ICP L6: Enamel homeostasis and caries development

Question 1

How can loss of tooth mineral occur

Answer 1

1. caries
2. gustatory acids
3. dietary sources
4. erosion
5. mechanical wear; attrition, abrasion, abfraction

Question 2

What is caries

Answer 2

Loss of tooth substance by metabolically produced acids, it is a bacterial disease and involves molecular level interactions between bacterium and sugars

Question 3

Define primary caries

Answer 3

Lesions on unrestored surfaces

Question 4

Define secondary caries

Answer 4

Recurrent lesions adjacent to fillings ocuring marginally

Question 5

Define residual caries

Answer 5

Demineralised tissue left behind before a filling has been placed

Question 6

Define active caries

Answer 6

This is considered to be a progressive form

Question 7

Define arrested caries

Answer 7

Considered a no longer progressive form

Question 8

What is a white spot lesion

Answer 8

The first visible sign by naked eye - detected by shining bright white light; these are reversible and do not need surgical intervention

Question 9

What is a brown spot lesion

Answer 9

An inactive white spot lesion discoloured by the uptake of dye from food debris

Question 10

What is rampant caries

Answer 10

Multiple active carious lesions in the same patient (often linked to xerostomia)

Question 11

What is hidden caries

Answer 11

Usually in dentine and only detectable by radiography (this means the lesion is large and so not reversible)

Question 12

How can white spot lesions be differentiated from defects

Answer 12

Defects will not change in shape or size and so successive visits can be used to differentiate between these

Question 13

What is the difference between an active cavitated and an active non-cavitated lesion

Answer 13

Non-cavitated is present on the tooth surface, cavitated white lesions go deeper into the underlying tooth material - this requires surgical intervention and so cannot be repaired naturally

Question 14

What are cavitated lesions filled with

Answer 14

Dental plaque

Question 15

Why do white lesions occur

Answer 15

Because there are micropores in the enamel surface as demineralisation has started; this scatters white light and so the white lesion is an optical phenomena for early caries detection

Question 16

Outline the structure of a white spot lesion and describe where demineralisation occurs

Answer 16

1. Surface layer
2. Body of lesion
3. Dark zone
4. Translucent zone

Demineralisation occurs at the subsurface level meaning the outer enamel surface is still intact

Question 17

What are the functions of saliva

Answer 17

1. Neutralise acids so inhibit demineralisation and enhance remineralisation
2. Recycle ingested fluoride in the mouth
3. Discourage bacterial growth
4. Contains proteins which sustain enamel surface
5. Protect tissue
6. Enhance taste
7. Lubricates food and so increases oral clearance
8. Digestion of carbohydrates

Question 18

Why is there a greater salivary concentration of Ca2+ in when the pH is lower

Answer 18

Because it is released from the salivary proteins to protect the teeth from acid attacks

Question 19

What are the causes of xerostomia

Answer 19

• autoimmune
• H+N radiotherapy
• salivary gland disease
• medication
• aplasia of salivary glands

Question 20

Which drugs can cause iatrogenic xerostomia

Answer 20

1. Dirutetics
2. Anti-inflammatorys
3. Anti-histamines
4. Anti-epileptics
5. Antihypertensives
6. Tricyclic antidepressants
7. SSRIs
8. Antipsychotics
9. Antihistaminics

Question 21

How is the stephan curve different for patients with xerostomia

Answer 21

It takes longer to return to a normal pH