RADIOGRAPHIC AIDS IN THE DIAGNOSIS OF

PERIODONTAL DISEASE

PRESENTER – PUNIT

PG

DEPARTMENT OF PERIODONTICS

CONTENTS

1. INTRODUCTION

2. SELECTION CRITERIA

3. RADIOGRAPHIC ASSESSMENTS OF

PERIODONTAL CONDITIONS

4. INTRAORAL RADIOGRAPHY

5. LIMITATIONS OF RADIOGRAPHY

6. RADIOGRAPHIC DIAGNOSIS IN

PERIODONTITIS

7. RADIOGRAPHIC CHANGES IN SYSTEMIC DISEASE

8. DIGITAL IMAGING

9. DIGITAL SUBTRACTION RADIOGRAPHY

10.TUNED APERTURE COMPUTED TOMOGRAPHY

11. COMPUTED TOMOGRAPHY

12. PRESURGICAL PLANNING

13.EXTRA ORAL RADIOGRAPHY

14.NEW FRONTIERS

15.CONCLUSION

16. REFERENCES

Limited number of major tools for the diagnosis of periodontal disease Patient’s history

• Visual inspection

• Periodontal probing and

•Radiographic examination

It is a valuable aid in the

•Diagnosis

•Prognosis

•Evaluation of treatment outcome

Image – info. of calcified tissues

Only clinical correlation will result in a accurate diagnosis.

IMAGE NEVER MAKES A DIAGNOSIS, THE CLINICIAN DOES.

However, it is an adjunct to the clinical examination, not a substitute for it.

INTRODUCTION

RADIOGRAPHIC ASSESSMENT OF PERIODONTAL

CONDITIONS

1. Amount of bone present

2. Condition of the alveolar crests

3. Bone loss in the furcation areas

4. Width of the periodontal ligament space

5. Local initiating factors that cause or intensify periodontal disease

• Calculus

• Poorly contoured or overextended restorations

6. Root length and morphology and the crown to root ratio

7. Anatomic considerations

• Position of the maxillary sinus in relation to a periodontal deformity

• Missing, supernumary or impacted teeth

8. Pathologic considerations

• Caries

• Periapical lesions

• Root resorptions

SELECTION CRITERIA

The necessity for radiographs and their quantity depend solely on the

patient’s

1. Clinical findings

2. Oral anatomy

3. Treatment planning goals

Simply put no radiograph should be exposed on a patient without performing

a thorough clinical examination.

The selection of radiographic projections, number of films, speed of film,

and settings on the X-ray source are all under the control of the clinician.

Proper selection will increase the likelihood of obtaining the required

diagnostic information while limiting the risk to the patient due to

radiation exposure.

Radiographic survey – 14 intraoral films and 4 posterior bitewing films

RADIOGRAPHIC IMAGE TYPES AND TECHNIQUES

INTRAORAL(TRANSMISSION) EXTRAORAL

PERIAPICAL BITEWING PANORAMIC VIEW

HORIZONTAL VERTICAL

ADVANCED TECHNIQUES

1. Digital radiography

2. Digital substraction radiography (DSR)

3. Computed assisted densitometric image analysis system (CADIA)

4. Computed tomography (CT)

5. Cone beam computed tomography (CBCT)

6. Local computed tomography

7. Optical coherence tomography

8. Indirect digital radiography or Computed radiography (CR)

FILM PLACEMENT AND BEAM ALIGNMENT

The teeth will be depicted in their correct positions relative to the alveolar process

when there is

(1) No overlapping of the proximal contacts between crowns,

(2) No overlapping of roots of adjacent teeth, and

(3) Overlapping of the buccal and lingual cusps of molars.

(4) Image of the crest as distinct radioopaque line.

With the teeth in a close approximation of their normal occlusion, the angulation used

(positive 7 to 10 degrees) is favorable to projecting the image of both the maxillary and

mandibular posterior teeth in their most parallel orientation.

