Bridgework Flashcards

1
Q

What is a dental bridge?

A

Prosthesis which replaces a missing tooth/teeth, and is attached to one or more natural teeth or implants.

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2
Q

Contra indications of bridgework?

A

Poor pt cooperation

Medical history - metal allergy

Poor OH

High Caries rate

Periodontal disease

Large pulp horns in young patients ‘conventional bridge’

High possibility of further tooth loss in the arch

Poor abutment quality / poor prognosis

Length of a span of bridge is too long

Poor ridge form / tissue or bone loss

Tilting and rotating of teeth

Largely restored dentition

Periapical status - no active endodontic or pulpal disease

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3
Q

Define abutment and Pontic

A

Abutment = tooth which serves as an attachment for a bridge

Pontic = tooth that is suspended from the abutment tooth / teeth

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4
Q

Define retainer with regards to bridgework

Define connector

A

Retainer = Extracorornal or intracoronal restorations that are connected to the Pontic, and cemented to the prepared abutment teeth

Connector = component which connects the Pontic to the retainer

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5
Q

Define a pier and a unit

A

Pier = An abutment tooth which stands between, and is supporting two Pontics. Each Pontic being attached to a further abutment tooth

Unit = either a retainer or a Pontic

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6
Q

What is a fixed - fixed bridge?

A

Bridge retainer either side of a Pontic

Retainer - Pontic - retainer

Can be adhesive/resin retained or conventional

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7
Q

What retainers are used for conventional and what are used for adhesive bridges

A

Conventional - crowns

Resin retained - metal NiCr or CoCr retainers

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8
Q

Advantages of a fixed fixed bridge

A

Robust

Maximum retention and strength

Splinted abutments can help perio cases

Can be used in longer spans

Simple lab work

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9
Q

Disadvantages of fixed - fixed bridgework

A

Large tooth preparation needed

Prep must be parallel and minimally tapered

Common path of insertion needed for all abutments

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10
Q

What is a cantilever bridge?

A

Can be fixed -fixed, or resin retained / adhesive

Retainer at only one end

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11
Q

Advantages of cantilever bridge?

A

More Conservative than fixed - fixed

Straightforward lab work

No need to ensure tooth preparations are parallel

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12
Q

Disadvantages of cantilever bridges

A

Less retentive than fixed fixed

Must be rigid to avoid distortion

Smaller span

Mesial cantilever is preferred

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13
Q

What is a fixed - moveable bridge?

A

Rigid connector distal to Pontic,

Moveable connector mesially, to allow for some vertical movement at the mesial abutment tooth

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14
Q

Advantages of fixed - moveable bridge?

A

Preps don’t require common path of insertion

More conservative

Allows minor tooth movement

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15
Q

Disadvantages of fixed - moveable bridges

A

Limited edentulous span

More complex labwork

Possible difficulty cleaning between moveable joint

Can’t construct a provisional

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16
Q

What is a hybrid bridge?

A

One end = conventional

One end = resin retained / adhesive

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17
Q

What is a spring cantilever bridge?

A

Pontic is attached to the end of a metal arm that runs across the palate, to a rigid connector on the palatal side of a retainer

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18
Q

Advantages of conventional spring cantilever bridge?

A

Useful if there is spacing between upper incisors

Useful where adjacent teeth are unrestored

Where a posterior tooth would provide suitable abutment - e.g. already has a large restoration or a crown

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19
Q

Disadvantages of conventional spring cantilever

A

Only used for maxillary incisors

Difficulty cleaning behind palatal connector on the retainer

May irritate palatal mucosa

Difficult to control movement of Pontic due to spring in the metal arm and displacement of soft tissues

20
Q

How should an abutment tooth be evaluated?

A

Must be able to withstand forces previously directed at missing teeth

Supporting tissues should be free of inflammation, and healthy

Crown : root ratio
- optimum ratio is 2:3, minimum is 1:1

21
Q

On an abutment, what should be considered when evaluating it for use in a bridge?

A

Root configuration

Angulation and rotation of the abutment

Periodontal health of the abutment

Occlusion of the abutment

Quality of enamel

Risk of pulpal damage (high horns in younger pt)

22
Q

What is the function of the Pontic?

A

Restore function

Restore aesthetics

Stabilise occlusion

23
Q

What are the main considerations when selecting a Pontic design?

A

Cleansability
- smooth and highly polished
- easy to clean
- free of plaque trap surfaces

Appearance
- tooth like
- correct shade

Strength
- longer the span = greater the thickness needed to withstand occlusal forces

24
Q

What is a wash through Pontic?

A

No contact with soft tissue

Functional rather than aesthetic

Consider for lower molars

25
Q

What is a dome Pontic?

