Podcast
Questions and Answers
What is the typical occlusal outline of the permanent mandibular third molar?
What is the typical occlusal outline of the permanent mandibular third molar?
What is the relationship between the mesial and distal lingual cusps (MLC and DLC) of the permanent mandibular third molar?
What is the relationship between the mesial and distal lingual cusps (MLC and DLC) of the permanent mandibular third molar?
What is the relationship between the mesial and distal buccal cusps (MBC and DBC) of the permanent mandibular third molar?
What is the relationship between the mesial and distal buccal cusps (MBC and DBC) of the permanent mandibular third molar?
What is the typical root morphology of the permanent mandibular third molar?
What is the typical root morphology of the permanent mandibular third molar?
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How does the occlusal table size of the permanent mandibular third molar compare to the second molar?
How does the occlusal table size of the permanent mandibular third molar compare to the second molar?
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What is the relationship between the mesial and distal root angulation of the permanent mandibular third molar?
What is the relationship between the mesial and distal root angulation of the permanent mandibular third molar?
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What is the shape of the pulp chamber in the permanent mandibular third molar?
What is the shape of the pulp chamber in the permanent mandibular third molar?
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Which of the following is NOT a characteristic of the lingual aspect of the permanent mandibular third molar?
Which of the following is NOT a characteristic of the lingual aspect of the permanent mandibular third molar?
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What is the characteristic cervical outline of the permanent mandibular third molar?
What is the characteristic cervical outline of the permanent mandibular third molar?
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How does the crown shape of the permanent mandibular third molar compare to the second molar?
How does the crown shape of the permanent mandibular third molar compare to the second molar?
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Study Notes
Lower 7
- Root trunk is longer than that of Lower 6
- Lingual Aspect: Lingual Convergency (Lingual surface is narrower than Buccal Surface)
- DLC and MLC are two lingual cusps, with Mesiolingual cusp > Distolingual cusp
- Lingual Developmental groove (LDG) separates MLC and DLC, and is a short groove that ends in the occlusal 1/3
Mesial Aspect
- The geometric outline is Rhomboid due to Lingual Inclination
- Deep depression on the root trunk from the cervical line to the bifurcation
- Buccal outline: Cervical ridge is less pronounced than Lower 6
- Occlusal outline: MLC is slightly longer and more pointed than MBC
- The tip of MLC is on line with the lingual outline of the mesial root
- Occlusal surface is more constricted buccolingually
- MMR is long and sharply concave (often V-shaped)
Distal Aspect
- Similar to the mesial surfaces with the following differences:
- 4 cusps can be seen
- Crown is shorter and narrower (distal convergence)
- B DCA is more cervically (Middle 1/3) and centralized
- No distal cusp, no DBDG as in first molar
- DR is shorter and narrower and has a more pointed apex than MR
- Shallower depression on the root, indicating the probability of the presence of 2 root canals
Occlusal Aspect
- The geometric outline is Rectangular
- The crown measurements: MD (width) is larger than BL (thickness)
- The crown converges lingually and distally (distolingual convergence)
- Buccal outline is larger than lingual outline
- Mesial outline is longer than distal outline
- Anatomical landmarks: 4 cusps with 4 triangular ridges
- Size: The 2 mesial cusps > The 2 distal cusps
- Size: MBC > MLC > DBC > DLC
- Height: MLC > DLC > MBC > DBC
Occlusal Aspect (Fossae and Developmental Grooves)
- There are 3 fossae: 1 major central fossae + pit, and 2 minor fossae (mesial and distal triangular fossae)
- The groove pattern is CROSS-SHAPED (grooves meet at right angle)
- Central Developmental Groove: Extends from the central fossa to the mesial and distal triangular fossae and pits
- B Developmental groove: Extends from Central fossa between the MBC and DBC onto the buccal surface
- L Developmental groove: Extends from Central fossa between the DLC and MLC onto the lingual surface
Permanent Mandibular Third Molar
- Has many Morphological Variations
- Mesial Distal: 8 occlusal
- Buccal Aspect: Either 4 or 5 cusp type
- The shortest of the mandibular teeth
- The buccal surface is convex
- MBC is larger than DBC
- 2 Short roots (MR and DR) may be fused in all or part of their length or very close to each other
- The axes of the roots are more inclined distally than 1st and 2nd molars
Permanent Mandibular Third Molar (Lingual Aspect)
- Lingual convergency
- Lingual cusps are longer than buccal cusps
- MLC=DLC in size, sometimes MLC is larger
Permanent Mandibular Third Molar (Mesial Aspect)
- It has a more bulbous crown as compared to 2nd molar
- The buccal cusp tips are closer to the lingual cusp tips, giving a small occlusal table
Permanent Mandibular Third Molar (Distal Aspect)
- Distal convergency
- DR is narrower than MR, so both roots are seen
- No DCA
Permanent Mandibular Third Molar (Occlusal Aspect)
- The geometric outline is similar to 1st or 2nd molars (5- cusp type Hexagonal or 4-cusp-type rectangular)
- There are numerous supplemental grooves and pits, giving the occlusal surface a wrinkled appearance
Pulp Cavity of Permanent Mandibular Molars
- Pulp Chamber: The pulp chamber is large, rectangular-shaped mesio-distally
- There is a pulp horn beneath each cusp
- Buccolingually: The pulp chamber is narrower than the M-D section
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Description
Test your knowledge on dental anatomy characteristics including root depression, lingual convergency, lingual cusps, and lingual developmental groove. Identify key features and distinctions between dental aspects.
