a clinical guide to orthodontics

BRITISH DENTAL JOURNAL VOLUME 195 NO. 8 OCTOBER 25 2003 433

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Orthodontics. Part 1: Who needs orthodontics?D. Roberts-Harry1 and J. Sandy2

There are various reasons for offering patients orthodontic treatment. Some of these includeimproved aesthetics, occlusal function and the long-term dental health.

1*Consultant Orthodontist, OrthodonticDepartment, Leeds Dental Institute,Clarendon Way, Leeds LS2 9LU; 2Professorin Orthodontics, Division of Child DentalHealth, University of Bristol Dental School,Lower Maudlin Street, Bristol BS1 2LY*Correspondence to: D. Roberts-HarryE-mail: [email protected]

Refereed Paperdoi:10.1038/sj.bdj.4810592' British Dental Journal 2003; 195:433437

This series of articles is designed to aid in the orthodontic evaluation of patients Not every malocclusion needs orthodontic treatment Not every patient is suitable for treatment Understanding the treatment benefit for the patient is important GDPs have an important role to play in assessing the need for orthodontic treatment

I N B R I E F

Orthodontics comes from the Greek wordsorthos meaning normal, correct, or straightand dontos meaning teeth. Orthodontics isconcerned with correcting or improving theposition of teeth and correcting any malocclu-sion. What then do we mean by occlusion andmalocclusion? Surprisingly the answer is notstraightforward. There have been variousattempts to describe occlusion using terms suchas ideal, anatomic (based on tooth morpholo-gy), average, aesthetic, adequate, normallyfunctioning and occlusion unlikely to impairdental health.

With these different definitions of what con-stitutes malocclusion, there is, not surprisingly adegree of confusion as to what should be treatedand what should not. Although some tooth posi-tions can produce tooth and soft tissue trauma, itis important to remember that malocclusion isnot a disease but simply a variation in the nor-mal position of teeth. Essentially, there are threeprincipal reasons for carrying out orthodontictreatment:

1. To improve dento facial appearance2. To correct the occlusal function of the teeth

1

ORTHODONTICS

1. Who needs orthodontics?

2. Patient assessment andexamination I

3. Patient assessment andexamination II

4. Treatment planning5. Appliance choices6. Risks in orthodontic

treatment7. Fact and fantasy in

orthodontics8. Extractions in

orthodontics9. Anchorage control and

distal movement10. Impacted teeth11. Orthodontic tooth

movement12. Combined orthodontic

treatment

Fig. 1a A child with a Class IIdivision 1 malocclusion andvery poor aesthetic appearance

Fig. 1b The same child asin Fig. 1a

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mTypewriter02-Patient assessment and examination ImTypewriter03-Patient assessment and examination IImTypewriter04-Treatment planningmTypewriter05-Appliance choicesmTypewriter06-Risks in orthodontic treatmentmTypewriter07-Fact and fantasy in orthodonticsmTypewriter08-Extractions in orthodonticsmTypewriter09-Anchorage control and distal movementmTypewriter10-Impacted teethmTypewriter11-Orthodontic tooth movementmTypewriter12-Combined orthodontic treatment

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434 BRITISH DENTAL JOURNAL VOLUME 195 NO. 8 OCTOBER 25 2003

3. To eliminate occlusion that could damage thelong-term health of the teeth and periodontium

DENTO FACIAL APPEARANCEImproving the appearance of the teeth is withoutquestion the main reason why most orthodontictreatment is undertaken. Although it might betempting to dismiss this as a trivial need, there islittle doubt that a poor dental appearance canhave a profound psychosocial effect on children.Figure 1 illustrates such a case with a child whohas a substantial aesthetic need for treatment.The case is shown before (Fig. 1a, b) and after(Fig 2a, b) orthodontic treatment. Few wouldquestion that there has been an improvement inboth the dental and facial appearance of thischild. Indeed, orthodontic treatment can have abeneficial psychosocial effect. For exampleShaw et al.1 found that children were teasedmore about their teeth than anything else, suchas the clothes they wear or their weight andheight (Table 1).

OCCLUSAL FUNCTIONTeeth, which do not occlude properly, can makeeating difficult and may predispose to temporo-mandibular joint (TMJ) dysfunction. However,the association with TMJ dysfunction and mal-occlusion is a controversial subject and will bediscussed in more detail in a later section. Indi-viduals who have poor occlusion, such as shownin Figure 3, may find it difficult and embarrass-ing to eat because they cannot bite through foodusing their incisors. They can only chew foodusing their posterior teeth.

DENTAL HEALTH Surprisingly there is no strong associationbetween dental irregularity and dental caries orperiodontal disease. It seems that dietary factorsare much more important than the alignment ofthe teeth in the aetiology of caries. Althoughstraight teeth may be easier to clean thancrooked ones, patient motivation and dental

Table 1 Features children most dislike or are teasedabout (Shaw et al.1)

Feature Disliked appearance or teased (%)

Teeth 60.7Clothes 53.8Ears 51.7Weight 41.5Brace 33.3Nose 29.3Height 25.3

Fig. 2a Same child as in Fig. 1 after orthodontictreatment

Fig. 2b Occlusion of the samepatient as in Fig. 2a, there hasbeen a significantimprovement in the buccalsegment relation and overjetcompared with the initialpresentation in Fig. 1b

Fig. 3 This patienthas a severeanterior open bitewith contact onlyon the molars

Fig. 4 Class IIDivision 1 with anincreased overjet.The anterior teethare at risk ofpotential traumawith an overjet of10 mm or greater

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hygiene seems to be the overriding factor in pre-venting gingivitis and periodontitis. That said,few of the studies that have investigated the linkbetween crowding and periodontal disease havebeen longitudinal, over a long term and includedolder adults. It would appear that aligned teethconfer no benefit to those who clean their teethwell because they can keep their teeth cleanregardless of any irregularity. Similarly, align-ment will not help bad brushers. If there is poortooth brushing, periodontal diseases will devel-op no matter how straight the teeth are. Howev-er, having straight teeth may help moderatebrushers, although there is no firm evidence tosupport or refute this statement. This is an areathat requires further study.

Some malocclusions may damage both theteeth and soft tissues if they are left untreated. It iswell known that the more prominent the upperincisors are the more prone they are to trauma2,3

(Table 2). When the overjet is 9 mm or more the risk of

damaging the upper incisors increases to over40%. Reducing a large overjet is not only bene-ficial from an aesthetic point of view but min-imises the risk of trauma and long-term com-plications to the dentition. Fig. 4 shows a childwith a large overjet and it is not difficult toimagine the likely dental trauma that wouldresult if he or she fell over.

Certain other occlusal relationships are alsoliable to cause long-term problems. Figure 5aand b show a case where there is an anteriorcross-bite with an associated mandibular dis-placement in a 60-year-old man. The constantattrition of the lower incisors against the upperwhen the patient bites together, have producedsome substantial wear. If allowed to continuethen the long-term prognosis for these teeth isextremely poor. In order to preserve the teeth,the patient accepted fixed appliance treatmentthat eliminated the cross bite and helped preventfurther wear Figure 5c and d.

Another example of problems caused by ananterior cross bite is shown in Figure 6. A trau-matic anterior occlusion produced a displacingforce on the lower incisors with apical migrationof the gingival attachment as a consequence. Pro-vided this situation is remedied early (Fig. 7) thesoft tissue damage stops and as the rest of thegingivae matures the situation often resolves

Table 2 Relation between size of overjet andprevalence of traumatised anterior teeth

Overjet (mm) Incidence %

5 229 24

> 9 44

Fig. 5a Anterior crossbite in a 60-year-old man occludingin the intercuspal position

Fig. 5b Shows the retruded contact position of the patient.To reach full intercuspation the mandible displaces forwardand this movement is probably associated with the wear onthe incisors

Fig. 5c The patient in fixed appliances in order to correct the displacement and the position of his upperanterior teeth

Fig. 5d After correction and space reorganisation the patientis wearing a prosthesis to replace the missing lateral incisors

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436 BRITISH DENTAL JOURNAL VOLUME 195 NO. 8 OCTOBER 25 2003

spontaneously and no long-term problems usu-ally develop.

Deep overbites can occasionally cause strip-ping of the soft tissues as shown in Figure 8aand b. This is a case where there is little aes-thetic need for treatment but because of thedeep overbite there is substantial damage tothe soft tissues. Clearly if this is allowed tocontinue there is a risk of early loss of thelower incisors that would produce a difficultrestorative problem.