BITEWING TECHNIQUE

Properly positioned and exposed bitewing radiographs (horizontal or vertical) are

considered mandatory in the periodontal "hard-tissue" assessment for most patients,

because of the characteristics outlined below:

1. The alveolar crest height is as accurately depicted as possible.

2. The relation of the cementoenamel junction (CEj) to the alveolar crest can be

accurately determined.

3. The presence of vertical bony defects can be demonstrated more precisely than with

periapical images.

4. Early crestal bone loss in the posterior dentition can be found more readily than with

periapical images.

BITEWING TECHNIQUE

ADVANTAGES1. The alveolar crest height is as accurately depicted as possible.

2. The relation of the cementoenamel junction (CEJ) to the alveolar crest can be accurately

determined.

3. Early crestal bone loss in the posterior dentition can be found more readily

4. Radiation dose is reduced.

5. To some extent standardized

DISADVANTAGE

Limited view of the osseous crest

Limited view of entire tooth & surrounding region

INDICATIONS FOR PERIAPICAL RADIOGRAPHY

1) Detection of apical infection /inflammation

2) Assessment of the periodontal status

3) After trauma to the teeth and associated alveolar bone

4) Assessment of the presence and position of unerupted teeth

5) Assessment of root morphology before extractions

6) During endodontics

7) Preoperative assessment and postoperative appraisal of apical surgery

8) Detailed evaluation of apical cysts and other lesions within the alveolar bone

9) Evaluation of implants postoperatively.

PERIAPICAL TECHNIQUE

• vertical bony defects can be demonstrated

• assessing the crown-to-root ratio,

• root morphology,

• periodontal ligament spaces, and

• periapical status

The two types of images discussed, bitewing and periapical, are

complementary and both image sets most likely will be necessary for

patients with periodontal problems.

PURPOSE AND USE OF EXTRAORAL RADIOGRAPHY

• As adjunct for full mouth IOPA

• Evaluation of tooth development (mixed dentition)

• Assist and assess orthodontic treatment

• Evaluate location of 3rd molar

• Extensive disease – large lesions which cannot be seen in the intra oral

radiographs

• Evaluation of developmental anomolies,cysts,tumors

• Evaluation of fractures following trauma

• Assess underlying bone for pre and post prosthodontic treatment

• Initial evaluation image in determining the need for other projections

EXTRAORAL RADIOGRAPHY(Panoramic radiography )

Advantages

1. Image acquisition is relatively fast and simple

2. No need for any intraoral manipulation.

3. It shows all dentoalveolar structures in a single image at a dose that is

considerably lower than for an intraoral full-mouth series .

Disadvantages

1. Lingual structures will be projected higher on the film than buccal structures.

2. Patient-positioning errors represent one of the main sources of error in

panoramic radiography.

3. It is technique sensitivity also.

4. Makes it difficult to reproduce the imaging geometry at a later date.

5. Images show less image detail than intraoral images.

6. Structures outside the image layer are not completely removed , cause so-called

ghost images.

RADIOGRAPHIC ANATOMY OF THE PERIODONTIUM

INTERDENTAL SEPTUM AND CRESTAL LAMINA DURAThe interterdental septum,

located between the roots of adjacent teeth

therefore more clearly visualized than bone that is located on the buccal or lingual

aspect of the tooth

Shape function of the morphology of the contiguous teeth.

Convex teeth Flatter, less convex

wider interdental space narrower interdental space

broader septa of larger mesiodistal width "septal peak"

seen in the anterior regions

Loss of this architecture results in "blunting" or loss of septal height and may

indicate early periodontitis (although evidence of clinical attachment loss will

precede radiographically evident bone loss).

LAMINA DURA

1) The interdental septum normally presents a thin radiopaque border, adjacent to the

periodontal ligament and at the crest, that is referred to as the lamina dura.

2) This appears radiographically as a continuous white line

3) At the top of the crest, it is known as the crestal lamina dura.

4) It has been suggested that loss of the crestal lamina dura may correspond to

periodontal disease activity.

