Bisecting Angle Tecnique `What is

What is the bisecting angle technique and how does it compare to paralleling?

A technique that uses the imaginary bisector rule

• Produces lower quality and more distorted images than paralleling

What does a periapiacal mage show and how is the receptor positioned 

Shows the entire tooth and surrounding bone 

• Receptor placed parallel to the teeth 

What is distortion and why is it common in bisecting?

Variation in true size/shape of tooth, caused by incorrect angulation since the bisector line is estimated

When is the bisecting Tecnique used?

When paralling cannot be done

• Small mouths, shallow palate

• Tori

• Gagging

• Special needs patients

Define the long axis of the tooth and its purpose

Imaginary line dividing the tooth lengthwise into two equals halves

• Used as reference for PID/receptor positioning

Where and how is the receptor placed?

• On the lingual surface 

• As close to the teeth as possible 

• With 1/8 inch extending beyond Incisal or occlusal edge 

What is the imaginary bisector and how should the x-ray beam be aimed?

Line dividing the angle between tooth axis and receptor 

• Beam aimed perpendicular to this line 

What happens with incorrect angulation?

• Horizontal: closed/overlapped contacts

• Vertical: wrong tooth length

  • Too flat → elongation (teeth long)

  • Too steep → foreshortening (teeth short)

Which film holders are used?

• Stable bite-blocks 

• Eezee-Grip (Snap-A-Ray)

List key advantages of bisecting

Easier for children, small mouths, tori, shallow palates and for topographical occlusal radiography

List key disadvtanges of bisecting 

Image distortion, difficulty estimating bisector, and possible zygomatic arch overlap on maxillary molars