WHO SHOULD BE TREATED?Dental irregularity alone is not an indication fortreatment. Most orthodontic treatment is carriedout for aesthetic reasons and the benefit an indi-

vidual will receive from this will depend on theseverity of the presenting malocclusion as well asthe patients own perception of the problem.Some individuals can have a marked degree ofdento-facial deformity and be unconcerned withtheir appearance. Although a practitioner maysuggest treatment for such an individual,patients should not be talked into treatment andmust be left to make the final decision them-selves. Mild malocclusions should be treated withcaution. Not only will the net improvement in theappearance of the teeth be small, but also asnearly all teeth move to some degree after ortho-dontic treatment the risk of relapse in these casesis high. Whilst minor movements after the cor-rection of severe malocclusions will still producea substantial net overall improvement for thepatients, the same is not true of minor problems.Many practitioners will have encountered theparent who can spot a 5-degree rotation of anupper lateral incisor from fifty metres and is con-vinced this will be the social death of their child.Regardless of how insistent the parent or child is,the practitioner should approach such problems

Fig. 6 A traumaticanterior occlusionis displacing thelower right centralincisor labially andthere is anassociateddehiscence

Fig. 7 The samepatient as in Fig. 6,but the cross bitehas been correctedwith a removableappliance andthere has been an improvement in the gingivalcondition

Fig. 8a This malocclusion has an extremely deep bite whichcan be associated with potential periodontal problems

Fig. 8b The same patient as in Fig. 8a, but not inocclusion. The deep bite has resulted in labial strippingof the periodontium on the lower right central incisor

Table 3 Index of Treatment Need

Dental health component Treatment need

1 No need2 Little need3 Moderate need4 Great need5 Very great need

Aesthetic component Treatment need

12 Little need3456 Moderate need789 Great need

10

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with care and only carry out the treatment if it is inthe best interests of the patient. It is essential thatthe patient and parent are fully aware of the limi-tations of treatment and that long term, ie perma-nent retention is currently the only way to ensurelong-term alignment of the teeth.

In order to assess the need for orthodontictreatment, various indices have been developed.The one used most commonly in the United King-dom is the Index of Orthodontic Treatment Need(IOTN).4 This index attempts to rank malocclu-sion, in order, from worst to best. It comprises twoparts, an aesthetic component and a dental healthcomponent (Table 3). The aesthetic componentconsists of a series of ten photographs rangingfrom most to least attractive. The idea is to matchthe patients malocclusion as closely as possiblewith one of the photographs. It is unlikely that aperfect match will be found but the practitionershould use his or her best guess to match to thenearest equivalent photograph. The dental healthcomponent consists of a series of occlusal traitsthat could affect the long-term dental health ofthe teeth. Various features are graded from 15(least severe worst). The worst feature of thepresenting malocclusion is matched to the list andgiven the appropriate score.

Many hospital orthodontic services will notaccept patients in categories 13 of the dentalhealth component or grade 6 or less of the aes-thetic component of the IOTN unless they are suit-able for undergraduate teaching purposes.

Whilst the IOTN is a useful guide in prioritisingtreatment and determining treatment need it

takes no account of the degree of treatment diffi-culty. For example, class II division 2 malocclu-sions are notoriously difficult to treat yet theymight have a low IOTN. Figure 9 illustrates such acase. The IOTN of this patient is only 2 but it is adifficult case to manage and treatment requires a high level of expertise.

1. Shaw W C, Meek S C, Jones D S. Nicknames, teasing,harassment and the salience of dental features among schoolchildren. Br J Orthod 1980; 7: 75-80.

2. Office of Population Censuses and Surveys (1994). Childrensdental health in the United Kingdom 1993. London: HMSO0116916079.

3. Office of Population Censuses and Surveys (1985). Childrensdental health in the United Kingdom 1983. London: HMSO0116911360.

4. Brook P, Shaw W C. The development of an index oforthodontic treatment priority. Eur J Orthod 1989; 11: 309-320.

Fig. 9 The Index ofTreatment Needfor this patient is 2. Although thisis low, the level ofexpertise requiredto treat it is high

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BRITISH DENTAL JOURNAL VOLUME 195 NO. 9 NOVEMBER 8 2003 489

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Orthodontics. Part 2: Patient assessment andexamination ID. Roberts-Harry1 and J. Sandy2

The patient assessment forms the essential basis of orthodontic treatment. This is dividedinto an extra-oral and intra-oral examination. The extra-oral examination is carried out firstas this can fundamentally influence the treatment options. The skeletal pattern, soft tissueform and the presence or absence of habits must all be taken into account.



Careful patient assessment is the most important part of treatment The extra-oral examination is conducted first The skeletal relationship must be assessed three-dimensionally The teeth lie in a position of soft tissue balance Habits such as thumb sucking can induce a malocclusion There is no proven association between TMJ dysfunction and orthodontics

I N B R I E F

The most important part of orthodontic treat-ment is the patient assessment. Once a particu-lar treatment strategy is started subsequentchanges are often difficult. If it is decided thatextractions are needed and since the process isirreversible, they must be carefully consideredin the treatment planning process. Inappropri-ate orthodontic treatment can produce adverseresults and it is essential that full examinationof skeletal form, soft tissue relationships andocclusal features are performed prior to under-taking treatment. It is sensible to carry out theassessment in a logical order so that none of thesteps are missed. A simple assessment shouldinclude the following:

Medical history Patients complaint Extra-oral examination Intra-oral examination Radiographs Orthodontic indices Justification for treatment Treatment aims Treatment plan

This section concentrates on the extra- andintra-oral examination of the patient.

EXTRA-ORAL EXAMINATIONIt is helpful to follow the examination sequenceoutlined:

Skeletal pattern Soft tissues Temporomandibular joint examination

Skeletal patternPatients are three-dimensional and therefore theskeletal pattern must be assessed in anterior-posterior (A-P), vertical and transverse relation-ships. Although the soft tissues can tip thecrowns of the teeth the skeletal pattern funda-mentally determines their apical root position.The relative size of the mandible and maxilla toeach other will determine the skeletal pattern.The smaller the mandible or the larger the maxil-la the more the patient will be Class II. Converse-ly with a bigger mandible or smaller maxilla thepatient will be more Class III. The bigger the sizediscrepancy between the maxilla and mandible,the more difficult treatment becomes and theless likely it is that orthodontics alone will beable to correct the malocclusion. Although someorthodontic appliances have a small orthopaediceffect, treatment is generally most easily accom-plished on patients with a normal skeletal pat-tern and a normal relationship of the maxilla tothe mandible.

Anterior-posterior (AP)Although precise skeletal relationships can bedetermined using a lateral cephalostat radi-ograph, many practices do not have this facilityand it is important to be able to assess the skele-tal relationships clinically.

To assess the AP skeletal pattern the patienthas to be postured carefully with the head in aneutral horizontal position (Frankfort Plane hor-izontal to the floor). Different head postures canmask the true relationship. If the head is tippedback the chin tends to come further forward andmakes the patient appear to be more Class III.

2

ORTHODONTICS1. Who needs

orthodontics?2. Patient assessment and

examination I3. Patient assessment and

examination II4. Treatment planning5. Appliance choices6. Risks in orthodontic






treatment

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490 BRITISH DENTAL JOURNAL VOLUME 195 NO. 9 NOVEMBER 8 2003

Conversely, if the head is tipped down the chinmoves back and the patient appears to be moreClass II. Sit the patient upright in the dentalchair and ask them to occlude gently on theirposterior teeth. Ask them to gaze at a distantpoint; this will usually bring them into a fairlyneutral horizontal head position. Look at thepatient in profile and identify the most con-cave points on the soft tissue profile of theupper and lower lips (Fig. 1).

The point on the upper lip is called soft tis-sue A point and on the lower lip soft tissue Bpoint. In a patient with a class I skeletal patternB point is situated approximately 1 mm behindA point. The further back B point is, the morethe pattern is skeletal II and the more anterior,the more skeletal III it becomes. Figure 2 showsa patient with a skeletal III pattern where theoutline of the hard tissues has been superim-posed on the photograph. This demonstratesthat although we are examining the soft tissueoutline this also gives an indication of the

underlying skeletal pattern. Obviously the softtissue thickness may vary and mask the APskeletal pattern to some degree but generallythe thickness of the upper and lower lips is sim-ilar. The underlying skeletal pattern is thereforeoften reflected in the soft tissue pattern. Themore severe the skeletal pattern is the more dif-ficult treatment of the resulting malocclusionbecomes. Figure 3a and b, shows an adult withan obvious skeletal III pattern and a malocclu-

Fig. 3a Profile of anadult who has anobvious skeletal IIIpattern

Fig. 2 Shows a patient with a skeletal III patternwhere a tracing of the lateral cephalostatradiograph has been superimposed on thephotograph. The soft tissue masks to someextent a significant skeletal III pattern

Fig. 3b Malocclusions of the samepatient in Figure 3a. The patienthas a Class III malocclusion which is beyond the scope oforthodontics alone

A

BFig. 1 A tracing of a lateral cephalostatradiograph identifying softtissue points A and B

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sion that is clearly beyond the scope of ortho-dontic treatment alone.