Greenstein and co-workers report that the crestal lamina dura is not significantly

related to any of a number of clinical periodontal parameters.

Absence of the crestal lamina is not indicative of current or impending disease

activity,

Presence of a crestal lamina dura may be associated with clinical stability.

5) Increased density of the crestal lamina dura has been reported after successful

periodontal therapy.

1) Normally, the alveolar crest meets

the lamina dura at a right angle

when teeth are tipped,

the appearance of the crestal lamina may

mimic a vertical bone defect because of the

Improper vertical angulation CEJ is inferior to

Adjacent tooth creating an impression of vertical defect but in reality no defect.

2) A similar "CEJ discrepancy" can occur as a anatomic variation

Some people have a mesial tilt to the posterior teeth

vertical defects adjacent to the mesial surfaces of multiple teeth

Ritchey and Orban report that lines drawn between the adjacent CEJs should

parallel the crestal lamina dura, and this simple test will readily distinguish

true vertical defects from "pseudo-defects" caused by tooth angulation.

PERIODONTAL LIGAMENT SPACE

1) Thin radiolucent line interposed between the root and the radiopaque

line that outlines the root.

2) The width of the PDL has been considered important in the diagnosis

of various conditions, including occlusal trauma .

3) However, the PDL width varies with varying tube/film geometry and

exposure conditions and with root morphology.

4) Occlusal trauma may be manifested as a widening of the PDL space or

may present as a funneling of the coronal aspect of the PDL space.

LIMITATIONS OF RADIOGRAPHS

A two-dimensional view of a three-dimensional situation.

Bony defects overlapped by higher bony walls may be hidden

Overlapping tooth structure

However, subtle changes in the density of the root structure (which is more

radiolucent) may indicate bone loss on the buccal or lingual aspect of the tooth.

Furthermore, use of multiple images made at different angulations, as in a full-

mouth set, allows the viewer to use the buccal object rule to obtain three-

dimensional information

Radiographs typically show less severe bone destruction than is actually

present. The earliest (incipient) mildly destructive lesions in bone do not cause

a sufficient change in density to be detectable.

Radiographs do not demonstrate the soft-tissue-to-hard-tissue relationships and

thus provide no information about the depth of soft tissue pockets.

Bone level is often measured from the cementoenamel junction; however, this

reference point is not valid in situations in which either overeruption or severe

attrition with passive eruption exists.

It is not possible to render a definitive periodontal diagnosis by means of a

radiograph.

For example,

1. Advanced periodontitis

good clinical response to therapy. minimal probing depths,

but the radiographic bone levels will likely remain largely unchanged after

treatment

It will be impossible to determine whether that individual requires further treatment

by examining post-treatment radiographs alone.

Conversely, serial radiographs taken at baseline (pretreatment) and at subsequent

appointments may reveal ongoing bone loss but only in the context of

supplementing the findings from the clinical examination.

2) Endodontically involved mandibular molar

reveals radiolucency in the furcation region

no increase in probing depth or clinical attachment loss ,there has been no apical

migration of epithelial attachment, sulcus is not continuous with furcation area.

This is strictly an endodontic problem unless and until the sulcus becomes

continuous with the furcation.

Nevertheless, the radiographic image may mimic the appearance of significant

furcation involvement caused by periodontal destruction.

ADDITIONAL RADIOGRAPHIC CRITERIA IN THE DIAGNOSIS OF

PERIODONTAL DISEASE

• Radiopaque horizontal line across the roots. This line demarcates the portion

of the root where the labial and/or lingual bony plate has been partially or

completely destroyed from the remaining bone supported portion.

• Vessel canals in the alveolar bone.

Hirschfeld described linear and circular

radiolucent areas produced by interdental

canals and their foramina, respectively.

