Enamel is the hardest tissue in the human body, with a Knoop hardness of 340-350. It is composed of 96% inorganic material, primarily hydroxyapatite crystals, which gives it its strength and durability.

Enamel's primary function is to protect the tooth from wear and tear. It is highly resistant to acids and abrasion, which helps to prevent cavities and tooth decay.

Dentin is the most abundant tissue in the tooth, making up about 70-80% of its volume. It is a hard, calcified tissue that is located beneath the enamel and surrounds the pulp chamber.

Dentin's primary function is to provide strength and support to the tooth. It is a hard, dense tissue that is able to withstand the forces of biting and chewing.

Enamel is avascular, meaning it does not contain any blood vessels. This is because enamel is a non-living tissue and does not require a blood supply.

Dentin is vascular, meaning it contains blood vessels. This is because dentin is a living tissue and requires a blood supply to maintain its health.

Hypoplasia, hypomineralization, and fluorosis are all types of enamel defects. Hypoplasia is a condition in which the enamel is underdeveloped, hypomineralization is a condition in which the enamel is not properly mineralized, and fluorosis is a condition in which the enamel is discolored due to excessive fluoride exposure.

Dentinogenesis imperfecta, dentin dysplasia, and root resorption are all types of dentin defects. Dentinogenesis imperfecta is a condition in which the dentin is underdeveloped, dentin dysplasia is a condition in which the dentin is abnormally formed, and root resorption is a condition in which the root of the tooth is resorbed.

The amelodentinal junction is the junction between the enamel and dentin. It is a complex interface that is responsible for the adhesion of the two tissues.

Odontoblasts are the cells that produce dentin. They are located in the pulp chamber and extend their processes into the dentin tubules.

The pulp chamber is the space in the center of the tooth that contains the pulp. It is located beneath the dentin and enamel.

Cementum is the tissue that surrounds the root of the tooth. It is a thin layer of calcified tissue that helps to anchor the tooth in the jawbone.

The periodontal ligament is the tissue that connects the tooth to the jawbone. It is a thin layer of connective tissue that helps to cushion the tooth and absorb shock.

The gingiva is the tissue that covers the gums. It is a thin layer of mucous membrane that helps to protect the underlying tissues.

The alveolar bone is the bone that supports the teeth. It is located in the upper and lower jaws and forms the sockets in which the teeth are embedded.