Week 8 -extraoral Flashcards
indications for panoramic rad
- overall mouth exam
- evaluate impacted tooth
- dentomaxillafacial trauma
- pathology
panoramic rad AKA
orthopantogram / dental panoramic tomography
center of panoramic image is projection of
anterior & midline structures
structures anterior & posterior to focal trough are
blurred
tube is angulated upwards to create
magnification & distortion
structures closest to IR are ___ and further from IR are ___
in focus; magnified & blurred
tube has ___ aperture & directed from __ to __
vertical slit; lingual to labial
resultant OPG image is uniformly magnified due to
long OID with some premolar contact overlapping
frankfurt line
horizontal line between top of ear canal to bottom border of eye along either side of skull
can patients use lead gown & thyroid shield for OPG
only lead gown
patient positioning for OPG
- patient upright with chin resting on chin rest
- bite onto incisor block using upper & lower incisors
- hold onto handle rails for support
- immobilize head using temple support
- laser lines to check frankfurt, MSP, canine lines
- put tongue to roof of mouth
- hold still for 15s
image critique of OPG
MESS TG
- minimal c-spine shadow visible
- entire maxilla & TMJ recorded
- symmetrical on both sides
- slight smile / downward curve of occlusal plane
- tongue against palate w/ lips closed
- good teeth representation w/ minimal magnification
common OPG errors
- ghost / double images
- artifacts
- palatoglossal airway space
- incorrect exposure settings
- chin too low, forward
- head not on chin rest
- movement
benefits of OPG
- entire overview of mouth
- low dose
- good for impacted tooth, soft tissue evaluation
- less painful than intraoral
limits of OPG
- no thyroid shield
- cannot visualize fine details & measurements due to distortion
- cannot pause & continue
- high exposure time
- difficult for short neck & wide shoulder, wheel chair bound patients