RADIOGRAPHIC DIAGNOSIS IN PERIODONTITIS

a. Bone Destruction in Periodontal Disease

slight radiographic changes in the periodontal tissues mean that

the disease has progressed beyond its earliest stages

The Earliest Signs Of Periodontal Disease Must Be Detected Clinically

The radiographic image tends to show less severe bone loss than that actually

present.

the difference between the alveolar crest height and the radiographic appearance

0 to 1.6 mm,

accounted for by x-ray angulation

b. Distribution of Bone Loss

The distribution of bone loss is an important diagnostic sign. It points to the location

of destructive local factors in different areas of the mouth.

d) Pattern of Bone Destruction

interdental septa may be reduced in height,

crest horizontal and septa may have a angular defect

perpendicular to the long axis

horizontal bone loss angular or vertical bone loss

Page & Schroeder (1982)

2.5 mm range of influence of the subgingival plaque

“when the bone surface has been resorbed to about 2.5mm apical or lateral to site of

bacteria, bone loss appears to cease and bone production takes over”

infrabony lesions seldom develop on the buccal surface

Tal (1984)

<2.6mm rarely infrabony defect seen

Interdental distance

>3.1mm infrabony defect seen

RADIOGRAPHIC CHANGES IN PERIODONTITIS

• Fuzziness and a break in the continuity of the lamina dura

• A wedge-shaped radiolucency

• The height of the interdental septum is progressively reduced by the extension of

inflammation and the resorption of bone.

RADIOGRAPHIC APPEARANCE OF CRATERS

appear as angular or vertical defects

• do not indicate the internal morphology or

• depth of the craterlike interdental defects

• do not reveal the extent of involvement on the facial and lingual surfaces

Reasons for this

1. Facial and lingual surface bone destruction is obscured by the dense root structure,

and

2. Bone destruction on the mesial and distal root surfaces may be partially hidden by

a dense mylohyoid ridge.

A reduction of 0.5mm or 1.0mm in the thickness of the cortical plate is sufficient

to permit radiographic visualization of destruction of the inner cancellous

trabeculae.

In most cases it can be assumed that bone losses seen interdentally continue in

either the facial or lingual aspects creating a troughlike lesion.

Gutta percha packed around the teeth increases the usefulness of the

radiograph for detecting the morphologic changes of osseous craters and

involvement of the facial and lingual surfaces. However, this is a cumbersome

technique and is seldom performed.

The true lesion can only be detected by clinically probing the defect.

Surgical exposure and visual examination provide the most definitive

information regarding the bone architecture produced by periodontal

destruction.

RADIOGRAPHIC CHANGES IN LOCALIZED, AGGRESSIVE

PERIODONTITISJuvenile periodontitis is characterized by a combination of the following

radiographic features:

• Bone loss may occur initially in the maxillary and mandibular incisor and/or

first molar areas, usually bilaterally, and results in vertical, arc like destructive

patterns .

b. Loss of alveolar bone may become generalized as the disease

progresses but remains less pronounced in the premolar areas.

RADIOGRAPHIC CHANGES IN TRAUMA FROM OCCLUSION

Trauma from occlusion can produce radiographically detectable changes in the

lamina dura,

morphology of the alveolar crest,

width of the periodontal space, and

density of the surrounding cancellous bone

PHASES OF TRAUMA FROM OCCLUSION

The injury phase

a loss of the lamina dura that may be noted in apices,

furcations, and/or marginal areas. The loss of lamina

dura results in widening of pdl space.

The repair phase

attempt to strengthen the periodontal structures

widening of the periodontal ligament space

More advanced traumatic lesions

result in deep angular bone loss when combined with

marginal inflammation lead to intrabony pocket.

RADIOGRAPHIC APPEARANCE OF PERIODONTAL ABSCESS

Abscess is that of a discrete area of radiolucency along the lateral aspect of the root .

However the radiographic picture is often not typical

• In the early stages presents no radiographic changes.

• The extent of bone destruction and the morphologic changes of the bone.

• The location of the abscess – lesion in the soft tissue wall of periodontal pocket

less likely to produce radiographic changes

FURCATION DEFECTS

Etiology

periodontitis

endodontic infection,

root perforation during dental procedures, or

occlusal trauma.