Vertical dimensionThis dimension gives some indication of thedegree of overbite. The vertical dimension isusually measured in terms of facial height andthe shorter the anterior facial height the morelikely it is that the patient will have a deep over-bite. Conversely the longer the facial height themore the patient is likely to have an anterioropen bite. Deep overbites associated with a shortanterior facial height and open bites with longface heights are difficult to correct with ortho-dontics alone. The greater the skeletal differencethe more likely it is that the patient will need acombination of orthodontics and orthognathicsurgery to correct the occlusion and the underly-ing skeletal discrepancy.

There are various ways of measuring thevertical dimension, one of the most common isto measure the Frankfort Mandibular PlanesAngle. This is not a very easy clinical angle tomeasure and the problem is compounded bythe fact that not many clinicians can identifythe Frankfort Plane correctly. A more practicalway of assessing this is simply to measure thevertical dimension as indicated in Figure 4.

The lower anterior facial height is the dis-tance from the base of the chin to the base ofthe nose. The upper anterior facial height isthe distance from the base of the nose to apoint roughly between the eyebrows. Thesedimensions can be measured with a ruleralthough the index finger and thumb will doalmost as well. The lower and upper facialheights are usually equal. If the lower anteriorfacial height is reduced, as illustrated in Fig-ure 5, this can result in a deep overbite thatcan be difficult to correct (Fig. 6). Conversely,if the lower anterior facial height is greater

than 50% this can produce an anterior open-bite (Fig. 7).

Transverse dimensionTo assess this dimension, look at the patienthead-on and assess whether there is any asym-

50%

50%

Fig. 4 Assessment offacial proportions.The upper andlower anterior face heightsshould beapproximatelyequal

Fig. 5 Profile of apatient with amuch reducedlower anteriorfacial height

Fig. 6 Occlusion of the patientshown in Figure 5. The reducedlower anterior face height isoften associated with a deepbite as shown

Fig. 7 Anterioropen bites areoften associatedwith an increase inlower anterior faceheight

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metry in the facial mid-line. If there appears tobe any mandibular asymmetry this may bereflected in the position of the teeth as shownin Fig. 8. If there is asymmetry it is importantto distinguish between false and true asymme-try. A false asymmetry arises when occlusalinterferences force the patient to displace themandible laterally producing a cross-bite inthe anterior or buccal region. If the displace-ment is eliminated then the mandible willreturn to a centric position. A true asymmetryarises as a consequence of unequal facialgrowth on the left or right side of the jaws. Inthese cases elimination of any occlusal cross-bites (which can be very difficult) is unlikely toimprove the facial asymmetry.

SOFT TISSUE EXAMINATIONThe soft tissues comprise the lips, cheeks andtongue and these guide the crowns of the teethinto position as they erupt. Ultimately, the teethwill lie in a position of soft tissue balancebetween the tongue on one side and the lips andcheeks on the other (Fig. 9).

In patients with a Class I incisor relation-ship the soft tissues rarely play an importantpart unless there is an anterior open-bite. Theanterior open-bite may be caused by a digitsucking habit, a large lower anterior facialheight, localised failure of eruption of theteeth, proclination of the incisors or to anendogenous tongue thrust. The latter cause isvery rare and is usually identified by a largethrusting tongue that seems to permanently sitbetween the upper and lower incisors. Thistype of anterior open-bite is extremely diffi-cult to correct. It is usually possible to reduceit, but on completion of treatment the tongueinvariably pushes between the teeth and theymove apart once again.

An important aspect of lip position is seenin patients with an increased overjet. If theupper incisor prominence is reduced, stabilityusually depends on the lower lip covering theupper incisors in order to prevent the overjetincreasing post-treatment. Therefore, carefulexamination of the position of the lower lip inrelation to the upper incisors is important. Ifthe lower lip does not cover the upper incisorssufficiently after treatment, relapse of theoverjet may occur. Similarly, if the overjet isto be reduced, full reduction is very importantin order to give the lip the best possiblechance of stabilising the incisors. Figure 10illustrates the point; partial reduction of theoverjet does not allow the lip to cover theupper incisors and they are likely to return totheir pre-treatment position.

Whilst many young children have incompe-tent lips, this is often just a normal stage ofdevelopment. As they pass through puberty, thelip length increases relative to the size of the faceand the degree of lip competence graduallyimproves (Fig. 11).1

Lip incompetence can be caused by either alack of lip tissue or an adverse skeletal pattern. If

Fig. 8 A centre lineshift where thelower centre line isto the left

Fig. 9 Teeth are in soft tissue balancebetween the tongue andthe lips

Fig. 10 These diagrams show how partial reduction of the overjet does not allow thelip to cover the upper incisors. The upper incisors are then quite likely to return totheir pre-treatment position

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the skeletal pattern is unfavourable in either thevertical or anterior-posterior position then evenwith normal lip length the soft tissues are stillwidely separated.

HABITSDigit sucking is a well-known factor in pro-ducing anterior open-bite, proclined upperincisors and buccal cross-bites. If the habitceases while the child is still growing then theincisors are very likely to return to their nor-mal position. However, once the teenage yearsare passed and facial growth slows down,spontaneous resolution becomes increasinglyunlikely. If the habit persists into adult life itmay be necessary to use appliance treatment tocorrect the habit induced anterior open-bite.Buccal cross-bite possibly produced by digitsucking habits, rarely resolve spontaneouslyon cessation of the habit because of occlusalinterferences. These buccal cross-bites often

need to be corrected with active appliancetreatment.

TEMPORO-MANDIBULAR JOINT PROBLEMSA comprehensive review of the literature byLuther2,3 failed to demonstrate any conclusiveassociation between TMJ dysfunction, maloc-clusion and orthodontic treatment. However, itis important that the joints are palpated andassessed for signs and symptoms of TMJ dys-function. Patients who present with TMJ painseeking an orthodontic solution to correct theproblems should be treated with caution.

1. Vig P S, Cohen A M. Vertical growth of the lips: a serialcephalometric study. Am J Orthod 1979; 75: 405-415.

2. Luther F. Orthodontics and the tempromandibular joint:where are we now? Part 1. Orthodontic treatment andtemporomandibular disorders. Angle Orthod 1998; 68:305-318.

3. Luther F. Orthodontics and the temporomandibular joint:where are we now? Part 2. Functional occlusion,malocclusion, and TMD. Angle Orthod 1998; 68: 305-318.

5

50-5

0

10 15 20

Age (years)

Overlap (mm)

Fig. 11 Lip length is thought to increase as children pass through the pubertal growthspurt. This will aid retention of overjet reduction


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Orthodontics. Part 3: Patient assessment andexamination IID. Roberts-Harry1 and J. Sandy2

The intra-oral assessment examines the oral health, individual tooth positions and inter-occlusal relationships. When this has been completed in conjunction with theextra-oral examination, a treatment plan can then be formulated.



Careful patient assessment is the most important part of treatment The intra-oral examination is conducted after the extra-oral assessment The degree of occlusal discrepancy influences the treatment options The dental health and patient motivation determine if appliance therapy can be used

I N B R I E F

INTRA-ORAL EXAMINATIONThere are various systems available to assess thisaspect but the following sequence is both practi-cal and thorough:

Dental health Lower arch Upper arch Teeth in occlusion Radiographs

Dental healthEven individuals with severe malocclusionsshould not have active orthodontic treatment inthe presence of dental disease. Orthodonticappliances accumulate plaque and if the patienthas a poor diet and tooth brushing then irre-versible damage can result as demonstrated inFigure 1. Although the patient has straight teeththere is considerable decalcification and it couldbe argued is worse off as a consequence of treat-ment. Clearly this could have serious medico-legal complications, particularly if the clinicianfails to write in the notes that appropriate dentalhealth advice has been given

Decalcification around orthodontic appliancesis a recognised hazard and will occur in the pres-ence of poor oral hygiene and a cariogenic diet.Not only will decalcification occur around thebrackets but tooth movement in the presence ofactive gingivitis or periodontal disease willaccelerate any bone loss. Attempting to moveteeth in the presence of active dental disease canhave disastrous consequences and must beavoided.

Therefore, treatment for patients with ques-

tionable dental health should be confined toextractions and spontaneous alignment of theteeth only. Figure 2 illustrates a case where thereis an obvious need for orthodontic treatment butthis was precluded by the patients extremelypoor oral hygiene.

