Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramic...Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material(amalgam) with an equal material(resin composite) being more esthetic but also biologically questionable? For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of nonbiocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.展开更多
After teeth are replanted,there are two possible healing responses：periodontal ligament healing or ankylosis with subsequent replacement resorption.The purpose of this study was to compare the fatigue resistance of v...After teeth are replanted,there are two possible healing responses：periodontal ligament healing or ankylosis with subsequent replacement resorption.The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes.Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C＆B.They were then randomly distributed into four groups（BP,CP,CA,BA）.The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis.All teeth had root canal treatment performed.Metal crowns were constructed for the CP and CA groups.The BP and BA groups only had composite resin restorations in the access cavities.All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2 x 106 cycles had been reached if no fracture occurred.Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests.Finally,interfaces of the resin luting agent were examined by scanning electron microscope.The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing.Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.展开更多
The current study aims to investigate a suitable adhesive for primary tooth enamel. Shear bond strength(SBS)of primary teeth and the length of resin protrusion were analyzed using one-way ANOVA with Bonferroni multipl...The current study aims to investigate a suitable adhesive for primary tooth enamel. Shear bond strength(SBS)of primary teeth and the length of resin protrusion were analyzed using one-way ANOVA with Bonferroni multiple comparison tests after etching with 35% H_(3)PO_(4). SBS and marginal microleakage tests were conducted with Single Bond Universal(SBU)/Single Bond 2(SB2) adhesives with or without pre-etching using a nonparametric Kruskal-Wallis test. Clinical investigations were performed to validate the adhesive for primary teeth restoration using Chi-square tests. Results showed that the SBS and length of resin protrusion increased significantly with the etching time. Teeth in the SBU with 35% H_(3)PO_(4)pre-etching groups had higher bond strength and lower marginal microleakage than those in the SB2 groups. Mixed fractures were more common in the 35% H_(3)PO_(4)etched 30 s + SB2/SBU groups. Clinical investigations showed significant differences between the two groups in cumulative retention rates at the 6-, 12-and 18-month follow-up evaluations, as well as in marginal adaptation, discoloration, and secondary caries at the 12-and 18-month follow-up assessments.Together, pre-etching primary teeth enamel for 30 s before SBU treatment improved clinical composite resin restoration, which can provide a suitable approach for restoration of primary teeth.展开更多
目的:测试自粘接树脂水门汀对修复用非贵金属和贵金属材料剪切粘接强度的影响。方法:用5种修复临床常用的金属材料(镍铬合金,钛合金,TypeⅢ金合金,金银钯合金,金属烤瓷金合金)铸造统一标准试件。将试件用6种自粘接树脂水门汀Maxcem(MA),...目的:测试自粘接树脂水门汀对修复用非贵金属和贵金属材料剪切粘接强度的影响。方法:用5种修复临床常用的金属材料(镍铬合金,钛合金,TypeⅢ金合金,金银钯合金,金属烤瓷金合金)铸造统一标准试件。将试件用6种自粘接树脂水门汀Maxcem(MA),Unicem(UN),Breeze(BR),Biscem(BI),Set(SE),Clearfil SA luting(CL)及1种传统树脂水门汀Resicem(RE)粘接。用万能材料试验机测试粘接强度。结果:各种金属的剪切粘接强度平均值为镍铬合金(9.9±7.8)MPa,钛合金(10.2±5.4)MPa,TypeⅢ金合金(2.6±1.9)MPa,金银钯合金(2.2±1.7)MPa,金属烤瓷金合金(5.0±2.3)MPa。BR、BI、CL在钛和镍铬合金组产生的剪切粘接强度高于其他水门汀(P<0.05),也高于其他3种金属材料组(P<0.05)。结论:自粘接树脂水门汀BR、BI、CL对非贵金属的粘接强度高于其他组别树脂水门汀。展开更多
文摘Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material(amalgam) with an equal material(resin composite) being more esthetic but also biologically questionable? For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of nonbiocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.
基金supported by the Jiangsu Province's Outstanding Medical Academic Leader Program(No.LJ201110)the National Natural Scientific Foundation of China(81070839)Key Project supported by Medical Science and Technology Development Foundation,Nanjing Department of Health(ZKX10030)
文摘After teeth are replanted,there are two possible healing responses：periodontal ligament healing or ankylosis with subsequent replacement resorption.The purpose of this study was to compare the fatigue resistance of vertically fractured teeth after bonding the fragments under conditions simulating both healing modes.Thirty-two human premolars were vertically fractured and the fragments were bonded together with Super-Bond C＆B.They were then randomly distributed into four groups（BP,CP,CA,BA）.The BP and CP groups were used to investigate the periodontal ligament healing mode whilst the BA and CA groups simulated ankylosis.All teeth had root canal treatment performed.Metal crowns were constructed for the CP and CA groups.The BP and BA groups only had composite resin restorations in the access cavities.All specimens were subjected to a 260 N load at 4 Hz until failure of the bond or until 2 x 106 cycles had been reached if no fracture occurred.Cracks were detected by stereomicroscope imaging and also assessed via dye penetration tests.Finally,interfaces of the resin luting agent were examined by scanning electron microscope.The results confirmed that the fatigue resistance was higher in the groups with simulated periodontal ligament healing.Periodontal reattachment showed important biomechanical role in bonded and replanted vertically fractured teeth.
基金supported by the Technology Development Fund of Nanjing Medical University(Grants No.NMUB2016115 and NMUB2020117)。
文摘The current study aims to investigate a suitable adhesive for primary tooth enamel. Shear bond strength(SBS)of primary teeth and the length of resin protrusion were analyzed using one-way ANOVA with Bonferroni multiple comparison tests after etching with 35% H_(3)PO_(4). SBS and marginal microleakage tests were conducted with Single Bond Universal(SBU)/Single Bond 2(SB2) adhesives with or without pre-etching using a nonparametric Kruskal-Wallis test. Clinical investigations were performed to validate the adhesive for primary teeth restoration using Chi-square tests. Results showed that the SBS and length of resin protrusion increased significantly with the etching time. Teeth in the SBU with 35% H_(3)PO_(4)pre-etching groups had higher bond strength and lower marginal microleakage than those in the SB2 groups. Mixed fractures were more common in the 35% H_(3)PO_(4)etched 30 s + SB2/SBU groups. Clinical investigations showed significant differences between the two groups in cumulative retention rates at the 6-, 12-and 18-month follow-up evaluations, as well as in marginal adaptation, discoloration, and secondary caries at the 12-and 18-month follow-up assessments.Together, pre-etching primary teeth enamel for 30 s before SBU treatment improved clinical composite resin restoration, which can provide a suitable approach for restoration of primary teeth.
文摘目的:测试自粘接树脂水门汀对修复用非贵金属和贵金属材料剪切粘接强度的影响。方法:用5种修复临床常用的金属材料(镍铬合金,钛合金,TypeⅢ金合金,金银钯合金,金属烤瓷金合金)铸造统一标准试件。将试件用6种自粘接树脂水门汀Maxcem(MA),Unicem(UN),Breeze(BR),Biscem(BI),Set(SE),Clearfil SA luting(CL)及1种传统树脂水门汀Resicem(RE)粘接。用万能材料试验机测试粘接强度。结果:各种金属的剪切粘接强度平均值为镍铬合金(9.9±7.8)MPa,钛合金(10.2±5.4)MPa,TypeⅢ金合金(2.6±1.9)MPa,金银钯合金(2.2±1.7)MPa,金属烤瓷金合金(5.0±2.3)MPa。BR、BI、CL在钛和镍铬合金组产生的剪切粘接强度高于其他水门汀(P<0.05),也高于其他3种金属材料组(P<0.05)。结论:自粘接树脂水门汀BR、BI、CL对非贵金属的粘接强度高于其他组别树脂水门汀。
