Felipe Weidenbach Degrazia1, Vicente Castelo Branco Leitune2, Fernanda Visioli3, Susana Maria Werner Samuel4, Fabrício Mezzomo Collares5. 1. Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil; School of Dentistry, University of Federal District - UDF, SHCS Q 704/904 - Asa Sul, 70390-045, Brasília, Brazil. Electronic address: fdegrazia@hotmail.com. 2. Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: vicente.leitune@ufrgs.br. 3. School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, Brazil. Electronic address: fernanda.visioli@ufrgs.br. 4. Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: susana.samuel@ufrgs.br. 5. Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, RS, Brazil. Electronic address: fabricio.collares@ufrgs.br.
Abstract
OBJECTIVE: The aim of this study was to evaluate physicochemical properties, long-term microtensile bond strength and cytotoxicity of methacrylate-based adhesive containing boron nitride nanotubes (BNNTs) as fillers. METHODS: A dental adhesive was formulated using BisGMA/HEMA, 66/33wt% (control). Inorganic BNNT fillers were incorporated into the adhesive at different concentrations (0.05, 0.075, 0.1 and 0.15wt%). Analyses of degree of conversion (DC), polymerization rate [Rp.(s-1)], contact angle (CA) on dentin, after 24h and 6 months microtensile bond strength (μTBS-24h and 6 months) were assessed. Cytotoxicity was performed through viability of fibroblast cells (%) by sulforhodamine B (SRB) colorimetry. RESULTS: DC and max. polymerization rate increased (p<0.05) after incorporating 0.075 and 0.1wt% BNNT. The contact angle on dentin increased (p<0.05) after incorporating 0.15wt% BNNT. The μTBS-24h showed no changes (p>0.05) after incorporating up to 0.15wt% BNNT comparing to control. After 6 months, μTBS decreased (p<0.05) for control and 0.15wt% BNNT and BNNT groups up to 0.15wt% showed higher μTBS than control (p<0.05). No difference of fibroblast growth was found among adhesives (p>0.05) and up to 19% of cell viability was found comparing 0.05wt% BNNT to positive control group (100%). SIGNIFICANCE: Incorporating boron nitride nanotubes up to 0.1wt% into dental adhesive increased the long-term stability to dentin without decreasing viability of fibroblast cell growth. Thus, the use of BNNTs as filler may decrease failure rate of current dentinal adhesives.
OBJECTIVE: The aim of this study was to evaluate physicochemical properties, long-term microtensile bond strength and cytotoxicity of methacrylate-based adhesive containing boron nitride nanotubes (BNNTs) as fillers. METHODS: A dental adhesive was formulated using BisGMA/HEMA, 66/33wt% (control). Inorganic BNNT fillers were incorporated into the adhesive at different concentrations (0.05, 0.075, 0.1 and 0.15wt%). Analyses of degree of conversion (DC), polymerization rate [Rp.(s-1)], contact angle (CA) on dentin, after 24h and 6 months microtensile bond strength (μTBS-24h and 6 months) were assessed. Cytotoxicity was performed through viability of fibroblast cells (%) by sulforhodamine B (SRB) colorimetry. RESULTS: DC and max. polymerization rate increased (p<0.05) after incorporating 0.075 and 0.1wt% BNNT. The contact angle on dentin increased (p<0.05) after incorporating 0.15wt% BNNT. The μTBS-24h showed no changes (p>0.05) after incorporating up to 0.15wt% BNNT comparing to control. After 6 months, μTBS decreased (p<0.05) for control and 0.15wt% BNNT and BNNT groups up to 0.15wt% showed higher μTBS than control (p<0.05). No difference of fibroblast growth was found among adhesives (p>0.05) and up to 19% of cell viability was found comparing 0.05wt% BNNT to positive control group (100%). SIGNIFICANCE: Incorporating boron nitride nanotubes up to 0.1wt% into dental adhesive increased the long-term stability to dentin without decreasing viability of fibroblast cell growth. Thus, the use of BNNTs as filler may decrease failure rate of current dentinal adhesives.
Authors: Sara Kalagi; Sabrina A Feitosa; Eliseu A Münchow; Victor M Martins; Ashley E Karczewski; N Blaine Cook; Kim Diefenderfer; George J Eckert; Saulo Geraldeli; Marco C Bottino Journal: Dent Mater Date: 2020-03-30 Impact factor: 5.304