Tooth Structure

Question 1

Tooth Structure

Answer 1

• Crown
• Enamel
• Dentin
• Pulp
• Root
• Apex
• Apical Foramen
• Cementum
• Gingiva
• Alevolar Process

Question 2

Tooth Crown

Answer 2

2 forms of crown, meets root at CEJ
anatomical:
- portion covered in enamel
- doesn’t change
- starts at CEJ and ends at top
clinical:
- portion visible by eye in clinic
- can vary in patients

Question 3

Enamel

Answer 3

• hardest material in body
• translucent in colour
• made of hydroxyapatite crystal
• not vital as contains no blood vessels or nerves
• no power to repair or grow
• any imperfections in development remain permanent

Question 4

Dentin

Answer 4

• main portion of tooth, extends almost entire length
• living tissue (sensory)
• contains forming cells called odontoblasts
• dentin production continues throughout life
• hard, dense, calcified tissue
• harder than bone but softer than enamel
• yellow-ish/brown in colour; teeth whiter in children as less dentin

Question 5

Dental Pulp

Answer 5

• sensory dentin reparative system
• inside the tooth, occupies pulp cavity and pulpal canals
• contains blood vessels, lymph, nerves and other connective tissues
• pulp is developed by fibroblast cells
• blood supply drives from branches in arteries from periodontal ligament

Question 6

Tooth Root

Answer 6

• meets crown at CEJ
• embedded in the alveolar process (jaw bone)
• covered by cementum
• anteriors have 1, posteriors have 1-3
• bifurcation: 2 roots
• trifurcation: 3 roots

Question 7

Root Apex

Answer 7

• found at the tapered end of each root
• the periapical of the root surrounds the apex
• apical foramen: opening at end of apex, allows blood vessels and nerves access into pulp cavity

Question 8

Cementum

Answer 8

• covers the root of the tooth, overlies the dentin
• meets enamel at CEJ
• thin at cervical line, increases at the apex
• bone-like structure
• primary function to anchor the tooth to the bone socket
• produced by cementoblasts
  cellular: confined to apical root, can repoduce
  acellular: covers entire anatomical root, cannot reproduce

Question 9

Tooth Junctions

Answer 9

CEJ: cementoenamel junction - cementum and enamel meet
DEJ: dentinoenamel junction - dentin and enamel meet
DCJ: dentinocemental junction - dentin and cementum meet

Question 10

Cusps

Answer 10

Elevations of the crown portion of the tooth
- divisonal part of the occlusal surface
- mesiobuccal / mesiolingual / distobuccal / distolingual / distal

Question 11

Marginal Ridge

Answer 11

Rounded boarders of the enamel that forms the proximal surfaces of premolars/molars and lingual surface of anteriors

Question 12

Cingulum

Answer 12

Lingual/Palatal lobe of anterior teeth
- makes up bulk of cervical third

Question 13

Mamelon

Answer 13

Any of the 3 rounded protuberances on the incisal edge
- an imperfection

Question 14

Lingual Fossa

Answer 14

Depression/concavity on lingual surface of incisors

Question 15

Pit

Answer 15

pinpoint depression located at junction of developmental grooves or terminals of those grooves

Question 16

Oblique Ridge

Answer 16

Type of transverse ridge
- unique to maxillary molars
- transverse diagonally rather than straight across buccolingually

Question 17

Triangular Fossa

Answer 17

on the occlusal surface, mesial or distal to marginal tidges
- where grooves meet or terminate

Question 18

Central Fossa

Answer 18

Ridges terminate at central point of depression
- found on molars

Question 19

Supplemental Groove

Answer 19

• linear depression
• does NOT mark junction of primary parts
• smaller grooves from mains

Question 20

Developmental Grooves

Answer 20

• shallow grooves between primary parts of the crown
• named by location eg central groove, mesiobuccal groove

Question 21

Triangular Ridge

Answer 21

Descends from the tips of the cusps on posterior teeth towards the centre (cusp slopes)

Question 22

Transverse Ridge

Answer 22

Union of 2 triangular ridges crossing transversely
- straight from mesiobuccal cusp to mesial lingual cusp etc