Minor apical root resorption is a commonconsequence of orthodontic tooth movement.However, this resorption can occasionally besevere. Tooth movement in the presence of api-cal pathology is known to accelerate resorptionand should be dealt with prior to commencingtreatment.

Lower archThe lower arch should be examined and plannedin the first instance. Whatever treatment is car-ried out in the lower arch often determines thetreatment to be carried out in the upper. Examinethe teeth for any tipping, rotations and crowd-ing. Teeth which are tipped mesially are muchmore amenable to treatment, both with remov-able and fixed appliances than teeth which aredistally tipped. They also respond much better toextractions and spontaneous alignment thanother teeth. The presence or absence of rotationsis important because rotated teeth are most easilytreated with fixed appliances. The more crowdedthe teeth are the more likely it is that extractionswill be needed in order to correct the malocclu-sion. A method of assessing crowding is given inFigure 3. Firstly, measure the size of the teethand add these together (length A). Then measurefrom the mid-line to the distal of the canine witha pair of dividers. Measure from the distal of thecanine to the mesial of the first permanent

3










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molar. Add these together to give you theapproximate arch length (length B). Subtract Bfrom A to give you the degree of crowding. Thismust be repeated for both sides of the arch.

The degree of crowing influences the need forextractions. Although one should not be dog-matic and several other factors influence theplanning of extractions, as a general rule thegreater the crowding the more likely extractionsare necessary. Table 1 gives an outline of therelation between degree of crowding and needfor extractions.

Upper archThis is examined in a similar way to the lowerarch. Additional points to note in the mixed den-tition are the presence of a mid-line diastemaand the position of the upper canines.

A mid-line diastema is commonly seen in themixed dentition. The aetiological factors to beconsidered are:

Normal (physiological) development Fraenum Small teeth Missing teeth Midline supernumerary

Physiologic spacing usually disappears as theocclusion matures, especially when the upperpermanent canines erupt and no treatment apartfrom observation is needed. Fraenectomies arerarely indicated and generally do not need to beremoved unless the fraenum is particularly largeand fleshy.

The upper permanent canine should be pal-pable in the buccal sulcus by 10 years of age. If not, and the deciduous canine is firm, parallaxradiography should be undertaken to determinewhere the permanent tooth is. If the tooth ispalatally positioned then the deciduous canineson both sides should be removed. This will helpguide the permanent tooth into a morefavourable path of eruption and prevent anycentre line shift caused by a unilateral deciduousextraction. It is essential that this palpation becarried out on all patients in this age group. Veryoften impacting canines are missed and thepatient not referred for treatment until 15 or 16years of age. Not only is this negligent, but thepatient may then need to undergo a lengthycourse of treatment at a socially difficult time.

Teeth in occlusionThe overjet and overbite should be measuredand the incisor classification assessed. TheBritish Standards Institute (BS EN21942 Part 1(1992) Glossary of Dental terms) defines theincisor classification as follows:

Fig. 1 Decalcificationattributable to fixedappliances and a patient withpoor oral hygiene throughouttreatment

Fig. 2 This patient has a reasonable need fororthodontic treatment, but the poor oral hygieneand gingival conditionprecludes this

Table 1 Relationship between crowding andextractions

Degree of crowding Need for extractions

< 5 mm No510 mm Possibly> 10 mm Yes

1+2+3+4+5 = A 1+2 = B

1

2

B A = Degree of crowding

Fig. 3 Assessment ofcrowding. The widths ofall the teeth anterior tothe molars are measuredand subtracted from thesum of two measurements(mesial of the lowerincisor to the distal of thelower canine, plus distalof lower canine to themesial of the first molar)to give the degree ofcrowding

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Class I. The lower incisor edges occlude withor lie immediately below the cingulum plateau(middle part of) the upper central incisors.

Class II. The lower incisor edges lie posteriorto the cingulum plateau of the upper centralincisors. There are two divisions:Division 1 there is an increase in the overjetand the upper central incisors are usually proclined.Division 2 the upper central incisors areretroclined. The overjet is usually minimal butmay be increased.

Class III. The lower incisor edges lie anteriorto the cingulum plateau of the upper centralincisors. The overjet is reduced or reversed.

The centre line should be measured by plac-ing a ruler down the patients facial mid-line andmeasuring how far away from this the centrelines deviate (Fig. 4). This can then be marked inthe notes as shown in Figure 5.

The buccal occlusion is assessed next, par-ticularly the molar relationship. This is impor-tant because when assessing the treatment, ithas to be decided whether the buccal occlusionis to be accepted or whether it should be cor-rected as part of the treatment plan. The canineand molar relationships should be recorded asclass I, II or III

Finally, the presence of any anterior or pos-terior cross-bites should be assessed and ifthere is a cross-bite, the clinician should checkto see whether there is any mandibular dis-placement associated with it. This is importantbecause any displacement will mask the posi-tion of the teeth and give a misleading indica-tion of the inter-occlusal relationships. Figure 6shows a child who has an apparently severeclass III incisor relationship. However, he canget his teeth into an edge-to-edge relationshipand in this position the occlusion does notappear to be so severe. The amount of procli-nation of the upper incisors needed to correctthe incisor relationship was quite mild andeasily accomplished using a removable appli-ance (Fig. 7 and 8).

Fig. 5 Method for recording deviations in thecentre line where the lower is to the right by 1mmand the upper to the left by 2 mm

Fig. 4 Measurement of centre linedeviation using a ruler placed inthe patients mid line

Fig. 6 Class IIImalocclusion with adisplacementanteriorly. The patientcan achieve an edge toedge incisor relation inthe retruded positionof the mandible

Fig. 8 The correctedincisor position forthe patient

Fig. 7 Upper removable appliance used to correct theanterior cross bite

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Orthodontics. Part 4: Treatment planningD. Roberts-Harry1 and J. Sandy2

The treatment plan is an integral part of orthodontic management. It should be divided intoboth treatment aims (what do you want to do?) and plan (how are you going to do it?). Thetreatment aims will include, for example overjet reduction. The plan will consider how tocreate space in order to accomplish this as well as the appliance system that will be used.


Refereed Paperdoi:10.1038/sj.bdj.4810820 British Dental Journal 2003; 195:683685

Treatment planning is an essential part of orthodontic management Consider the treatment aims first, then the treatment plan The teeth and periodontium must be healthy before starting orthodontic treatment To help ensure a successful treatment outcome the oral hygiene and diet must be good Choosing the correct appliance is important

I N B R I E F

Treatment planning is the second mostimportant part of orthodontic managementfollowing the patient examination. It is help-ful to divide treatment planning into two sec-tions, treatment aims and treatment plan.Although it is possible that orthodontic treat-ment can influence the skeletal form whengrowth-modifying (functional) appliancesare used, it has little effect on soft tissues,tooth size and arch length. Remember that itis not necessary to treat every malocclusionand the benefits to the patient should becarefully assessed prior to undertaking anyorthodontic treatment.

TREATMENT AIMSThe following list is not comprehensive and hasto be tailored to the individual case. Some of theproblems that may need to be addressed duringtreatment are:

Improve dental health Relieve crowding Correct the buccal occlusion Reduce the overbite Reduce the overjet Align the teeth

As emphasised previously, it is essential thatthe oral health is of a high standard before treat-ment starts. Carious teeth should be restored andthe periodontal condition and oral hygieneshould be excellent before treatment starts.

Relieve crowdingThe decision to extract teeth needs to be careful-ly considered and depends on the degree ofcrowding, the difficulty of the case and thedegree of overbite correction.

Correct the buccal occlusionThe key to upper arch alignment is to get thecanines into a Class I relationship (Fig. 1).

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Fig. 1 It is important to achieve a Class I canineposition in order to fully correct the overjet andthe buccal segment relations

VERIFIABLE CPD PAPER

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684 BRITISH DENTAL JOURNAL VOLUME 195 NO. 12 DECEMBER 20 2003

Providing the lower incisors are well aligned,achieving this will generally produce suffi-cient space to align the upper incisors.

In order to get the canines Class I there are, ingeneral two choices for the molar relationship atthe end of treatment; either Class I or a full unitClass II. This will be covered in more detail laterin the section on treatment plan.

Overbite and overjet reductionThe overbite should always be reduced beforeoverjet reduction is attempted. A deep overbitewill physically prevent the overjet from beingreduced because of contact between the upperand lower incisors.

