Marina Ciccone Giacomini1, Polliana Mendes Candia Scaffa2, Rafael Simões Gonçalves3, Giovanna Speranza Zabeu4, Cristina de Mattos Pimenta Vidal5, Marcela Rocha de Oliveira Carrilho6, Heitor Marques Honório7, Linda Wang8. 1. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil. Electronic address: marina.giacomini@usp.br. 2. Division of Biomaterials and Biomechanics, Department of Restorative Dentistry, Oregon Health & Science University, OHSU, 2730 SW Moody Ave, Portland, OR, 97201, USA. Electronic address: mendesca@ohsu.edu. 3. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil. Electronic address: rafael895@hotmail.com. 4. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil. Electronic address: giovanna.zabeu@gmail.com. 5. Department of Operative Dentistry, College of Dentistry, University of Iowa, 801 Newton Rd, DSB S245, Iowa City, IA, 52242, USA. Electronic address: cristina-vidal@uiowa.edu. 6. College of Dental Medicine Illinois, Midwestern University, Chicago, 555 31st St. Downers Grove, IL, 60515, USA. Electronic address: mcarri@midwestern.edu. 7. Department of Pediatric Dentistry, Orthodontics and Collective Health, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil. Electronic address: heitorhonorio@usp.br. 8. Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru, SP, 17012-901, Brazil. Electronic address: wang.linda@usp.br.
Abstract
The incorporation of functional monomers and proteolytic inhibitors into adhesive systems have shown to be promising strategies to improve the longevity of adhesive restorations. The aim of this study was to evaluate the long-term bonding performance and anti-gelatinolytic effect of a 10-MDP-based universal adhesive system applied in combination with 2% chlorhexidine digluconate (CHX). For that, this study assessed the resin-dentin bond strength and the in situ gelatinolytic activity profile at the adhesive interface at initial and after 6 month of storage. One hundred and two sound human third molars were prepared and randomly divided into 3 groups according to the adhesive strategy: SB (two-step etch-and-rinse adhesive, Adper Single Bond 2, 10-MDP-free control group); SU-ER (Adper Single Bond Universal, 10-MDP containing universal adhesive applied on etch-and-rinse mode); and SU-SE (SU applied on self-etching mode). The groups were subdivided into two according to the dentin pretreatment: W - water or CHX- 2% chlorhexidine digluconate aqueous solution (SB-W; SB-CHX; SU-ER-W; SU-ER-CHX; SU-SE-W; SU-SE-CHX) and subsequently restored according to the manufacturer's instructions. Bond strength (n = 12) was assessed by a microtensile test (μTBS) (500N/0.5 mm/min) after 24h or after 6 months of storage. In situ zymography was performed to evaluate anti-gelatinolytic activity (n = 5). Resin-dentin samples were incubated with fluorescein-conjugated gelatin for 24 h at 37 °C and analyzed by confocal laser scanning microscopy. Fluorescence indicating gelatinolytic activity at hybrid layer zone and adjacencies was quantified using Image J. Data was analyzed by three-way ANOVA and Tukey post-hoc tests (p < 0.05). Results: SU-SE showed the highest bond strength values, while similar results were observed for SU-ER and SB. No statistical significant differences were observed between pretreatment (CHX vs. W) or storage time (initial vs. 6 months of aging). For in situ zymography, fluorescence was detected in all groups and CHX pre-treatment was able to inhibit the gelatinolytic activity in all conditions. The 10-MDP-based universal adhesive system in self-etching mode was the strategy that showed the best bonding performance irrespective of its combination with chlorhexidine. Pre-treatment with CHX did not impair the bond strength when used in combination with 10-MDP and it may promote collagen stability overtime.
The incorporation of functional monomers and proteolytic inhibitors into adhesive systems have shown to be promising strategies to improve the longevity of adhesive restorations. The aim of this study was to evaluate the long-term bonding performance and anti-gelatinolytic effect of a 10-MDP-based universal adhesive system applied in combination with 2% chlorhexidine digluconate (CHX). For that, this study assessed the resin-dentin bond strength and the in situ gelatinolytic activity profile at the adhesive interface at initial and after 6 month of storage. One hundred and two sound human third molars were prepared and randomly divided into 3 groups according to the adhesive strategy: SB (two-step etch-and-rinse adhesive, Adper Single Bond 2, 10-MDP-free control group); SU-ER (Adper Single Bond Universal, 10-MDP containing universal adhesive applied on etch-and-rinse mode); and SU-SE (SU applied on self-etching mode). The groups were subdivided into two according to the dentin pretreatment: W - water or CHX- 2% chlorhexidine digluconate aqueous solution (SB-W; SB-CHX; SU-ER-W; SU-ER-CHX; SU-SE-W; SU-SE-CHX) and subsequently restored according to the manufacturer's instructions. Bond strength (n = 12) was assessed by a microtensile test (μTBS) (500N/0.5 mm/min) after 24h or after 6 months of storage. In situ zymography was performed to evaluate anti-gelatinolytic activity (n = 5). Resin-dentin samples were incubated with fluorescein-conjugated gelatin for 24 h at 37 °C and analyzed by confocal laser scanning microscopy. Fluorescence indicating gelatinolytic activity at hybrid layer zone and adjacencies was quantified using Image J. Data was analyzed by three-way ANOVA and Tukey post-hoc tests (p < 0.05). Results: SU-SE showed the highest bond strength values, while similar results were observed for SU-ER and SB. No statistical significant differences were observed between pretreatment (CHX vs. W) or storage time (initial vs. 6 months of aging). For in situ zymography, fluorescence was detected in all groups and CHX pre-treatment was able to inhibit the gelatinolytic activity in all conditions. The 10-MDP-based universal adhesive system in self-etching mode was the strategy that showed the best bonding performance irrespective of its combination with chlorhexidine. Pre-treatment with CHX did not impair the bond strength when used in combination with 10-MDP and it may promote collagen stability overtime.