Molars and Dentition Notes

Permanent molars are the most posterior teeth, located behind premolars.
Largest teeth, with six molars per dental arch (three in each quadrant).
Types: first, second, and third molars (wisdom teeth).
First molars erupt around age 6, second molars around age 12.
Third molars erupt between 17 and 21 years.
Molars grind food and support cheek and lower face soft tissue.
Wider with more cusps than other teeth, four-sided and trapezoidal shape.
First molar is the largest, decreasing in size posteriorly.
Large crown, prominent cervical ridge, occlusal surface with cusps, grooves, and pits.
Maxillary molars have three roots, mandibular molars have two roots for stability.

Largest and strongest maxillary teeth.
Four well-developed cusps and the cusp of Carabelli(fifth cusp).
Crown wider buccolingually than mesiodistally, located in the center of each arch.
Three roots (trifurcated): two buccal, one lingual/paletal (longest root).
- Buccal Surface:
- Crown is trapezoidal.
- Mesiobuccal cusp is broader than distobuccal cusp.
- Buccal developmental groove divides buccal cusps.
  Lingual Surface:
- Lingual developmental groove present.
- Cusp of Carabelli attached to mesiolingual surface of the mesiolingual cusp. —> not always present
- Mesial Surface:
- Increased buccolingual dimension.
- Mesiobuccal, mesiolingual, and cusp of Carabelli are visible.
- Distal Surface:
- Buccolingual measurement is less than on mesial.
- Sharp cervical dip of the distal marginal ridge (more straighter).
- Occlusal Surface:
- Rhomboid shape.
- Four major cusps and cusp of Carabelli.
- Oblique ridge runs from mesiolingual to distobuccal(higher).
- Major fossae: Central and distal.
- Minor fossae: Mesial and distal triangular.
Roots: Widely divergent, palatal root is longest
upper first - young man- strong legs.

Occlusal surface less rhomboidal (4 cusps) or heart-shaped (3 cusps).
Cusp of Carabelli is absent.
More supplementary grooves are present , oblique ridge is less prominent or even disappears. (like wrinkles as they’re older)
- Heart shape occlusal surface has 3 cusps only- mesiobuccal (MB),distobuccal;(DB) and mesiolingual (ML).
- DL cusp is a
- bsent or may be very small, and no oblique ridge or lingual developmental groove is present.
Roots tend to be close together and may be fused.

Crown is roughly trapezoidal. All five cusps can be seen in this view.
Mesiobuccal cusp is the widest.
- Buccal Surface:
- Crown is trapezoidal.
- Five cusps visible.
- Mesiobuccal developmental groove & Distobuccal developmental groove present.
Lingual Surface:
- Three cusps visible (two lingual, one buccal).
- Lingual developmental groove present.
Occlusal Surface:
- Hexagonal shape.
- Five cusps: Three buccal(mesiobuccal, distobuccal, distal) and two lingual(mesiolingual, distolingual).
- Developmental grooves: Mesiobuccal, distobuccal, lingual, and central (zigzag).
- Major fossa: central
  - Minor fossae : Mesial and distal triangular.
- Roots: Mesial root is longer than distal root.

Occlusal outline is rectangular.
There are four cusps – two buccal and two lingual cusps.
Buccal developmental groove, Lingual developmental groove and Central developmental groove (cross-shaped) are present.
- Major fossae- Central fossa
- Minor fossae- Mesial triangular fossa & Distal triangular fossa

Third molar removal is common, but controversial.
25% of patients need removal by age 25 due to infection, decay, cysts, periodontal disease.
Evaluation recommended by age 25.
Periodontitis affects molar root support.
Treatment involves instrumentation, treating each root separately.
Molars may have tubercles or developmental disturbances (enamel pearls, dilaceration).
Children with congenital syphilis may develop mulberry molars.

Human teeth are grouped into primary, mixed, and permanent dentitions.
Change from primary to permanent dentition indicates malocclusion development.
Tooth formation begins around the sixth week of prenatal life.
Jaws develop all stages of tooth formation.
Babies may be born with erupted lower front teeth.
Mandibular central incisors emerge first around 6-10 months, followed by other front teeth by 13-16 months.
Primary first molars appear around 16 months, canines around 19-20 months, second molars around 27-29 months.
Primary dentition forms fully by 30 months.
Transition period starts around 8 years old.

First transition period starts with permanent mandibular first molars emerging and ends when the last primary tooth is lost (around 11-12 years).
Initial phase lasts for two years: permanent first molars emerge, primary incisors shed, permanent incisors emerge.