Radiation Biology and Protection

Where can you visually clinical examine caries?

occlusal surfaces

What are the characteristics of caries viewed under radiographs?

- 30-40% demineralization
- dark/radiolucent

What are the limitations of radiography?

- can not differentiate between active + arrested caries
- inaccurate depth of lesion (depth is usually greater than seen)

What is cervical burnout?

Apparent radiolucency below the CEJ causing decreased x-ray absorption
(artifact, not caries)

How does cervical burnout appear?

diffuse, ill-defined borders

What are the characteristics of facial/lingual caries?

well-defined
circular/ovoid shape

How can you differentiate between facial/lingual caries?

you can not (2D image)

Where are root/cementum caries usually seen?

patients with gingival recession + perio bone loss

Where are recurrent caries usually seen?

around margins of existing restoration

What are rampant caries?

rapid progressing caries seen in young children or those with poor oral habits

What are done once a year?

vertical bitewings

What are radiation caries?

caries induced by lack of salivary flow from radiotherapy and usually affects the cervical region (xerostomia)

What is used to view posterior interproximal caries?

bitewings

What is used to view anterior interproximal caries?

periodical

What is used to view occlusal caries?

bitewings
periapical

What is used to view incisal caries?

periapical

What is the purpose of diagnostic imaging?

accurately depicts distance between CEJ + alveolar crest

What are the limitations of periapical imaging?

distorted view between teeth and alveolar crest

What are the limitations of 2D intramural radiographs?

- lack of ability to completely represent periodontitis
- buccal/lingual overlap
- depicts bone loss as not as severe as it actually is
- can't see soft tissue changes

What are the characteristics of early periodontitis of anterior teeth?

- blunting of alveolar crest
- slight loss of crystal bone height

What are the characteristics of early periodontitis of posterior teeth?

- loss of acute angle between lamina dura + alveolar crest

What is stage 1 periodontitis?

bone loss of 15% root length

What is stage 2 periodontitis?

bone loss of 15-33% root length

What is stage 3 periodontitis?

bone loss extending to middle third of root + beyond

What is horizontal bone loss?

- crest is >2mm apical to CEJ
- crest is parallel to imaginary line joining CEJ's of adjacent teeth

What is vertical bone loss?

- v-shaped
- oblique bone loss angulation
- superimposition

What is superimposition?

not able to appreciate number of walls in intraoral radiographs

What are interdental craters?

- 2 walled, trough like depression
- Buccal and lingual cortical plates extend coronal than cancellous bone (resorption)