Lecture 5 - Normal Anatomy

Question 1

Enamel

Answer 1

Most radiopaque
Densest substance in body
90% mineralized

Question 2

Dentin

Answer 2

75% mineralized

Meets with enamel at DEJ

Question 3

Pulp

Answer 3

Soft tissue from interior of crown to apex of roots
Radiolucent
Pulp chamber decreases with age due to secondary dentin deposition (apex to crown)

Question 4

Secondary dentin deposition

Answer 4

Age
Acute trauma
Caries
Erosion
Attrition

Question 5

Cementum

Answer 5

50% mineralized
Thin layer, mainly on root surface
Meets with enamel at CEJ
Can’t be seen on radiograph, same density as dentin

Question 6

Cause of divergent roots

Answer 6

1) Tooth and roots still developing - in a mature tooth, the pulp walls in apical region constrict
2) Trauma such as bruxism

Question 7

Dental papilla

Answer 7

Forms dentin and primordial pulp

Question 8

Cervical burnout

Answer 8

Normal

Radiolucent area b/t enamel and crest of alveolar ridge

Question 9

Lamina dura

Answer 9

Thin, radiopaque, well-defined layer of dense bone that surrounds the tooth socket
Continuous with cortical bone at alveolar crest
Thicker/denser with greater occlusal stress
Intact lamina dura usually indicates vital pulp

Question 10

Alveolar crest

Answer 10

Radiopaque line represents gingival margin of alveolar process b/t teeth
Continuous and forms sharp angle with lamina dura
Shorter in anterior teeth than posterior
Recedes with age & periodontal disease

Question 11

Periodontal ligament

Answer 11

Composed of collagen
Radiolucent space b/t root and lamina dura
Extends whole tooth from alveolar crests
Thinner at root apex, wider at alveolar crest

Question 12

Intermaxillary suture

Answer 12

Thin, radiolucent line in midline of maxilla
B/t central incisors superior to anterior nasal spine and posterior b/t palatine processes to the posterior aspect of the hard palate
Bordered by radiopaque thin cortical bone lines

Question 13

Anterior nasal spine

Answer 13

Radiopaque at junction of the inferior end of nasal septum, between maxillary central incisors
1.5-2 cm above alveolar crest

Question 14

Nasal fossa

Answer 14

Air-filled
Radiolucent
Inferior border is radiopaque lines extending bilaterally from base of anterior nasal spine

Question 15

Incisive/nasopalatine foramen

Answer 15

Oral terminus of nasopalatine canal
Vessels and nerves to max. central incisors
Radiolucent b/t roots and middle-apical 1/3 of central incisors

Question 16

Superior foramina of nasopalatine canal

Answer 16

Origin of nasopalatine canal in floor of nasal cavity

Travel on either side of nasal septum and unite at foramen

Question 17

Lateral fossa

Answer 17

Depression in maxilla near apex of lateral incisor
Diffusely radiolucent on periapical
Not pathologic if lamina dura is intact

Question 18

Nasolacrimal canal

Answer 18

Drains under the inferior concha of nasal cavity

Above apex of canine on periapical