Cementum Of Tooth Question And Answers

Cementum Of Tooth Question And Answers

Question 1. Describe the macroscopic and microscopic appearance of cementum. (or) Cementoenamel junction
Answer:

Cementum:

• It is a mineralized, hard connective tissue that covers the anatomical roots of teeth.

Macroscopic appearance:

• Cementum provides a medium for tire attachment of collagen fibers that bind tire tooth to, the surrounding structures.
• It is avascular and non-innervated.

Read And Learn More: BDS Previous Examination Question And Answers

• Cementum can form throughout the life of a tooth.

Extend:

• Cementum begins at the tire cervical portion of the tire tooth at the tire cementoenamel junction and continues to the apex.
• Sometimes, it extends to the inner wall of the dentin for a short distance.

Color:

• Cementum is light yellow in color.
• It lacks luster as present in enamel, n It is lighter in color than dentin.

Microscopic appearance:

• The cementum consists of

1. Fibres.

Types:

1. Intrinsic fibers:
   • Collagen fibers secreted by tire cementoblast are called intrinsic fibers.
   • They are densely packed to the root surface.
   • They run parallel.
2. Extrinsic fibers:
   • Collagen fibers produced by fibroblasts of periodontal ligament are incorporated into the cementum as sharpe/s fibers form extrinsic fibers.
   • They are large and haphazardly incorporated.
   • They run perpendicular to the root surface.

Function:

• Fibres anchor the tooth to the bone.
• They distribute masticatory forces.

2. Cementoblasts:

• The cells forming the cementum are called cementoblasts.
• They have numerous mitochondria, a well-formed Golgi apparatus, and a large amount of granular endoplasmic reticulum.
• They intermingle with the fibroblasts of the periodontal ligament.
• They have basophilic cytoplasm.

Functions:

• Cementoblasts synthesize collagen and protein polysaccharides which form an organic matrix of cementum.
• This organic matrix of cementum forms a fibrous fringe where collagen fiber bundles of periodontal ligament become anchored.

3. Cementocytes:

• Some cementoblasts become entrapped within their own matrix, they are called cementocytes.
• They have very little cytoplasm and numerous processes called canaliculi.
• They are present in spaces called lacunae.
• Cementocytes in the deeper layers are non-viable.
• They have reduced secretory activity.

4. Incremental lines:

• The incremental lines in cementum are called the lines of salter.
• These lines indicate periodic formation.
• They can be best seen in decalcified specimens.
• They are highly mineralized areas with less collagen and more ground substance than other portions of the cementum.
• These lines are far apart in the cellular cementum and closely placed in the acellular cementum.
• The number of incremental lines is used for the age determination of an individual.

5. Cementodentinal junction:

• It is the interface between cementum and dentin.
• It is relatively smooth in permanent teeth, while scalloped in deciduous teeth.
• It is a wide zone containing large quantities of collagen associated with glycosaminoglycan which increases its water content.

Functions:

• It contributes to the stiffness of cementum
• It helps to redistribute occlusal loads to the alveolar bone.

6. Cementoenamel junction:

• The relation between cementum and enamel at the cervical region of teeth is called a cementoenamel junction.

Types:

• In 30% of cases – the cementum and enamel meet as a butt joint.
• In 10% of cases – a gap exists between the cementum and enamel.
• In 60% of cases – cementum overlaps enamel.

Question 2. Enumerate the difference between cellular and acellular cementum.
Answer: