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Restorative Dentistry > Bridgework > Flashcards

Bridgework Flashcards

1
Q

What are the treatment options for missing teeth?

A
  1. No treatment/leave space
  2. Replace tooth/teeth- denture, bridgework, implant
  3. Close the space- ortho
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2
Q

What is a bridge?

A

A prosthesis which replaces a missing tooth or teeth and is attache to one or more natural teeth.

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3
Q

What would be the indications for bridgework?

A

Restore function and stability of dentition
Restore appearance
Speech
Psychological reasons- reluctant to have removable teeth
Epilepsy- no removable appliances in these patients
Big abutment teeth- better retention an resistance form
Heavily restored teeth- would suggest fixed-fixed bridge work
Favourable abutment angulations
Favourable occlusion

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4
Q

What would be the contraindications for bridgework?

A

Unco-operative patient
Medical history- allergy to CoCr or other metals in bridgework
Poor oral hygiene
High caries rate
Uncontrolled peril disease
Large pulps
High possibility of further tooth loss int hat arch
Poor prognosis of abutments
Length of bridge span too large
Ridge form and tissue loss
Tilting and rotation of teeth
Degree of restoration- how much tooth tissue will be left after preparation?
Periapical status

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5
Q

What is a cantilever bridge?

A

This type of bridge has a retainer only at one side of the Pontic.

It can be conventional- crown prep on the abutment tooth.
Or adhesive- wing extends from the Pontic to the abutment tooth.

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6
Q

What is a fixed-fixed bridge?

A

This type of bridge has a retainer at each end with a Pontic in the middle, join day a rigid connector.

It can be conventional or adhesive.

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7
Q

Describe the different type of bridges you can offer to a patient?

A

Fixed-fixed adhesive bridge
Fixed-fixed conventional bridge
Adhesive cantilever
Conventional cantilever

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8
Q

What are the advantages of a resin-retained bridge?

A

Less destructive to tooth tissue- minimal or no preparation required
No anaesthetic needed
Less costly
Less surgery time
Can be used as a provisional restoration
If it fails, usually less destructive than alternatives
No temporary required
Fewer visits

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9
Q

What are the disadvantages of resin-retained bridges?

A

Rigorous clinical technique- need everything very dry.
Metal shine through from the wing
Chipping porcelain
Can debone
Occlusal interference- different guide paths
No trial period possible
Can only be done for short spanning bridges

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10
Q

What are the indications for a resin-retained bridge?

A

Young teeth- less destructive
Good enamel quality for bonding
Large abutment tooth surface area
Minimal occlusal load
Good for single tooth replacement
Simplify partial denture design

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11
Q

What are the contraindications for a resin-retained bridge?

A

Insufficient or poor quality enamel
Long span
Excess soft or hard tissue loss
Heavy occlusal force- bruxism
Poorly aligned, tilted or spaced teeth
Poor OH
High caries rate
Diastemas

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12
Q

In terms of history, what is important to find out from the patient?

A

Are they aware that they grind their teeth?
Do they bite their nails?
Smoker?
Alcohol?
Do they play any contact sports

Medical history- epilepsy, any diseases that will impact retention of a prosthesis or would be a choking hazard if it fell out

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13
Q

On examination, what is important to look for when thinking of placing a bridge?

A

Look for signs of toothwear and bruxism.
Full charting
Periodontal assessment
Radiological assessment- look for PA pathology, bone loss, caries.
Dynamic occlusal relationships.
Contact points- what would the bridge be contacting? Over-erupted teeth?
Guidance
Root:crown ratio
Interocclusal space
Over-eruption of teeth
Quality of restorations
Gingival contour and biotype

E/O
- Smile line
- Level of incisal show
- OVD and RVD
- Freeway space

Specifically look at abutment teeth and soft tissue contour.
- must have at a minimum 1:1 crown:root ratio but ideally you want to have more root surface area than crown surface area.

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14
Q

After examination, what might you want to do at the first appointment?

A

Take impressions for study models and facebow registration.
This will allow the technician to mount the casts with the same condylar relationship that is present within the patient.

