Teeth are the hardest organs in the body. They are located in the oral cavity at the upper (Maxillae) and the lower (Mandible) jaws. Humans have two sets of teeth during their life-time which are:
Primary teeth also called baby teeth which are the first set of 20 teeth babies are born with and often start erupting 6 months after birth.
Permanent teeth are second set of teeth that include 32 adult teeth.
Each of the quadrants of the mouth contains 8 permanent teeth that include four types namely: 2 incisors, 1 cuspid (also known as canines), 2 bicuspids (also known as premolars) and 3 molars. Incisors are used for cutting food, cuspids are used for tearing, premolars are adapted for crushing and molars have bigger and flatter chewing surfaces and their job is chewing and grinding food.
Each tooth have three parts, including:
- Crown: The visible part of tooth. It is completely covered by enamel.
- Neck or cementoenamel junction (CEJ): The area where the crown joins the root.
- Root: The part of tooth that is found under CEJ and is covered with cementum.
Tooth is composed of four dental tissues. Three of them (enamel, dentin and cementum) are hard tissues and the fourth one is called pulp or the center of the tooth which is a soft or non-calcified tissue.
Enamel: Hard and resistant layer covering the dentin in the crown of the tooth. It is the hardest tissue in the body. Enamel have no living cell so it cannot repair damage.
Dentin: A specific calcified tissue that lies under enamel and cementum surrounding the Pulp Chamber. Whereas dentin contains microscopic tubules, it becomes sensitive to stimuli.
Pulp Chamber: The space occupied by dental pulp. Dental pulp is a soft tissue that contains nerves, blood vessels and connective tissue.
Cementum: The bonelike connective tissue made of minerals and collagen fibers. This layer covers the root of tooth and is attached to the Periodontal Ligament.
Periodontal Ligament. A system of collagenous connective tissue fibers that connect the root of the tooth to its socket.