Concept about Teeth-The course is designed for the basic understanding of anatomical structures and physiological functions of human body, musculoskeletal system, digestive system, respiratory system; cardiovascular system; urinary system, endocrine system, reproductive system, nervous system, hematologic system, sensory organs, integumentary system, and immune system.The aim of the course is to acquire knowledge and skills regarding anatomy and physiology.
Concept about Teeth
The teeth (dentes) are accessory digestive organs located in bony sockets of the mandible and maxillae. The sockets are covered by the gingivae or gums and are lined with the periodontal ligament (peri around; odont = tooth). This dense fibrous connective tissue anchors the teeth to bone.
A typical tooth has three major external regions: the crown, root, and neck.
- The crown is the visible portion above the level of the gums.
- The root consists of one to three projections embedded in the socket.
- The neck is the junction line of the crown and root, near the gum line.
Internally, dentin forms the majority of the tooth. Dentin consists of a calcified connective tissue that gives the tooth its basic shape and rigidity. The dentin of the crown is covered by enamel that consists primarily of calcium phosphate and calcium carbonate.
Enamel, the hardest substance in the body and the richest in calcium salts (about 95% of its dry weight), protects the tooth from the wear and tear of chewing. Narrow extensions of the pulp cavity run through the root of the tooth and are called root canals.
Each root canal has an opening at its base through which blood vessels bring nourishment, lymphatic vessels offer protection, and nerves provide sensation.
Humans have two sets of teeth.
- The deciduous teeth begin to erupt at about 6 months of age, and one pair appears about each month thereafter until all 20 are present. They are generally lost in the same sequence between 6 and 12 years of age.
- The permanent teeth appear between age 6 and adulthood. There are 32 teeth in a complete permanent set.
Humans have different teeth for different functions.
❖ Incisors are closest to the midline, are chisel shaped, and are adapted for cutting into food,
❖ Cuspids (canines) are next to the incisors and have one pointed surface (cusp) to tear and shred food;
❖ Premolars have two cusps to crush and grind food; and
❖ Molars have three or more blunt cusps to crush and grind food.
(Ref-J. TORTORA. The essentials of anatomy and physiology, 8th edition, P-486,487)
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