RetentionOnce the overjet has been reduced and or upperincisors have been aligned a retainer should be

fitted. These are designed to reduce the risk ofrelapse post treatment by allowing remodellingand consolidation of the alveolar bone aroundthe teeth and reorganisation and maturation ofthe periodontal fibres. There are many differenttypes of retainers but they are generally remov-able or fixed. There are no hard and fast rulesregarding the length of time retention shouldcontinue. The authors recommend for removableappliance treatment that retention should con-tinue for 3 months full time and 3 months atnight-time only. For fixed appliance cases thisshould be 3 months full time and a minimum of9 months at night-time only. At the end of thisminimum years worth of retention, discre-tionary wear should be advised. This means thatthe patient is given the option of discarding theretainer if they are fed up with wearing it, orcontinuing on a part-time regime to give theteeth the best possible chance of stayingstraight. If they decide to stop wearing theretainer they should be warned there is no guar-antee that the teeth will remain straightthroughout life and the only way to improve thisprospect is by indefinite (ie life-long) wearing ofthe retainer.

Some cases, especially those that were spacedor where rotations were present prior to treat-ment, should be retained indefinitely, usuallywith bonded retainers.

TREATMENT PLANThe treatment plan should be considered as follows:

Oral health Lower arch Upper arch Buccal occlusion Choose the appliance

Oral healthTooth brushing and diet advice must be givenand written in the notes. Daily fluoride rinses arealso recommended. Caries must be treated andperiodontal problems appropriately addressed.

Lower archPlan the lower arch first. The size and form ofthe lower arch should generally be accepted.Excessive expansion in the buccal regions orproclination of the lower incisors is contra-indicated in most cases because the soft tis-sues will generally return the teeth to theiroriginal position.

The need for extractions depends on thedegree of crowding. In some cases, slight procli-nation of the lower incisors and expansion inthe lower premolar region is acceptable,although this should be kept to a minimum incarefully planned cases. Generally this type oftreatment is confined to the correction of mildcrowding (less than 5 mm), cases where incisorshave been retroclined by a digit habit or trappedin the vault of the palate, or during developmentof Class II Division 2 malocclusions especially

Fig. 2 The importance ofkeeping extraction patternssymmetrical is demonstrated.The lower arch crowding hasbeen dealt with by removal oftwo lower premolars. The lossof the corresponding upperpremolars means the molarrelationship at the end oftreatment should be Class I

Fig. 3 Where upper premolarsalone are extracted (assumingno crowding in the lower arch),reduction of the overjet andspace closure means the molarrelationship must be a full unit Class II

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where there is a deep bite. Any case where theoverbite is excessive must be very carefullyassessed before extraction decisions are made.

As the degree of crowding increases from 510 mm the need for extractions increases andwith more than 10 mm of crowding extractionsare nearly always required. If spontaneousalignment or removable appliances are to beused, first premolars are usually the extractionof choice because they are near to the site ofcrowding, allow the canines to upright and pro-duce the best contact point relationship. If otherteeth are to be extracted then generally fixedappliances will be required. Crowding tends toworsen with age and is thought to be related tofacial growth which continues at least until thefifth decade.

Upper archPlan the upper arch around the lower. If extrac-tions are undertaken in the lower arch theseshould generally be matched by extractions inthe upper. If no extractions are carried out in thelower arch the space for upper arch alignmentmay come from either distal movement of theupper buccal segments or extraction of upperpremolars. The choice depends on the spacerequirements and the buccal occlusion. As thedegree of crowding and overjet increase, thenthe space requirements will also increase and itis more likely that extractions as opposed to dis-tal movement will be indicated.

Determine whether the teeth are favourablypositioned for spontaneous alignment. If appli-ances are needed can removable or fixed appli-ances accomplish the tooth movements?

Plan the buccal occlusionConsider whether this needs to be corrected andif so how. If headgear is to be used, should it beused in conjunction with a removable or a fixedappliance? If the lower arch is crowded, spacemay be created by the removal of two lower pre-molars. This is then matched by upper premolarextractions and the molar relationship must beClass I at the end of treatment to allow the arch-es to fit together (Fig. 2).

However if the lower arch is well aligned,space to align the upper arch can be created byeither upper premolar extractions or by distalmovement of the upper buccal segments. Thechoice depends on how much space is requiredand what the molar relationship is at the startof treatment. Generally the more Class II themolars are the more likely one will opt for pre-molar extraction rather than distal movement.Moving molars more than 34 mm distally is

possible but becomes increasingly demandingon patient co-operation. In circumstanceswhere the space requirements are large, upperpremolar extraction reduces the treatmenttime and increases patient compliance. Figure3 shows the sequence of events when upperpremolar extraction alone is undertaken as anaid to overjet reduction.

The nearer to Class I the initial buccal occlu-sion is, the more likely it will be that distalmovement is appropriate. Therefore, spacerequirements that involve less than half a unitClass II correction can be accomplished by distalmovement of the molars in a relatively shorttime with more chance of good patient co-oper-ation (Fig. 4). Extracting upper premolars inthese cases produces an excess of space and mayincrease the treatment time.

Choose the applianceOnce the need for extractions has been consid-ered the appropriate appliance should be select-ed. This can involve allowing some spontaneousalignment to occur, using removable, fixed orfunctional appliances with the addition of extra-oral traction or anchorage. Appliance choicesare covered in the next section.

Fig. 4 Where a relatively smallClass II correction is required this can be achieved throughdistal movement of the molars.The loss of upper premolars inthis case would produce anexcess of space

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Orthodontics. Part 5: Appliance choicesD. Roberts-Harry1 and J. Sandy2

There are bewildering array of different orthodontic appliances. However, they fall into fourmain categories of removable, fixed, functional and extra-oral devices. The appliance has tobe selected with care and used correctly as inappropriate use can make the malocclusionworse. Removable appliances are only capable of very simple movements whereas fixedappliances are sophisticated devices, which can precisely position the teeth. Functionalappliances are useful in difficult cases and are primarily used for Class II Division Imalocciusions. Extra-oral devices are used to re-enforce anchorage and can be an aid inboth opening and closing spaces.

1Orthodontic Department, Leeds DentalInstitute, Clarendon Way, Leeds LS2 9LU;2Division of Child Dental Health, Universityof Bristol Dental School, Lower MaudlinStreet, Bristol BS1 2LY


The correct appliance choice is essential for optimum treatment outcome Removable appliances have an important but limited role in contemporary orthodontics Fixed appliances are usually the appliance of choice Functional appliances are helpful in difficult cases but may not have an effect on

facial growth Extra-oral devices include headgear, face-masks and chin-caps

I N B R I E F

There are four main types of types of appliancethat can be used for orthodontic treatment.These are removable, fixed, functional and extraoral devices.

REMOVABLE APPLIANCES In general these are only capable of simple toothmovement, such as tipping teeth. Bodily move-ment is very difficult to achieve with any degreeof consistency and precise tooth detailing andmultiple tooth movements are rarely satisfactory.These appliances have received bad press overthe past few years because studies have shownthat the treatment outcomes achieved can oftenbe poor.1,2 In these studies as many as 50% ofcases treated with removable appliances wereeither not improved or worse than at the start oftreatment. When faced with evidence such asthis, one might be justified in discarding remov-able appliances completely. However, providedthey are used in properly selected cases they stillcan be very useful devices and the treatmentoutcome can be satisfactory.3 In general, remov-able appliances are only recommended for the following:

Thumb deterrent Tipping teeth Block movements Overbite reduction Space maintenance Retention

Thumb deterrentDigit sucking habits which persist into theteenage years can sometimes be hard to breakand may result in either a posterior buccal crossbite or an anterior open bite with proclination ofthe upper and retroclination of the lower inci-sors. In general, if the habit stops before facialgrowth is complete then the anterior open biteusually resolves spontaneously and the overjetreturns to normal.4

Figs. 1ac show a case with an anterioropen bite associated with an avid digit suck-ing habit. A simple upper removable appliancewas used successfully to stop the habit. Theappliance simply makes the habit feel less of acomfort and acts as a reminder to the patientthat they should stop sucking the thumb.Complex appliances with bars or tongue cribsare rarely needed. In this patient once thehabit had stopped the open bite closed downon its own without the need for further ortho-dontic treatment.

TippingOne of the major uses of removable appliancesis to move one incisor over the bite as shown inFigs 2ad. A simple upper removable applianceutilized a T spring constructed from 0.5 mmwire activated 12 mm which delivered a forceof about 30 g to the tooth. After only a fewweeks the cross bite was corrected without theneed for complex treatment. Note the anterior

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NOW AVAILABLE AS A BDJ BOOK

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10 BRITISH DENTAL JOURNAL VOLUME 196 NO. 1 JANUARY 10 2004

retaining clasp that prevents the appliancefrom displacing downwards when the spring isactivated.

