01/08/2026
For the next time I am questioned by a third grader “why do sharks have lots of teeth and humans only have two sets?”
CLASSIFICATION OF DENTITION – MEDICALLY ACCURATE NOTES
🔹 1. Based on Development
Primary Dentition (Deciduous / Milk teeth)
→ First set of teeth
→ Total teeth: 20
→ Eruption begins around 6 months
→ Completed by 2–2.5 years
→ No premolars present
→ Teeth are smaller, whiter, with short roots
Permanent Dentition
→ Second set of teeth
→ Total teeth: 32
→ Begins erupting around 6 years
→ Includes premolars and third molars
→ Teeth are larger, stronger, and more durable
Mixed Dentition
→ Period when both primary and permanent teeth are present
→ Age range: 6–12 years
→ Important phase for orthodontic assessment
🔹 2. Based on Function (Type of Teeth)
Heterodont Dentition
→ Different types of teeth with different functions
→ Includes incisors, canines, premolars, molars
→ Seen in humans and mammals
→ Allows cutting, tearing, and grinding
Homodont Dentition
→ All teeth are similar in shape and size
→ Seen in fish and reptiles
→ Mainly used for grasping rather than chewing
🔹 3. Based on Mode of Tooth Replacement
Diphyodont
→ Two successive sets of teeth
→ Primary dentition → permanent dentition
→ Seen in humans
Monophyodont
→ Only one set of teeth throughout life
→ No replacement
→ Example: dolphins
Polyphyodont
→ Teeth are continuously replaced throughout life
→ Seen in fish, reptiles, sharks
🔹 4. Based on Mode of Attachment / Jaw Positioning
Thecodont
→ Teeth embedded in bony sockets (alveoli)
→ Seen in humans and mammals
→ Strong attachment, precise occlusion
Acrodont
→ Teeth attached to the crest of the jaw bone
→ Seen in some reptiles
→ Teeth usually not replaced
Pleurodont
→ Teeth attached to the inner surface of the jaw
→ Seen in lizards
→ Teeth can be replaced
🔹 5. Based on Shape and Form of Occlusal Surface
Bunodont
→ Rounded cusps
→ Suitable for grinding and crushing
→ Seen in humans, pigs
Lophodont
→ Cusps form ridges (lophs)
→ Efficient for grinding plant material
→ Seen in horses, elephants
Selenodont
→ Crescent-shaped cusps
→ Adapted for herbivorous diet
→ Seen in ruminants (cow, deer)
Secodont
→ Sharp, blade-like cusps
→ Designed for shearing flesh
→ Seen in carnivores (dog, cat)