Maicon Sebold1, Marcelo Giannini2, Carolina Bosso André3, Beatriz Ometto Sahadi4, Tatjana Maravic5, Uros Josic6, Annalisa Mazzoni7, Lorenzo Breschi8. 1. Department of Restorative Dentistry, Operative Dentistry Division, University of Campinas, Piracicaba Dental School, Avenida Limeira 901, Areião, 13414-903 Piracicaba, SP, Brazil. Electronic address: maiconsebold92@gmail.com. 2. Department of Restorative Dentistry, Operative Dentistry Division, University of Campinas, Piracicaba Dental School, Avenida Limeira 901, Areião, 13414-903 Piracicaba, SP, Brazil. Electronic address: gianinni@unicamp.br. 3. Department of Restorative Dentistry, Operative Dentistry Division, Federal University of Minas Gerais, School of Dentistry, Avenida Presidente Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil. Electronic address: carolina.bosso@gmail.com. 4. Department of Restorative Dentistry, Operative Dentistry Division, University of Campinas, Piracicaba Dental School, Avenida Limeira 901, Areião, 13414-903 Piracicaba, SP, Brazil. Electronic address: bia_sahadi@live.com. 5. Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, BO, Italy. Electronic address: tatjana.maravic2@unibo.it. 6. Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, BO, Italy. Electronic address: uros.josic2@unibo.it. 7. Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, BO, Italy. Electronic address: annalisa.mazzoni@unibo.it. 8. Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, BO, Italy. Electronic address: lorenzo.breschi@unibo.it.
Abstract
OBJECTIVES: Etching approaches [37% phosphoric acid, self-etching, 10-3 solution (3% ferric chloride dissolved in 10% citric acid), or 1.4% nitric acid] were evaluated regarding enamel shear bond strength (24 h), dentin microtensile bond strength (24 h and 2 years), failure mode, enzymatic activity of the hybrid layer, and nanoleakage (24 h and 2 years) of Prime&Bond Universal (PBU, Dentsply-Sirona) and Gluma Bond Universal (GBU, Kulzer). METHODS: Adhesives were applied on blot-dried (wet-bonding, positive control) or air-dried (remaining groups) dentin after acid-etching (15 s) or in self-etch mode. Enamel and dentin bond strength tests used 160 human teeth (n = 10). Failure mode of tested samples and nanoleakage within the dentin-adhesive interface (n = 5) were analyzed by scanning electron microscopy. Dentin enzymatic activity was investigated by in situ zymography (n = 3). RESULTS: Enamel bond strengths did not differ statistically among groups. Wet-bonding with 37% phosphoric acid showed similar dentin bond strength compared to 10-3 solution or 1.4% nitric acid at 24 h for both adhesives. None of the etchants inhibited enzymatic activity, and all groups showed dentin bond strength reduction after 2-year storage. GBU showed higher nanoleakage. Experimental etchants did not affect enamel bond strength. Dentin bond strength was not stable after 2 years, despite promising 24-hour results. SIGNIFICANCE: This study suggests multiple etching approaches to optimize and achieve stable dentin bonding, while also offering in-depth information about the performance of recently released universal adhesive systems.
OBJECTIVES: Etching approaches [37% phosphoric acid, self-etching, 10-3 solution (3% ferric chloride dissolved in 10% citric acid), or 1.4% nitric acid] were evaluated regarding enamel shear bond strength (24 h), dentin microtensile bond strength (24 h and 2 years), failure mode, enzymatic activity of the hybrid layer, and nanoleakage (24 h and 2 years) of Prime&Bond Universal (PBU, Dentsply-Sirona) and Gluma Bond Universal (GBU, Kulzer). METHODS: Adhesives were applied on blot-dried (wet-bonding, positive control) or air-dried (remaining groups) dentin after acid-etching (15 s) or in self-etch mode. Enamel and dentin bond strength tests used 160 human teeth (n = 10). Failure mode of tested samples and nanoleakage within the dentin-adhesive interface (n = 5) were analyzed by scanning electron microscopy. Dentin enzymatic activity was investigated by in situ zymography (n = 3). RESULTS: Enamel bond strengths did not differ statistically among groups. Wet-bonding with 37% phosphoric acid showed similar dentin bond strength compared to 10-3 solution or 1.4% nitric acid at 24 h for both adhesives. None of the etchants inhibited enzymatic activity, and all groups showed dentin bond strength reduction after 2-year storage. GBU showed higher nanoleakage. Experimental etchants did not affect enamel bond strength. Dentin bond strength was not stable after 2 years, despite promising 24-hour results. SIGNIFICANCE: This study suggests multiple etching approaches to optimize and achieve stable dentin bonding, while also offering in-depth information about the performance of recently released universal adhesive systems.