If teeth are to be pushed over the bite withremovable appliances, a stable result is morelikely to be achieved if the tooth is retroclined inthe first instance, the overbite is deep and there

is an anterior mandibular displacement associ-ated with a premature contact. Tipping teethtends to reduce the overbite because the tip ofthe tooth moves along the arc of a circle asshown in Figure 3a. Excessive tipping may alsomake the tooth too horizontal which can be notonly aesthetically unacceptable but may also

Fig. 1ac A 9 year-old patient with an anterioropen bite caused by a thumb sucking habit. Notethe wear on the thumb as a result of this. Shewas fitted with a simple upper removableappliance and gently encouraged to stop thehabit. She did so successfully and the open biteclosed down spontaneously in 6 months

Fig. 2a an anterior cross bite involving the upperleft and lower left central incisors

Fig. 2c The appliance in place. The T spring isactivated 12 mm every 4 weeks

Fig. 2d The completed case. Active treatment took12 weeks

Fig. 2b An upper removable appliance with Adamscribs for retention made from 0.7 mm wire on thefirst permanent molars and the upper left centralincisor. A T spring made from 0.5 mm wire isused to push the tooth over the bite. The anteriorretention is to prevent the front of the appliancebeing displaced as the spring is activated

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result in excessive non-axial loading of thetooth as illustrated in Figure 3b.

Overbite reduction when teeth are over pro-clined is illustrated in Figures 4ad. In this caseboth the upper lateral incisors were pushed overthe bite with an upper removable appliance. Thecross bite was corrected but note the reductionin overbite on the lateral incisors. Six monthsafter completion of treatment the upper rightlateral had relapsed back into cross bite.

Block movementsIf a cross bite involves a number of teeth, forexample a unilateral buccal cross bite, remov-able appliances can be used to correct this. The

sequence of events is shown in Figures 5af.Adams cribs are generally placed on the firstpremolars and the first permanent molars and amidline expansion screw is incorporated intothe base plate. This midline screw is opened0.25 mm (one quarter turn) twice a week untilthe cross bite is slightly overcorrected. Posteri-or buccal capping can also be used to disen-gage the bite and prevent concomitant expan-sion of the lower arch. Once the cross bite iscorrected the buccal capping can be removedand the appliance used as a retainer to allowthe buccal occlusion to settle in. Occasionallytwo appliances will be needed if a considerableamount of expansion is needed.

Fig. 3a The effect of tipping anteriorteeth on the overbite. As the teethmove around a centre of rotation theincisal tip moves along the arc of acircle. By the laws of geometry, asthe tooth is proclined the overbitereduces once it moves past thevertical

Fig. 3b Excessive tipping not onlyreduces the overbite but also makesthe axial inclination of the teeth too horizontal. In thesesituations stability is reduced, theappearance is poor and the tooth maysuffer from unwanted non-axial loading

Fig. 4a Both the upper lateral incisors are in crossbite

Fig. 4c The cross bites have been corrected. Notethe reduction in the overbite

Fig. 4d 6 months later the upper right lateral hasrelapsed into cross bite due to the reducedoverbite

Fig. 4b An upper removable appliance was used totip the laterals over the bite

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Fig. 5a Narrowness of the upper arch can produce a traumatic bite

Fig. 5c An upper removable appliance with a mid line expansionscrew can be used to correct the cross bite. The screw is opened one-quarter turn twice a week by the patient

Fig. 5d The corrected cross bite. The treatment time varies with theamount of expansion needed but usually takes about twelve weeks

Fig. 5b To avoid painful cuspal contact the patient may move themandible to one side producing a mandibular deviation and a crossbite

Fig. 5e Once active treatment is completed the appliance can beworn as a retainer. The posterior capping can be reduced to allowinterdigitation of the buccal teeth thus helping to prevent anyrelapse

Fig. 5f The completed case

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Overbite reductionRemovable appliances are very effective in cor-recting a deep overbite, especially in a growingpatient. An upper removable appliance with ananterior bite plane is used which disengages themolars by 23 mm whilst at the same timeestablishing lower incisor contact with the biteplane (Fig. 6). Eruption of the posterior teethproduces a reduction in the overbite. It is essen-tial that the inter-incisor angle is corrected atthe completion of treatment so that an occlusalstop between the upper and lower incisors isproduced preventing re-eruption of the incisorsand a relapse of the overbite. Bite planes areusually used in conjunction with fixed appli-ances to help the overbite reduction (Figures7ad) or can be used as an aid to restoration of the anterior teeth. Figures 8ad show a patient with a deep bite who had marked enamelerosion. Porcelain crowns were to be placed onthe anterior teeth to restore them, but the deepbite made this technically difficult. The overbite

was therefore reduced with a bite plane to makeroom for the crowns.

Space maintenance Space maintainers are rarely indicated in ortho-dontic treatment but occasionally can be used,particularly if the upper canine is buccally crowd-ed. Whilst the extraction of the first premolarswill often create space for the canines, there is a danger that the space will close before thecanine erupts as the buccal teeth drift mesially.Figures 9ae illustrate such a case where the fit-

ting of a space maintainer proved useful. Theappliance was fitted just prior to the emergenceof the permanent canines. The four first premo-lars were then extracted and the appliance left inposition until the canines erupted. This tookabout 6 months and saved a considerableamount of extra treatment for the patient byallowing spontaneous alignment of the canines.

RetentionMany orthodontists use various types of remov-able appliances to act as retainers, usually at the

2-3mm

Fig. 6 Overbite correction with a removable appliance. The posterior teethshould be separated by about 23 mm

Fig. 7a A case with a deep bite and retroclinedupper incisors

Fig. 7c Once the overbite is fully reduced theupper fixed appliance can be placed

Fig. 7d The completed case with good overbitereduction

Fig. 7b An upper removable appliance is used tohelp the overbite reduction whilst palatal springssimultaneously move the first permanent molars distally

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Fig. 8a, b A patient with severe erosion of theteeth

Fig. 8c A bite plane was used to reduce theoverbite

Fig. 8d Strip crowns were placed on the incisorsonce the overbite was reduced

Fig. 9a, b A case with severe upper arch crowding. The upperpermanent canines were unerupted, buccally positioned andvery short of space

Fig. 9c An upper removable space maintainer. Adam cribs havebeen placed on the first permanent molars and a Southend claspon the upper central incisors

Fig. 9d,e The first premolars have been extracted and the upper caninesare erupting into a good position

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completion of fixed appliance treatment.Removable retainers are usually held in positionwith Adams Cribs on the first permanent molarswith a labial bow and possible acrylic coverageof the anterior teeth (Fig. 10).

FIXED APPLIANCESThese appliances are attached to the crowns ofteeth and allow correction of rotations, bodilymovements of teeth and alignment of ectopicteeth. They have increased in sophisticationenormously over the past 1015 years andtogether with advancements in arch wire tech-nology are capable of producing a very highlevel of treatment result. Simultaneous multiple

tooth movements can be achieved, invariablycreating a better treatment outcome than can beachieved with removable appliances. Althoughthere are a variety of fixed appliances availablethey all operate in a similar way producing afixed point of attachment to control the positionof the teeth. Brackets are attached to the teethand wires (arch wires) are placed in the bracketslots to move the teeth. The closer the fit of rec-tangular arch wires in a rectangular slot on thebracket the greater the control of the teeth(Fig 11). As treatment progresses, thicker rectan-gular wires are used to fully control the teeth inthree dimensions. Fixed appliances are theappliances of choice for most orthodontic treat-

ment because the results are far more predictableand of a higher standard achieved than by othermeans. However, they are relatively complexappliances to use and further training in thesedevices is essential. An example of a case treatedwith fixed appliances is shown in Figure 12aj.The anchorage requirements for the bodilymovement of teeth are considerably greater thanfor tipping movements (Fig. 13).

FUNCTIONAL APPLIANCESThese are powerful appliances capable of impres-sive changes in the position of the teeth. Theyare generally used for Class II Division I maloc-clusions although they can be used for the

Fig. 10 One exampleof the manydifferent types ofremovable retainers

Fig. 11 Rectangular arch wire in rectangular bracketslots allows three-dimensional control of the teeth. The tighter the fit of the wire in the slotthe greater the control of the teeth

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Fig. 12a, b Pre treatment photographs of a patient with palatallyimpacted canine, a buccal cross bite, an increased overjet andcrowding in both arches

Fig. 12c Upper first and lower secondpremolars were extracted and the caninessurgically exposed

Fig. 12d A tri-helix was used to expand the upperarch and a sectional fixed appliance used to pullthe canine into the line of the arch

Fig. 12e Full fixed appliances were then used to reduce the over biteand overjet, move the apex of the canine into the line of the arch andcorrect all the other features of the malocclusion. The initial archwire was a very thin flexible wire. If a thick wire is used at this stageexcess force will be applied to the teeth that can produce rootdamage and be very painful for the patient

Figs 12f,g Once initial alignment of the teeth is producedprogressively thicker, stiffer wires are employed. Because these fitthe bracket slot more closely they control tooth position moreprecisely than the thinner aligning wires

Fig. 12h,i Thecompleted case.The canine is fullyaligned and theoverjet reducedwithout anyunwanted tippingof the teeth

Fig. 12j Appropriate extractionsand treatment mechanics havenot been detrimental to the facialappearance

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correction of Class II Division II and Class IIImalocclusions on occasion. They are eitherremovable from the mouth or fixed to the teeth,and work by stimulating the muscles of mastica-tion and soft tissues of the face. This produces adistalising force on the upper dentition and ananterior force on the lower. Whilst they are capa-ble of substantial tooth movement, like allremovable appliances they are not capable ofprecise tooth positioning and cannot deal effec-tively with rotations or bodily tooth movement.

