12 Panoramic viewing and evaluation

Question 1

panoramic radiograph viewing overview

Answer 1

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

Question 2

coronoid process

Answer 2

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

Question 3

coronoid hyperplasia

Answer 3

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

Question 4

medial sigmoid depression

Answer 4

just below and medial to sigmoid notch, variable in size, may be unilateral or bilateral

Question 5

head of condyle

Answer 5

examine cortical rim for fractures or erosions. normal bone with breaks or erosions suggests inflammation or neoplasia

Question 6

rheumatoid arthritis development

Answer 6

autoimmune synovitus produces macrophage filled pannus that breakdown cartilage and bone. cortical erosions first sign of rheumatoid arthritis

Question 7

rheumatoid arthritis effects

Answer 7

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

Question 8

osteoarthritis

Answer 8

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

Question 9

fovea

Answer 9

large, ovoid radiolucency may be seen on medial condyle

Question 10

bifid condyle

Answer 10

may be in medial-lateral or antero-posterior direction

Question 11

cortical border of mandible

Answer 11

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

Question 12

fractures

Answer 12

appears at two distinct lines that join at inferior border

Question 13

fracture classifications

Answer 13

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

Question 14

prominent antegonial notch

Answer 14

masseteric hypertrophy, gum chewing, or parafunctional habits cause bumpy remodel of gonial angle and prominent antegonial notch

Question 15

lingula

Answer 15

at top of mandibular canal

Question 16

impacted teeth

Answer 16

assess relationship of impacted teeth to mandibular canal for possible paresthesia following extraction

Question 17

IAN bundle

Answer 17

90% of IAN bundle exits at mental foramen, remaining 10% sometimes visible on radiographs

Question 18

Stafne defect

Answer 18

lingual submandibular gland depression in mandible near angle. 80-90% male

Question 19

trabecular bone quality

Answer 19

thin (<3mm) trabeculae, too few or too far apart at angle of madible described as osteopenic pattern. refer to physician for possible mineral disorder

Question 20

external auditory meatus

Answer 20

well-defined unilocular radiolucency lateral to condylar head

Question 21

zygomatic arch

zygomatico-temporal suture

Answer 21

arch - medial to condyle

suture - often not visible, but can be wide. not a fracture

Question 22

air cell defect

Answer 22

1% display well-defined uni- or multilocular radiolucency in articlular eminence or distal zygomatic arch from mastoid air cells. no treatment needed

Question 23

pterygomaxillary fissure

Answer 23

upside down teardrop radiolucency at lateral border of maxillary sinus where PSA enters sinus. pharyngeal malignancies can cause erosions of fissure

Question 24

pterygoid plates

Answer 24

two triangular radiopacities inferior to pterygomaxillary fissure, superimpose over coronoid process

Question 25

hamular process

Answer 25

radiopaque spiny structure lateral to maxillary tuberosity, best seen in edentulous

Question 26

orbit

Answer 26

superior to maxillary sinus, infraorbital canal also visible

Question 27

malar process of zygoma

Answer 27

medial to pterygomaxillary fissure, vertical band of bone, superimposed on lateral 3rd of maxillary sinus

Question 28

hard palate

Answer 28

linear horizontal radiopacity superimposed over midportion of maxillary sinus and nose

Question 29

calcified styloid ligament

Answer 29

styloid ligament may become calcified and can lead to Eagle’s or carotid artery syndrome

Question 30

hyoid bone

Answer 30

body is radiopacity inferior to molars, greater cornu lateral to body, lesser cornu at 45degrees from body

Question 31

transverse foramina of C2

Answer 31

C2 is only vertebrae with nonvertical foramen

Question 32

nose

Answer 32

ala, nasolabial folds, and conchae can sometimes be seen

Question 33

epiglottis

Answer 33

superior to hyoid bone and at base of tongue is the curve outline of the epiglottis

Question 34

palatoglossal airspace

Answer 34

if tongue is not placed against the palate a radiolucency will be superimposed over roots of maxillary teeth and sinus floor

Question 35

oropharyngeal airspace

Answer 35

with tongue against the palate the remaining airspace is space around tonsils in oropharynx

Question 36

nasal air

Answer 36

two thin oblique slits superimposed over soft tissue outline of nose