Pain on tooth preparation even on the enamel layer

 # Some patients experience pain on tooth preparation even on the enamel layer. This may be due to:

A. Enamel Tufts

B. Enamel lamellae

C. Enamel spindles

D. Striae of Retzius

The correct answer is C. Enamel Spindles.

Odontoblastic processes occasionally cross the DEJ into enamel; these are termed enamel spindles when their ends are thickened. They may serve as pain receptors, explaining the enamel sensitivity experienced by some patients during tooth preparation.

Ref: Sturdevant’s Art and Science of Operative Dentistry, 7e, André V. Ritter, Lee W. Boushell, Ricardo Walter, Second South Asia Edition, 2019

Page No: 8

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The largest portion of a tooth is formed by:

 # The largest portion of a tooth is formed by:

A. Enamel

B. Dentin

C. Pulp

D. Cementum

The correct answer is B. Dentin.

Dentin forms the largest portion of the tooth structure, extending almost the full length of the tooth. Externally, dentin is covered by enamel on the anatomic crown and cementum on the anatomic root. Internally, dentin forms the walls of the pulp cavity (pulp chamber and pulp canals).

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Number of enamel rods in a maxillary molar is about:

 # Number of enamel rods in a maxillary molar is about:

A. 8 million

B. 12 million

C. 20 million

D. 30  million

The correct answer is B. 12 million.

The rods vary in number from approximately 5 million for a mandibular incisor to about 12 million for a maxillary molar. The rods are densely packed and intertwined in a wavy course, and each extends from the dentinoenamel junction (DEJ) to the external surface of the tooth.

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Teeth with longest roots in human dentition are:

 # Teeth with longest roots in human dentition are:

A. Incisors

B. Canines

C. Premolars

D. Molars

The correct answer is B. Canines.

Canines possess the longest roots of all teeth and are located at the corners of the dental arch. They function in the seizing, piercing, tearing and cutting of food. From a proximal view, the crown also has a triangular shape, with a thick incisal ridge. The anatomic form of the crown and the length of the root make these teeth strong, stable abutment teeth for a fixed or removable prosthesis.

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