resin-bonded fixed partial dentures rbfpd

1. Resin-Bonded Fixed Partial Dentures (RBFPD) Dr Wael Al-Omari BDS, MDentSi, PhD

3. Bonded Pontic Extracted natural tooth or acrylic pontic bonded with composite resin directly to proximal ad lingual surfaces of abutment teeth. Have limited lifetime Short-term replacement

4. Cast perforated resin bonded FPD (Mechanical retention) Rochette Bridge (1973) Cast perforated metal retainers bonded to abutment teeth and metal-ceramic pontic to replace missing tooth Periodontal splint Cemented with composite Disadvantages: 1- Weakening of metal retainer by perforations 2- Wear of exposed resin at the perforations. 3- Limited adhesion of the metal provided by perforations.

5. Etched cast resin bonded FPD (Micromechanical retention- “Maryalnd Bridge” ) Advantages over perforated retainers: 1- Retention improved due to bonding of resin to etched metal bond which is stronger than resin to etched enamel. 2- Oral surface of cast retainers is highly polished and reduce plaque accumulation. Electrolytic etching of base metal alloys. Chemical etching or gel etching with similar results. First generation of resin cement was used for bonding (Comspan)

6. Macroscopic mechanical resin bonded (Virginia bridge) Visible macroscopic mechanical undercuts Lost salt crystal technique Cast mesh pattern

7. Chemical bonding resin bonded FPD (Adhesion bridge) Direct bonding to metal using chemically active agents. Super bond(methyl methacrylate polymer powder and MMA liquid)? highest initial bond strength , low elastic modulous, high fracture toughness. BisGMA based composite luting cement modified with adhesion promoter Panavia ? excellent bond to base metal alloys an to tin-plated gold and gold palladium – based alloy. Panavia F 2.0? dual cure system that releases fluoride. Improve bonding by air abrasion, silica-carbon layer & silanation and Rocatec system (silica with alumina)

8. Advantages of RBFPD Minimal tooth preparation Minimal pulpal trauma Anesthesia is not required. Less periodontal irritation Impression making is simplified Provisional restorations usually not required. Chair time and cost are reduced. Rebonding possible

9. Disadvantages of RBFPD Uncertain longevity Irreversible procedure (Enamel removal). No space correction No alignment correction. Esthetic compromised in posterior teeth

10. Indications Short span with caries free and properly aligned abutments. For children and adolescents Mandibular and maxillary incisors replacement. Single posterior tooth replacement with favorable occlusion. Periodontal splint

11. Contraindications Long span Deep overbite Parafunctional activity Extensive caries or restoration Compromised enamel structure Nickel allergy Edentulous space is larger or smaller than normal tooth size Presence of diastema

12. Fabrication Three Fabrication Phases: Preparation of the abutment teeth Design of the restoration Bonding

13. Preparation of the abutment teeth Principle of abutment preparation Distinct path of insertion Proximal undercuts removed Occlusal or cingulum rests Proximal groove or slots to increase resistance. More than half the circumference of the tooth prepared (wrapped around). Definitive supragingival margin established

14. Anterior tooth preparation & framework design Use the largest possible surface of enamel without compromising esthetics. Ideally, replacing single missing tooth, single mesial & distal abutment is sufficient. If two teeth to be replaced, double abutments can be considered if abutments were periodontally compromised. Cantilever design proved successful Supragingival chamfer finish line is preferred. Light chamfer finish line 1.0 mm supagingivally

15. Anterior tooth preparation & framework design Margin extend incisally & interproximally. Margin on the proximal plane should extend as far facially as possible, extending beyond the proximal contact point at the proximal surface adjacent to edentulous space Prepare 0.5mm slot slightly lingual to the facial margin. At least 0.5mm interocclusal clearance is needed Preparation should be 2.0 mm of the incisal edge

17. Posterior tooth preparation & framework design

18. Posterior tooth preparation & framework design

20. Clinical Success

21. Step by Step procedure Leave the margin 1mm from the incisal/occlusal edge, & 1mm from the gingival margin Prepare more than half the abutment if possible “180o” Make definitive impressions Provide temporary occlusal stops.

22. Bonding the Restoration Cements: Composite resin are used in bonding metal framework to etched enamel. Conventional BIS-GMA resins have been replaced by the recently developed resin-metal adhesives (ex. Panavia). Use oxygen barrier at the margins Always air abrade the fitting surface with 50 micron aluminum oxide Use tin plating and metal primers for noble alloys The use of silica coating enhances the bonding. Rubber dam isolation reduces risk of debonding

23. Step by Step Bonding Clean the tooth with pumice & water, etch the enamel for 30 seconds Apply the primer for 30 seconds then dry Apply the luting cement to the fitting surface of the restoration Seat the restoration firmly & maintain pressure while removing the excess of the cement Light cure the margins and apply Oxyguard II to exclude air & allow setting around the margins After 2 minutes remove & rinse ruminants of the Oxyguard material

27. Postoperative Care Regular check ups are important to monitor any possible debonding Aid of visual examination & gentle pressure with sharp explorer should be performed to confirm such complication Patients should be warned about such complications Attention to periodontal health is critical Clean with air abrasion and acid etch enamel before re-bonding