Influence of pre-treatment with diode laser and Nano silica coating crosslinking matrix metalloproteinase inhibitor on the stabilization of resin-dentine interfaces

This study was performed to assess the impact of exposing the bonding agent to diode laser irradiation before cure and nano-silica coating proanthocyanidin (Nano silica-PA) matrix metalloproteinases (MMP) inhibitor on the microtensile bond strength (µTBS) and hybrid layer morphology.

Twenty-eight sound premolar teeth were sectioned to expose dentin and were then randomly divided into four groups (n = 7) based on the pretreatment methods. The control group (EB): was etched followed by adhesive Adper Single Bond 2 (SB) application and curing; Laser group (EBL): etching, (SB) application, diode laser irradiation, then (SB) curing; for Nano silica coating MMP inhibitor group (EMB): etching, (Nano silica-PA) application, (SB) application and curing; and the mixed group (EMBL): after etching, Nano silica-PA, (SB) applied, diode laser exposure, and (SB) cured on the surfaces. Next, all samples were built up with Z350 composite and after 6 months of distilled water storage, µTBS was evaluated using a universal testing machine and Scanning Electron Microscope (SEM) for morphological observation.

The µTBS values in EBL and EMB had higher bond strengths than the EMBLgroup but were not significantly different from the control, with cohesive and mixed failures being more prevalent in EMBL and control groups. SEM images revealed deeper resin tag infiltration in laser group compared to other groups, while EMB was exhibited a thick hybrid layer with residual silica particles on the dentin surface.

After a long-term evaluation, both MMP inhibitors; diode laser irradiation and Nano silica-PA could maintain bond strength stability, while using them together reduces it. The residual nanosilica particles could resist collagen biodegradation through the generation of a nucleus for the remineralization of demineralized dentin.