Bridgework 1- Resin Bonded Flashcards
What are the treatment options for missing teeth?
No treatment/Leave space
Replace tooth/teeth
Close space (Orthodontics)
What are the reasons for treating tooth loss?
To maintain:
Aesthetics
Function
Speech
Dental health- prevent tilting and over-eruption
What are the options when replacing teeth?
Denture- more missing teeth
Bridgework
Implants- false titanium roots, which are drilled into alveolar bone then restored with crown, bridge or denture
What is a bridge?
A prosthesis which replaces a missing tooth or teeth and is attached to one or more natural teeth (or implants)
What is the main difference with a bridge and a partial denture?
An RPD replaces bone and soft tissue
What is an abutment?
A tooth which serves as an attachment for a bridge
What is a Pontic?
The artificial tooth which is suspended from the abutment teeth/tooth
What is a retainer?
The extracoronal or intracoronal restorations that are connected to the pontic and cemented to the prepared abutment teeth
What is a connector?
Component which connects the pontic to the retainers/retainer
What is the span?
Edentulous space between natural teeth that is to be filled by a bridge or partial denture
What is the saddle?
Area of the edentulous ridge over which the pontic will lie
What is a pier?
An abutment tooth which stands between and is supporting two pontics, each pontic being attached to a further abutment tooth
What is a unit?
Either a retainer or a pontic
e.g. A bridge with two retainers and one pontic = 3 unit bridge
What are the types of bridgework?
Adhesive- most common
• Held on by wings on palatal surfaces
Conventional- held on by crowns
What are the general indications for bridgework?
To provide function and stability
Appearance
Speech
Psychological reasons- reluctance to wear dentures
Systemic disease e.g. in epileptics it prevents risk of inhaling denture
Co-operative patient
What are the local indications for bridgework?
Big teeth
Heavily restored teeth- don’t have to be as conservative
Favourable abutment angulations
Favourable occlusion
What are the general contra-indications for bridgework?
Uncooperative patient
Medical history contra-indications- allergy
Poor oral hygiene
High caries rate
Periodontal disease
Large pulps (conventional bridge)- more likely to expose pulp and lose vitality of tooth
What are the local contradictions for bridgework?
High possibility of further tooth loss within arch
Poor prognosis of abutment
Length of span too great- more than 1/2 teeth (causes flexing and failure)
Ridge form and tissue loss
Tilting and rotation of teeth
Overly restored
Poor periapical status
Poor periodontal status (bone loss)
What is a fixed-fixed bridge design?
This type of bridge has a retainer at each end with a pontic in the middle joined by rigid connectors.
E.g. (Retainer)-(pontic)-(Retainer)
What is a cantilever bridge design?
This type of bridge has a retainer (or retainers) at one side of the pontic only
E.g. (Retainer)-(pontic)
What are the other names for Adhesive Bridgework
Resin Bonded/ Retained
Minimal preparation bridgework
Maryland bridge
Resin bonded fixed partial denture (RBFPD)
What are the types of Adhesive cantilever bridges?
All ceramic
Traditional with metal wing (CoCr or nickel alloy)
What are the advantages of Adhesive Bridges?
Minimal or no preparation
No anaesthetic needed
Less costly
Less surgery time
Can be used as a provisional restoration
If it fails - usually less destructive than alternatives
When may it be useful to use an Adhesive bridge as a provisional?
Hypodontia patients- before they are old enough to receive implants
What are the disadvantages of Adhesive Bridges?
Rigorous clinical technique- must be dry
Metal shine-through- due to poor design/ cementation or translucent incisal edge
Chipping pocelain
Can debond- high chance of recurrent debonding
Occlusal interferences- especially dynamic
No trial period possible
Why are bridges often cemented high?
Daal Concept- occlusion reorganises naturally in 10-14 days
What are the indications for adhesive bridges?
Young teeth- Less destructive
Good enamel quality
Large abutment tooth surface area- more space for bonding
Minimal occlusal load
Single tooth replacement
To simplify partial denture design
What are the contraindications for Adhesive Bridges?
Insufficient or poor quality enamel
Long spans
Excess soft or hard tissue loss
Heavy occlusal force e.g. Bruxist
Poorly aligned, tilted or spaced teeth
Contact sports?
What should be checked before placing Adhesive bridge?