May want to consider diagnostic wax ups to show the patient.

Request lab constructs a vacuum-formed stent- allows you to check that you have done enough reduction of the tooth during preparation and allows construction of a provisional bridge.

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15
Q

What aspects of bridgework would you want to make the patient aware of before embarking on treatment?

A

Make sure they understand what a bridge is- ask what they know about it already.

Ensure the pt knows the pros and cons of it- always give them the option of doing nothing and alternative options.

Ensure the pt understands the limitations of bridges.

Ensure they are aware that OH is paramount to the success of these restorations.

Ensure they’re aware that this will not last forever and you must make them aware of potential options when it does fail.

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16
Q

What is direct resin-bonded bridgework?

A

Apply bridgework directly chair side.
- useful in emergency situations when a tooth is extracted immediately or if the tooth is lost traumatically.

Ideally use the patient’s own tooth but can also use an acrylic denture tooth, polycarbonate crown or cellulose matrix filled with composite.

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17
Q

If you were using the patient’s own tooth for the direct resin-retained bridge, what would be the procedure?

A

Extract the tooth.
Cut off the root and remove any pulpal tissue.
Etch the contact point of the extracted tooth and add composite to the pulp chamber.
Etch the contact points of adjacent teeth.
Prime and bond the etched surfaces and place composite into the sides of the teeth that the tooth will bond to.

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18
Q

As a general, rule, what type of bridgework would you provide for an anterior and posterior tooth?

A

Anterior- cantilever
Posterior- fixed-fixed

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19
Q

Why are cantilever bridges more successful anteriorly?

A

Divergent guidance paths

Anteriorly, the longitudinal axis of the teeth are different as you move around the arch. So, the occlusal forces are directed down the long axis in different directions.
So if you were to put a fixed-fixed bridge in anteriorly, then there will be 2 different occlusal forces applied to the abutment teeth and will cause the bridge to jolt, causing it to move and potentially fall off or become loose.

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20
Q

When considering if you can use abutment teeth, what aspects would you be thinking about?

A

Periodontal health
Caries
Large restorations
Mobility
Over-eruption
Enough sound enamel present
If amalgam is present, then consider replacing to composite because it will not have a good bond to composite cement.
At least 1:1 crown:root ratio
Long bulbous roots- good root surface area.

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21
Q

What factors would you keep in mind when considering bridgework?

A

Patient’s preferences- a lot of patients prefer fixed pros work compared to removable

Age- usually avoid bridgework in older patients, think of biological age compared to chronological age.

Attitude to dentistry- OH, periodontal health, anxious patients

MH- Epilepsy, physical disabilities

Diet, smoking, cost.

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22
Q

How can you increase retention of a bridge?

A

Maximise available bonding surface area
Sandblasting fitting surface of wing
Cut grooves, rests, notches and locating margins
Incorporate rest seats to maximise bonding surface area and t direct axial forces.

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23
Q

What factors should you consider when deciding what bridge design to have?

A

Quality of bonding surface- do you have adequate enamel for bonding? Is there a large amalgam restoration present?
Quality of bonding procedure
Design of the retainer
Design of the Pontic
Occlusal management

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24
Q

What might you consider for a temporary restoration where a bridge will be going?

A

Consider RPD or Essex retainer
If prep is only into enamel- no need for temporary
If prep is into dentine and the tooth becomes sensitive- place bond on the tooth

25
Q

Why do you want to aim to fit the bridge as quickly as possible?

A

Minimise over-eruption and tooth movement

26
Q

What metal would the retainer be made out of?

A

Cobalt chrome or nickel chromium alloy.

Surface is sand blasted by the technician and aluminium oxide added.

27
Q

What cement would you use for an adhesive bridge?

A

Panavia

28
Q

Describe the process of cementation of an adhesive bridge with panavia?

A

Apply rubber dam
Etch abutment tooth
Apply A and B primer
Place panavia onto the fitting surface of the retainer
Seat it home and remove excess cement
Oxygen inhibitor (Oxyguard II) placed around the cement margin for 3 minutes and then wash off.
Check occlusion
Demonstrate to th patient how to clean around and underneath the bridge- superfloss and interdental brushes

29
Q

Under what circumstances might you use a fixed-fixed bridge anteriorly?

