2.3 Molars, wisdome teeth etc

What is function of molars?

• Main mastication

• maintain vertical dimensions

• Less aesthetic influence

What are the five surfaces of molars?

1. buccal

2. lingual

3. mesial

4. distal

5. occlusal

Maxillary molars - roots

Three roots - mesiobuccal, distobuccal and palatal (lingual)

Maxillary molars - Lingual View

• Lingual surface is narrower at the cervical third

What are the two well-defined cusps of first maxillary molar?

• First maxillary molar has two well-defined lingual cusps: larger mesiolingual cusp and smaller distolingual cusp. Small fifth cusp (Cusp of Carabelli) is often present on the mesiolingual cusp

Maxillary molars - Proximal view

• Maxillary molar crowns are short and broad. Distal surface of the crown is narrower than the mesial

Maxillary molars - Occlusal view

The four cusps form a primary cusp triangle (Trigon), especially noticeable in three-cusp second molars

Mandibular molar - buccal view

• These molars are wider mesiodistally than high cervico-occlusally

• Mandibular first molar has the largest mesiodistal dimension of any tooth

Mandibular molar - Lingual view

• Lingual cusps are slightly longer and more pointed than buccal cusps.

• Roots are mesial and distal, with the mesial root being longer

Mandibular molar - Occlusal view

Mandibular molars have a rectangular occlusal surface with well-defined cusps

Why are wisdom teeth more difficult to clean and cause more problems?

Due to their posterior location, making them harder to clean and their wrinkled occlusal surface which makes them prone to decay

What are some traits of the third molars that make them different to the second and third molars?

• Typically smaller than first and second molars

• Often more bulbous crowns with smaller occlusal table

• Roots shorter, frequently fused, and often curved distally

What are the shortest of all mandibular teeth?

Mandibular third molars

What is the shortest of all permanent teeth?

Maxillary third molars

What is the difference in the size of teeth between temporary and permanent teeth?

Temporary - smaller in size

Permanent - larger in size

What is the difference in enamel thickness between permanent and temporary teeth?

Temporary - thinner enamel (about 1mm)

Permanent - thicker enamel (about 2-3mm)

what is the difference in occlusal planes of permanent and temporary teeth?

Temporary - flat occlusal plane and prominent cervical ridges

Permanent - curved occlusal plane

Do permanent teeth or temporary teeth have mamelons and if so then on what teeth?

Temporary - no

Permanent - yes on incisors

Compare the length, thickness, shape of roots and features of permanent and temporary teeth

Temporary - longer, slender with less rot trunk and the roots reabsorb during exfoliation (shedding)

Permanent - shorter, more bulbous, larger root trunks

Compare the size, thickness of dentin of temporary and permanent teeth

Temporary - Larger pulp chambers, thinner dentin (making teeth more prone to wear and decay)

Permanent - smaller pulp chamber, denser dentin

Compare the colour and mineralisation of temporary and permanent teeth

Temporary - whiter, less mineralized

Permanent - more mineralized, stronger enamel and dentin

What are the 4 types of teeth identification marks?

1. Angle mark (for incisors)

2. Segment Mark (Cusped Teeth)

3. Curvature Mark (all teeth)

4. Root mark (all teeth)

What is the Angle mark (for incisors)?

The angle between the incisal edge and mesial surface is sharp while the distal surface is more rounded

What is the Segment Mark (for cusped teeth)?

Mesial cusp ridge is shorter than the distal (except for upper first premolar)

What is Curvature mark (for all teeth)?

Mesial part of the crown is larger than the distal part

What is the Root Mark (all teeth)?

The root apex typically bends distally