Dentition

Dentition refer to the number, arrangement and conformation of teeth in an organism. Animals have different dentition patterns to fit the needs of their diet

Types of dentition.

1. Homodont dentition: The organisms have the same type of teeth. All the teeth are of the same shape, size and functions. Homodont dentition can be found in fishes, amphibians and reptiles.
2. Heterodont dentition: The organism possesses teeth of different shapes, sizes and functions. Heterodont dentition can be found in mammals(humans, dogs, rhinos etc).

Each group of mammals has a peculiar type of dentition related to its diet even though mammals generally have heterodont dentition. They have incisors, canines, premolars and molars. Each tooth has a different shape and function. Man has two sets of teeth during his lifetime; the milk teeth when young and the permanent teeth when mature. There are 20 milk teeth and 32 permanent teeth.

Types of teeth

1. Incisors: Flattened, chisel-like teeth with a sharp edge used for cutting and holding food or prey. They are located at the front of the jaw.
2. Canines: Long and pointed teeth used for tearing food, such as flesh from bone. They are positioned next to the incisors.
3. Premolars: Large teeth with ridged, flat surfaces used for chewing food. They are located toward the back of the jaw.
4. Molars: Broad, ridged teeth used for chewing and grinding food. They are found at the extreme back of the jaw.

structure of teeth

A mammal's tooth is divided into three regions:

• Crown: The part that projects above the gum.
• Root: The part that is embedded in the jaw bones.
• Neck: The junction between the crown and the root.

In the center of the tooth is a pulp cavity that contains blood vessels and nerves, making it extremely sensitive to heat, cold, and pain. The pulp is enclosed by dentine, a hard, bone-like material. Covering the dentine is the enamel, a white, hard material that protects both the dentine and the pulp. At the root, a thin layer of cement covers the dentine. This cement is surrounded by the periodontal membrane, a fibrous tissue that anchors the tooth to the jaw bone.

Dental Formula

The dental formula expresses the number and types of teeth a mammal possesses. It is typically written as four 'fractions', one for each type of tooth, with the upper and lower lines representing the upper and lower jaws, respectively. Different mammals have unique dental formulas depending on their diet.

• Man=2[ I=2/2, C=1/1, P=2/2, M=3/3] = 32.
• Dog=2[I=3/3 , C=1/1 , P=4/4 , M=2/3] = 42
• Rabbit=2[I= 2/1, C= 0/0, P=3/2, M=3/3] = 28.
• Rat=2[I=1/1, C= 0/0, P=0/0, M=3/3] = 16

Dentition in herbivores

Herbivores have a typical dental formula of 2[I=2/1, c=0/0, p=3/2, m=3/3]

Adaptations

• Incisors: Long and chisel-like for cutting grass.
• Good blood supply allows for continuous tooth growth.
• The space left behind by the canines (diastema) provides room for repositioning food while chewing.
• Molars and premolars: Have transverse ridges for grinding food.

Dentition in omnivores

Omnivores have a typical dental formula of 2[I=2/2, C=1/1, P=2/2, M=3/3]

Adaptations

• Premolar and molars have broad surfaces for grinding food.
• Sharp incisors for cutting food.

Dentition in carnivores

Carnivores have a typical dentition formula of 2[I=3/3, c=1/1 , p=4/4, m=2/3]

Adaptations

• Sharp incisors for catching and holding prey.
• Long pointed and curved canines for attacking and holding prey.
• Molars and premolars have pointed cusps for crushing bones.

Dental care

Tooth decay is caused by bacteria and the fermentation of carbohydrates that get stuck in the teeth. It can be prevented by:

1. Practicing regular oral hygiene.
2. Avoiding sweet, very hot, and very cold foods.
3. Eating a balanced diet with enough vitamins, phosphorus, and calcium.
4. Regularly visiting a dentist.