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PERI-APICAL RADIOGRAPHS

VS

Bisecting Angle Technique

Parallel Angle Technique SALMAN ZAHID DEPARTMENT OF OPERATIVE DENTISTRYSUPERVISED BY DR. SADAF ALI

Peri-apical radiograph:Intraoral techniques designed to show individual teeth and the tissues around the apices.

Peri-apical radiograph Indications:

Caries detection

Pulp chamber & canal

Anatomy of pulp chamber and canal is highly variablePulp Stones

Canal length determination

Secondary caries detection

Status of Root Filling

Follow up

Trauma

Peri-apical pathology

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Root resorption

Bone loss Alveolar bone heightAlveolar bone healthGeneralised vs localised alveolar bone loss

Basically two techniques for peri-apical radiographs have been developed

1- Parallel angle technique2- Bisecting angle technique

Paralleling techniqueIn this technique film is positioned parallel to the long axis of the tooth under investigation and beam is directed perpendicularly

Film Central axis of tooth

FilmCentral axis of toothCentral rays of x-ray beam

Bisecting angle techniqueBased on principal of aiming x-ray beam at 90 degrees to an imaginary line which bisects the angle between the longitudinal axis of the tooth and the film

comparISON OF advantages of the two techniques

Vertical and horizontal angulation automatically determinedReproducible radiographs when placed in holderRelative position of film, teeth and x-ray beam are always maintained Paralleling techniqueBisecting techniquePositioning of the film is comfortablesimple and quicksame length of tooth formed on radiograph

comparISON OF advantages of the two techniques

Vertical and horizontal angulation automatically determinedReproducible radiographs when placed in holderRelative position of film, teeth and x-ray beam are always maintained Paralleling techniqueBisecting techniquePositioning of the film is comfortablesimple and quicksame length of tooth formed on radiograph

comparISON OF advantages of the two techniques

Vertical and horizontal angulation automatically determinedReproducible radiographs when placed in holderRelative position of film, teeth and x-ray beam are always maintained Paralleling techniqueBisecting techniquePositioning of the film is comfortablesimple and quicksame length of tooth formed on radiograph

comparISON OF disadvantages of the two techniques

Paralleling technique1. Positioning of image receptor can be very uncomfortable and causes gagging2. Positioning film holder with in the mouth is difficult3. Anatomy of mouth makes technique impossible e.g curved palate4. Technique can not performed satisfactorily using a short focal distance because of resultant magnification

Bisecting technique1. Involvement of variable causes distortion of image2. Zygomatic buttress frequently overlies the root of molar3. Non reproducible views4. Coning off or cone cutting may result if beam not aimed at center5. Incorrect horizontal angulation cause overlapping

comparISON OF disadvantages of the two techniques

Paralleling technique1. Positioning of image receptor can be very uncomfortable and causes gagging2. Positioning film holder with in the mouth is difficult3. Anatomy of mouth makes technique impossible e.g curved palate4. Technique can not performed satisfactorily using a short focal distance because of resultant magnification

Bisecting technique1. Involvement of variable causes distortion of image2. Zygomatic buttress frequently overlies the root of molar3. Non reproducible views4. Coning off or cone cutting may result if beam not aimed at center5. Incorrect horizontal angulation cause overlapping

comparISON OF disadvantages of the two techniques

Paralleling technique1. Positioning of image receptor can be very uncomfortable and causes gagging2. Positioning film holder with in the mouth is difficult3. Anatomy of mouth makes technique impossible e.g curved palate4. Technique can not performed satisfactorily using a short focal distance because of resultant magnification

Bisecting technique1. Involvement of variable causes distortion of image2. Zygomatic buttress frequently overlies the root of molar3. Non reproducible views4. Coning off or cone cutting may result if beam not aimed at center5. Incorrect horizontal angulation cause overlapping

REFERENCES:ESSENTIAL OF RADIOGRAPHY AND RADIOLOGY BY ERIC WHAITESIMAGES FROM INTERNET