Which of the following is true of cellular cementum?

 # Which of the following is true of cellular cementum?

A. Forms during root formation

B. Forms after eruption of the tooth

C. Seen at the coronal portion of the tooth

D. Formation is a slow process

The correct answer is B. Forms after eruption of the tooth. 

The cellular cementum is also known as secondary cementum as this is formed later than the AEFC (Acellular Extrinsic Fiber Cementum). The cellular cementum found in the apical third is mainly of two types—the cellular mixed fiber cementum which forms the bulk of secondary cementum and occupies the apical interradicular regions and the CIFC (Cellular intrinsic fiber cementum) which is present in the middle and apical third. These types are mainly involved in the adaptation and repair of cementum. Since the secondary cementum is formed rapidly the incremental lines are placed further apart than in AEFC (Acellular Extrinsic Fiber Cementum).

Reference: Orban's Oral Histology and  Embryology

Which of the following is indicative of ageing?

 # Which of the following is indicative of ageing?

A. Expression of dead tracts

B. Widening of predentin

C. Increase in tubular diameter

D. Increase in peritubular dentin

The correct answer is A. Expression of dead tracts. 

It is rather difficult to separate age and functional changes in dentin. Dentin is laid down throughout life. This dentin is termed secondary dentin. If dentin forms as a result of pathological process, like caries, it is termed tertiary dentin. Tertiary dentin shows irregularity in size, shape, number and arrangement of dentinal tubules. Dentinal tubules degenerate due to injury resulting in the formation of dead tracts. Mineralization of dentinal tubules results in the formation of sclerotic dentin. This makes the tooth to appear transparent in these areas.

Reference: Orban's Oral Histology and Embryology

The formation of hard tissue takes place in the:

 # The formation of hard tissue takes place in the:

A. Bud stage

B. Cap stage

C. Advanced bell stage

D. Early bell stage

The correct answer is C. Advanced bell stage.

Advanced bell stage is characterized by the commencement of mineralization and root formation. During the advanced bell stage, the boundary between inner enamel epithelium and odontoblasts outlines the future dentinoenamel junction. The formation of dentin occurs first as a layer along the future dentinoenamel junction in the region of future cusps and proceeds pulpally and apically.

Reference: Orban's Oral Histology and Embryology, 14th Edition

Paget’s test is done in the examination of

 # Paget’s test is done in the examination of:

A. A small swelling

B. Serum calcium

C. Urine analysis for alkaline phosphatase

D. Cytologic smear

The correct answer is A. A small swelling.

Paget's test is done for small swellings to know the consistency (cystic/solid). The centre and peripheries are palpated with index finger. Cystic swelling feels softer at centre than periphery whereas solid swelling feels firmer at center than periphery.