Crown fitting and cementation

Question 1

When looking at your models what question should you be asking yourself?

Answer 1

1. Is the restoration you received it what you asked for
2. Does everything look right
3. Has there been any damage to the models

Question 2

What might you put on your models to help the technician?

Answer 2

Black check lines to help the technician get a better idea of the patients occlusion

Question 3

When looking at the crown what questions should you be asking yourself?

Answer 3

1. Do the margins of the crown correspond to finishing lines on the restoration
2. is the restoration itself well finished
3. Are the contours of the crown correct
4. Is the shade of the crown right
5. Can you see any obvious flaws

Question 4

When meeting your patient for the crown fitting appointment what questions should you ask them?

Answer 4

1. Has the tooth been symptom free
2. Has the temporary crown remained intact and comfortable
3. How sensitive is the tooth

Question 5

What could have happened in the appointment between placing a temp crown on and the crown fitting appointment?

Answer 5

Over eruption may have occurred

Question 6

Talk through the steps you’d take BEFORE placing your permanent crown on a tooth

Answer 6

1. Remove the temporary as carefully as possible (use the excavator under the margin and lift)
2. Check the occlusion
3. Ensure all temporary cement is removed
4. Clean the preparation with pumice and water
5. Protect the airway with gauze

Question 7

How should you remove the temporary restoration

Answer 7

Use an excavator under the margins and lift

Question 8

What equipment do you need to fit a restoration

Answer 8

1. Dental floss
2. Fit checker spray
3. Gold thickness gauge
4. Occlusal indicator paper
5. Straight hand piece

Question 9

Talk through the steps of checking if your crown fits

Answer 9

1. Check the margins with a probe
2. Check contacts with floss
3. Check occlusion using thin occlusal indicator paper

Question 10

What can happen if the contact point between your restoration and the neighbouring tooth is too loose?

Answer 10

Food packing can occur

Question 11

What can happen if the contact point between your restoration and the neighbouring tooth is too tight

Answer 11

will be uncomfortable

Question 12

How do you check the occlusion of the crown

Answer 12

Use articulating paper to se if there is any high points

Use a high speed rugby shaped burr to remove an extra high points on the restoration

Question 13

Talk through the stages of cementation

Answer 13

1. Isolate and dry the preparation
2. Clean and dry the restoration
3. Mix cement
4. Place a player of cement in the restoration
5. Seat restoration firmly and apply pressure
6. Check occlusion
7. Remove excess cement thoroughly
8. Floss through the contacts

Question 14

After cementing the crown what should you do?

Answer 14

1. Ask the patient to occlude normally to check the casting is fully seated
2. Ask patient to occlude on a cotton wool roll while cement sets

Question 15

After your crown fitting appointment when should you next see the patient

Answer 15

Review patient in 2 weeks time (or tell them to call if they experience any problems)

Question 16

What does luting cement form

Answer 16

The interface between cast restoration and the tooth

Question 17

When choosing a cement what do we need to take into consideration

Answer 17

1. How much adhesion is needed
2. Aesthetics
3. Will you need to remove the restoration in the future?

Question 18

List the ideal properties of a cement

Answer 18

1. Prevents micro leakage
2. Good mechanical properties
3. Biocompatible
4. Ease of use

Question 19

Why does a cement need to be able to prevent micro leakage?

Answer 19

1. To protect the pulp
2. Maintain aesthetics
3. Prevents sensitivity
4. Prevent secondary caries

Question 20

List some good mechanical properties a cement should have

Answer 20

1. High compressive strength
2. Low solubility
3. Retentive to tooth and restoration
4. Low firm thickness

Question 21

Why is it important for cement to be biocompatible ?

Answer 21

1. So it doesn’t harm the pulp

2. So it doesn’t harm the gingiva

Question 22

What do we mean when we say the cement should be easy to use

Answer 22

1. Should have a sufficient working time
2. Easy to clean up excess
3. Crown can be removed if necessary

Question 23

Name the different categories cements can fall under

Answer 23

1. Traditional cements
2. Glass ionomer
3. Resin cements

Question 24

Give examples of traditional cements

Answer 24

1. Zinc phosphate

2, Zinc polycarboxylate

Question 25

Name some glass ionomer cements

Answer 25

1. Traditional | 2. Resin modified

Question 26

Give examples of resin cements

Answer 26

1. Multi step adhesives | 2. Simplified and all in one adhesives

Question 27

What are the benefits of using zinc phosphate to cement crowns?

Answer 27

1. Has a long record of clinical success 2. High compressive strength 3. Acceptably low film thickness 4. 5 minute working time 5. No adhesive properties

Question 28

What are the indications for using zinc phosphate as a cement

Answer 28

For 1. Full crowns 2. Conventional bridges 3. Cast posts

Question 29

What is the trade name for zinc poly carboxylate

Answer 29

Poly F

Question 30

What are the benefits of using zinc poly carboxylate to cement crowns?

