Tooth Wear

Question 1

What is tooth wear?

Answer 1

It is the cumulative surface loss of mineralised tooth substance/tissue due to physical or chemo-physical processes.

It is not considered the result of dental caries, resorption or trauma

Question 2

Which processes may lead to tooth wear?

Answer 2

erosion, attrition, abrasion

Question 3

Parafunction or bruxism would be responsible for what process that leads to tooth loss?

Answer 3

Attrition (tooth to tooth)

Question 4

Which process is caused by acid?

Answer 4

Erosion - can be extrinsic or intrinsic

Question 5

What could cause tooth wear via abrasion (mechanical factor)?

Answer 5

Tooth brushing 
Abrasive toothpaste
Toothpicks 
piercings
nail biting 
pen chewing

Question 6

What is the theory of abfraction?

Answer 6

It is the belief that occlusal forces/stresses causes tooth wear, but little evidence to suggest this

Question 7

What percentage of dentate patients have tooth wear into dentine in their anterior teeth as per the 2009 UK Dental Health Survey?

Answer 7

77%

Question 8

Tooth wear prevalence is increasing - why could this be?

Answer 8

Fruits are available out of season
Increasing number of snacks
More soft drink consumption

Question 9

What are the percentages of enamel constituents?

Answer 9

96% enamel (calcium hydroxyapatite)
3% water
1% organic tissue

Question 10

What is aprismatic enamel?

Answer 10

It is the outside layer of enamel that is present on tooth eruption. It is relatively disorganised and contains no prisms. It is up to 100 microns deep.
It has the highest mineral content - containing fluoride and phosphate

Question 11

Why is aprismatic enamel more protective against acid attack and mechanical challenges?

Answer 11

Due to it’s structure and it’s high mineral content containing fluoride and phosphate in the form of fluorohydroxyapatite.

Question 12

Outline the percentage constituents of dentine

Answer 12

75% mineral
20% organic material
5% water

Question 13

What type of dentine is closest to the enamel and how thick is it?

Answer 13

The mantle dentine
15-30 microm thick
It is similar to aprismatic layer in enamel - it is disorganised and only has a few thin, curved tubules

Question 14

Describe the main bulk of dentine within a tooth

Answer 14

It consists of intertubular dentine - type 1 collagen-rich structure
Collagen network is moisture rich and elastic resulting in reduced hardness and higher susceptibility to wear

Question 15

What type of dentine is found within the lumen of the tubules?

Answer 15

Peritubular dentine
Formed by network of proteins and apatite crystals with no collagen fibrils.
It is highly mineralised = more susceptible to acid challenge

Question 16

Outline what happens when teeth are exposed to an acidic environment (3 points)

Answer 16

• Minerals are released from the surface = softens outermost layer (0.2-2 microm thick)
• Initial breakdown of interface between prism and interprismatic layer widening the prism > prism cores richer in carbonate so are more susceptible to erosion
• Liquid can move through enamel prisms of teeth causing subsurface softening.