A

Class 2 incisor relationship and do not have close occlusal contact of the mandibular teeth onto the maxillary teeth so the bridge went flex as much

Anterior open bite- lower incisor teeth do not occlude with the upper anterior teeth.

30
Q

What are the advantages of a fixed-fixed bridge?

A

Robust design

Maximum retention and strength

Abutment teeth splinted together (perio cases with mobile teeth)

Can be used in longer spans

Laboratory construction straightforward

31
Q

What are the disadvantages of a fixed-fixed bridge?

A

Preparation is difficult
Preparation must be minimally tapered
Common path of insertion for abutments
Removal of tooth tissue- issue with pulp exposure.

32
Q

What happens if abutment teeth are not parallel?

A

The restoration will not eat correctly because the abutment teeth have different paths of insertion.

33
Q

What are the advantages of a conventional cantilever bridge?

A

Conservative design (compared to fixed-fixed conventional)

Laboratory construction straightforward

No need to ensure multiple tooth preparations are parallel

34
Q

What are the disadvantages of a conventional cantilever bridge?

A

Short span only
Rigid to avoid distortion
Mesial cantilever preferred- abutment tooth is more posterior and the Pontic is the anterior tooth

35
Q

In a conventional cantilever design, a menial cantilever should be selected, why is this desirable?

A

When people occlude, they are more likely to occlude on the posterior tooth first, so if you did a distal cantilever, the heavy contact would be on the posterior Pontic and there would be a see saw effect, where the restoration lifts up anteriorly.

36
Q

If abutment teeth are not parallel and you’re unable to make them parallel through preparation, what could you use?

A

Fixed movable bridge.

37
Q

What is a fixed movable bridge?

A

Bridge comes in two components
- prepare both abutment teeth for a crown and then place the “crowns” on individually to the teeth and then slot them together to make a moveable bridge.

There is usually a rigid connector at the distal end of the Pontic and a movable connector medially.

38
Q

What are the advantages of a conventional fixed-movable bridge?

A

Preparations don’t require a common path of insertion

Each preparation designed to be retentive indent of others

More conservative of tooth tissue

Allows minor tooth movement

May be cemented in two parts

39
Q

What are the disadvantages of a conventional fixed-movable bridge?

A

Length of span of bridge is limited- only want to replace one tooth with this design because it will flex when the patient bites down on it

Laboratory construction more complicated

Possible difficulty in cleaning beneath movable joint- patient must have excellent OH

Can’t construct provisional bridge- need to provide 2 provisional crowns and an Essex retainer to replace the missing teeth

40
Q

What is a hybrid bridge?

A

One retainer has a conventional preparation and the other retainer has minimal preparation for an adhesive bond.

41
Q

What are some of the issues associated with a hybrid bridge?

A

The occlusal forces will be directed towards the tooth that has been conventionally prepped- this will cause the bridge to flex and the adhesive bond can debond- causing caries to develop down the back of that tooth behind the wing.

42
Q

Describe the different types of conventional bridges?

A

Fixed-fixed
Adhesive cantilever
Fixed-movable
Spring cantilever

43
Q

Under what circumstances might you want to use a fixed-movable bridge?

A

If abutment teeth are tilted and you won’t be able to make the preparations parallel
- teeth have different path of insertions.

44
Q

What is the success rate of resin-bonded bridges at 5 and 10 years?

A

80%

Must make patients aware that these restorations will fail at some point, it is just a matter of time when it will fail.

45
Q

When evaluating a potential abutment tooth, what might you look for?

A

Periodontal status, bone loss
Caries
PA pathology
Root to crown ratio
Mobility of tooth
How much tooth tissue is left?
Angulation and rotation of the tooth
Surface area for bonding and duality of enamel
How far occlusal is the pulp? Is there risk of pulpal damage?
Look at the quality of the root filling- is it well condensed, is it within 2mm of radiographic apex, are there voids?
Is the abutment tooth heavily restored and if so, what material?

