[8] Maxillary and Mandibular Molars

Molars

Most posterior teeth in the arch

Mastication

• grinding/crushing

• The wide occlusal tables of these teeth makes it very efficient for crushing and grinding of food

• Important for digestion

Key to Occlusion

1st molars are “_____” which is the basis for the height of the lower face

Maxillary First Molar

• Largest tooth in the maxillary arch

• Prototype for all maxillary molars

• Greater buccolingual than mesiodistal diameter

• 4 well-developed cusps with one supplemental cusp

  • The cusp of carabelli

    • Found on the lingual surface of the mesiolingual cusp

• Has 3 roots

  • 2 buccal 

  • 1 palatal or lingual

Maxillary Second Molar

• exhibits the same general outlines as that of the maxillary molars EXCEPT for a few differences.

  • Oblique ridge. 

    • This ridge gets smaller as you go more posteriorly.

  • Distolingual cusp. 

    • Like the oblique ridge, this cusp also gets smaller as one goes more posteriorly.

  • Roots. 

    • The roots less flared.

    • bent towards the distal

  • Size. 

    • The molars get smaller from the 1st to the 3rd

  • Shape. 

    • less squarish in appearance.

    • Parallelogram or rhomboidal unlike the 1st molar which is more squarish

  • Apex.

    • The apex of the lingual root is in line with the distobuccal cusp tip. 

    • This is because the roots are inclined more distally than that of the 1st molar.

Maxillary Third Molar

• The size and shape of this tooth is very variable. 

• It is smaller than the first or second molar

  • the roots are shorter and the root trunks are proportionally longer than the first or second molars.

• The crown is short cervicoocclusally. 

• The roots are fused and tapers toward the apex. 

• The mesial outline of the roots are inclined to the distal

  • gives an impression of the tooth tilting towards the distal.

• The most prominent feature of the tooth is the large mesiolingual cusp. 

• The distolingual cusp and groove and the oblique ridge are usually non-existent. 

• The lingual half of the occlusal table is made up of the large mesiolingual cusp that is convex, larger and longer than the other cusps. 

• The size and shape of the ML cusp and the buccal groove gives the tooth a

• "heart-shaped" appearance.

Mandibular First Molar

first permanent teeth to erupt

Non-succeedaneous

All mandibular molars are _____

Mandibular Molars

• Eruption:

  • 1st - 6 years old

  • 2nd - 13 to 13 years old

  • 3rd - 17-21 years old

• Erupts ahead of their maxillary counterparts

• Crowns

  • Wider mesiodistally than buccolingual diameter

  • Have greater mesiodistal length than cervico-occlusal height

  • Taper towards the lingual and towards the distal. 

    • The buccolingual dimensions of the mesial side is greater than the distal and the mesiodistal dimension of the  buccal half is greater than the lingual.

  • Tilt distally on the root. 

    • Occlusal surface slopes towards the cervix from mesial to distal.

  • The cusps are nearly equal in size.

  • Crowns are tilted lingually in the proximal view.

  • 4 Major Cusps

• Roots

  • 2 roots: Mesial and Distal Roots