Lesson 16. Special teeth anatomy. Upper molars

Learning objective: to study the peculiarities of the anatomical structure of maxillary molars, to learn to identify the distinctive features of the first and second molars, the difference between the teeth belonging to the right and left side.

FIRST UPPER MOLAR

This is the largest upper tooth. There are 4 cusps on its occlusal surface: mesio-buccal, disto-buccal, mesio-palatal and disto-palatal divided by grooves. There is an additional tuberculum on the mesio-palatal cusp - Cara-belli tuberculum (fig. 16.1-16.3).

There are 4 grooves: buccal, medial, central, and disto-palatal forming the "H" sign.

The pulp chamber is wide and more likely copies the shape of crown.

There are 3 roots: mesio-buccal, disto-buccal and palatal. The palatal root is straight and massive. Buccal roots are flattened laterally, deflected posteriorly. The mesiobuccal root is larger than the distobuccal one.

► Crown height 6-8.5 mm.

► Medio-distal diameter of the neck 9-11 mm.

► Cheek-palatal diameter of the neck 11-13 mm.

► Root length 13-16 mm.

SECOND UPPER MOLAR

There are 4 types of this tooth:

► looking like first upper molar but without Carabelli tuberculum;

► with a rhombus-shaped crown;

► with fused lingual cusps;

► triangular with 3 cusps.

There are 4 cusps usually: mesio-buccal, disto-buccal, mesio-palatal and disto-palatal.

Viewed from the vestibular surface, there is a vestibular groove. On the oral surface there is a posterior palatal groove. Viewed from the lateral surfaces, there is an additional distal tubercle dis-tally, and an additional medial tubercle medially (fig. 16.4-16.6).

Fig. 16.4

Fig. 16.5

Fig. 16.6

The pulp chamber follows to the external shape.

There are three roots. Sometimes all roots fuse in one, cone-shaped; in this case there are grooves in the areas of fusion.