P1-ENDO-CHAPTER 5

○ Diagnosis

○ Various treatment phases

○ Evaluation of the success or failure of treatment

Radiographs contribute to

○ Achieve films of maximal diagnostic quality

○ Minimize retaking of films

○ Avoid additional exposure of patients

It is necessary to master radiographic techniques to:

○ Recognizing deviations from the norm

○ Understanding the limitations associated with endodontic radiography

Expertise in radiographic interpretation is essential for

Periapical radiograph

Primary radiograph used in endodontics:

○ Abnormal conditions in the pulp

○ Periradicular tissues

Functions of the Periapical Radiograph In DIAGNOSIS

○ Number of roots and canals

○ Location of canals

○ Root curvatures

Functions of the Periapical Radiograph TO DETERMINE

Radiograph

It is a two-dimensional image (major limitation

Tooth in the center of the films

Technical Requirements for Endodontic Radiographs

3 mm

Endodontic radiograph should have At least ____ of bone visible beyond the apex of the tooth

○ Misdiagnosis

○ Improper interpretation of the apical extent of a root

○ Incorrect determination of file lengths for canal cleaning and shaping

Failure to capture 3mm of apex of the tooth will have a result of

○ Elongation

○ Foreshortening

Image shape distortion

Interpretive errors during diagnosis and treatment

Distortion may lead to:

Bite-wing Radiograph

Has less image distortion due to parallel placement

○ Anatomic extent of the pulp chamber

○ Pulp stones or calcifications

○ Recurrent caries

○ Depth of existing restorations

○ Evidence of previous pulp therapy

In Bite-wing Radiograph it provides information about the anatomic crown of the tooth, including:

Relationship of remaining tooth structure to crestal height of bone

Bitewing radiograph indicates

Restorability of the tooth

Bitewing radiographs aids in determining

○ Rubber dam system is in place

○ Visibility is reduced

○ Bows of the clamp restrict precise film positioning

Technique is more critical because:

○ Canal working lengths

○ Location of superimposed objects, canals, and anatomic landmarks (by altering cone angulations)

○ Biomechanical instrumentation

Master cone adaptation

Periradicular radiographs used to determine

○ Medical and dental history

○ Clinical examination

○ Pulp-testing procedures

Information from radiographs must be integrated with:

○ Allows a privileged look inside the jaw

○ Provides essential information

○ Information cannot be obtained from any other source

Advantages of Radiographs

Inability to detect bone destruction or pathosis limited to cancellous bone

Major limitation of Radiographs

External erosion of the cortical plate

■ Internal erosion of the cortical plate

Radiolucencies: Usually do not appear unless there is

Symptomatic

Teeth may be: ____ with no radiographic changes

Cortical plate is especially thin

Radiolucent lesions may be visible earlier if:

Paralleling technique

This produces the most accurate periradicular radiograph

Long-cone technique

Right-angle technique

Other name for Paralleling technique

Film placed parallel to the long axis of the teeth

Film placement for parelling technique

Central beam

In parelleling technique it is directed at right angles to the film and ligned through the root apex

○ Film positioned away from the tooth

○ Toward the middle of the oral cavity

○ Especially when the rubber dam clamp is in position

To achieve parallel orientation

Long-cone (16 to 20 in) aiming device:

○ Increases focal spot-to-object distance

○ Directs only the most central and parallel rays

○ Reduces size distortion

○ Shallow palatal vault

○ Tori

○ Extremely long roots

○ Gagging

True parallel placement may be impossible due to

○ Up to 20 degrees from the long axis of the tooth ‘

○ With minimal longitudinal distortion

Film may diverge:

Maxillary molars

Increased vertical angulation increases superimposition of the zygomatic process

○ Projects the zygomatic process superiorly

○ Away from the molar roots

Vertical angle of not more than 15 degrees:

10 to 20 degrees

Modified paralleling technique: increases vertical angulation by

foreshortening

Modified paralleling technique Introduces small degree of

Modified paralleling technique

Increases periradicular definition

Snapex system:

○ Film holder and aiming device

○ Altered for the modified paralleling technique

Distal angulated radiograph:

○ 10–20 degree horizontal shift of the cone from the distal

○ Enhances anatomic clarity

○ Beam directed toward the mesial

■ Buccal roots

■ Zygomatic process to the mesia

Distal angulated radiograph projects

Bisecting-Angle Technique

Not preferred for endodontic radiography

○ Modified paralleling technique cannot be used

Bisecting-Angle Technique used only when

■ Difficult anatomic configurations

■ Patient management problems

○ Modified paralleling technique cannot be used due to

Film placed directly against the teeth without deforming the film

Film placement for bisecting technique

○ Plane of the film

○ Long axis of the teeth

An angle exists between:

Foreshortened image

If beam directed: perpendicular to the film

Elongated image

If beam directed perpendicular to the long axis of the teeth →

○ Directing the beam perpendicular to an imaginary line

○ That bisects the angle between tooth and film

In bisecting technique Correct image length achieved by:

○ Film and object are not parallel

○ Beam is not at right angles to both

In bisecting technique Image distortion occurs because:

○ More frequent superimposition of the zygomatic arch

○ Especially over apices of maxillary molars

Distortion of Bisecting will result to

Film holders and aiming devices

required for the paralleling technique

○ Film

○ Central beam

○ Tooth

Film holder reduce geometric distortion caused by misorientation of

○ Minimize cone cutting

○ Improve diagnostic quality

○ Allow similarly angulated radiographs during:

■ Treatment

■ Recall

Film holders can

○ Reduce film displacement

○ Minimize retakes

○ Make it easier for:

■ Patient

■ Clinician

■ To properly position the film

By eliminating the patient’s finger from the x-ray field, they:

Hemostat

One of the most versatile film-holding devices

90-degree angle to the film

Hemostat Cone positioned at a

○ Ostby frame

○ Young frame

Radiolucent, plastic, rubber dam frame should be used:

Stabe disposable film holder

Ideal for:

■ Pretreatment films

■ Posttreatment films (

● Dunvale Snapex system

● XCP (extension cone paralleling) instruments

● EndoRay II endodontic film holder

● Uni-Bite film holder

● Snap-A-Ray film holder

● Snapex system film holder with aiming device

● Crawford film holder system

Commercial Film-Holding and Aiming Devices

XCP System Variations

Prevent displacement of the rubber dam clamp

Increase periradicular coverage

Off center in the bite block

In XCP System Variations the film is placed

Off center relative to the aiming ring

In XCP System Variations the cone is placed

○ Placement of the bite block adjacent to the rubber dam clamp without altering the parallel relation of the cone to the film

XCP System Variation allows

Customized hemostat

○ With rubber bite block attached

○ Assists film placement during working radiographs

EndoRay

Crawford film holder system

Designed to:

Secure parallel working films

With rubber dam clamp in pla

Density

Degree of darkening of the film

Contrast

: Difference between densities or shades of gray

○ Quantity and quality of radiation

○ Subject thickness

○ Developing/processing conditions

Density depends on

Milliamperage (mA)

Controls electron flow from cathode to anode

Greater electron flow

greater quantity of radiation

○ Milliamperage

○ Exposure time

Density primarily controlled by:

Kilovoltage (kVp)

Controls quality and penetrability of x-rays

Higher kVp

shorter wavelengths → more penetrating rays

○ Amount of radiation reaching the film

○ Degree of darkenin

Kilovoltage affect density by alterning

long-scale/low contrast

High kVp (e.g., 90 kVp)

High kVp (e.g., 90 kVp

○ More shades of gray

○ Less distinct differences

short-scale/high contrast

Low kVp (e.g., 60–70 kVp)

Low kVp (e.g., 60–70 kVp) →

Sharp differences between few shades

Exposure time and milliamperage

○ Control number of x-rays

○ Influence mainly film density

Kilovoltage

○ Controls penetrability

○ Influences contrast

Optimal kVp and exposure time

Must be individualized for each radiograph unit and exposure requiremen

Proper darkroom organization

film handling

adherence to time and temperature

critical for high-quality film

<1–2 minutes

Rapid Processing for Working Films produce films in

■ Shelf life

■ Tank life

■ Production of permanent-quality films

Rapid-processing solutions:

○ Commercially available

○ Vary in

10 minutes

Return film to fixer fo

20 minutes

Wash for

Double film packets

○ One processed rapidly

○ One processed conventionally

○ Pretreatment ○ Posttreatment ○ Recall radiographs

Controlled time and temperature method used for

○ Small areas of resorption

○ Invaginated enamel

○ Separated files

○ Minute fracture lines

○ Extra canals or roots

○ Curved and calcified canals

Frequently overlooked features include:

○ Avoid problems during treatment

○ Save time and reduce extra expense

● Thorough radiographic examination helps:

○ Mental foramen

○ Incisive foramen

Commonly misinterpreted anatomic structures:

○ Exposures at different angulations

○ Pulp-testing procedures

Differentiation methods

Radiolucencies not associated with the root apex

○ Move or are projected away from the apex when angulation varies

Sparse trabeculation

May simulate radiolucent lesions

■ Lamina dura

■ Periodontal ligament space

Sparse trabeculation Must be differentiated from

Periapical cemental dysplasia

Common Misinterpreted Osteolytic Lesions

cementoma

Periapical cemental dysplasia also known as

Lamina dura

Layer of compact bone lining the tooth socke

cribriform plate or alveolar bone proper

Lamina dura also called as

Noxious products from the root canal system

Changes in lamina dura can be caused by: