Wear Part 2- Lecture 1 Part 2

Question 1

What are the issues associated with lack of posterior support?

Answer 1

Increased severity of wear

Increased progression rate of wear

Occlusal collapse

Functional and aesthetic issues

Question 2

Why do patients with tooth wear have a lack of posterior support?

Answer 2

Denture intolerance/refusal
-> less likely to wear dentures if no immediate aesthetic issue

Supervised neglect- removing posteriors and not replacing with dentures intentionally

Question 3

Why may you want to avoid complete dentures in bruxism patients?

Answer 3

• Bruxism habit does not stop
• More likely to fracture
• More ridge resorption
• More pain and ulceration due to forces on mucosa

Question 4

How can rehabilitation of a dentition be achieved?

Answer 4

Through fixed pros, indirect restorations and removable pros
-> slight increase in OVD often necessary

Question 5

What removable prosthodontics is used in tooth wear cases?

Answer 5

Overdentures

Transitional dentures

Metal base dentures

Simplifying small saddles

Question 6

What are overdentures?

Answer 6

Any removable prosthesis that rests on one or more remaining natural teeth/roots of natural teeth (and/or dental implants)

Question 7

What are the advantages of overdentures?

Answer 7

• Cutting teeth down can even up occlusion and improve aesthetics
• Support- tooth and mucosal
• Tooth wear management esp if 2/3 of crown height loss (composite build ups will likely fail)
• Preservation of ridge form- for implants at later stage
• Proprioception- keeping roots keeps PDL (better sensation of food and chewing)
• Denture retention- roots gives better undercuts
• Precision attachments- keep simple to keep repair simple
• Avoids extractions if patient undergoing radiotherapy/MRONJ
• Psychological benefits
• Eases transition to edentulism

Question 8

What are the disadvantages of overdentures?

Answer 8

• Fail in poor OH
• Increased caries and Periodontal problems
• Denture fracture- less material as they are thinner
• Discomfort/infection around roots- would need to be extracted in these situations (further complicated by medical condition)
• Carious root extraction can be more traumatic esp. if sub alveolar

Question 9

How is prep for overdentures carried out?

Answer 9

• Cut roots down to gum level
• Put protective coating on teeth

Question 10

What can be done to make over dentures fit better around roots?

Answer 10

Sectional reline

Question 11

How should you approach planning for overdentures?

Answer 11

Decide on good and bad points of dentition
-> Keep robust roots- get rid of hopeless teeth

Question 12

How is care for overdentures maximised?

Answer 12

Good oral hygiene

Fluoride toothpaste application to roots

Regular examinations & radiographs
-> Keep eye on bone loss, PA areas, RCTs

Denture hygiene

Question 13

What is the purpose of transitional dentures?

Answer 13

Tests if patient with lack of posterior support can cope with dentures AND increased OVD
-> Allows space for restorations to be placed to increased OVD (dentures should increase OVD to the non-worn level)

Question 14

What can be done to give some anterior tooth contact and keep occlusion balanced in transitional denture?

Answer 14

Add some tooth coloured acrylic to go over surface of worn anteriors

Question 15

What is done once it is determined that the patient can cope with dentures and increased OVD?

Answer 15

Get rid of hopeless teeth

Place crowns/composite build ups with rest seats and undercuts at new OVD (unworn level)

Fit definitive dentures at same OVD

Question 16

What can be done for bruxist patients with cobalt chrome dentures where the teeth keep fracturing off from saddles?

Answer 16

Extend metal onto the biting surfaces of the denture as a backing to strengthen it

Question 17

What must be done before making the chrome complete with metal backings?

Answer 17

A tooth trial to confirm tooth position

Question 18

What can be added to complete dentures to prevent bruxism patients from fracturing them?

Answer 18

CoCr bar in lower

CoCr backing and palate in upper

-> again tooth trial required before casting chrome

Question 19

What is the issue with the chrome palate in complete dentures?

Answer 19

CoCr gives inadequate peripheral seal so most posterior part of the denture is made of acrylic
-> acrylic post dam

Question 20

What is an overlay denture and its purpose?

Answer 20

Fits over teeth and gives them CoCr biting surface in order to protect teeth below and discourage wear of anteriors (if on posteriors)

• trial required before casting

Question 21

What are the issues with small anterior saddles in bruxism?

Answer 21

Force of bruxist will cause small weak saddle to break off
-> aim to remove this

Question 22

How can small saddles be simplified?

Answer 22

• Cantilever bridges can be used to fill these small saddle spaces
• Difficult with adhesive bridges- lateral or protrusive forces on pontic can cause debonding in bruxists

Question 23

When does conforming to the current occlusion work best?

Answer 23

Stable occlusion with sufficient index teeth -> Ensure your prosthesis/restoration does not alter the occlusion

Question 24

When does changing or rehabilitating an occlusion work best?

Answer 24

• In cases due to occlusal collapse there is no stable occlusion or sufficient index teeth
• Difficult to record occlusion- OVD needs to be decided on (generally we think about where teeth would’ve been before wear)
• In tooth wear the OVD will often need to be increased

Question 25

What can help you decide where the OVD should be?

Answer 25

Look for any teeth/restorations that occlude at the old OVD still

Question 26

What can be done if conforming but teeth are edge to edge?

Answer 26

Keep OVD the same but attempt to change to class 1 relationship with restorations

Question 27

What are the issues with using many crowns to rehabilitate a dentition?

Answer 27

Destructive preparation

Risk of pulpal issues

Risk of caries around margins

Question 28

What 2 interocclusal records should be taken when rehabilitating?

Answer 28

One at current OVD

One at planned increase in OVD

Question 29

What are the steps that can be helpful in planning when conforming and changing?

Answer 29

Impressions & facebow
-> Mounted articulated casts on semi-adjustable articulator + or – surveying

High quality Interocclusal record – with & without increasing the OVD

Diagnostic wax up(s)
-> Stents – mock-up – temporaries (if indirect); for build-ups; aids consent

Temporary (transitional) dentures

Clinical photographs- before and afters

Radiographs

Question 30

How are casts mounted?

Answer 30

Using Alminax and face-bow recording at OVD
-> diagnostic wax up can then be done

Question 31

What is the Dahl technique?

Answer 31

Disclude posterior teeth by propping anteriors up canine to canine
-> Extrusion occurs and occlusion re-establishes itself

Question 32

What should be done when carrying out a diagnostic wax up?

Answer 32

• Use as much of buccal surface as possible- enamel is better for retention of composite build ups (if increasing OVD- consider if palatal surfaces can be used for this too)
• Build up itself is best guess at how teeth would’ve looked pre-wear

Question 33

What are diagnostic wax ups used for?

Answer 33

Wax-up is duplicated in stone
- Gives working cast to make stents- vacuum formed retainer (some people use silicone- which you can light cure through)
- We can put over initial cast to see how much teeth are being built up
- We can use stent and fill with protemp to give patient an idea what it will look like

Question 34

What is it important that the patient knows before undergoing occlusal rehabilitation treatment for tooth wear?

Answer 34

Likely to be multiple long appointments for build ups
-> more if dentures required

Question 35

Who can you seek advice from when treating tooth wear if the case is complex?

Answer 35

• Principle/trainer
• Restorative specialist