A

Bullet-shaped or torpedo

  • useful for lower incisor or premolars
  • useful for upper molars

Poor aesthetics if gingival 1/3 of tooth visible

26
Q

What is a modified ridge lap Pontic?

A

Buccal surface looks as much like a tooth as possible

Cut away lingual surface

Problems with food packing on lingual surface

Good for maxillary incisors

27
Q

What is a ridge lap Pontic?

A

Greatest contact with soft tissue

Can be cleansed if designed properly

Less food packing than modified ridge lap

Must not bleach tissue or displace soft tissue too much

28
Q

What are the first steps for producing a bridge after all examinations have been done?

A

Produce mounted study models, with a vacuum formed stent.

  • allows checking of reduction and ability to produce a provisional bridge
29
Q

What material is used to bond conventional metal bridges / metal ceramic?

A

GI luting cement

RMGI luting cement - e.g. relyX

30
Q

What is used to bond resin bonded bridges?

A

Panavia 21

Anaerobic dual cure resin cement

31
Q

What is used to bond all ceramic bridges?

A

NEXUS dual cure resin cement

32
Q

Why are distal cantilevers avoided? When may one be considered to be ok?

A

Concern occlusal forces on Pontic will produce leverage forces on abutment tooth

Premolar abutment where opposing arch is edentate or a denture

33
Q

What is a LAVA 3M ESPE material in bridges?

A

Milled zirconium oxide frame
Feldspathic porcelain overlying

Good aesthetics and can withstand occlusal forces

Similar reduction to MCC

34
Q

Advantages of using resin bonded bridgework?

A

Minimal to no preparation of the tooth

Can be used as a provisional restoration e.g. hypodontia patient who should get implants, but when older

No anaesthetic needed

Less costly and less surgery time

If it fails, less destructive than other alternatives

35
Q

Disadvantages of RBB

A

Rigorous clinical technique - moisture control is essential

Metal can shine through the tooth - translucent incisal edge
- do not overextend retainer

Chipping of the porcelain Pontic

Can debond, once fallen off, higher chance of future debonding

Occlusal interferences
- these usually disappear within 14 days through axial tooth movement to restore occlusion

No trial period possible

36
Q

Indications for RBB

A

Young teeth - less destructive option

Good enamel quality

Large abutment tooth surface area

Minimal occlusal load

Single tooth replacements

Simplify partial denture design

37
Q

Contraindications of RBB?

A

Poor quality enamel

Long spans

Excess hard or soft tissues

Heavy occlusal forces - bruxism

Poorly aligned, tilted or spaced teeth

Contact sports? Possible contraindication.

38
Q

What should cross my mind when deciding if a patient is suitable for bridgework

A

Is it appropriate, are there other treatment options?

I should take care if patient insistent on bridgework. Explain what it is, and what they can and cannot do.

Look at: abutments, occlusion and aesthetics, para-functional habits etc.

Can patient maintain the oral hygiene for complex work?

39
Q

What are direct and indirect RBBs?

A

Direct - emergency situations, tooth xla immediately and pt cannot leave with edentulous space

Indirect - prosthesis is made in a lab and is cemented at another appt

40
Q

How might one manufacture a Pontic for a direct RBB?

A

Ideally use patients existing tooth, cut the root off and clear pulpal chamber.

Can use an acrylic denture tooth

Prefab polycarbonate crown

Matrix in tooth shape, filled with composite

41
Q

How can the patients existing tooth be bonded to the adjacent as a direct Pontic?

A

Etch and bond the contact points of the Pontic and the abutment teeth

‘Splint’ teeth with composite temporarily

Complete long term treatment

42
Q

What areas are fixed - fixed and cantilever usually used?

A

F-F in posterior teeth

C in anterior teeth

43
Q

What prep may need to be done for a RBB?

A

180 degree ‘wrap around’ prep

Rest seats - posterior teeth
Cingulum rest - anterior teeth
- both can help with locating the correct position on the tooth for cementation.

Proximal grooves can aid mechanical retention

Supra gingival chamfer finish line - 0.5mm supragingival

Prep remain in enamel

44
Q

How thick typically is the metal retainer for an anterior RBB?

A

0.7mm thick

45
Q

If you have prepped a tooth for a RBB and pt is getting sensitivity, how can this be treated?

A

Consider duraphat sensitivity toothpaste

Layer of DBA over exposed dentine

Fix bridge ASAP, 2 weeks most likely
- risk over eruption or tooth movement

46
Q

What should be done post cementation?

A

Check occlusion
- heavy contact on Pontic, adjust them
- heavy contact on retaining wings - axial tooth movements should solve

Show pt how to clean under and around Pontic
- superfloss - thin bit under Pontic, pull and then sweep under
- interdental brushes

47
Q

What are the typical survival rates for resin bonded bridgework?

A

80.8% at five years

80.4% at ten years

King et. Al

Most likely to fail in first two years