Dental and Oral Biology

Incisors are cutting and biting type of teeth.

Molars and premolars are chewing and grinding type of teeth.

The pharynx is at the back of buccal cavity. The pharynx is a common channel for food and air.

Ameloblasts are present only during tooth development.

Mastication is the process by which food is crushed and grinded by teeth. It is the first step of digestion and it increases the surface area of foods to allow more efficient break down by enzymes. During the mastication process, the food is positioned between the teeth for grinding by the cheek and tongue.

Wisdom teeth are the third and final set of molars that most people get in their late teens or early twenties (ages 17-25). They are called 'wisdom teeth' because they appear at a more mature age, when people are supposedly wiser than childhood. These teeth often cause problems because there is not enough room in the jaw for them to emerge properly, leading to impaction that may require surgical removal.

The vestibule is the space between the teeth, lips, and cheeks, and the gums. Polar space (B) is not a dental term, dentures (C) are artificial teeth, and dentine (D) is the tissue beneath tooth enamel. The vestibular space is crucial for proper oral hygiene and orthodontic appliance placement.

Tonsils are lymphoid tissues located in the throat area that form part of Waldeyer's ring, acting as the first line of defense against pathogens entering through the mouth and nose. They trap bacteria and viruses, initiating immune responses. The gums, teeth, and tongue have structural and digestive functions, not immune defense.

This is the correct answer as only statement a is correct.

In carnivores, canines are well developed to pierce and tear flesh.

This is a 'which is NOT correct' question. Crocodiles do have thecodont teeth (set in sockets). Snake fangs are indeed poison teeth. Birds completely lack dentition and enamel. Human teeth have closed pulp cavities after eruption - the statement claiming they are 'open' is the incorrect one.

Diastema refers to any gap or space between teeth. This can occur between incisors and canines (common in herbivores), between incisors and premolars, or between two incisors. Since all these are valid locations for diastema, 'all of the above' is correct.

Enamel is the hardest substance in the human body, rating 5 on the Mohs scale. It covers all teeth - incisors, canines, premolars, and molars. Therefore, saying 'all of the above' is correct because enamel on any tooth type is the hardest substance.

Enamel is derived from ectoderm, specifically from ectodermal ameloblasts during tooth development. This is a fundamental embryological fact - enamel is the only ectodermal-derived hard tissue in the body. Dentin and cementum are mesodermal in origin.