Question

Dentine is
A Hard protective covering on the heart.
B The cavity which contains nerves and blood vessels in a tooth.
C The soft invisible covering present in a tooth.
D The nerve that connects the tooth and the brain.

Answer 1

Hint Dentin is a calcified bodily tissue that is one of the four primary components of teeth, along with enamel, cementum, and pulp. It covers the whole pulp and is generally coated by enamel on the crown and cementum on the root. Dentin is composed of 45 percent mineral hydroxyapatite, 33 percent organic material, and 22 percent water by volume.

Complete answer:
The pericardium is a strong, two-layered fibroserous sac that surrounds and protects the heart. The pericardial cavity, which is the gap between the two layers of serous pericardium, is filled with serous fluid that shields the heart from any external jerk or shock.
The nerves and blood vessels that provide the tooth with sensations of dental sensitivity or pain are found in the pulp, which is located in the middle of the tooth.
The enamel, the hard outer coating, the dentine, and the pulp, the soft tissue present, are the three fundamental structures present in the teeth.
One of the cranial nerves with both sensory and motor activity is the trigeminal nerve. The placement of the cranial nerves is also used to classify them using Roman numbers. The cranial nerve V is also known as the trigeminal nerve.

So, the option C is correct.

Additional information
Due to the translucency of enamel, it has a significant impact on the colour of a tooth. Dentin, which is less calcified and brittle than enamel, is required to keep enamel in place. On the Mohs scale of mineral hardness, dentin is a 3 on the scale.
Dentin differs from enamel in two ways: First, it develops throughout life; and second, due to the sensory role of odontoblasts, dentin is sensitive to temperature fluctuations and can become hypersensitive to them, especially when enamel recedes and dentin channels become exposed.

Note: The calcification of dentinal tubules characterises dentinal sclerosis/transparent dentin-sclerosis of primary dentin, a regressive change in tooth. It can happen as a result of cavities or abrasion to the dentin, or as part of the natural ageing process.