Dental Panoramic Radiographs Flashcards
Clinical indications for OPT?
Lesion/ unerupted tooth is of size/position can’t be seen w/ intra-oral film
Pathology all 4 quadrants
Periodontal disease >6mm
Assessment 3rd molars prior surgical XLA
Orthodontic assessment mixed dentition
Follow trauma
Implant planning
What is dose of panoramic radiograph?
20uSv
Principles of OPT image formation?
A tomograph of the jaw (slices)
X-ray tube and image receptor orbit around the patient head
Why does the jaw need to be in the focal trough?
Structures within the focal trough are sharp - outside is distorted
How to position the patient?
Use the chin rest or bite peg w/ light beam markers to ensure midline in central and Frankfort plane is horizontal and canine light lies between upper lateral and canine
What happen if position pt too far in?
Anterior teeth narrow and blurred
Premolar overlap
Loss cervical spine
What happens if position pt too far out?
Incisors widen and blurred
Condyles missed off edge of film
What happens if pt position chin up?
Roots of upper incisors blurred
Grumpy face
Condyles lost off film
What happens if pt position chin down?
Lower incisors roots blurred
Hyoid bone over mandible
Smiley face
What happens if pt rotated their head?
Magnification of one side of the jaw
What happens if the pt moves during exposure?
If pt moves can mimic fracture lines
What happens if pt swallows during exposure?
Well-defined air-density over the tongue over the dorm
Unilateral distortion of hyoid
Radiolucency over ramus
Why do normal shadows appear?
Bc OPG is a tomograph where x-ray photons pass through most structures twice
What is a ghost image?
Formed when inject lies between the centre of rotation of x-ray time and image receptor
Where do ghost image appear?
Opposite side to real image and higher up and blurred
