Resin bonded FPD

1. RESIN BONDED Fixed Partial Denture Presenter ; Dr. Priyansh Yadav

2. Contents Definition Introduction Indications Contraindications Advantages Disadvantages Classification Post insertion management Causes of failure

3. DEFINITION A prosthesis that is luted to tooth structure, primarily enamel , which has been etched to provide mechanical retention for the composite resin.

4. INTRODUCTION These are prosthesis that requires minimal removal of tooth structure , particularly for abutment teeth that are intact and caries free. The primary goal of the resin bonded FPD is the replacement of missing teeth and maximum conservation of tooth structure.

5. INDICATIONS For abutment with sufficient enamel to etch for retention. For splinting of periodontally compromised teeth. Stabilizing of dentition after orthodontic treatment. Medically compromised & adolescent patients. Prolonged placement of certain prosthesis for correction of craniofacial abnormalities.

6. CONTRAINDICATIONS Patients with sensitivity to base metal alloys. When abutment requires facial esthetics . Abraded teeth. Inadequate enamel surface to etch.

7. ADVANTAGES Non invasive to dentin Conservative Decreased tissue irritation. Less chairside time. Reduced cost. Doesn’t require cast alterations

8. DISADVANTAGES Demanding technique and tooth preparation. Even minor laboratory errors cannot be corrected easily. Plaque accumulation. Intolerable bulky contour. Not ideal for replacing more than one tooth. The resultant aesthetic is not good.

9. CLASSIFICATION Mechanical Micro-Mechanical Macro-Mechanical Chemical Rochette bridge Maryland bridge Virginia bridge Cast mesh fixed partial denture Adhesive bridge Based upon type of retention

10. ROCHETTE Bridge It was the 1st resin prosthesis to be developed. Developed by:- Rochette in 1973 He used a wing-like retainer with funnel shaped perforation with the base towards the tooth surface.

11. ROCHETTE Bridge The diameter of the funnel was greater towards the outside by 0.5mm. Diameter towards outside- 1.5mm Diameter towards tooth surface- 1mm He also used silane-coupling agents for additional retention. The major disadvantage of this design is external stress, abrasion & marginal leakage.

12. MARYLAND Bridge Developed by:- Livaditis & Thompson in 1981 He used electrolytic etching to provide micro-mechanical retention to the non-perforated base metal retainers which were bonded by resin cement. Micro-porosities were created by etching the tissue surface of the retainer which provides mechanical retention.

13. MARYLAND Bridge In this method, of electrolytic etching the etchant used was 3.5% solution of nitric acid. A current of 250mA/cm2 is supplied for 5 minutes. This is followed by immersion of retainer in 18% HCL in an ultrasonic cleanser for 10mins. Note: Before the etching is done, retainer is coated with paraffin wax in those areas that are not to be etched. Advantage:- It has good retention as compared to perforated ones. Disadvantage:- Expensive & technique sensitive.

14. VIRGINIA Bridge Developed by:- Moon & Hudgins in 1983 These are resin bonded fixed partial dentures which use particle roughened retainers. The retainer wax patterns are fabricated using resin. Advantages:- Even noble metal alloys can be used. Surface treatment of retainer is not necessary.

15. VIRGINIA Bridge Lost salt technique ; 150-250 µm salt crystals are sprinkled on the cast prior to resin fabrication. The salt crystals get incorporated onto the tissue surface of the resin pattern. The salt crystals are dissolved by keeping pattern in ultrasonic cleanser. The resin pattern is invested and cast. Dissolved crystals will produce voids in the resin pattern. These voids are reproduced in the cast metal retainer and they help in mechanical retention.

16. CAST MESH FPD A nylon mesh is placed over the tissue surface of the retainer wax pattern.

17. CAST MESH FPD The mesh is placed on the cast before fabricating the wax pattern. Now, the fabrication of the pattern is done at the mesh. The mesh becomes incorporated and as casting is done it provides retention for resin to metal. Disadvantages:- Nylon mesh may not adapt well to the cast during pattern fabrication. The wax may not flow between the mesh locking all the undercuts.

18. ADHESIVE Bridge Bonding of resin cement to metal is done. Advantages:- High bond strength, fracture toughness & good clinical success. Materials used for chemical bonding:- Modified Bis GMA cement Superbond Rocatec system Chemical bonding between the resin and the metal retainer can be produced by chemical etching or tin-plating or using chemical adhesives.

19. ADHESIVE Bridge Chemical etching; A gel consisting of Nitric and Hydrochloric acids is applied to the internal surface of the metal framework for approximately 25 minutes. Tin plating; Tin has the ability to form organic complexes with several specific adhesive resins resulting in significantly greater bond strengths. Precious alloys can be plated with tin and used as frameworks for resin retained fixed partial denture. Composite resins play an important role in the bonding of the metal framework to etched enamel.

20. POST INSERTION MANAGEMENT All resin-bonded restorations should receive significant attention after insertion. Hence, frequent recall appointments should be followed to ensure the success of the prosthesis.

21. CAUSES OF FAILURE Inappropriate patient selection Mal-alignment of tooth Insufficient vertical length of abutment tooth Inadequate enamel for bonding History of metal sensitivity Decreased labio- lingual dimensions of abutments

22. CAUSES OF FAILURE Incomplete tooth preparation Insufficient proximal and lingual surface reduction Incomplete extension of retainer (less than 180°) Lack of accommodation to mandibular protrusion Bonding failure Contamination Prolonged mixing Inappropriate luting agent