IADR Abstract Archives
Does Chlorhexidine Inhibit MMPs After 10-years Aging In Artificial Saliva?
Objectives: Dentinal endogenous enzymes degrade the collagen fibrils exposed after bonding to dentin, impairing the longevity of the hybrid layer (HL). Chlorhexidine (CHX) inhibits matrix metalloproteinases (MMP)-2, -8 and 9 in very low concentrations. The aim of this study was to investigate the ability of an additional CHX-containing primer (0.2% aqueous solution) to inhibit dentinal enzymes after 10 years, using in situ zymography.
Methods: Non-carious teeth (N= 5 per group) were assigned to two groups, cut into slabs exposing middle/deep dentin, etched for 15 s with 35% phosphoric acid and bonded according to the manufacturer’s instructions: G1: with Adper Scotchbond 1XT (SB1XT) (control group); G2: treated with 0.2% CHX aqueous solution for 1 min and then bonded with SB1XT. 1-mm-composite build-ups were made using a flow composite Filtek, 3M. Specimens were cut to expose the HL, glued to glass slides and polished. In situ zymography was performed on the specimens immediately (T0) and after 10-year aging (T10yr) at 37°C in artificial saliva in accordance with Mazzoni et al., 2014. Self-quenched fluorescein-conjugated gelatin mixture was placed on top of each specimen, protected with a cover slip and incubated in a dark humidified chamber at 37°C for 12 h. Detection of endogenous gelatinolytic enzyme activity within the HL was evaluated with a multi-photon confocal laser scanning microscope.
Results: In situ zymographic assay at T0 showed a less pronounced enzymatic activity in the CHX-pretreated groups. Aged samples presented higher activity in both tested groups compared to T0, maintaining however a lower level of fluorescence in the experimental group.
Conclusions: The inhibitory effect of CHX on the MMPs seems to be present even after 10 years. Further studies are necessary to investigate whether the silencing of the enzymatic activity after 10 years reflects preservation of the HL over time.
Methods: Non-carious teeth (N= 5 per group) were assigned to two groups, cut into slabs exposing middle/deep dentin, etched for 15 s with 35% phosphoric acid and bonded according to the manufacturer’s instructions: G1: with Adper Scotchbond 1XT (SB1XT) (control group); G2: treated with 0.2% CHX aqueous solution for 1 min and then bonded with SB1XT. 1-mm-composite build-ups were made using a flow composite Filtek, 3M. Specimens were cut to expose the HL, glued to glass slides and polished. In situ zymography was performed on the specimens immediately (T0) and after 10-year aging (T10yr) at 37°C in artificial saliva in accordance with Mazzoni et al., 2014. Self-quenched fluorescein-conjugated gelatin mixture was placed on top of each specimen, protected with a cover slip and incubated in a dark humidified chamber at 37°C for 12 h. Detection of endogenous gelatinolytic enzyme activity within the HL was evaluated with a multi-photon confocal laser scanning microscope.
Results: In situ zymographic assay at T0 showed a less pronounced enzymatic activity in the CHX-pretreated groups. Aged samples presented higher activity in both tested groups compared to T0, maintaining however a lower level of fluorescence in the experimental group.
Conclusions: The inhibitory effect of CHX on the MMPs seems to be present even after 10 years. Further studies are necessary to investigate whether the silencing of the enzymatic activity after 10 years reflects preservation of the HL over time.