IADR Abstract Archives
Impact of HEMA Formulation on 2-Step Self-etch Bonding Agent Performance
Objectives: Historically, most dentin bonding systems including both of primer and adhesive in 2-Step bonding agent have been formulated with HEMA and MDP, in order to obtain compatibility with dentin structure. However, such monomers have essentially negative impact on durability since they are hydrophilic and/or low polymerization reactivity. Our One-Step bonding technology could be utilized in priming step successfully without HEMA and MDP containing adhesive. Based on this technology, impact of HEMA and MDP formulation in adhesive of material performance of 2-Step self-etch bonding agent was evaluated.
Methods: Three trial 2-Step self-etch Bonding agents, Control (BZF which consist primer and adhesive free of HEMA and MDP, GC), +HEMA (including 30% of HEMA in Control) and +MDP (including 20% of MDP in Control) were examined. Bovine dentin surface was with 400-grit SiC paper. Each primer and adhesive were applied on prepared dentin surface, then composite resin was applied to prepare bonding specimen according to ISO29022. After storage in water at 37 oC for 24 hrs., bonding specimen were subjected to shear bond strength (SBS) test. Flexural strength specimens of Each adhesive were prepared, stored in water at 37 oC for 1 week. Flexural strength tests were according to ISO4049. Data were statistically analyzed (ANOVA, p<0.05)(n=5).
Results: Mean(±SD) SBS values were 50.7(±5.5), 38.0(±10.6) and 36.6(±11.4) MPa for Control, +HEMA and +MDP respectively. Mean(±SD) flexural strength values were 124.1(±7.8), 108.3(±6.3) and 75.6(±10.8) MPa for Control, +HEMA and +MDP respectively. +HEMA and +MDP showed significantly reduction of both bond strength and flexural strength compared with Control.
Conclusions: Formulation of HEMA and MDP had negative impact on material performance and this might indicate HEMA and MDP free adhesive may result in high durability clinical performance.
Methods: Three trial 2-Step self-etch Bonding agents, Control (BZF which consist primer and adhesive free of HEMA and MDP, GC), +HEMA (including 30% of HEMA in Control) and +MDP (including 20% of MDP in Control) were examined. Bovine dentin surface was with 400-grit SiC paper. Each primer and adhesive were applied on prepared dentin surface, then composite resin was applied to prepare bonding specimen according to ISO29022. After storage in water at 37 oC for 24 hrs., bonding specimen were subjected to shear bond strength (SBS) test. Flexural strength specimens of Each adhesive were prepared, stored in water at 37 oC for 1 week. Flexural strength tests were according to ISO4049. Data were statistically analyzed (ANOVA, p<0.05)(n=5).
Results: Mean(±SD) SBS values were 50.7(±5.5), 38.0(±10.6) and 36.6(±11.4) MPa for Control, +HEMA and +MDP respectively. Mean(±SD) flexural strength values were 124.1(±7.8), 108.3(±6.3) and 75.6(±10.8) MPa for Control, +HEMA and +MDP respectively. +HEMA and +MDP showed significantly reduction of both bond strength and flexural strength compared with Control.
Conclusions: Formulation of HEMA and MDP had negative impact on material performance and this might indicate HEMA and MDP free adhesive may result in high durability clinical performance.