ILA

Question 1

What are potential intrinsic forms of erosive toothwear and what can they be triggered by?

Answer 1

GORD: Can be triggered directly by gastric reflux or side effect of medications

Question 2

How can dentists test the progression of erosive tooth wear?

Answer 2

Scratch test using an explorer

Question 3

Why is citric acid particularly dangerous for tooth wear?

Answer 3

Lemons pH 2 (Citric Acid): highly damaging due to both direct acid attack and chelation.

Chelation works when the acidic anion (citrate) works to sequester calcium away from both the tooth and the saliva. This prevents remineralisation.

Question 4

What tooth wear patterns are evident for intrinsic acid sources?

Answer 4

Wear of palatal as well as occlusal surfaces

Question 5

Why might dentinal hypersensitivity occur with erosive tooth wear?

Answer 5

Acidic dissolution of smear layer leaves dentinal tubules open and exposed.

Question 6

How would severe tooth wear on both arches manifest for a patient’s occlusion?

Answer 6

1. Changed intercuspal position
2. Intercuspal Position no longer in concert with Centric Relation
3. Shortened facial profile - making the chin closer to the nose
4. Side profile - will appear more convex in nature

Question 7

A loss of canine guidance will result in what?

Answer 7

Use of group function by 1-2nd pre-molars

Question 8

When rebuilding OVD, what are some goals in restoring masticatory and occlusal function

Answer 8

1. Stability for muscles of mastication
2. Even Distribution of Load whilst in intercuspal occlusion
3. Unimpeded Mandibular Movements - posterior disclusion on Lateral Excursion, Incisor-to-Incisor

Question 9

When would repairing an amalgam be indicated and how would you do the subsequent restoration

Answer 9

If the existing amalgam is sound, and removal puts the tooth at risk

New amalgam

1. All corrosion products from old amalgam removed
2. Adequate mechanical retention
3. Amalgam must be highly compacted and burnished on margins

Question 10

You have a patient where you wish to re-establish the biofilm subsequent to preventative treatment. What would you prescribe for home use?

Answer 10

Colgate Savacol Original Mouthwash (0.2%) 2mg/mL chlorhexidine gluconate. Use 2x daily for 2 weeks.

Question 11

You have a 10 year old who has high caries risk with mixed dentition. What fluoride should you be advising them to use?

Answer 11

For both 18mths - 6yrs and 6yrs - teenager groups, moderate and high risk individuals should use:

1. Drink Fluoridated Water
2. Brush with standard toothpaste 2+ times/day
3. Spit no Rinse

Question 12

You have a high caries risk patient. On completion of the treatment plan, what should the recall frequency be based off Caries Management System?

Answer 12

Every 3 months until:

1. Home Care goals hav ebeen achieve (OH and Fluoride)
2. Lesion Progression has arrested/reversed
3. Reclassification as medium / low risk

Question 13

You have a medium caries risk patient. On completion of the treatment plan, what should the recall frequency be based off Caries Management System?

Answer 13

Every 6 months after completion of treatment plan

Question 14

You have a low caries risk patient. On completion of the treatment plan, what should the recall frequency be based off Caries Management System?

Answer 14

Every 12 months after completion of treatment plan

Question 15

What is a twin block appliance used for?

Answer 15

Growth modification application that can help correct an overbite whilst the jaw is still in development. It is typically worn 24 hours/day.

Question 16

What are some oral implications of Tricyclic Antidepressants?

Answer 16

Increases the chances of GORD and erosive wear via reflux/regurgitation.

Question 17

What is the chemistry of direct acid attack on tooth enamel?

Answer 17

Direct attack by the H+ below the critical pH of FA (4.5) and HA (5.5) combine with the CO3 and/or PO4
releasing ions from the crystal surface leading to direct surface etching

Question 18

What is the pH of intrinsic acids involved with tooth wear?

Answer 18

Hydrochloric Acid = pH 1

Question 19

What factors modify the severity of acid erosive potential on teeth?

Answer 19

Food pH
Total Volume of Acid (Titratable Acid)
pKa
Calcium Chelation Properties
Host Calcium / Phosphate / Fluoride concentration in saliva
Adhesion factors

Question 20

How does calcium chelation work?

Answer 20

Citrate in citric acids sequesters calcium away from the tooth and saliva. Moving it out of a closed ecosystem prevents remineralisation

Question 21

How does tooth wear affect masticatory function?

Answer 21

Loss of occlusal stability
Loss of anterior / canine guidance
Progression to Group Function
Loss in Cusp Height
Change in OVD
Muscle tenderness/pain from lack of coordination of muscles of mastication
Remodelling of masticatory pattern
TMJ remodelling 
Flattening of Condyle