Maxillary Molars

Molar generalities

Largest teeth in the mouth

First permanent teeth to erupt

Non succedaneous teeth (don’t replace any primary teeth)

Form from 4 or 5 lobes, some 2nd and 3rd molars have 4

Maxillary 1st molars generalities

Largest maxillary teeth

Form from 5 lobes

Crown is broad MD and just slightly wider BP

Where do the 5 cusps of maxillary first molars form

1st to 3rd lobe form from 3 major cusps

4th forms from minor cusp

5th forms from supplementary cusp (Cusp of Carabelli)

What are the locations of the 5 cusps

2 buccal

2 palatal

1 Carabelli’s cusp

Maxillary first molars buccal aspect

2 cups seen here, MB and DB

2 buccal cusps are divided by a buccal developmental groove

The groove is not very deep, but at its end it splits into a buccal pit

Maxillary first molars palatal aspect

2 cusps seen here, MP and DP (these cusp are distal to the buccal cusps)

Mp cusp is larger/longer than buccal cusps

The cusp of carabelli is present in different % depending on population/ethnic groups

How are the Cusp of carabelli and MP cusp separated

A fifth developmental groove, the mesiopalatal groove seperates them

What other grooves are on the maxillary 1st molars palatally and also distally

Palatal developmental groove, extends from the centre of the palatal surface between 2 palatal cusps

Distal oblique groove, as the palatal developmental groove curves distally, it becomes this

Maxillary 1st molars palatal aspect (grooves and cusp explanation)

Palatal and distal oblique grooves are sometimes considered as one:

Distopalatal developmental groove

Distopalatal cusp is small (occupies around 40 percent of palatal surface)

Maxillary 1st molar mesial aspect

can very easily see the cusp of carabelli from this view

Buccopalatal measurement of the crown is greater than when measured distally

maxillary first molar distal aspect

Crown tends to taper distally

Distal marginal ridge is shorter, less prominent than mesial

Maxillary first molar occlusal aspect (shape and functional cusps)

Has a rhomboidal occlusal outline, wider crown mesially than distally

4 functional cusps and 1 afunctional cusp (carabelli)

Major fossae found on maxillary 1st molar occlusal aspect

Central fossa (mesial to oblique ridge)

Distal fossa (distal to oblique ridge)

Minor fossae found on maxillary 1st molar occlusal aspect

Located on the inside of the respective marginal ridges:

Mesial and distal fossa

Maxillary 1st molars occlusal aspect transverse ridge

Formed by two triangular ridges joining and crossing the surface of a posterior tooth diagonally rather than straight across buccopalatally

Maxillary 1st molars occlusal aspect oblique ridge

Oblique ridge: transverse ridge, characteristics of maxillary molars

Formed by the triangular ridges of the mesiopalatal and distobuccal cusp

Maxillary first molar occlusal view labelled (image)

Maxillary first molars data (name fdi, number of roots, pulp horns, cusps and developmental lobes

How can maxillary first molars be identified (6 characteristics)

Might have cusp of carabelli

Square/rhomboidal occlusal outline (not triangular)

Well developed mesiopalatal cusp

Prominent oblique ridge and distal buccal and palatal grooves

Crown similar width MB and BP

3 widely separated roots

Maxillary 1st molars (image)

Maxillary 2nd molars generalities (function and comparison)

Supplement first molars function, similar but less accentuated features

Shorter occlusocervically

Narrower mesiodistally

Maxillary second molar grooves, ridges, and cusps (also comparison)

Have more supplemental (secondary grooves and pits)

Less prominent oblique ridge

Usually no cusp of carabelli (fifth lobe)

Less developed distopalatal cusp

Maxillary 2nd molars shape

Less rhomboidal compared to 1st, more heart shaped (not imo tho)

Maxillary 2nd molars roots

Tend to be closer together, may even be fused

Mesiobuccal root tends to curve distally in the apical third, straighter distal root

Root is almost as long, sometimes longer than first molars

More variety in crown and roots than first molars

Maxillary 2nd molar buccal aspect

Crown:

Shorter C - O (cervicoocclusally)

Narrower M- D

Distobuccal cusp smaller compared to first molars

Maxillary second molars palatal aspect

No cusp of carabelli (usually)

Smaller distopalatal cusp than firsts

Maxillary second molars proximal aspects

Crown is shorter, buccopalatal measurement is about the same

Roots are closer together

Maxillary second molars occlusal aspect

Smaller M-D diameter

Same BP diameter

More supplemental grooves/pits

Maxillary second molar data (name FDI, number of roots, pulp horns, cusps, developmental lobes)

Maxillary second molars identifying characteristics (5)

Fifth cusp usually absent

Less developed DP cusp

Less prominent oblique ridge

Crown:

Shorter cervicoocclusally

Narrower MD

Just as wide BP

More heart shaped occlusal outline (less rhomboidal)

3 roots are less separated

Maxillary second molars image

Maxillary 3rd molars generalities

Most variation of all molars in size, shape, and relative position to other teeth

Often a developmental anomaly or doesn’t form at all

Crown is shorter than second, roots tend to fuse (one fused root)

Occlusal outline is more heart shaped

Poorly developed or absent distopalatal cusp

What tends to happen to maxillary 3rd molars (obvious answer)

High tendency to become impacted (no eruption due to obstruction by bone, other teeth, or angle that it sits in the bone)

Also congenitally (meaning at or before birth) missing

Maxillary third molars data (name FDI, number of roots, pulp horns, cusps, and developmental lobes)

Maxillary third molar identifying characteristics (4)

Varies in form more than any others

Usually has no DP cusp

Occlusal outline is heart shaped with 3 cusps

Usually 3 very close together or fused roots with extreme distal inclination

Maxillary third molars roots

3 roots, MB, DB, and P

Trifurcated (meaning single root trunk divides into 3 separate roots

Palatal root is longest, distobuccal is shortest

Buccal roots incline distally

MB starts to curve at middle thirds

Maxillary molar root characteristics

Roots are shorter the farther posterior (maxillary 1st molar longest)

Roots are less divided the farther posterior the maxillary molar

Roots vary more in shape, size, and direction of curvature the more posterior the molars