There is some controversy as to the precisemode of action of functional appliances. Someclinicians feel they have an effect on this facialskeleton, promoting growth of the mandibleand/or maxilla. Others feel that the effects aremainly dento-alveolar and that the resultsachieved are accomplished by tipping the upperand lower teeth. Unfortunately many of the stud-ies relating to functional appliance treatmenthave been poorly constructed and their conclu-sions should be treated with caution. A large-scale, prospective, randomized clinical trialcurrently being undertaken in United Kingdomstrongly suggests that 98% of the occlusal

Fig. 13 Bodily movement of the teeth requires a greater degree offorce than tipping movements

Fig. 14c A functionalappliance was used tocorrect the saggitalrelationship

Fig. 14d The final resultafter detailing of theocclusion with fixedappliances

Fig. 14e,f Thefacial appearancefollowingtreatment

Fig. 14a,b Pre-treatmentphotographs of a 12-year-old girl with an increasedoverjet and a class II skeletalpattern associated with aretrognathic mandible

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correction is by tipping of the teeth with analmost negligible effect on the skeletal pattern.5

Nevertheless, dramatic occlusal changes are pos-sible with these appliances and they can aid thecorrection of some quite severe malocclusions.Figures14af show a case treated with a function-al appliance that had a marked effect not only on the occlusion but also on the patient's facialappearance.

EXTRA-ORAL DEVICESThese are headgear devices, chin caps and facemasks, which are used to provide an externalsource of anchorage or traction for teeth in one orboth arches. The commonest type is headgear forthe distal movement of the buccal teeth. A metalface bow is attached to either a removable or afixed appliance inside the mouth and elastic trac-tion applied to it. As well as force being applieddistally to either the maxilla or the mandible itcan be applied mesially via a facemask. This istypically used in Class III cases to correct an ante-

rior cross bite or in cases where the buccal seg-ments are being moved forward to close spaces inthe arches. Examples of extra oral tractiondevices are shown in Figures 15, 16a and b. Chincaps have been used to try and restrain mandibu-lar growth in Class III malocclusions. However,the evidence from the literature suggests that theyare not terribly effective and their use hasdeclined in recent years.

1. Richmond S, Shaw W C, O'Brien K D et al. The development ofthe PAR index (Peer Assessment Rating): reliability and validity.Eur J Orthod 1992; 14: 125-139.

2. Richmond S, Shaw W C, Roberts C T, Andrews M. The PAR index(Peer Assessment rating): methods to determine the outcomeof orthodontic treatment in terms of improvements andstandards. Eur J Orthod 1992; 14: 180-187.

3. Kerr W J S, Buchanan I B, McColl J H. The use of the PAR index inassessing the effectiveness of removable orthodonticappliances. Br J Orthod 1993; 20: 351-357.

4. Leighton B C. The early signs of malocclusion. Trans EuropOrthod Soc 1969; 353-368.

5. O'Brien K, Wright J, Conboy F et al. Effectiveness of treatmentfor Class II malocclusion with the Herbst or twin-blockappliances: a randomized, controlled trial. Am J OrthodDentofacial Orthop 2003; 124: 128-137.

Fig. 16a,b A facemask or reverse headgearFig. 15 Extra-oral tractionapplied via an Interlandiiheadgear

A letter to the BDJ highlighting the concerns of one of its members.

Sir, - There is a movement on foot to establish a Section of Dental Surgery in theBritish Medical Association, of which membership is only possible to those members ofthe British Dental Association who are on the Medical register.

I beg you most emphatically to protest against any new section, or society of dentalsurgeons being formed to which every member of the British Dental Association is noteligible. I am strongly in favour of every dentist being a surgeon as well (if possible), butI protest against a revival of the Association of Surgeons practising Dental Surgery inthis insidious form.

Yours trulyS. J. Hutchinson, M. R. C. S., LDS.Eng

BR Dent J, 1903; 24: 828

One Hundred Years Ago

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Orthodontics. Part 6: Risks in orthodontic treatmentH. Travess1, D. Roberts-Harry2 and J. Sandy3

Orthodontics has the potential to cause significant damage to hard and soft tissues. The most important aspect oforthodontic care is to have an extremely high standard of oral hygiene before and during orthodontic treatment. It isalso essential that any carious lesions are dealt with before any active treatment starts. Root resorption is a commoncomplication during orthodontic treatment but there is some evidence that once appliances are removed this resorptionstops. Some of the risk pointers for root resorption are summarised. Soft tissue damage includes that caused byarchwires but also the more harrowing potential for headgears to cause damage to eyes. It is essential that adequatesafety measures are included with this type of treatment.

1Senior Specialist Registrar, 2 ConsultantOrthodontist, Orthodontic Department,Leeds Dental Institute, Clarendon Way,Leeds LS2 9LU; 3Professor of Orthodontics,Division of Child Dental Health, Universityof Bristol Dental School, Lower MaudlinStreet, Bristol BS1 2LY


Before any active orthodontic treatment is considered it is essential that the oral hygiene isof a high standard and that all carious leions have been dealt with

Arch wires, headgears and brackets themselves may cause significant damage either duringan active phase of treatment or during debonding. Much care needs to be taken wheninstructing patients about their role in orthodontic treatment

The aim of this section is to outline potential risks in orthodontic treatment and to giveexamples. There are also a number of illustrations to help highlight these points

I N B R I E F

If orthodontic treatment is to be of benefit to apatient, the advantages it offers should outweighany possible damage it may cause.1 It is impor-tant to assess the risks of treatment as well as thepotential gain and balance these aspects of treat-ment before deciding to treat a malocclusion.The psychological trauma of having orthodontictreatment, or indeed not having treatmentshould not be overlooked and is an importantconsideration in treatment planning. Patientselection plays a vital role in minimising risks oftreatment and the clinician should be vigilant inassessing every aspect of the patient and theirmalocclusion. However, clinically there are anumber of areas of concern for risk manage-ment. These are discussed in detail under thebroad categories of intra-oral, extra-oral and systemic risks.

INTRA-ORAL RISKS

Enamel demineralisation/cariesEnamel demineralisation, usually on smooth sur-faces, is unfortunately a common complicationin orthodontics; figures range from 296% oforthodontic patients (Fig.1).2 This large variationprobably arises as a result of the variety of meth-ods used to assess and score the presence ofdecalcification. There is also inconsistency onwhether idiopathic lucencies are included orexcluded in the study design.3 The teeth mostcommonly affected are maxillary lateral incisors,maxillary canines and mandibular premolars.4

However, any tooth in the mouth can be affected,and often a number of anterior teeth show decal-

cification. Whilst the demineralised surfaceremains intact, there is a possibility of remineral-isation and reversal of the lesion. In severe cases,frank cavitation is seen which requires restora-tive intervention (Figs. 2 and 3).

Gorelick et al.5 in a study on white spot for-mation in children treated with fixed appliances,found that half of their patients had at least onewhite spot after treatment, most commonly onmaxillary lateral incisors. The length of treat-ment did not affect the incidence or number ofwhite spot formations, although O'Reilly andFeatherstone6 and Oggard et al.7 found thatdemineralisation can occur rapidly, within thefirst month of fixed appliance treatment. Thishas obvious aesthetic implications and high-lights the need for caries rate assessment at thebeginning of treatment. Interestingly, Gorelick et al.5 found no incidence of white spot forma-tion associated with lingual bonded retainers,which would suggest salivary buffering capaci-ty, and flow rate have a role in protection againstacid attack.

