Felipe Weidenbach Degrazia1, Vicente Castelo Branco Leitune2, Susana Maria Werner Samuel3, Fabrício Mezzomo Collares4. 1. Laboratório de Materiais Dentários, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, Brazil. Electronic address: fdegrazia@hotmail.com. 2. Laboratório de Materiais Dentários, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, Brazil. Electronic address: vicente.leitune@ufrgs.br. 3. Laboratório de Materiais Dentários, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, Brazil. Electronic address: susana.samuel@ufrgs.br. 4. Laboratório de Materiais Dentários, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2492, Rio Branco, 90035-003, Porto Alegre, Brazil. Electronic address: fabricio.collares@ufrgs.br.
Abstract
OBJECTIVE: This study aimed to evaluate the physical-chemical properties of experimental dental adhesives containing boron nitride nanotubes (BNNTs) as inorganic fillers. METHODS: An experimental adhesive resin was prepared using HEMA-BisGMA, 66/33wt% (control). Inorganic BNNT fillers were first analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and then incorporated into the adhesive at different concentration (0.05, 0.075, 0.1, 0.15wt%). Degree of conversion (DC), ultimate strength, contact angle, surface free energy (SFE) microhardness, softening in solvent and bioactivity were assessed. RESULTS: Scanning and transmission electron microscopy (SEM and TEM) showed BNNTs with diameter ranging from 5 to 10nm with close end tips. No changes in DC were observed after incorporating BNNTs up to 0.15wt%. The contact angles of water and α-bromonaphthalene increased (p<0.05) and consequently the SFE decreased after incorporating BNNTs to the polymer matrix. Microhardness and solvent degradation strength increased after incorporation of 0.075, 0.1 and 0.15wt% BNNTs. Mineral deposition was found after 7days of immersion on adhesive specimens after incorporation of BNNT. CONCLUSIONS: The incorporation of BNNTs up to 0.15wt% improved the chemical and mechanical properties of dental adhesives and promoted mineral deposition. CLINICAL SIGNIFICANCE: Incorporation of boron nitride nanotubes into adhesive resin materials improved physical-chemical properties and increased mineral deposition on its surface allowing enhanced properties of the resin-dentin interface. Thus, the novel adhesive material is promising as a dental adhesive and may contribute to the stability of the dentin-resin bonding.
OBJECTIVE: This study aimed to evaluate the physical-chemical properties of experimental dental adhesives containing boron nitride nanotubes (BNNTs) as inorganic fillers. METHODS: An experimental adhesive resin was prepared using HEMA-BisGMA, 66/33wt% (control). Inorganic BNNT fillers were first analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and then incorporated into the adhesive at different concentration (0.05, 0.075, 0.1, 0.15wt%). Degree of conversion (DC), ultimate strength, contact angle, surface free energy (SFE) microhardness, softening in solvent and bioactivity were assessed. RESULTS: Scanning and transmission electron microscopy (SEM and TEM) showed BNNTs with diameter ranging from 5 to 10nm with close end tips. No changes in DC were observed after incorporating BNNTs up to 0.15wt%. The contact angles of water and α-bromonaphthalene increased (p<0.05) and consequently the SFE decreased after incorporating BNNTs to the polymer matrix. Microhardness and solvent degradation strength increased after incorporation of 0.075, 0.1 and 0.15wt% BNNTs. Mineral deposition was found after 7days of immersion on adhesive specimens after incorporation of BNNT. CONCLUSIONS: The incorporation of BNNTs up to 0.15wt% improved the chemical and mechanical properties of dental adhesives and promoted mineral deposition. CLINICAL SIGNIFICANCE: Incorporation of boron nitride nanotubes into adhesive resin materials improved physical-chemical properties and increased mineral deposition on its surface allowing enhanced properties of the resin-dentin interface. Thus, the novel adhesive material is promising as a dental adhesive and may contribute to the stability of the dentin-resin bonding.