DOH114 Lecture Notes - Lecture 6: Premolar, Calcification, Developmental Lines
POSTERIOR TEETH
1. Greater relative faciolingual measurement compared with the mesiodistal
measurement
2. Broader contact areas
3. Contact areas more nearly at the same level
4. Less curvature of the cervical line mesially and distally
5. Shorter crown, cervico-occlusally than that of anterior teeth
Premolars
Maxillary first premolars
Evidence of Calcification 1.5-1.75 yrs
Enamel Formation 5-6 yrs
Eruption 10-11 yrs
Root completed 12-13 yrs
Functions:
- Long and sharp buccal cusp assists canine as a tearing tooth
Identifying features:
- Shorter crown and root than canines, with longer crowns than molars but
equal root length
- 2 cusps: buccal cusp 1mm longer than lingual
- Angular crown
- 2 roots, 2 pulp canals (only premolar with 2 roots)
- Not as wide MD as canine
Aspect
Features
Drawing
Buccal
1. Crown is roughly trapezoidal with
convex buccal surface and buccal ridge
2. Mesial outline is slightly concave
from cervical line to the mesial contact
area
3. Distal outline is straighter than
mesial outline
4. Buccal cusp is long and sharp, and
thus resembles canine.
Document Summary
Long and sharp buccal cusp assists canine as a tearing tooth. Shorter crown and root than canines, with longer crowns than molars but equal root length. 2 cusps: buccal cusp 1mm longer than lingual. 2 roots, 2 pulp canals (only premolar with 2 roots) Distal: convex distal surface with no depression at cervical third, absence of deep developmental groove, curvature of cervical line is less than on mesial aspect. Mesial: roughly trapezoidal in shape with longest side towards cervical portion, and shortest towards occlusal portion, buccal and palatal outlines are. Occlusal smoothly curved from the cervical line till the tips of buccal and palatal cusps: mesial developmental depression is found cervical to mesial contact area bordered by mesiobuccal and mesiolingual line angles. This depression continues apically beyond cervical line and joins the deep developmental depressions of roots: developmental groove is found in enamel of mesial marginal ridge.
