Cementum

Question 1

Patterns of arrangement at edj

Answer 1

Cementum overlaps enamel (predominant)

Cementum and enamel meet at joint

Cementum and enamel fail to meet, dentine exposed —> dentine hypersensitivity

Question 2

What makes cementum different from bone

Answer 2

Avascular (no blood and innervation), will be degenerated, does not undergo remodelling

Question 3

How is cementum formed

Answer 3

Dental follicle cells come into contact with and attach to hyaline layer, causing them to differentiate into cementoblasts. Cementoblasts deposit cementum continuously throughout life for continual reattachment of PDL fibres

Question 4

Function of cementum

Answer 4

Attachment to Sharypey’s fibres (attach to acellular cementum). Maintain tooth in functional position. Maintain tooth height via cementum deposition at apical area to compensate for tooth attrition. Maintain integrity of root, preventing dentine resorption and strengthen root bifurcation against occlusal load

Question 5

Physical properties of cementum

Answer 5

Pale yellow with dull surface. Permeability decreases with age. Cementum is soft and thin, can be easily removed by abrasion when gingival recession exposes root surface to oral environment, exposing dentine, which leads to dentine hypersensitivity.

Question 6

What are cementicles

Answer 6

Small globular masses of cementum that form due to microtrauma

Question 7

What is ankylosis

Answer 7

Fusion of cementum and alveolar bone with obliteration of PDL due to chronic inflammation , occlusal trauma

Question 8

What happens as cementum ages

Answer 8

Becomes less permeable. Increased cementum width due to continual deposition. Accumulate resorption bays due to cementum resorption, resulting in increased surface irregularity