDOWS 98,2000,XP

Platform

QUICK CEPH SYSTEM QC MACINTOSH Platform

VISTA DENT GAC WINDOWS XP Pro

PRACTICE WORKS OTP WINDOWS

COMPARISION OF CURRENT PREDICTION IMAGING

PROGRAMS

5 programs with the largest market share was chosen

J.Dempsey Smith and Paul M. Thomas, AJO May 2004

Case No:1 Short Face Patient (Actual and Predicted Outcomes)

Surgery Done – Mandibular Advancement

.

7

Case No:2 Long Face Patient (Actual and Predicted Outcomes)

Surgery done - Maxillary impaction and mandibular set back RESULTS

Dentofacial planner ( DFP) was the clear favorite

in both observer group [short face and long face]

Dolphin imaging (DI) and Quick ceph (QC) were the

next favorites with DI handling long face subjects

better and QC more competent with the short face

group

For GAC and OTP- both consistently rated poor

regardless of facial type

J.Dempsey Smith and Paul M. Thomas, AJO May 2004

PREDICTION IMAGING PROGRAMS

1) Prescription Planner/Portrait software system (PP)

2) Orthognathic Treatment Planner (OTP)

3) Dentofacial planner (DFP)

4) Quick Ceph (QC)

5) Dolphin Imaging (DI)

6) Vistadent (GAC)

7) Orthognathic Prediction Analysis (OPAL)

8) Nemoceph

9) Dr.Ceph

THREE DIMENSIONAL IMAGE CAPTURING SYSTEM

FOR FACIAL PROFILES (C3D software)

The analog picture of a stereopair of video cameras

are converted into a digital mode with a standard frame

grabber (A device for converting a television picture to a digital

array of numbers). The software does the entire capture in 50

milliseconds

3D imaging of the face enables the orthodontist to evaluate the face from any

direction. Here, a skeletal Class III case is displayed in different views

.

8

Applications of CT and MRI

in orthodontics

Equipment-

Gantry – houses the patient. Patient is surrounded by magnetic coils

Magnetic Resonance Imaging

Magnetic fields are caused by rotating electric charges.

Essentially it is the- imaging of the water in the tissue.

Images are generated from protons of the hydrogen nuclei of water.

Indications of MRI✓ MRI imaging of TMJ

✓ Cleft lip and palate

✓ Tonsillitis and adenoiditis, optimum assessment of upper airway

✓ Cysts, infections and tumors

Contraindications

Patients with cardiac pacemakers.

Patients with cerebral metallic aneurysm clips.- Slight

movement of the clip could produce bleeding

Stainless steel and other metals produce artifacts ; obliterate

image details of the facial area.

✓ Determine the structural relationship between the Condyle,

Articular disc and Glenoid fossa

✓ Detect inflammation, hematoma and effusion for the soft tissue

components

Importance of MRI imaging of the TMJ

Short comings Inability to identify ligament tears or perforations

Dynamics of tissue joint not possible

Cannot be used in patients suffering from

claustrophobia

In a single scan, the x-ray source and a reciprocating x-ray sensor rotate around the patient's head and acquires 360 pictures in 17 seconds of exposure time.

The entire maxillofacial volume(13 cm-diameter field of view) isenlarged, and the patientreceives an absorbed dosesimilar to a peri apical survey ofthe dentition.

NewTom QR 9000 CT Scanner

.

9

The 360 acquired images

undergo a primary

reconstruction to

mathematically replicate the

patient's anatomy into a single

3D volume.

Applications

Location of impacted tooth

relative to roots of adjacent

teeth

ADVANTAGES OF DIGITAL IMAGING IN

DIAGNOSIS AND MANAGEMENT OF

IMPACTED TEETH

Conventional radiography is by far the standard method for

viewing impacted canine but it has following short comings,

➢ Difficulty in assessing position (buccal/palatal)

➢ Difficulty in assessing level and extent of resorption of

adjacent teeth

IO - Xray OPG Occlusal View

IMPACTED MAXILLARY CANINE

COMPUTERIZED TOMOGRAPHYPERIAPICAL

RADIOGRAPH

Tomogram of the head

showing the cutting

direction of the beam

through the anterior

part of the maxilla

perpendicular to the

long axis of the

maxillary incisors.

TECHNIQUE OF ACQUIRING CT

Slice thickness of 2mm are normally taken for assessing

the canine position

BUCCALY POSITIONED IMPACTED MAXILLARY CANINE

MAXILLARY CANINE PALATALLY POSITIONED IMPACTED

.

10

Periapical radiograph – not

showing extent of resorption

ASSESSMENT OF ROOT RESORPTION USING CT SCAN

CT scan of the same region

showing the extent of

resorption of lateral incisors

palatally

Lateral incisor after extraction;

Palatal view showing the total extent of

the resorption

DIGITAL IMAGING AND

SMILE ANALYSIS

The flaw in traditional smile

analysis has been based on the

tracing of the lateral

cephalogram, which is taken in

repose (at rest)

Due to this limitation incisor

position has been determined

from a static rather than a

dynamic record.

The orthodontist as an architect of the smile

needs to identify and quantify the elements of the smile that

needs

▪ correction,

▪ enhancement

▪ and improvement

as well as identifying the positive elements of the smile that

must be saved.

Smile Analysis with the SMILE MESH PROGRAMME

This methodology was first used manually by Hulsey and later

modified and computerized by Ackerman

The frame that best represents the patient’s social smile is selected

and saved as a JPEG file.

The smile image is then opened in a program called SmileMesh,

which measures 15 attributes of the smile

Before expansion(more of dark space on smile)

After expansion(reduced dark space after treatment)

Smile mesh analysis after RAPID MAXILLARY EXPANSION

BEFORE RME AFTER RME

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RAPID PROTOTYPING

(RPT)

It is a group of manufacturing processes that enable the direct physical realization of 3D computer models. This technology converts the 3D computer data provided by a dedicated file (STL file) format directly to a physical model, layer by layer with a high degree of accuracy.

STEREOLITHOGRAPHY (SLA)

Stereolithography (SLA) is the most widely distributed process of RPT

RAPID PROTOTYPING (RPT)

APPLICATIONS :

1. Custom made brackets for individual patient anatomy of crowns.[lingual brackets]

2.Various mock surgery procedures can be practiced on the 3D Biomodels, allowing optimal input into the management decision, pre-operative planning and choice of surgical technique.

LIMITATIONS• Cost

• Radiation exposure of the patient (CT scanning)

With wider use and further technological development, these drawbacks will be minimized. The 3D SLA biomodels may in future become an adjunct to diagnosis, and treatment planning in Orthognathic surgery.

BRACKET MANUFACTURING BY RPT

Using state-of-the-art CAD/CAM technology, the two

normally separate processes of bracket production and

bracket positioning are fused into one unit.

• The brackets manufactured for lingual orthodontics is based

on digital registration of the malocclusion.

• The brackets are then individually designed and optimally

positioned in the computer using Rapid prototyping.

A silicone impression is used for preparation of a malocclusion cast and a therapeutic set-up.

• The set-up is digitized with a high-resolution 3D scanner.

• The individual brackets are generated on this surface at a computer workstation.

• First, appropriate pads are designed on the lingual surfaces of the teeth.

• The next step is optimal positioning of the bracket bodies

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• The brackets are then constructed on a high-precision prototyping machine from a wax-like material. These wax blanks are embedded and cast in gold.

• As the brackets are made of an alloy with a high gold content, they offer an interesting alternative especially for patients who are allergic to nickel

• In parallel with this design process, the archwire definition data are generated.

ADVANTAGES OF BRACKETS

FABRICATED BY RPT :

1. The exact correspondence of the bracket

and tooth interfaces results in a positive

lock when the bracket is pressed onto the

tooth, making incorrect positioning

unlikely.

2. Reduced bracket loss rate due to the shorter

lever arm in the event of mastication-

induced shearing.

3. Exact finishing due to better expression of

tip & torque.

4. Enhanced wearing comfort due to optimum

size and shape of the bracket.

Normal Lingual Brackets

Bracket manufactured by

RPT

ADVANTAGES OF

DIGITAL IMAGING IN

DIAGNOSIS OF

SLEEP APNEA

Disadvantages Of Lateral Cephalograms:

1.Two dimensional data only of evaluating a complex

three dimensional anatomical structure

2.Difficulty in taking cephs in supine position

3.Static investigation is only possible

CT Advantages:

1.Volumetric & 3-dimensional

reconstructions of the airway

and other peripharyngeal

structures are possible.

2.The study can be performed

in the supine position.

3. High spatial resolution

Volumetric reconstruction and

3-dimensional imaging is only

possible with the newer Helical

CT scanner.

MRI Advantages:

1.Non invasive with high contrast resolution

2. Allows scanning in multiple planes, allowing the whole

airway to be visualized at one time.

3.Allows examination of the entire pharynx in a short time

4.Drawbacks of radiation exposure minimized.

http://ajrccm.atsjournals.org/cgi/content/full/158/4/1259/F2

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A single excitation is used to obtain mid-sagittal and axial

projections during transnasal shallow respiration at rest,

simulation of snoring.

Uvula & narrowed airwayNormal upper airway

Awake position Asleep state

THE PAST IS A SOURCE OF KNOWLEDGEAND FUTURE IS A SOURCE OF HOPE.

TO LOVE THE PAST IMPLIES

A FAITH IN THE FUTURE.

AcknowledgementThe Management & Principal

Ragas Dental College & Hospital

Our team

Dr. N.R.Krishnaswamy

DR. LODD MAHENDRA

DR. VENKATESWARAN

DR. SAPNA

DR. AJIT

DR. BALAJI

&

Post Graduate students

Mr. Ashok(Graphic designer)

Thank you





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canine impactions

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