Dental Anatomy Overview

Dental Anatomy Study Notes

• Dental anatomy is the study of the structure and form of teeth.
• Molars are posterior teeth in the back of a mammal's mouth used for grinding food; they are unique in structure.
• Permanent molars: 12 teeth, 3 per quadrant.
• Deciduous molars: 8 teeth, 2 per quadrant.
• Molars are described as "strange or primitive" due to their distinct anatomical features.
• Human molars are the largest and strongest teeth due to their crown size and multiple roots for anchorage in bone.
• Molars are non-succedaneous, meaning they are not shed and replaced by others. In other words, they do not directly follow the shedding of primary teeth.
• Molars have large occlusal surfaces.
• Lower permanent molars typically have two lingual cusps and two roots (mesial and distal).
• The notation systems for mandibular molars include Universal, FDI, and Palmer.
• The 7 primary functions of teeth are mastication, swallowing, speech, expressions, psychological, aesthetics, and craniomandibular stabilization (most important in molars).
• Molars are crucial for chewing, crushing, grinding food, and overall mastication.
• Molars also influence aesthetics in smiling and speaking.
• Molar size and root structure support the muscles of mastication, and help in preserving alveolar bone.
• Loss of molars affects facial dimensions.
• Molars, particularly the mandibular ones, show progressive reduction in size as they move posteriorly.
• The mesio-distal dimension is larger than the bucco-lingual dimension in molars.
• The first molar is the largest and shows the least morphological variation.
• The third molar is the smallest with the most morphological variation, and has a fifth distal cusp, present only in the first molar.
• Root portions of molars in the mandible are typically shorter than other mandibular teeth but with combined measurements, result in superior anchorage and efficiency.
• The sum of the combined mesio-distal measurements of mandibular molars is equal to, or greater than, the sum of anteriors and premolars combined.
• Molars typically develop 5 functional cusps (MB/ML/DL/DB) and a distal cusp.
• The distal cusp is located above the buccal side.
• The two lingual cusps are usually equal in size.
• The first molar erupts around 6 years of age.
• Early decay is common on proximal sides of teeth/molars due to early eruption, and bad oral habits, resulting in an increased risk of loss.
• The occlusal view of a molar often resembles a "hot cross bun" in its shape.
• The first molars are narrower mesio-distally than molars further back in the mouth.
• The mesial cusps are usually larger than distal cusps (excluding the maxillary first premolars).
• First molars (mandibular and maxillary) typically contain 3, and second molars typically contain 2, and third molars contain 2-3 canals at their cervical region.
• Mandibular (and maxillary) third molars frequently show significant developmental variation compared to other permanent teeth.
• Third molars are also frequently congenitally missing in some individuals.
• The third molar shape and structure often resemble or differ significantly from the adjacent second molar.
• Class I occlusal relationship: Mandibular first molar is one/half tooth mesial to the maxillary first molar, similar relationship is seen between the second molars as well.
• Tooth chronology for mandibular molars varies, but in general involves significant differences in the timing of eruption (calcification, enamel completion, root completion) of maxillary molars.

Pulp Morphology

• Molars typically have 3 canals and 3 orifices, with a triangular shape, distally broad and mesially narrower pulp canal/triangle.
• ML and MB canals are typically smaller than the distal canal.
• Two horns (mesio-lingual and disto-buccal horns) are present in mesio-distal cross-sections of molars.
• Two roots are common with narrow canals present in bucco-lingual cross-sections.