BIOLOGY CH20 Organ Systems in Animals — Science STD 9 — Question

• Teeth are hard structures meant for holding, cutting, grinding, and crushing the food.
• In human beings, two sets of teeth (Diphyodont) are developed in their lifetime. The first appearing set of 20 teeth called temporary or milk teeth are replaced by the second set of thirty-two permanent teeth, sixteen in each jaw. Each tooth has a root fitted in the gum (Theocodont).
• Permanent teeth are of four types (Heterodont), according to their structure and function namely incisors, canines, premolars, and molars.
• Dental formula represents the number of different types of teeth present in each half of a jaw (upper and lower jaw).
• The types of teeth are denoted as incisors (i), canine (c), premolars (pm) and molars (m). The dental formula is presented as:

For Milk teeth in each half of upper and lower jaw:\frac{2,1,2}{2,1,2}=10 \times 2=20For Permanent teeth in each half of upper and lower jaw:\frac{2,1,2,3}{2,1,2,3}=16 \times 2=32Types of teeth and their functio