46
Q

What aspects of the occlusion would you want to evaluate before providing a bridge to a patient?

A

What is the patient’s incisor relationship?
Do they have canine guidance or group function?
Is there OVD changed due to toothwear? Will you need to increase the freeway space?
Are the opposing teeth over-erupted
Will the bridge interfere with the current occlusion?
Are there signs of parafunction?

47
Q

Describe the details of bridge design?

A

Select abutment teeth- judge longevity of adjacent teeth

Select retainer- RBB or conventional prep?

Select Pontic and connector- lots of different types

Plan the occlusion

Prescribe the material

48
Q

What aspects of the Pontic function and design are desirable?

A

Restore appearance of missing tooth
- smooth, polished and glazed.

Stabilise the occlusion

Improve masticatory function

Cleansable- smooth, polished, embrasure space smooth and cleanable

Strength- longer the span, the greater the thickness required to withstand occlusal forces

49
Q

Describe the different Pontic designs for ridge surface?

A
  1. Wash through
    - makes no contact with soft tissues, consider in lower molar area
  2. Dome shaped
    - Useful in lower incisor. premolar or upper molar areas. Acceptance if occlusal 2/3 of buccal surface visible- poor aesthetics if gingival 1/3 of tooth is visible
  3. Modified ridge lap
    - Buccal surface looks like a tooth but the lingual surface is cut away.
    - Issues with food packing on lingual surface of the ridge
  4. Ridge lap/sadle
    - Greatest contact with soft tissue, less food packing than modified ridge lap
  5. Ovate pontic
    - Moulds the gingivae to make it look like the tooth is coming out of the gum. Patient must have excellent OH
50
Q

What materials are available for conventional bridges?

A

All metal- gold, nickel/CoCr, stainless steel
Metal ceramic
All ceramic- zirconia, lithium disilicate
Ceromeric (not commonly used anymore)

51
Q

What cement are you going to use for each bridge design?

A

All metal conventional- aquacem or relyX
Metal ceramic- aquacem or RelyX
Adhesive/resin bonded- Panavia 21
All ceramic- NEXUS kit

52
Q

Why is a distal cantilever not advisable?

A

The occlusal forces will be directed on the Pontic, producing leverage forces on abutment tooth causing it to tilt.

May consider it for a premolar abutment if unopposed or opposed by a denture

53
Q

If a patient asks how long their bride is likely to last, what would you tell them?

A

Adhesive bridge- 80% survival rate at 5 and 10 years.
Conventional fixed-fixed MC- 93% at 5 years, 89% at 10 years
Conventional fixed-fixed caeramic- 88% at 5 years
Conventional cantilever bridge- 91% at 5 years, 80% at 10 years

54
Q

For study casts, in a dentate patient, what stone is used to cast the impressions?

A

100% dental stone

55
Q

What is the purpose of a face bow transfer?

A

To articulate the casts with the same relationship of the maxilla to the condyles.

Can facilitate a more accurate representation of the excursive movement between the casts on the articulator.

56
Q

What technique can be used which utilises a diagnostic wax up, in order to provide a provisional restoration?

A

Impressions- construct study casts.
Diagnostic wax up of the proposed restorations.
Another impression of the wax up and create a vacuum formed splint.
Use this as a guide to make a temporary restoration- using direct composite without bond.

Can also use this technique as an intra-oral diagnostic wax up.

57
Q

What is the purpose of Oxyguard in Panavia?

A

Panavia is an anaerobic setting cement- the oxyguard prevents oxygen from interfering with the cement setting process.

Also contains a polymerisation accelerator- more efficient set.

58
Q

What prep is required for an anterior adhesive cantilever bridge?

A

No prep required if there is 0.7mm of inter occlusal space for the retainer.

May want to do a 0.5mm chamfer line palatally or lingually to increase retention of the retainer.

If you are prepping the tooth, make sure to stay within enamel so that you don’t induce sensitivity.

Restorative Dentistry (9 decks)

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