These changes are most readily seen in the mandibular molar region.

Maxillary molars have three roots, early change in their furcation areas are more

difficult to assess.

But 30% to 55% of grade 2 or 3 furcation involvements have a

furcation arrow present on the radiograph.

Diagnostic criteria are suggested:

• The slightest radiographic change in the furcation area should be investigated

clinically, especially if there is bone loss on adjacent roots .

• Diminished radiodensity in the furcation area in which outlines of bony

trabeculae are visible suggests furcation involvement.

• Whenever there is marked bone loss in relation to a single molar root, it may

be assumed that the furcation is also involved .

ROOT MORPHOLOGY

The radiograph is the only method, short of direct observation, of visualizing the

morphology of the roots.

Radiographic parameters help in clinical significance:

length of the root trunk

root length,

root divergence/convergence

root resorption, and

root shape

gemination or fusion

root dilacerations

OPEN CONTACTS

a. When the mesial and distal surfaces of adjacent teeth do not touch, the patient

has an open contact. This condition is potentially dangerous to the

periodontium.

b. Similar potential situations in which periodontal disease may develop include

discrepancies in the height of two adjacent marginal ridges or tipped teeth.

LOCAL IRRITATING FACTORS

a. Calculus

b. Overhanging restoration margin

SKELETAL DISTURBANCES MANIFESTED IN THE JAWS

a. Osteitis fibrose cystica (Recklinghausen's disease of bone) develops in

advanced primary or secondary hyperparathyroidism and causes osteoclastic

resorption of bone with fibrous replacement and hemorrhage with hemosiderin

deposition, creating a mass known as brown tumor.

b. In Paget's disease, the normal trabecular pattern is replaced by a hazy, diffuse

meshwork of closely knit, fine trabecular markings, with the lamina dura

absent, or scattered radiolucent areas may contain irregularly shaped

radiopaque zones.

c. Fibrous dysplasia may appear as a small radiolucent area at a root apex or as an

extensive radiolucent area with irregularly arranged trabecular markings. There

may be enlargement of the cancellous spaces, with distortion of the normal

trabecular pattern ("ground glass" appearance) and obliteration of the lamina

dura.

d. Langerhans cell Histiocytosis they appear as single or multiple radiolucent

areas, which may be unrelated to the teeth or entail destruction of the tooth

supporting bone.

e. In osteopetrosis (marble-bone Albers-Schonberg disease) the outlines of the

roots may be obscured by diffuse radiopacity of the jaws. In less severe cases

the increased density is confined to the bone in relation to the nutrient canals

and the lamina dura.

f. In scleroderma, the periodontal ligament is uniformly widened at the expense

of the surrounding alveolar bone.

PRESURGICAL PLANNING FOR PLACEMENT OF IMPLANTS

Before surgical intervention, it is necessary to know the location of vital structures

that may be in proximity to the surgical site.

Many implant protocols call for a certain minimal space (e.g., 2 mm) between the

apical extent of the osteotomy site and any vital structure, such as the

mandibular canal.

Because this type of surgery often involves placing implants in relatively close

proximity to such structures, it is necessary to know the vertical and horizontal

magnification of the radiographic image.

DIGITAL RADIOGRAPHY

There are currently two competing technologies available for the implementation of

digital imaging. One uses solid-state detectors, the other photostimulable

phosphor

Digital imaging offers a number of advantages compared to film.

• The elimination of chemical processing is considered one of the main benefits.

• Shorter exposure-to-display time.

• Integration with existing electronic office and patient-management systems.

• Image processing can be used to enhance the perceived quality, either to

restore the subjective quality of the image as a whole or to enhance a selected

region in the image for a specific diagnostic task.

• Furthermore, the software offers a variety of measurement tools, most of

which are digital versions of existing analog tools.

• The benefits of digital imaging are obtained along with a reduction in radiation

exposure, although the amount of exposure reduction is dependent on the type

of receptor.

