Naji Kharouf1, Davide Mancino2, Asâd Naji-Amrani3, Ammar Eid4, Youssef Haikel2, Joseph Hemmerle3. 1. Department of Endodontics, Faculty of Dental Medicine, Strasbourg University, Strasbourg, France; INSERM UMR_S 1121, Biomaterials and Bioengineering, Strasbourg, France, Phone: +33 667522841, e-mail: dentistenajikharouf@gmail.com. 2. Department of Endodontics, Faculty of Dental Medicine, Strasbourg University, Strasbourg, France; INSERM UMR_S 1121, Biomaterials and Bioengineering, Strasbourg, France. 3. INSERM UMR_S 1121, Biomaterials and Bioengineering, Strasbourg, France. 4. Department of Endodontics, Faculty of Dental Medicine, Damascus University, Syria.
Abstract
AIM: The purpose of this study was to evaluate the microscopic and chemical effects of phosphoric acid gel, phosphoric acid liquid, and polyacrylic acid application for 15 seconds (s) on coronal dentin. MATERIALS AND METHODS: Twelve extracted teeth were selected. Three etching acids were used to prepare the dentin surfaces. Scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX) were used to analyze the chemical and morphological changes of the dentinal surfaces, including the depth of demineralization. Collected data were statistically analyzed by the one-way analysis of variance test. RESULTS: Dentin etched with phosphoric acid gel or liquid showed greater peritubular dentin dissolution, including complete removal of the smear layer. In addition, there were many silica particles on the dentin etched by phosphoric acid gel 37%. The dentin that was etched with 25% polyacrylic acid for 15 seconds showed no smear layer removal. Chemical analysis (EDX) showed that dental surfaces etched with phosphoric acid liquid 37% for 15 seconds showed the strongest mineral dissolution at the calcium surface, with a calcium content of 5.25%. On the other hand, EDX analysis of the dental surface etched with 25% polyacrylic acid showed more surface enrichment in calcium (17.19%). CONCLUSION: Although phosphoric acid (gel or liquid) 37% cleans the dental surface, phosphoric acid gel precipitates silica particles on the etched dentin surface. These particles cannot be removed by rinsing off this acid. The application of polyacrylic acid for 15 seconds does not noticeably demineralized dentin, nor remove the smear layer. CLINICAL SIGNIFICANCE: The clinician should use phosphoric acid (gel or liquid) to clean dental surfaces to prepare them for the bonding process. The low demineralizing effects of the polyacrylic acid permits its use near the pulp.
AIM: The purpose of this study was to evaluate the microscopic and chemical effects of phosphoric acid gel, phosphoric acid liquid, and polyacrylic acid application for 15 seconds (s) on coronal dentin. MATERIALS AND METHODS: Twelve extracted teeth were selected. Three etching acids were used to prepare the dentin surfaces. Scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX) were used to analyze the chemical and morphological changes of the dentinal surfaces, including the depth of demineralization. Collected data were statistically analyzed by the one-way analysis of variance test. RESULTS: Dentin etched with phosphoric acid gel or liquid showed greater peritubular dentin dissolution, including complete removal of the smear layer. In addition, there were many silica particles on the dentin etched by phosphoric acid gel 37%. The dentin that was etched with 25% polyacrylic acid for 15 seconds showed no smear layer removal. Chemical analysis (EDX) showed that dental surfaces etched with phosphoric acid liquid 37% for 15 seconds showed the strongest mineral dissolution at the calcium surface, with a calcium content of 5.25%. On the other hand, EDX analysis of the dental surface etched with 25% polyacrylic acid showed more surface enrichment in calcium (17.19%). CONCLUSION: Although phosphoric acid (gel or liquid) 37% cleans the dental surface, phosphoric acid gel precipitates silica particles on the etched dentin surface. These particles cannot be removed by rinsing off this acid. The application of polyacrylic acid for 15 seconds does not noticeably demineralized dentin, nor remove the smear layer. CLINICAL SIGNIFICANCE: The clinician should use phosphoric acid (gel or liquid) to clean dental surfaces to prepare them for the bonding process. The low demineralizing effects of the polyacrylic acid permits its use near the pulp.