Maxillofacial radiology

Question 1

Dental caries best demonstrated with

Answer 1

Bitewings or long-cone periapical radiographs

Question 2

Dental caries

Answer 2

Caries can only be detected when there has been 30-40% demineralisation, so that lesion can be differentiated from normal dentine and enamel
Because of this limitation, carious lesion is larger (up to 25%) than that seen on radiographs
Magnification useful for identifying early lesions

Question 3

Proximal surface caries

Answer 3

Enamel caries seen as triangular radiolucency, just below contact point, that has apex pointing towards ADJ
When caries reaches ADJ, it spreads along junction, often forming 2nd radiolucent triangle, with apex pointing towards pulp

Question 4

Occlusal caries

Answer 4

More difficult to diagnose radiographically if lesion is restricted to enamel
Often first indication is thin radiolucent line at ADJ with intact enamel
As lesion progresses it becomes easier to detect

Question 5

Smooth surface caries

Answer 5

Should be visible clinically, but radiograph can provide confirmation

Question 6

Root caries

Answer 6

Radiographs may reveal root surface caries that is not evident clinically, usually interproximally
Remember that cervical burnout can mimic root caries
-in cervical burnout there is still an image of root edge
-usually bilateral and symmetrical on any one tooth

Question 7

Recurrent caries

Answer 7

Radiographically, this appears as zone of > radiolucency along margins of restoration
Radiopaque materials such as metals can obscure recurrent caries, and radiolucent lining materials can make detection difficult

Question 8

Periapical pathology (draw diagram)

Answer 8

Caries & trauma –> pulp necrosis –> apical periodontitis
chronic apical periodontitis –> perapical granuloma –> radicular cyst or osteomyelitis
Acute apical periodontitis –> periapical abscess –> osteomyelitis
Periapical granuloma periapical abscess

Question 9

Periapical pathology

Answer 9

Radiographic signs of periapical periodontitis depend on time course of disease process
Earliest sign is usually widening of apical periodontal ligament, followed by loss of lamina dura
As inflammatory process progresses, one of two possible radiographic features emerge, depending on whether there is mainly bone resorption (rarefying osteitis) or mainly bone formation (sclerosing osteitis)

Question 10

Periapical granuloma

Answer 10

In attempt to heal from chronic apical periodontitis, formation of granulation tissue is stimulated
This appears as well-defined radiolucency surrounding apex of non-vital tooth
Lesion>1cm diameter probably radicular cyst
No white line around it
Acute exacerbations of chronic lesiosn can occur intermittently

Question 11

Sequelae of periapical periodontitis

Answer 11

Root resorption
Radicular cyst formation
Osteomyelitis

Question 12

Periodontal disease

Answer 12

No radiographic signs of gingivitis, but useful in demonstrating form of bone loss in chronic periodontal disease, as well as local factors e.g. calculus or overhanging restorations
Alveolar crest normally seen within 1.5mm of ACJ

Question 13

Patterns of bone loss

Answer 13

Early: erosion of interdental crest
Later: ‘horizontal’ loss of bone generliased or localised
‘Complex’: osseous defects

Question 14

Dental anomalies

Answer 14

Developmental anomalies can occur in following ways:
Anomalies of tooth number
Anomalies of tooth form
Anomalies of tooth structure

Question 15

Anomalies of tooth number

Answer 15

• missing teeth e.g. hypodontia, anodontia
• extra teeth e.g. supernumerary, mesiodens, supplemental
• gemination: 2 teeth joined together but arising from single tooth germ
• fusion: 2 teeth joined due to fusion of 2 tooth germs
• consresence: 2 teeth joined by cementum

Question 16

Anomalies of tooth form

Answer 16

Dens invaginatus: infolding of outer surface of tooth into interior
Dilaceration: sharp bend in root direction, usually due to previous trauma
Taurodontism: enlarged pulp chambers, short roots (cow teeth), usually of no clinical significance

Question 17

Anomalies of tooth structure

Answer 17

Amelogenesis imperfecta: inherited condition affecting enamel formation, which is thin, pitted or grooved (up to 14 variants identified)
Dentinogenesis imperfecta: inherited condition affecting dentine formation, which is discoloured and soft (can occur with osteogenesis imperfecta)
Odontomes: benign odontogenic tumours (WHO) forming dental hard tissues, compound or complex

Question 18

‘Juvenile’ periodontitis

Answer 18

Localised, aggressive

Bone loss around 6s and 1s

Question 19

Compound vs complex odontomes

Answer 19

Compound: lots of little denticles
Complex: large lump