Answer 30

1. Moderate compressive strength 2. Acceptable low film thickness 3. Chemical adhesion to tooth 4. Fluoride release

Question 31

What are the indications for using zinc poly carboxylate as a cement

Answer 31

For: 1. Full crowns 2. Conventional bridges 3. Inlays/ onlays 4. Temporary filling materials

Question 32

What does RMGIC stand for?

Answer 32

Resin modified glass ionomer cement

Question 33

What is the trade name for RMGIC

Answer 33

Fuji plus

Question 34

List some of the benefits of using RMGIC as a cement

Answer 34

1. High compressive strength 2. Acceptably low film thickness 3. Chemical adhesion to tooth and all base metals 4. Fluoride release 5. Low solubility

Question 35

What does RMGIC need to give optimal results?

Answer 35

Require a dentine conditioner (citric acid) for optimal results

Question 36

What are some of the indications for RMGIC

Answer 36

for: 1. Full crowns 2. Conventional bridges 3. Inlays/onlays

Question 37

What is a disadvantage of zinc phosphate?

Answer 37

Has a high solubility

Question 38

What is the trade name for resin adhesive multi step cement?

Answer 38

Panavia F

Question 39

What is a disadvantage of resin adhesive multi step cement?

Answer 39

Has multiple compounds and steps

Question 40

List the steps for using resin adhesive multi step cement

Answer 40

1. Acid etc 2. Paste A 3. Paste B 4. Liquid A 5. Liquid B 6. Metal primer 7. Ceramic primer 8. Oxyguard

Question 41

What are some of the benefits of using resin adhesive multi step cement

Answer 41

1. Dual cure resin composite system 2. Very high strength to tooth and metal alloy 3. High compressive strength 4. Acceptably low film thickness 5. Fluoride release 6. Low solubility 7. Multiple components

Question 42

What are some of the indications for using resin adhesive multi step cement

Answer 42

For: 1. Full crowns 2. Conventional bridges 3. Inlays/ onlays 4. Resin retained bridges 5. Veneers 6. Posts 7. Bonded amalgam

Question 43

What is the trade name for resin adhesive simplified?

Answer 43

Rely X ultimate

Question 44

Name the 2 components that make up resin adhesive simplified

Answer 44

1. Scotchbond universal | 2. Rely x ultimate cement

Question 45

What are some of the benefits of resin adhesive simplified

Answer 45

1. Self adhesive dual cure resin composite 2. Very high bond strength to tooth and metal allow 3. High compressive strength 4. Acceptably low film thickness 5. Low solubility 5. Built in metal and ceramic primer so less steps so less chance of error

Question 46

List some of the indications for resin adhesive simplified cement usage

Answer 46

For 1. Full crowns 2. Conventional bridges 3. Inlays/ onlays 4. Resin retained bridges 5. Veneers 6. Posts

Question 47

Looking at the criteria below which cement would you recommend for this crown prep: 1. FVC/MCC crown prep 2. Adequate retention 3. Larger than 3mm 4. An adequate taper

Answer 47

RMGIC (Fuji plus)

Question 48

Looking at the criteria below which cement would you recommend for this crown prep: 1. Unretentive prep 2. Short crown 3. Inlay/ onlay

Answer 48

Adhesive redin cement (panavia or rely X ultimate

Question 49

Looking at the criteria below which cement would you recommend for this crown prep: 1. Resin retained bridge

Answer 49

Adhesive redin cement (panavia or rely X ultimate

Question 50

Looking at the criteria below which cement would you recommend for this crown prep: 1. Fibre post

Answer 50

Adhesive redin cement (rely X ultimate

Question 51

Looking at the criteria below which cement would you recommend for this crown prep: 1. Cast metal post 2. Needs to be easily removable for Endo later

Answer 51

Traditional cement (Zinc phosphate)

Question 52

What are some of the problems that can arise during the fitting of a crown

Answer 52

1. Crown feels to high to patient

Question 53

What would you do if the crown feels high to the patient

Answer 53

Check margins to see if the crown is fully seated then use using shim stock

Question 54

If the crown is fully seated but the patient feel like it is high what should you do?

Answer 54

1. Check the occlusion with occlusal indicator wax or articulating paper 2. Adjust the crown checking the thickness doesn't become less than 3mm 3. Polish crown before cementing 4. Check the fitting of the crown again 5. If it still doesn't fit you will need to re make it

Question 55

What is the minimum thickness your crown should be?

Answer 55

3mm

Question 56

If the crown is NOT fully seated and the patient feel like it is high what should you do ?

Answer 56

1. Check the fitting surface for obvious defects 2. Check the prep for remaining temporary cement 3. Make sure the prep doesn't have an undercut 4. Check the model isn't damaged

Question 57

Talk through the steps you'd after you have evaluated if the fitting surface has an defects

Answer 57

2. IF there is any defects adjust and retry 3. If there isn't any defects check the contact points to see if they are too tight 4. Use fit checking medium inside the crown 5. If none of that works you will need to remake the crown

Question 58

How do we check if the crown is too high?

Answer 58

Using shim stock

Question 59

What is Shimstock?

Answer 59

8 microns thick metal foil that we can place between the teeth to see if there is a good contact