ADVANCED DIAGNOSTIC TECHNIQUES

Most assessment of bone loss in clinical practice today is achieved by visual

comparison of the radiographs.

The radiograph contains so much information that it is difficult for the human eye

to detect small changes in bone support in the presence of a busy background

containing the teeth and bone.

Studies have shown that a 30% to 50% change in bone mineral is needed to be

visible even to the experienced clinician.

Techniques have been developed that enhance our ability to “see” small changes

over time in the bone. These include

• Digital Substraction radiography

• Computer assisted densitometric image analysis

DIGITAL SUBTRACTION RADIOGRAPHY (DSR)

Zeidses des Plantes (1935) : 1st demonstrated use of subtraction imaging

Depends up on conversion of serial radiographs into digital images.

The serially obtained digital images are superimposed & image intensities of corresponding pixels are subtracted

If change has occurred

The brighter area represents gain

Darker area represents loss

CONCEPT OF DSR

• When two images of the same object are registered and the image intensities of

corresponding pixels are subtracted, a uniform difference image will be

produced.

• If a change in the follow-up image has occurred, this change will show up as a

brighter area when the change represents gain and as a darker area when the

change represents loss.

• The strength of DSR is that it cancels out the complex anatomic background

against which this change occurs.

d. Subtraction images allow detection of mineral changes of as little as 5%. In

addition to early detection, a number of quantitative measurements can be

made, such as linear, area, perimeter and density measurement.

e. An early technical challenge in DSR was the requirement that the consecutive

images be closely aligned for an accurate comparison to be made. This was

accomplished using custom stents and other devices that made the technique

less practical.

f. For clinical use recent technologic enhancements have enabled

compensation for imprecision in placement, thereby allowing for the accurate

"superimposition" of the images, which is required for DSR. This has made

DSR much easier, and it is widely used in periodontal research. However, the

technique is still not commonly used by clinicians.

Overall contrast is

improved

Trabecular marrow

spaces are visualized

Enhancement of low

and high density

images

no objective description

High standardization of x

rays

No reduction in exposure

ADVANTAGES DISADVANTAGES

COMPUTER ASISTED DENSITROMETRIC IMAGE ANALYSIS SYSTEM

Introduced by Urs Brägger et al 1988

A video camera measures the light transmitted through the a radiograph

Signal are converted to grey scale images

Camera is interfaced with computer and image processor for storage and mathematic manipulation of image

Offers an objective method for studying alveolar bone changes quantitatively

High degree of sensitivity ,accuracy and reproducablity

Advantages

Objective method – Quantitative measurements

Higher sensitivity

reproducibility

Higher accuracy

Urs Brägger et al in 1988

CADIA was more sensitive than subtraction radiography CADIA was capable of assessing differences in

remodeling activity over 4–6 weeks after periodontal surgery

Objective method to quantify alveolar bone density

CONVENTIONAL X-RAY TOMOGRAPHY

PRINCIPLE

Designed to image a slice or plane of tissue

It consists of an x ray tube and radiographic film rigidly connected which

moves about a fixed axis and fulcrum

As exposure begins tube and film move in opposite direction

simultaneously .

Objects located with in the fulcrum remain in fixed positions and are

viewed clearly

ADVANTAGES

Offers true cross sectional images of the alveolar ridge

Useful during placement of single or multiple implants

LIMITATIONS

Blurring of structures on either side of focal plane

Time required for reposition of the patient for every image.

Cost is higher

COMPUTED TOMOGRAPHY

PRINCIPLE

A thin fan-beam of X rays rotates around the patient to generate in one revolution

a thin axial slice of the area of interest.

Multiple overlapping slices are obtained

With the help of a computer a 3 D digital map of the jaws is the advantage of the CT.

