12 Panoramic viewing and evaluation Flashcards
panoramic radiograph viewing overview
use viewbox with strong illumination and reduced ambient lighting.
use a routine, orderly approach, starting at the same spot and ending at the same spot each time
first, evaluate osseous structures, then soft tissue, then air spaces, and teeth last
coronoid process
begin radiograph viewing at right process
tip of process can be below, superimposed, or 1cm above zygomatic arch.
if more than 1cm above - coronoid hyperplasia
coronoid hyperplasia
unilateral usually due to osteochondroma.
bilateral almost always in males, slowly reducing opening, possibly due to excess GH or testosterone receptors on process
intraoral coronoidectomy effective treatment
medial sigmoid depression
just below and medial to sigmoid notch, variable in size, may be unilateral or bilateral
head of condyle
examine cortical rim for fractures or erosions. normal bone with breaks or erosions suggests inflammation or neoplasia
rheumatoid arthritis development
autoimmune synovitus produces macrophage filled pannus that breakdown cartilage and bone. cortical erosions first sign of rheumatoid arthritis
rheumatoid arthritis effects
erosions destroy condylar head leaving thin, sharp residua which perforate the disk. crepitus, fibrous adhesions or bony ankylosis follow with anterior open bite
75% of patients with RA in TMJ
parotid malignancy, osseous or cartilagenous neoplasms can cause cortical erosions without RA
osteoarthritis
pathologic remodeling in direction of loading joint (TMJ loads in ateriomedial direction)
flattened, irregular condyle head leads to spurs and osteophytes (osteophytes fracture - loose bodies)
subcortical cysts may be visible in cortical rim
condylar head or temporal bone may show sclerosis
joint sounds w/o pain or limited function do not need condylar shave procedure
fovea
large, ovoid radiolucency may be seen on medial condyle
bifid condyle
may be in medial-lateral or antero-posterior direction
cortical border of mandible
follow from right condyle around to left condyle looking for fractures
fractures appear wider 2 weeks post-injury due to resorption
4-6 weeks post-injury only radiolucent fracture line visible, fuzzy radiopacity over line is callus that will remodel within a year
fractures
appears at two distinct lines that join at inferior border
fracture classifications
greenstick: one cortex broken while other is bent
comminuted: bone shattered in multiple fragments
compound: exposes fracture to external environment through skin, mucosa, or PDL
simple: inferior border to superior border, may be between teeth
jaw fractures usually compound (75%) or simple
prominent antegonial notch
masseteric hypertrophy, gum chewing, or parafunctional habits cause bumpy remodel of gonial angle and prominent antegonial notch
lingula
at top of mandibular canal
impacted teeth
assess relationship of impacted teeth to mandibular canal for possible paresthesia following extraction
IAN bundle
90% of IAN bundle exits at mental foramen, remaining 10% sometimes visible on radiographs
Stafne defect
lingual submandibular gland depression in mandible near angle. 80-90% male
trabecular bone quality
thin (<3mm) trabeculae, too few or too far apart at angle of madible described as osteopenic pattern. refer to physician for possible mineral disorder
external auditory meatus
well-defined unilocular radiolucency lateral to condylar head
zygomatic arch
zygomatico-temporal suture
arch - medial to condyle
suture - often not visible, but can be wide. not a fracture
air cell defect
1% display well-defined uni- or multilocular radiolucency in articlular eminence or distal zygomatic arch from mastoid air cells. no treatment needed
pterygomaxillary fissure
upside down teardrop radiolucency at lateral border of maxillary sinus where PSA enters sinus. pharyngeal malignancies can cause erosions of fissure
pterygoid plates
two triangular radiopacities inferior to pterygomaxillary fissure, superimpose over coronoid process
hamular process
radiopaque spiny structure lateral to maxillary tuberosity, best seen in edentulous
orbit
superior to maxillary sinus, infraorbital canal also visible
malar process of zygoma
medial to pterygomaxillary fissure, vertical band of bone, superimposed on lateral 3rd of maxillary sinus
hard palate
linear horizontal radiopacity superimposed over midportion of maxillary sinus and nose
calcified styloid ligament
styloid ligament may become calcified and can lead to Eagle’s or carotid artery syndrome
hyoid bone
body is radiopacity inferior to molars, greater cornu lateral to body, lesser cornu at 45degrees from body
transverse foramina of C2
C2 is only vertebrae with nonvertical foramen
nose
ala, nasolabial folds, and conchae can sometimes be seen
epiglottis
superior to hyoid bone and at base of tongue is the curve outline of the epiglottis
palatoglossal airspace
if tongue is not placed against the palate a radiolucency will be superimposed over roots of maxillary teeth and sinus floor
oropharyngeal airspace
with tongue against the palate the remaining airspace is space around tonsils in oropharynx
nasal air
two thin oblique slits superimposed over soft tissue outline of nose
