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DETERMINATION OF SHEAR BOND STRENGTH OF

DETERMINATION OF SHEAR BOND STRENGTH OF NANOCOMPOSITE TO PORCELAIN AND METAL ALLOY Dr. Zenab Sarfraz Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, Lahore, Pakistan Abstract

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DETERMINATION OF SHEAR BOND STRENGTH OF

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  1. DETERMINATION OF SHEAR BOND STRENGTH OF NANOCOMPOSITE TO PORCELAIN AND METAL ALLOY Dr. Zenab Sarfraz Interdisciplinary Research Centre in Biomedical Materials, COMSATS Institute of Information Technology, Lahore, Pakistan Abstract Fracture of porcelain and metal alloy crown and bridges is a common ordeal all dentists go through. Although fracture of prosthesis does not necessarily mean failure, the replacement process is expensive, prolonged and may lead to weakening, pulpal damage and tooth fracture.

  2. Complete prosthesis replacement : • Costly • Traumatic Repair where possible is a good option to offer • Time consuming INTRODUCTION • Dental prosthesis are mainly made from Porcelain(ceramic) and/or metal alloys for single/multiple teeth replacement. • Incidence of fracture in porcelain prosthesis: 5% to 10% In use for (10 YEARS)1 • Brittleness of Porcelain &Complex processing • New porcelain cannot be added intra orally. • Fractures do not necessarily Failure • BUT • Impairs aesthetics and function • Currently porcelain repair carried out with the conventional (micro hybrid) resin composites. • Problems with Conventional composite bonded to Porcelain 2 • Inadequate wear resistance under masticatory load Fracture • Undesirable water sorption Staining • Improper marginal adaptation due to polymerization shrinkage • Bacterial ingress Secondary Caries

  3. OBJECTIVES HYPOTHESIS Measure Shear bond strengths of Nano composite to porcelain and metal alloy substrate and compare with those of the conventional Micro hybrid composite which is currently being used for porcelain repair purpose. Assess How? Nano composite would function as material of choice for repair of porcelain as well as metal alloy. The Shear bond strength of Nano composite to porcelain and metal alloys is more than that of Conventional Micro hybrid composite to porcelain and metal alloys.

  4. PREPARATION&AGING OF SAMPLES Cylindrical discs : (Diameter 1.0 cm and height 0.4 cm) BEFORE Composite application are roughened by: Wet sanding with 240 grit and then 600 grit silicon carbide abrasive. Surface treatment with 50 um Aluminum oxide is carried out in an air abrasive unit. Specimens are ultrasonically cleaned in distilled water for 10min prior to resin application. After Composite application &storage in Distilled water for 24 hours at 37 C, the Specimens are Thermo cycled between 5 and 55 C for 200 cycles for a dwell time of 30 sec. After Thermo cycling, storage in Distilled water at 37C for further 7 days before being tested for Shear bond strength

  5. OUTCOME&UTILIZATION • NANO COMPOSITE AS PORCELAIN REPAIR MATERIAL: • Aesthetic properties • Superior mechanical • Improved durability • Longevity of Fractured porcelain &metallic dental prosthesis. To test Shear bond strength: Universal Testing machine at a Crosshead speed of 0.5mm/min until fracture / de bonding occurs at PORCELAIN/METAL- RESIN INTERFACE. The Shear force is calculated in Newtons (N ) at the point of failure/debonding and Force calculated in mega pascals (mPa)

  6. CONCLUSION REFERENCES • The enhanced bonding between two substrates owing to excellent properties of Nano composite would serve as a good repair option where indicated in porcelain/porcelain-metal fracture. • This material when used as a porcelain repair option, will prove to be patient friendly and also: • Compliant • Conservative • Cost effective • Time saving • Less Traumatic • Compared to complete replacement of entire prosthesis 1 Chung & Hwang 1997. Bonding strengths of porcelain repair systems with various surface treatments. Journal of Prosthetic Dentistry 78(3), p.267-274 Ozcan . 2003 Fracture reasons in ceramic fused to metal restorations. Journal of Oral Rehabilitation 30(3), p.265-9 Strassler 2002. Aging patients/aging restorations: predictable crown and fixed partial denture repair. ContempEsthet Restorative Pract. 6(11), p.20-32 2 Yap , Soh &Siow. 2004. Comparative Depths of Cure among Various Curing Light Types and Method Oper. Dent 29(1), p.18 Yesil , Serpil , Akyil &Seven. 2007. Evaluation of the bond strength of different composite resins to porcelain and metal alloy. International Journal of Adhesion & Adhesives . 27(3), p.258–262

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