Bond strength of hard and soft relining materials to thermoplastic monomer free microcrystalline polymer ( In-vitro comparative study)

Abstract

Purpose analysis of bond strength of various denture relining materials to recently introducedthermoplastic monomer free semi rigid microcrystalline polymer and heat cured denture basematerials.Materials and methods: designed with cylindrical –shaped silicon patterns with dimensions20 mm in length and 8mm in diameter. Samples branched into four groups(20 samples for eachgroup):GI: heat cured acrylic resin samples with hard relining material, GII: heat cured acrylic resinsamples with soft relining material. GIII: thermoplastic monomer free semi-rigid microcrystallinepolymer (karadent) samples with hard relining material, GIV: thermoplastic monomer free semirigidmicrocrystalline polymer samples with soft relining material .Tensile and shear bond strength of hard & soft reliner to the two denture base materialsexamined by Instron Universal Testing Machine . Multiple group comparisons was assisted byone-way ANOVA test followed by T- test for pair wise comparisons to estimate any significantdifferences between groups. The tests deemed significant when p ≤ 0.05 and highly significantwhen p ≤ 0.001.Results: Highly significant differences for both tensile and shear bond strength mean valueswas found between groups regarding the mean applied loads, P-value ≤ 0.001. The t- test forcomparison showed a extremely significant variance in the mean tensile & shear bond strengthbetween groups. Hard relining material showed greater mean values of both shear and tensile bondstrength regarding the heat cured denture base material (GI) followed by karadent one (GIII) . Thelowest mean values was found in soft relining material, specially that with karadent denture basematerial ( GIV) for both shear and tensile bond strength.Conclusion: supporting on the results of this research, it might be terminated that newlyintroduced thermoplastic monomer free semi rigid microcrystalline polymer successfully acceptrelining specially with hard relining material .It overcomes the main problems of thermoplasticresins that can’t accept relining