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

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