Bridgework 3 Flashcards
What are the treatment options to offer the patient as an alternative to bridges?
No restoration
Denture(s)
Implants(s)
What is involved in holistic treatment planning for Bridgework?
Look at the whole mouth
Not only at a specific tooth
Plan for retrievability (always have a back-up plan)- consider remaining options as deterioration occurs each time (replacement not like for like)
What will the dentition be like in 10-years- 90% success rate over this time
What are the occlusal considerations for bridgework
Incisal classification
Canine-guided or group function
Are opposing tooth over-erupted?
Will bridge interfere with current occlusion?
Signs of parafunction- wear facets, attrition
How can occlusal information be analysed?
Look intra-orally
Produce study models and mount using face bow
What are the considerations when planning and designing bridges?
Minimal preparation or conventional preparation- conservation of tooth tissue
Material- Ceramic, MC
Abutment evaluation
Cleansability- bridges will fail if OH isn’t easily performed
Appearance/Aesthetics - confirm that the patient’s expectations are achievable
What is considered in an abutment evaluation?
Amount of tissue remaining (would crown lengthening be helpful?)
root configuration (larger and multirooted teeth are better)
Absence of pulpal/periodontal/periapical path.
Angulation/rotation
RCT quality evaluation- redo if required
Surface area for bonding and Enamel Quality
What developmental disorder can cause issues with bonding?
Amelogenesis imperfecta
What are the steps in bridgework design?
Select abutments- judge longevity of adjacent teeth
Select retainer- consider preparation
Select pontic and connector
Plan occlusion
Prescribe material
What are the types of pontic design?
Sanitary/Wash-through pontic
Dome/Bullet/Torpedo
Modified ridge lap
Total ridge lap
Ovate pontic
What is the function of a pontic?
Restore appearance of missing tooth
Stabilise the occlusion
Improve masticatory function
What are the considerations for pontic design?
Cleansability:
-> Should always be smooth, with highly polished or glazed surface (prevents plaque adherence)
-> Surface should not harbour join of metal and porcelain (if metal-ceramic design used)
-> Embrasure space smooth and cleansable (reduce if highly aesthetic case)
Appearance:
Anteriorly - as ‘tooth like’ as possible
Posteriorly - may compromise
Strength:
Longer the span - Greater the thickness required to withstand occlusal forces
What are the surfaces of a Bridge?
Occlusal surface- Resemble surface of tooth it replaces, should have sufficient occlusal contact
Approximal surface- Connector: strength, Embrasure: space
Buccal & lingual surface
Ridge surface
What are the features/uses of Wash Through pontics?
Makes no contact with soft tissue
Functional rather than for appearance- gives another occlusal surface to bite on
Consider in lower molar area
What are the features/uses of dome pontics
Useful in lower incisor, premolar or upper molar areas
Acceptable if occlusal 2/3 of buccal surface visible (appears tooth like)- Poor aesthetics if gingival 1/3 of tooth visible (narrower)
What are the features and uses of Modified Ridge lap pontic?
Buccal surface looks as much like tooth as possible- good facial aesthetics
Lingual surface cut away- may allow better cleaning (or does it create food trap)
Line contacts with buccal of ridge
What are the features of Ridge Lap pontics (full saddle)?
Greatest contact with soft tissue
If designed carefully: can be cleansed
Less food packing than ridge-lap
Care taken not to displace soft tissue or cause blanching of tissue
What are the features of Ovate Pontics?
Best aesthetics- tooth looks like it has erupted from gum
Requires meticulous OH
How does an Ovate pontic work?
Presses down on gingivae and remoulds it to make it look natural
->Requires essix retainer with ovate tooth beforehand, composite can be added to this to control tissue remodelling
What are the different materials that can be used to make bridges?
All metal- Gold , Nickel/Cobalt chromium, Stainless steel
Metal ceramic (most common)
All ceramic- Zirconia
E.g. LAVATM and Procera®
Lithium disilicate
E.g. - E.max
Ceromeric- BelleGlass™, Vectris® , Targis® Vectris®
What are the advantages/disadvantages of Gold Bridges?
ADV- strong, malleable (good in posteriors)
DIS- expensive, not tooth coloured
What are the advantage/disadvantages of all ceramic bridges
ADV:
Excellent aesthetic (lithium disilicate is best)
Modern materials rivalling metal in strength
Similar reduction as MCC (LAVA),
DIS:
Prone to fracture
Maximum span is 3-4,
What are the forms of Zirconia that can be used in bridges?
Preparations on casts scanned
Straűmann© – 7 Series by Dental Wings
Nobel BioCare © – Series 5
KATANA© zirconia
Multi-layered (ML) zirconia
Ultra translucent multilayer (UTML) zirconia
Milled
+/- feldspathic (layer) porcelain on top (if area not involved in occlusion)
What are ceromeric materials and their purpose?
Combination of composite (good at withstanding occlusal forces) and ceramic (aesthetic)
What are the steps in conventional bridgework?
- Produce mounted study models
Consider diagnostic wax-up and custom impression tray - Request laboratory to construct vacuum-formed stent allows checking of reduction during tooth preparation, allows construction of provisional bridge
- Select shade
- Use Laboratory made stent or make pre-operative putty impression for provisional bridge
- Occlusal or incisal reduction
- Separation of teeth- Aim for parallelism of tapered surface of each preparation (confirm)
-> Consider retentive features if short clinical crown height or overtapered- Slots, grooves - Construct provisional bridge
- Make impression and occlusal registration
- Temporarily cement provisional bridge
- Demonstrate cleaning with Superfloss™
- Write/draw prescription for technician- abutments, pontic, shape of pontic, shade, material
Example of how to achieve parallelism:
Preparation of fixed-fixed bridge for 13 12 11:
Prep mesial of 11, then mesial of 13
Prep distal of 11, then distal of 13
Prep labial (2-planes) of 11, then labial 13 …..etc
When is parallelism required?
For Fixed-fixed conventional bridge (Single POI with no undercuts)
What are the methods of achieving parallelism?
Paralleling by eye:
Direct vision, one-eye closed
Large mouth mirror (posteriorly)
Use of a straight (right angle) probe like a laboratory surveyor, but in the mouth
Extra-oral survey:
Quick impression, Pour a model, Use a laboratory surveyor (useful in long span multiple unit bridges)
When is parallelism required?
For Fixed-fixed conventional bridge (Single POI with no undercuts)
What is used for definite cementation of bridges (by material)?
All metal conventional bridgework/MCC- Aquacem (GI luting cement), RelyX™Luting (RMGI luting cement)
Adhesive/resin-bonded/resin-retained bridgework (all types)- Panavia 21 (anaerobic duel cure resin cement with 10-MDP)
All ceramic- NEXUS® kit (duel cure resin cement)
Why are distal cantilevers avoided?
Concern that occlusal forces on pontic will produce leverage forces on abutment tooth causing it to tilt
-> may consider if premolar region and opposed by denture
What are the failure rates in different bridge types?
Resin-bonded/Resin retained/adhesive- 80.8% (5-years), 80.4% (10-years)
Conventional fixed-fixed(metal ceramic)- 93.8% (5-years), 89.2% (10-years)
Conventional fixed-fixed (ceramic)- 88.6% (5-years)
Conventional cantilever bridge- 91.4% (5-years), 80.3% (10-years)
Implant retained bridge- 95.2% (5-years), 86.7% (10-years)