6










treatment

Fig. 1 Decalcification on labial surfaces ofnumerous teeth


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The dominant hand may also influence thearea of decalcification as brushing is more diffi-cult on the side of the dominant hand. Whilstgood oral hygiene is vital, dietary control ofsugar intake is also needed in order to minimisethe risk of decalcification. Fluoride mouthwash-es used throughout treatment can prevent whitespot formation8 surprisingly, compliance withthis is low (13%). Other fluoride release mecha-nisms include fluoride releasing bonding agents,elastic ligatures containing fluoride, and depotdevices on upper molar bands.9

Preventive measures to minimise damageinclude patient selection, vigorous oral hygienemeasures and dietary education. Reinforcementof oral hygiene and dietary education should beperformed at each visit. Positive reinforcementeven where oral hygiene is satisfactory willencourage the patient further. Inspection of thelabial surfaces of the teeth at each adjustmentappointment will identify cases that require moreintervention and advice. It is important whenexamining the teeth that they are plaque-freeotherwise early demineralisation may be missed.This can be done by instructing the patient toclean their teeth in the surgery with or without thewires in place, or by professional prophylaxis. Theuse of auxillaries such as dental health educatorsand hygienists is highly desirable. Removal of theappliance in cases with extreme demineralisationor poor hygiene is the last resort, but should notbe discounted by the clinician.

Where demineralisation is present post treat-ment, fluoride application either via toothpaste,

or by adjunct fluoride mouthwash (0.05% sodi-um fluoride daily rinse or 0.2% sodium fluorideweekly rinse), can be helpful in remineralisingthe lesion and reducing the unsightliness of thedecalcification.10 Acid/pumice micro abrasionhas also been advocated to improve the aesthet-ics of stabilised lesions.11,12 This procedureshould be delayed at least 3 months followingdebond to allow for spontaneous improvementof the lesions and remineralisation with fluorideapplications.13 Persistent lucencies should beabraded with 18% hydrochloric acid in finepumice under rubber dam in bursts of 30 sec-onds for a maximum of 10 times. After the lastapplication the tooth is washed well and a fluo-ride varnish applied.11

Enamel traumaWhen placing appliances careless use of a bandseater can result in enamel fracture. Care isrequired when large restorations are presentsince these can result in fracture of unsupportedcusps.14 Debonding can also result in enamelfracture, both with metal and ceramic brackets(Fig. 4).15,16 Care must always be taken toremove brackets and residual bonding agentsappropriately to minimise the risk of enamelfracture. The use of debonding burs has thepotential to remove enamel, especially in air tur-bine fast handpieces. Care and attention is need-ed when adhesives are removed.

Enamel wearWear of enamel against both metal and ceramicbrackets (abrasion) may occur. It is common onupper canine tips during retraction as the cusptip hits the lower canine brackets (Fig. 5). It mayalso be seen on the incisal edges of upper ante-rior teeth where ceramic brackets are placed onlower incisors.17 Ceramic brackets are veryabrasive and therefore contraindicated for thelower anterior teeth where there is any possibil-ity of the brackets occluding with the upperteeth, bearing in mind that the overbite may

Good oral hygieneis essential for successful orthodontic treatment

Daily fluoride rinses may prevent and reduce decalcifications

Care is neededwhen debracketingas there is thepotential for enamel damageespecially withceramic brackets

Fig. 3 Obvious caries in the disto-occlusalaspect of a lower molar

Fig. 4 Enamel fracture at debond

Fig. 2 Cavitation at the gingival margin ofthe lower right canine and first premolarrequiring restoration

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increase in the early stages of treatment. Anyenamel erosion must be recorded prior to treat-ment commencing and appropriate dietaryadvice given to minimise further tooth sub-stance loss. Carbonated drinks and pure juicesare the commonest causes of erosion and shouldbe avoided in patients with fixed appliances.

Pulpal reactionsSome degree of pulpitis is expected withorthodontic tooth movement which is usuallyreversible or transient. Rarely it leads to lossof vitality, but there may be an increase inpulpitis in previously traumatised teeth withfixed appliances. Light forces are advocatedwith traumatised teeth as well as baselinemonitoring of vitality which should be repeat-ed three monthly.18 Transient pulpitis mayalso be seen with electrothermal debonding ofceramic brackets19 and composite removal atdebond.20

Root resorptionSome degree of external root resorption isinevitably associated with fixed appliancetreatment, although the extent is unpre-dictable.21 Resorption may occur on the apicaland lateral surface of the roots, but radiographsonly show apical resorption to a certain degree.Many cases will not show any clinically signif-icant resorption but, microscopic changes arelikely to have occurred on surfaces which arenot visualised with routine radiographs.Resorption however rarely compromises thelongevity of the teeth.22 Vertical loss of bonethrough periodontal disease creates a fargreater loss of attachment and support than itsequivalent loss around the apex of a tooth.

The mechanism of tooth resorption is unclear.Theories include excessive force and hyalinisa-tion of the periodontal ligament resulting inexcessive cementoclast and osteoclast activity.What is clear are the risk factors which are asso-ciated with cases with severe resorption. Thesecan be summarised as:

Blunt and pipette shaped roots show a greateramount of resorption than other root forms.

Short roots are more at risk of resorption thanaverage length roots.

Teeth previously traumatised, have anincreased risk of further resorption.

Non vital teeth and root treated teeth have anincreased risk of resorption.

Heavy forces are associated with resorption,as well as the use of rectangular wires, Class IItraction, the distance a tooth is moved and thetype of tooth movement undertaken.

Combined orthodontic and orthognathic pro-cedures.

Treatment of ectopic canines may induceresorption of the adjacent teeth because of thelength of treatment time and the distance thecanine is moved. Tooth intrusion is also associ-ated with increased risk as well as movement ofroot apices against cortical bone. Above the ageof 11 years the risk of resorption with treatmentseems to increase. Adults have shorter roots atthe outset and the potential for resorption isincreased.

Opinion is divided on whether treatmentlength is associated with increased resorp-tion. Some find no correlation with treatmenttime, whereas others find that there isincreased resorption with increased treatmenttime. In a few patients systemic causes maycontribute, for example hyperthyroidism, butfor the most part no underlying cause is iso-lated other than individual susceptibility.Familial risk is also known.

A wide range in the degree of resorption isseen, highlighting the role of individual sus-ceptibility over and above the risk factorsidentified. Research is still required in this areato identify the mechanisms of resportion, trig-ger factors and reparative mechanisms if treat-ment modalities are to be modified in thefuture to minimise root damage. Currently, nocase is immune from the risk of root resorp-tion, to some degree, and patients should bewarned at the outset of treatment that such arisk exists. Recognition of specific risk factors,accurate radiographs and interpretation ofradiographs at the outset of treatment areimportant if root resorption is to be minimised.Once resorption is recognised clinically duringtreatment, light forces must be used, rootlength monitored six monthly with radi-ographs and treatment aims reconsidered tomaximise the longevity of the dentition. Theuse of thyroxine to minimise root resorptionhas been advocated by some authors, but thisis not routinely used.23, 24

Periodontal tissuesFixed appliances make oral hygiene difficulteven for the most motivated patients, andalmost all patients experience some gingivalinflammation (Fig. 6). Resolution of inflamma-tion usually occurs a few weeks after debond,bands cause more gingival inflammation thanbonds, which is not surprising since the mar-gins of bands are often seated subgingivally.

Root resorption isinevitable withfixed appliancetreatment

On average 1-2 mmof apical root is lostduring a course of orthodontictreatment

Previously traumatised teethhave an increasedrisk of root resorption

Fig. 5 Upper canine tip showing abrasion from thelower canine metal bracket

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For the most part, the literature suggeststhat orthodontic treatment does not affect theperiodontal status of patients over the longterm. Patients with pre-existing periodontaldisease require special attention, but bone lossduring treatment does not seem to be relatedto previous bone loss. The need for excellentoral hygiene during treatment must beemphasised in patients with existing peri-odontal disease. The use of bonds rather thanbands on molars and premolars may be moreappropriate to eliminate unwanted stagnationareas. Plaque retention is increased with fixedappliances and plaque composition may alsobe altered. There is an increase in anaerobicorganisms and a reduction in facultativeanaerobes around bands, which are thereforeperiopathogenic.25

Oral hygiene instruction is essential in allcases of orthodontic treatment, and the use ofadjuncts such as electric toothbrushes, inter-proximal brushes, chlorhexidine mouthwash-es, fluoride mouthwashes and regular profes-sional cleaning must be emphasised. However,patient motivation and dexterity are para-mount in the success of hygiene, and there willalways be cases where oral hygiene is unsatis-factory from the outset. This should be careful-ly considered when advising a patient to havetreatment. Experience shows those patientswho are unable to maintain a healthy oralenvironment in the absence of fixed orthodon-tics will fail spectacularly with braces in place.Benefit must therefore significantly outweighthe risk of carrying out treatment in suchpatients (Figs. 7 and 8).

AllergyAllergy to orthodontic components intra-orally is exceedingly rare, however, there havebeen studies on the nickel release and corro-sion of metals with fixed appliances. Gjerdetet al.26 found a significant release of nickeland iron into the saliva of patients just afterplacement o

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