Effect of Thermocycling on the Flexural Strength of Various PMMA Resins Reinforced with Different Fibres: An In vitro Study
Kamal Nayan *
Department of Prosthodontics, Mithila Minority Dental College and Hospital, Darbhanga, Bihar, India
A. K. Verma
Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India
Mariyam Ali
Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India
Lalima Kumari
Department of Orthodontics and Dentofacial Orthopaedics, Haldia Institute of Dental Sciences and Research, West Bengal, India
Saurabh Chaturvedi
Department of Prosthodontics, College of Dentistry, King Khalid University, Abha, Saudi Arabia
Naeem Ahmad
Department of Prosthodontics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India
*Author to whom correspondence should be addressed.
Abstract
Introduction: Fracture of an acrylic resin complete denture base after aging, poses problem for patients, dentists and dental laboratory technicians. This study was performed to determine the effect of thermocycling on the flexural strength of a commercially available, heat-polymerized acrylic denture base material reinforced with glass fibers, carbon fibers, aramid fibers and high (HI) impact resins.
Materials and Methods: Forty specimens were made of similar dimension from five groups of materials. Each group had eight specimens. A commercially available heat polymerized P.M.M.A denture base resin was selected as control and PMMA reinforced with glass, carbon, aramid fibres and HI impact resin were compared. All specimens were then subjected to thermocycling before testing. Flexural strength was evaluated with universal testing machine. The results were analyzed with Analysis of Variance (ANOVA) followed by Turkey HSD test.
Results: All reinforced specimens and HI impact resins showed better flexural strength than the conventional acrylic resin after thermocycling. Specimens reinforced with glass fibers showed the highest flexural strength, followed by HI impact resin, carbon fibers and aramid fibers. After artificial aging, a significant improvement in the flexural strength of conventional acrylic resin was observed when it was reinforced with glass fibers.
Conclusion: Within the limitations of this study, incorporation of 2% by weight of glass fibre in PMMA resin exhibited statistically significant maximum flexural strength followed by high impact resin, carbon, polyaramid reinforced P.M.M.A denture base resin. These can readily be used in the fabrication of dentures subjected to heavy masticatory loads.
Keywords: High impact resin, thermocycling, reinforcement, PMMA resin, glass fibers, flexural strength.