Bingqing Li1, Xiaoming Zhu1, Lin Ma2, Fangping Wang3, Xiaoqiang Liu1, Xu Yang1, Jianfeng Zhou4, Jianguo Tan5, David H Pashley6, Franklin R Tay7. 1. Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China. 2. Department of Stomatology, Peking Union Medical College Hospital, Beijing, PR China. 3. Department of Prosthodontics, Qingdao Stomatological Hospital, Qingdao, Shandong, PR China. 4. Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China. Electronic address: dentistzjf@163.com. 5. Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China. Electronic address: tanwume@vip.sina.com. 6. The Dental College of Georgia, Augusta University, Augusta, GA, USA. 7. The Dental College of Georgia, Augusta University, Augusta, GA, USA. Electronic address: ftay@augusta.edu.
Abstract
OBJECTIVE: The present study tested the central hypothesis that selective demineralisation of dentine extrafibrillar minerals by lowering the phosphoric acid concentration improves the quality of the resin-dentine interface. METHODS: Dentine surfaces were etched with different concentrations of phosphoric acid (1, 5, 10, 20, 30 or 40wt%). Scanning electron microscopy was used to observe the micromorphology of the etched dentine surfaces. Energy dispersive X-ray analysis was performed to determine the residual Ca-content of the demineralised dentine matrix. Atomic force microscopy-based nanoindentation was used to analyse the nanomechanical properties of the treated dentine surfaces. The influence of H3PO4 concentration on resin-dentine bond strength was evaluated by microtensile bond strength testing. One-way ANOVA was used to compare the residual Ca-content ratio, reduced elastic modulus (Er) of the treated dentine surfaces and microtensile bond strength among groups. RESULTS: Collagen fibrils appeared to be wider in diameter after etching with 5% and 10% H3PO4. The partially-demineralized collagen scaffold retained part of its rigidity to maintain an uncollapsed three-dimensional structure. Etching with 1% H3PO4 resulted in the highest residual Ca-content ratio and Er of demineralised dentine matrix, followed by 5% H3PO4. Those values were all significantly higher than values derived from the other groups. Etching with 30% H3PO4 resulted in the lowest Ca-content ratio and Er. Using 5% H3PO4 as etchant resulted in the highest resin-dentine bond strength. CONCLUSIONS: Selective demineralisation of the dentine matrix may be achieved by lowering the H3PO4 concentration to 5wt%, to achieve better bonding performance. CLINICAL RELEVANCE: By retaining intrafibrillar minerals, more through air-drying of the partially demineralised collagen matrix may be accomplished without the need to worry about collapsing a mineral-free collagen matrix during air-drying. This may result in the elimination of water-wet bonding during the application of etch-and-rinse adhesives. Published by Elsevier Ltd.
OBJECTIVE: The present study tested the central hypothesis that selective demineralisation of dentine extrafibrillar minerals by lowering the phosphoric acid concentration improves the quality of the resin-dentine interface. METHODS: Dentine surfaces were etched with different concentrations of phosphoric acid (1, 5, 10, 20, 30 or 40wt%). Scanning electron microscopy was used to observe the micromorphology of the etched dentine surfaces. Energy dispersive X-ray analysis was performed to determine the residual Ca-content of the demineralised dentine matrix. Atomic force microscopy-based nanoindentation was used to analyse the nanomechanical properties of the treated dentine surfaces. The influence of H3PO4 concentration on resin-dentine bond strength was evaluated by microtensile bond strength testing. One-way ANOVA was used to compare the residual Ca-content ratio, reduced elastic modulus (Er) of the treated dentine surfaces and microtensile bond strength among groups. RESULTS: Collagen fibrils appeared to be wider in diameter after etching with 5% and 10% H3PO4. The partially-demineralized collagen scaffold retained part of its rigidity to maintain an uncollapsed three-dimensional structure. Etching with 1% H3PO4 resulted in the highest residual Ca-content ratio and Er of demineralised dentine matrix, followed by 5% H3PO4. Those values were all significantly higher than values derived from the other groups. Etching with 30% H3PO4 resulted in the lowest Ca-content ratio and Er. Using 5% H3PO4 as etchant resulted in the highest resin-dentine bond strength. CONCLUSIONS: Selective demineralisation of the dentine matrix may be achieved by lowering the H3PO4 concentration to 5wt%, to achieve better bonding performance. CLINICAL RELEVANCE: By retaining intrafibrillar minerals, more through air-drying of the partially demineralised collagen matrix may be accomplished without the need to worry about collapsing a mineral-free collagen matrix during air-drying. This may result in the elimination of water-wet bonding during the application of etch-and-rinse adhesives. Published by Elsevier Ltd.
Authors: Lívia Tosi Trevelin; Jose Villanueva; Camila A Zamperini; Mathew T Mathew; Adriana Bona Matos; Ana K Bedran-Russo Journal: Dent Mater Date: 2019-04-08 Impact factor: 5.304
Authors: F Yu; M L Luo; R C Xu; L Huang; H H Yu; M Meng; J Q Jia; Z H Hu; W Z Wu; F R Tay; Y H Xiao; L N Niu; J H Chen Journal: Bioact Mater Date: 2021-03-23