Habits- bruxism
Condition of abutments- caries/periodontal disease (radiographs)
Dynamic occlusal relationships- mount on semi-adjustable articulator with facebow
Soft tissue contour
Patient motivation- will they take care of prothesis
What should be considered when checking occlusion before placing Adhesive Bridge?
Opposing dentition- contacts, over erupted teeth
Parafunction- look for attrition
Dynamic relationships- looking clinically AND at study models/wax-ups
When are direct adhesive bridges used?
Emergency situations- trauma or loss of tooth
What can be used as a Pontic in direct adhesive bridges?
Patients own tooth (ideal)
Acrylic ‘denture’ tooth
Polycarbonate crown
Cellulose matrix filled with composite
What are the steps in using patient’s own tooth to produce a direct adhesive bridge?
- Cut off root and remove pulpal tissue
- Etch contact points of removed tooth and adjacent teeth
- Cover pulp with composite
- Join teeth together with composite interproximally
What are the requirements for a successful indirect adhesive bridge?
Generous palatal/lingual coverage- greater surface area of enamel covered gives greater bond
Good quality enamel
Keep supra-gingival to allow cleaning- ideally 0.5mm
Care with coverage near incisal edge
What adhesive bridge design is favoured in Anterior and Posterior Teeth?
Ant- cantilever
Post- fixed-fixed
Why are fixed-fixed Adhesive bridges rarely used in anterior teeth?
If one wing debonds, resultant bacterial ingress can cause caries
Cantilevers are favoured as they are not affected by divergent guidance paths
What should you do if Abutments have previously been restored?
Composite- consider replacement if restoration is old as bond will be better to new composite
Amalgam- replace
What are the requirements of a preparation for an adhesive bridge?
180º ‘wrap-around’ preparation
Rest seats (posterior teeth)/ Cingulum rest (anterior teeth)- helps with relocating
Proximal grooves (vertical cuts)- aid mechanical retention
Supra-gingival chamfer finish line ~0.5mm
Ideally prep should remain in enamel
What are the features of a minimal prep for an anterior cantilever adhesive bridge?
(May require no prep)
Occlusal contact reduction- if heavy contacts
Cingulum undercut removal only- simplifies POI
Chamfer margin (0.5mm supra-gingival, 0.5mm in width)
What are the features for a heavier preparation for an anterior cantilever adhesive bridge?
0.5mm palatal reduction(NOTE – metal retainer wing should be 0.7mm thick)
Cingulum rest
+/- Proximal grooves
Chamfer margin (0.5mm supra-gingival)
What are the features of a prep for a posterior adhesive bridge?
Occlusal rests- 2mm in depth
180º wrap-around with chamfer finish line (0.5mm supra-gingival)
+/- Proximal grooves
Why is fixed-fixed preferred in posteriors?
Helps spread the occlusal load over two teeth (replacing a large tooth)
What are the options for temporisation when placing indirect adhesive bridges?
RPD
Essix retainer
No temporary- if prep only into enamel
If prep is into dentine, what can be used to prevent sensitivity/need for temporisation?
DBA
Duraphat
Desenitising toothpaste
Why should bridge be placed as quickly as possible?
most labs take 2 weeks
As it minimises chance of over-eruption and tooth movement
How should the fitting surface of the metal wing be prepared?
Sandblasting using aluminium oxide- provides micro-mechanical retention
How can an adhesive bridge be tried-in before cementation?
Held with finger
Locating cleat- hook that goes over incisal edge to hold tooth in place temporarily
Small bit of composite can be used- but this will need to be cleaned via re-sandblasting, ultrasonic baths, ethanol
What cement is used in Adhesive bridges?
Dual cure composite resin luting cement- PANAVIA 21
Steps in fitting an Adhesive Bridge
- Prophylaxis
- Isolate with dental dam
- Etch tooth: 37% ortho-phosphoric acid (some preparations are 40%)
4.Wash & dry
5. Apply primer (A and B mixed together) for 30 seconds- Air dry for 2 seconds
6. No need to cure (unlike for direct composite restorations)
7. Fit retainer (coated with luting cement) to abutment tooth/teeth
8. Remove excess cement
9. Oxygen inhibitor (Oxyguard II) placed around cement margins for 3 minutes- wash off
10. Adjust any heavy occlusal contacts on pontics- be less concerned about wings
What can be used to maintain cleanliness of Adhesive bridges?
ID brushes
Superfloss
What is the survival rate of adhesive bridges?
5 year- 80.8%
10 year- 80.4%
Most failures occur in first 2 years
