Indirect Tooth Coloured Restorations

Question 1

Give 2 anterior options for tooth restorations.

Answer 1

1. Veneers - composite or porcelain.
2. Complete crowns - mcc, all porcelain.

Question 2

Give 4 posterior options for tooth restorations.

Answer 2

1. Composite inlay/onlay.
2. Porcelain inlay/onlay.
3. Partial crowns (not included as it is metal)
4. Complete crowns - MCC, all porcelain.

Question 3

Give 5 positives to veneers.

Answer 3

1. Conservative
2. Sometimes no cutting necessary
3. Margins supragingival
4. Improvement in colour
5. Improvement in shape
6. Cheaper in some cases.

Question 4

What are the 2 types of veneers?

Answer 4

direct - composite
indirect - composite/porcelain

Question 5

Give 6 positives to direct veneers.

Answer 5

1. Easy to do - but time consuming
2. Easily adjustable
3. No preparation necessary
4. Cheap - but costly for dentist time
5. Quick
6. No need for impressions or lab but fit may not be as accurate.

Question 6

Give 2 ways direct veneers are constructed.

Answer 6

1. Composite applied directly to the teeth.
2. Make a splint from a diagnostic wax up first.

Question 7

Give 2 negatives for indirect veneers.

Answer 7

1. May need preparation especially for porcelain.
2. More expensive

Question 8

Compare composite and porcelain indirect veneers.

Answer 8

1. Composite is easily adjustable.
2. If porcelain veneer fractures, a new veneer will be needed.
3. Composite stains, whilst porcelain stains less than enamel. This means porcelain is more suitable for smokers.
4. Porcelain can give better aesthetics.
5. For lower teeth composite may be preferred due to the high load experienced here.

Question 9

Give 7 indications for veneers.

Answer 9

1. Stained or darkened teeth
2. Hypocalcification
3. Multiple diastemas
4. Peg laterals
5. Chipped teeth
6. Lingual positioned teeth
7. Malposed teeth not requiring orthodontics

Question 10

Give 6 contraindications for veneers.

Answer 10

1. Insufficient tooth substrate (enamel for bonding)
2. Labial version
3. Excessive interdental spacing
4. Poor oral hygiene or caries
5. Parafunctional habits (clenching, bruxism)
6. Moderate to severe malposition or crowding

Question 11

Give 6 contraindications for veneers.

Answer 11

1. Insufficient tooth substrate (enamel for bonding)
2. Labial version
3. Excessive interdental spacing
4. Poor oral hygiene or caries
5. Parafunctional habits (clenching, bruxism)
6. Moderate to severe malposition or crowding

Question 12

Define an inlay.

Answer 12

1. Indirect.
2. Intra-coronal restoration (within crown)
3. Does not provide cuspal coverage.
4. Proximal and occlusal surfaces are replaced.

Question 13

How is an tooth prepared for an inlay?

Answer 13

1. Isthmus is 1.5-2mm.
2. Axial wall is tapered 4-6 degrees for retention.
3. Flat pulpal floor.
4. If ceramic: butt-joint (90 degree) cavo-surface margin angle.
5. If metal: 20-30 degree bevel on cavosurface margins.
6. Rounded internal line angles.
7. Proximal contact point cleared.

Question 14

What are 2 indications for inlays?

Answer 14

1. Occlusal and/or proximal cavities
2. Failed direct restoration replacement.

Question 15

Define an onlay.

Answer 15

1. Indirect.
2. Intra and extra-coronal (beyond crown)
3. That incorporates cusps.
4. And provides cuspal coverage.

Question 16

How is a tooth prepared for an onlay?

Answer 16

1. Isthmus - follow the restoration pattern.
   
   2. Flat pulpal floor
   3. 4-6 degree tapered walls.
   4. Butt-joint 90 degree cavo-surface margins.
   5. Contact points clear proximally only.
   6. Rounded internal angles.
   7. Axial shoulder or chamfer 1mm reduction.
   8. For ceramic: functional cusp 2mm reduction, non-functional cusp 1.5mm reduction.
   9. For gold type III: functional cusp 1mm, reduction, 0.5mm reduction.

Question 17

What are 5 indications for onlays?

Answer 17

1. Cusp fracture.
2. Toothwear.
3. Caries weakening the tooth structure.
4. Pre-existing failed restoration with a large isthmus.
5. Restoration of RCT teeth.

Question 18

Define isthmus.

Answer 18

Root canal isthmus,a narrow ribbon-shaped communication between two root canals

important anatomical feature because of the fact that it may contain pulp remnants, necrotic tissues, and micro-organisms and their byproducts.

Question 19

Give 3 materials inlays and onlays can be made of.

Answer 19

1. Gold
2. Composite
3. Porcelain.

Question 20

Why have inlays and crowns been phased out?

Answer 20

Onlays are the most conservative.

Crowns are only used when there is a high aesthetic demand or an onlay is not possible.

Question 21

Define a crown.

Answer 21

1. Indirect restoration
2. Fully covers the coronal aspect of the tooth.

Question 22

How is a tooth prepared for a crown?

Answer 22

1. Flat pulpal floor.
2. 4-6 degree tapered walls.
3. No undercuts.
4. Rounded line angles.

Ceramic:
Functional cusp: 2mm reduction.
Non-functional cusp: 1.5mm reduction.

Gold type Ill:
- Functional cusp: 1mm reduction.
- Non-functional cusp: 0.5mm reduction.

Axial reduction:
- PFM:
Buccal: 1.5mm shoulder.
Metal palatal/lingual: 1mm chamfer.
Porcelain palatal/lingual: 1.5mm shoulder.

• All ceramic:
  1mm rounded chamfer.
• Metal:
  0.5-1mm chamfer.

Question 23

Give 7 indications for a crown.

Answer 23

1. Cusp fracture.
2. Toothwear
3. Caries weakening the tooth structure.
4. Pre-existing failed restoration with a large isthmus.
5. Restoration of RCT teeth.
6. High aesthetic demand.
7. Onlay not possible.

Question 24

How do we measure the gingival extension when preparing teeth for crowns?

Answer 24

Exterior of the bevel to the gingival crest

Question 25

How do we measure occlusal reduction when preparing teeth for crowns?

Answer 25

Measured at the reduced cusp tips to the opposing fossa or marginal ridge

Question 26

How do we measure margin reduction when preparing teeth for crowns and how thick should margins be?

Answer 26

Measured from the base of the axial wall to the external of the tooth perpendicular to the external surface:

Question 27

- What does an overtapered crown preparation increase or reduce?

Answer 27

Reduces Retention

Question 28

What can a lip on a crown preparation lead to?

Answer 28

increased risk of fracture and a poor fit

Question 29

What is the minimum height needed on teeth to be suitable for a crown and what can be done to modify these teeth for crowns?

Answer 29

1. 3 mm is the proposed minimal height for premolars and anterior teeth with 10 -20° TOC 2. 4 mm is the minimal proposed height for molars Teeth that do not possess these minimal dimensions should be modified with auxiliary resistance features such as grooves/boxes.