Victor P Feitosa1, César Pomacóndor-Hernández2, Fabrício A Ogliari3, Fernanda Leal4, Américo B Correr5, Salvatore Sauro6. 1. Division of Dental Materials, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. Electronic address: victorpfeitosa@hotmail.com. 2. Division of Dental Materials, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. Electronic address: cesar.pomacondor.hernandez@gmail.com. 3. Materials Engineering School, Federal University of Pelotas, Pelotas, Brazil. Electronic address: ogliari@gmail.com. 4. Materials Engineering School, Federal University of Pelotas, Pelotas, Brazil. Electronic address: fernandableal@gmail.com. 5. Division of Dental Materials, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. 6. Dental Biomaterials Departamento de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, Valencia, Spain. Electronic address: salvatore.sauro@uch.ceu.es.
Abstract
OBJECTIVES: Zinc-doped dentine adhesives have been recently advocated to interfere with metallo-proteinases-mediated collagen degradation. Nevertheless, there is a little information about the effects of zinc ions on the chemical interaction of self-etch functional monomers to dentine. The aim of this study was to assess if the inclusion of zinc into the primers of self-etch adhesives containing MDP (10-methacryloyloxi-decyl-dihydrogen-phosphate) may interfere with their chemical interaction to calcium/dentine. METHODS: Caries-free human molars were bonded using two commercial self-etching adhesives [Clearfil SE bond (CSE) and S3 bond (S3)] doped with zinc nitrate and submitted to microtensile bond strength (μTBS) and interface nanoleakage evaluation. Moreover, MDP was synthesised to evaluate the chemical interaction with calcium/dentine through atomic absorption spectroscopy (AAS) and SEM-EDX in the presence or absence of zinc ions. RESULTS: AAS showed increasing formation of MDP-zinc rather than MDP-calcium salts (p=0.002) in the presence of zinc. SEM-EDX confirmed the formation of zinc-rich phosphate deposits that were probably responsible for the significant reduction in μTBS and increased interfacial nanoleakage attained with zinc-doped CSE and S3. CONCLUSION: These outcomes demonstrated that the excessive presence of zinc ions may jeopardise the bonding performance of MDP-containing self-etch adhesives.
OBJECTIVES: Zinc-doped dentine adhesives have been recently advocated to interfere with metallo-proteinases-mediated collagen degradation. Nevertheless, there is a little information about the effects of zinc ions on the chemical interaction of self-etch functional monomers to dentine. The aim of this study was to assess if the inclusion of zinc into the primers of self-etch adhesives containing MDP (10-methacryloyloxi-decyl-dihydrogen-phosphate) may interfere with their chemical interaction to calcium/dentine. METHODS: Caries-free human molars were bonded using two commercial self-etching adhesives [Clearfil SE bond (CSE) and S3 bond (S3)] doped with zinc nitrate and submitted to microtensile bond strength (μTBS) and interface nanoleakage evaluation. Moreover, MDP was synthesised to evaluate the chemical interaction with calcium/dentine through atomic absorption spectroscopy (AAS) and SEM-EDX in the presence or absence of zinc ions. RESULTS: AAS showed increasing formation of MDP-zinc rather than MDP-calcium salts (p=0.002) in the presence of zinc. SEM-EDX confirmed the formation of zinc-rich phosphate deposits that were probably responsible for the significant reduction in μTBS and increased interfacial nanoleakage attained with zinc-doped CSE and S3. CONCLUSION: These outcomes demonstrated that the excessive presence of zinc ions may jeopardise the bonding performance of MDP-containing self-etch adhesives.