ADVANTAGES

1. Three dimensional

2. Precise detailed information

3. Images can be adjusted and printed without magnification.

4. Vertical & horizontal rulers adjacent to each image.

5. Digital format

6. Bone & soft tissue contrast

7. Excellent resolution

CT Image construction

Computer algorithms use photon counts to construct

digital images

Images are displayed in individual blocks -----VOXELS

Each square of the image is matrix----PIXELS

Each pixel is assigned a CT number representing tissue

density

CT number HOUNSFIELD units

Range -1000 to 1000

DISADVANTAGES

• Requires specialised equipment

• Much higher radiation dose to the patient

• Metallic restorations can cause artifacts.

• Cost is significantly high.

CONE BEAM COMPUTED TOMOGRAPHY (CBCT)

Developed in 1982 for angiography

Utilizes cone shaped source of ionizing radiation & 2D area detector fixed

on a rotating gantry .

Multiple sequential images are produced in one scan

• Rotates 360° around the head

• Scan time typically < 1 minute

CT V/S CBCT

Conventional CT scanners make use of a fan-beam and Provides a set of consecutive slices of image

Conventional CT makes use of a lie-down machine with a large gantry.

Greater contrast resolution &More discrimination between different tissue types (i.e. bone, teeth, and soft tissue

Utilize a cone beam, which radiates from the x-ray source in a cone shape, encompassing a large volume with a single rotation.

a sitting-up machine of smaller dimensions

Commonly used for hard tissue Ease of operation Dedicated to dental Both jaws can be imaged at the

same time Lower radiation burden

TUNED APERTURE COMPUTED TOMOGRAPHY (TACT®)

The motivation behind the development of TACT® was to be able to achieve 3 D

with existing dental equipment and without the high cost and dose associated

with computed tomography.

PRINCIPLE

TACT® is built on the basic principles of tomosynthesis: by shifting and

combining a set of basic projections, arbitrary slices through the object can be

brought into focus.

The basic projections are conventional transmission radiographs. Each radiograph

is taken from a different angle relative to the object and the receptor.

Ongoing research seeks to further improve this technology and determine optimal

parameters for various clinical applications.

OPTICAL COHERENCE TOMOGRAPHY

Optical coherence tomography (OCT) generates cross-sectional images of

biological tissues using a near-infrared light source.

The light is able to penetrate into the tissue without biologically harmful

effects.

Differences in the reflection of the light are used to generate a signal that

corresponds to the morphology and composition of the underlying tissues.

The feasibility of its clinical use was demonstrated by capturing high-

resolution images of oral structures, including soft tissue and hard tissue

boundaries of the periodontium.

While it is yet too early to judge the potential success of OCT as a routine

clinical tool, the initial results warrant keeping an eye on further developments

of this technology.

CONCLUSIONa. Radiographs can provide critical information for diagnosis and treatment

planning, which can also serve as baseline information for the assessment of

treatment outcomes.

b. Commonly used modalities include bitewing, periapical and panoramic

radiography.

c. One of the main limitations is the two-dimensional representation of three-

dimensional structures.

d. There also needs to be a substantial amount of mineral loss (30–50%) before

bone resorption can be detected. These limitations reduce the sensitivity of

conventional radiography and generally result in underestimating actual bone

loss even when high quality images are produced.

e. Misdirection of the central ray of the X-ray beam as well as exposure and

processing errors further limit accuracy.

f. The radiograph and clinical periodontal examination complement one another.

Neither is sufficient by itself, but together they can provide a sound

foundation for diagnosis and treatment planning.

g. Despite certain limitations, the conventional dental radiograph is an

indispensable adjunct in diagnosis and treatment planning.

REFERENCES

1. Carranza’s Clinical Periodontology 10th Edition.

2. Oral Radiology – White & Pharoah

3. Periodontics Medicine, Surgery,and Implants - Rose, Mealey

4. Periodontology 2000, vol-34, 2004, 34-48.

5. Clinical practice of dental hygienist, 9th edition, Wilkin’s

6. Fundamentals of periodontics – Wilson & Korman

7. Advances in periodontics – Wilson, Korman

8. Diagnosis & risk prediction of periodontal disease - Axelsson

KEY POINTS