This document provides details on the anatomy and morphology of premolars. It notes that premolars are located between the anterior teeth and molars, have two cusps and roots, and erupt around ages 10-11 years. The document describes premolars' numbering, development timeline, measurements, and characteristics from the buccal, lingual, mesial, distal, and occlusal aspects. It also details that most premolars have two roots - a buccal and lingual root, though sometimes there can be one or three roots.

1. By
Dr. Abhishek Solanki

2. INTRODUCTION
 Premolars are so named because they are
placed between the anterior teeth and the molars
(pre = before)
 Premolars assist canines & molars in tearing and
chewing food
 Have two cusps (bicuspid) & two roots (buccal &
lingual)
 Eruption : at 10-11 years

3. TOOTH NUMBERING
 Universal : #5 , #12
 Z-P : 4 4
 FDI : 14, 24

4. CHRONOLOGY
 First evidence of calcification :1.5 – 1.75 yrs
 Enamel Completion : 5-6 yrs
 Eruption : 10-11 yrs
 Root completion : 12-13 yrs

5. DIMENSIONS (in mm)
Cervico-occlusal Length of Crown 8.5
Length of Root 14
Mesiodistal Diameter of Crown 7
Mesiodistal Diameter of Crown at Cervix 5
Labio- or Bucco-lingual Diameter of Crown 9
Labio- or Bucco-lingual Diameter of Crown at Cervix 8
Curvature of Cervical Line—Mesial 1
Curvature of Cervical Line—Distal 0

6. Buccal Aspect
 Crown : Pentagonal shaped
 Crown closely resembles to maxillary
canine and second premolar
 Mesial margin joins the mesio-occlusal
slope to create an obtuse mesio-occlusal
angle

7.  Contour of the mesial outline is concave
from the contact area to the cervical line
 The mesial slope of the buccal cusp is
longer than distal slope, which is the
opposite of canine
 Disto-occlusal angle is a little less
prominent and the cervical concavity is not
as deep

8.  Occlusal margin of this tooth is, similar to
the incisal margin of the maxillary canine
 Buccal ridge
 Mesio-buccal & distobuccal developmental
depressions on each side of buccal ridge

9. Lingual Aspect
• The crown tapers towards the lingual aspect
• The lingual cusp is shorter than the buccal
cusp
• The lingual cusp is smooth from the cervical
portion to the area near the cusp tip

10. • The cusp tip is pointed with mesial and
distal slope meeting at an angle of about
90 degrees
• Small portion of the buccal cusp can be
seen from this aspect
 Smoothly convex in all directions
 There is no clearly defined lingual ridge

11.  Mesial and distal outlines are normally
somewhat convex & shorter than the same
outlines of the buccal surface
 Lingual cusp tip is not as sharply pointed as
the buccal cusp tip
 The mesio-occlusal slope is shorter than the
disto-occlusal slope

12. Mesial Aspect
• From the mesial and distal aspect both the
buccal and lingual cusps are visible
• A well developed mesial marginal ridge
and a mesial marginal developmental
groove is present
• In the middle of the mesial surface is the
mesial developmental depression which
continues beyond the cervical line

13.  Mesial concavity
 Shape of the mesial surface is trapezoidal
 Buccal outline is generally convex, with
the height of contour in the cervical third
 Lingually the outline takes the form of
an even arc, with the height of contour
in the middle third

14.  Occlusal margin is irregularly concave
and the majority of it is made up of the
mesial marginal ridge.
 A prominent mesial marginal groove is
usually present indenting the occlusal
margin almost two-thirds of the way
from the buccal to the lingual outline.

15. Distal Aspect
 There is no developmental depression or
groove on this aspect, instead it is convex
at almost all points
 The curvature of the cervical is less on this
aspect
 The contact area is near the junction of
occlusal and middle third
 distal is remarkably similar to the mesial
surface, although it is slightly shorter
occluso-cervically.

16.  Lingual margin is almost symmetrical & is
quite convex, especially in middle third,
where height of contour is located
 Occlusally, distal is similar to mesial aspect,
except that marginal ridge is located at a
more cervical level
 There is normally no marginal groove

17. Occlusal Aspect
• Within cusp ridges and marginal
ridges the following are present
TBC & TLC : Tip of Buccal & Lingual
cusp
BTR & LTR : Buccal & Lingual
Triangular ridge
DBDG: disto-buccal developmental
groove
DTF & MTF : Mesial & Distal
triangular fossa
CG : Central groove

18.  outline of crown can be described as
hexagonal or six-sided and it is wider
buccolingually than mesiodistally
 prominent buccal ridge is primary
contributor to generally convex buccal
outline
 lingual margin is evenly convex, almost
in a semicircle
 Proximal margins are relatively straight
& they converge toward lingual

19. Root
• Most Maxillary first premolars have 2 roots,
but one and three roots can also be seen
• Two roots : buccal and lingual
• Buccal portion of the root resembles canine

20. • The root when viewed from the proximal side shows a big
trunk and bifurcation area from where the buccal and
lingual root separate
• A developmental depression is seen on the mesial aspect
of the trunk
TRUNK

21. REFERENCES
 CONCISE DENTAL ANATOMY & MORPHOLOGY :
JAMES L FULLER
 DENTAL ANATOMY, PHYSIOLOGY & OCCLUSION:
WHEELER’S
 TEXTBOOK OF DENTAL ANATOMY, PHYSIOLOGY &
OCCLUSION: RASHMI GS (PHULARI)
 INTERNET