Module 10 - Maxillary Molars

Maxillary First Molars (#3 & #14) - Overall Features

• Erupt between 6 & 7 years of age

• First teeth to erupt in maxillary arch

• Nonsuccadaneous

• Erupt distal to the primary maxillary second molars

• Largest tooth in maxillary arch

Root Features - Maxillary First Molars

• Root completion at age 9-10 years

• Roots are larger and more divergent than other maxillary molars

• Roots are twice as long as crown

• Palatal root: largest and longest

• MB root: 2nd largest

• DB root: smallest

• Mesiobuccal and distobuccal resemble a set of pliers

Other Root Features - Maxillary First Molars

• Buccal furcation at center of buccal surface

• Mesial and distal furcations: access from lingual

• 4 pulp horns

• 3 pulp canals

Buccal View Features - Maxillary First Molars

• All four major cusps are seen from this view

• MB cusp is wider

• MB groove extends between two buccal cups and runs apically (toward the apex)

• Buccal groove separates tooth

• Distal outline more rounded compared to mesial

Lingual View Features - Maxillary First Molars

• Mesiolingual (ML) cusp outline is much longer and larger

• Palatal (lingual root) is largest and longest

• Common to have 5th cusp

  • ML cusp

  • Nonfunctioning

  • Called cusp of Carabelli

• Distolingual groove (DL)

  • Usually ends in a lingual pit

Proximal Views - Maxillary First Molars

• CEJ relatively stright

• Mesial

  • Only 2 cusps seen (MB and ML)

  • Mesial marginal groove

• Distal

  • Distal marganical groove

Occlusal View - Maxillary First Molars

• Rhomboidal outline

• Buccal groove

• Lingual groove

• Mesial and distal marginal ridge grooves

• 4 ridges and 4 inclines planes on each cusp

Occlusal Table

• Cusp tips in size order (largest to smallest)

  • ML

  • MB

  • DB

  • DL

  • Cusp of Carabelli (if present)

• Oblique ridge

• Transverse ridge

Fossae

• Central

• Mesial triangular

• Distal triangular

• Distal

Grooves

• Triangular

  • MB

  • ML

  • DB

• Central groove

What are the clinical considerations?

• Loss can affect function

• Tooth deposits

Maxillary Second Molars (#2 & #15) - Overall Features

• Erupt between 12 & 13 years

• Nonsuccedaneous

• Usually has 4 cusps, but can have 3

Root Features - Maxillary Second Molars

• Root completion 14-16 years

• 3 roots are smaller than first molars

• Roots are less divergent compared to 1st molar

• Lingual root is still the longest and largest

• Furcation areas same as 1st molar, just narrower

• 4 pulp horns and 3 main pulp canals

Buccal View Features - Maxillary Second Molars

• Shorter occlusocervically and narrower mesiodistally than a first molar

• Buccal groove is located farther distally when compared to 1st molar

• Mesiobuccal cusp is longer than distobuccal cusp

• Mesial and distal contacts are in the middle third of tooth

Lingual View Features - Maxillary Second Molars

• Distolingual (DL) cusp is smaller and shorter than on the 1st molar and sometimes not present

• 5th cusp usually does not exist

• Lingual pit usually present at the end of the DL groove

Proximal View Features - Maxillary Second Molars

From the distal, the DL and DB cusps are smaller on a second molar than a first molar

Occlusal View Features - Maxillary Second Molars

• Outline of crown is narrower mesiodistally than that of a maxillary 1st molar but about the same width buccolingually

• 2 shapes

  • Rhomboidal

    • More common

    • Similar to maxillary 1st molar

  • Heart-shaped

    • Less common

    • Similar to maxillary third molar

Maxillary Third Molar (#1 & #16) - Overall Features

• May erupt between 17 to 21 years

• Nonsuccedaneous

• Smallest molar

• Most variable tooth in shape in the permanent dentition

Root Features - Maxillary Third Molar

• Root completion ages 18 to 25

• Trifurcated

  • Close together/fused - may give appearance of a single root

  • Roots poorly developed

  • Roots shorter than 2nd molar

  • Roots curve distally

Occlusal View - Maxillary Third Molar

• Heart shaped outline

  • Most common

  • Typically only has 3 cusps

  • DB cusp shorter than the MB cusp

• Rhomboidal type

  • Four cusps

  • Small, nonfunctioning DL cusp

  • No oblique ridge present

  • DB cusp shorter than the MB cusp

What are the clinical considerations?

• Access

• Anodontia

• Increased risk of disease

• Microdontia

• Removal?

• Accessory roots