Title: 0223 - Influence of BAC-Containing Adhesives on the Longevity of Resin-Dentin Bonds
Tatjana Maravic (Presenter)
University of Bologna
Allegra Comba, University of Bologna
Sandra Cunha, Faculdade de Odontologia da USP
Claudia Mazzitelli, DIBINEM, University of Bologna
Vittorio Checchi, University of Bologna
Nicola Scotti, University of Turin
Annalisa Mazzoni, University of Bologna
Lorenzo Breschi, University of Bologna
Objectives: Benzalkonium chloride (BAC) has been shown to inhibit dentin matrix metalloproteinases (MMPs). The aim of the study was to compare the All-Bond Universal (ABU) multi-mode adhesive system with experimental ABU adhesives blended with different concentrations of BAC using mechanical and biochemical tests.
Methods: 40 intact molars were selected and assigned to the following groups according to the adhesive protocol applied: G1) ABU SE; G2) ABU E&R; G3) ABU+0.5%BAC SE; G4) ABU+0.5%BAC E&R; G5) ABU+1%BAC methacrylate SE; G6) ABU+1%BAC methacrylate E&R. Composite buildups were created on the bonded surfaces, specimens were cut for microtensile bond strength test and stressed to failure after 24-hour (T0) or a 12-month (T12) storage in artificial saliva. Additionally, adhesive/dentin interfaces were obtained for nanoleakage analysis at T0 and T12. Zymography and in situ zymography were also performed to assess the ability of the different formulations to inhibit MMP-2 and -9 activity.
Results: All groups showed a detectable and significant decrease in microtensile bond strength values over time. ABU+1%BAC methacrylate performed significantly lower than ABU and ABU+0.5%BAC. Interfacial nanoleakage infiltration showed a statistically lower presence of silver nitrate both at T0 and T12 of the groups treated in the ER mode, irrespective from the adhesive. Zymographyc assay revealed that all the BAC-containing formulations decreased MMPs expression. In situ zymography demonstrated a decrease in enzymatic activity at T0 in all experimental groups, with ABU + 1%BAC methacrylate showing the lowest level of fluorescence over time, which is not in accordance with the µTBS results.
Conclusions: The MMPs-inhibitory potential of BAC-containing adhesives did not reflect the bond strength results. In fact, ABU+1%BAC methacrylate SE group presented the lowest bond strength values at T12, possibly due to the properties of the material itself, and its sensitivity to hydrolysis.
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE