Objective To study the types of matrix metalloproteinases (MMPs) involved in dentin bonding interface degradation.Methods Dentin slices were prepared and treated with two adhesive systems (Single Bond 2 or Clearfil S3 Bond). The dentin surface was bonded with composite resin. All specimens were immersed in sterile artificial saliva for 0 or 6 months, and their micro-shear bond strength (μSBS) were measured. The fracture modes were observed through field emission scanning electron microscope (FE-SEM). Dentin slices with 4 mm×3 mm×1 mm dimensions were prepared. The slices were divided into three groups according to the treatment modes (negative control, Single Bond 2, and Clearfil S3 Bond). All specimens were stored in sterile artificial saliva for 0 or 6 months. The concentrations of MMP-1, -2, -3, -8, and -9 of each group were detected through fluorescent microsphere immunoassay.ResultsThe μSBS of bothadhesive systems significantly decreased after storage aging. Significant differences in failure modes within the four groups testedinthis study were observed. Compared with the negative control, the concentrations of MMP-1 and MMP-3 in different adhesive groups showed no significant difference after storage aging. However, the concentrations of MMP-2, -8, and -9 in Single Bond 2 group and the concentrations of MMP-8 and -9 in Clearfil S3 Bond group significantly decreased after 6 months of storage aging.ConclusionSignificant degradation occur in the dentin bonding interface of both adhesive groups under 6 months aging challenge. The concentrations of dentinal MMP-2, -8, and -9 significantly decrease after treatment with adhesives and aging, indicatingthat these MMPs have animportant function in dentin bonding interface degradation.
