Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlay...Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlays, crowns, anterior and posterior fixed partial dentures (PFPDs). These restorations certainly offer the potential for better biocompatibility coupled with superior aesthetic qualities, especially when compared with the conventional prostheses made from porcelain that is fused with metal ceramic restorations. However, brittleness and extreme sensitivity of all-ceramic materials to micro-like defects or cracks that are inherently present, or may grow, in their microstructure during different laboratory fabrication steps, during necessary clinical adjustments, or from post-placement chewing activity, remain major shortcomings of these dental restorations. In fact, many researchers are of the opinion that the improved mechanical properties can significantly improve the lifetime of all-ceramic restorations and result in enhanced reliability. Therefore, efforts of researchers, as well as manufacturers, have been directed towards the improvement of the mechanical properties in order to overcome such limitations. This article reviews the characterization of the most important mechanical properties that can delineate the behavior of all-ceramic dental materials upon loading. These include fracture mechanics, the brittle nature of ceramics, the relationship between microstructural features and fracture behavior, sources of cracks and flaws that may initiate a fracture and the effect of different fabrication procedures and/or clinical adjustments on the mechanical behavior of dental ceramics are also reviewed and discussed.展开更多
目的评价3D打印白硅钙石(bredigite,BRT)骨支架材料在大鼠Onlay骨移植中的效果。方法通过3D打印技术制备骨BRT支架材料作为实验组,β⁃磷酸三钙(β⁃tricalcium phosphate,β⁃TCP)骨支架材料作为对照组,通过扫描电镜(scanning electron mi...目的评价3D打印白硅钙石(bredigite,BRT)骨支架材料在大鼠Onlay骨移植中的效果。方法通过3D打印技术制备骨BRT支架材料作为实验组,β⁃磷酸三钙(β⁃tricalcium phosphate,β⁃TCP)骨支架材料作为对照组,通过扫描电镜(scanning electron microscopy,SEM)、X射线衍射(X⁃ray diffraction,XRD)、力学测试和体外降解测试实验对其进行表征观察。建立SD大鼠颅骨Onlay骨移植的动物模型,根据移植物的不同,分为自体骨移植组(Auto组)、β⁃TCP组及BRT组。术后12周获取标本行大体观察、micro⁃CT扫描检测分析、组织学HE染色。结果SEM观察显示,BRT有规则的多孔结构,XRD衍射峰较为锐利。与β⁃TCP组(11.29±1.30)MPa相比,BRT支架材料(46.80±3.44)MPa具有更好的力学强度(P<0.001);在体外第35天时,BRT降解率为27.18%±1.41%,并且在降解过程中释放钙、镁、硅离子。micro⁃CT及组织学染色实验结果提示,Auto组有一定程度的骨吸收,β⁃TCP和BRT组均有一定新骨生成。micro⁃CT和组织学定量结果,BRT组新生骨组织占比分别为16.83%±2.11%和19.08%±2.17%,均高于β⁃TCP组(8.48%±1.85%,10.81%±1.33%)(P<0.05)。结论3D打印BRT骨支架材料促进Onlay骨移植中的骨再生。展开更多
Objective:To describe the outcome of female anterior wall(pubic side)onlay urethroplasty with buccal mucosal graft using laterally extended surgical dissection in patients with previously failed minimally invasive tec...Objective:To describe the outcome of female anterior wall(pubic side)onlay urethroplasty with buccal mucosal graft using laterally extended surgical dissection in patients with previously failed minimally invasive techniques.Methods:From January 2016 to April 2018,17 symptomatic patients with previously failed minimally invasive procedures were enrolled in the study.The diagnosis of urethral stricture was confirmed based on a combination of patients’symptoms,post-void residual urine,video-urodynamics,and cystoscopy.Urethroplasty with lower lip mucosal graft was performed using the modified laterally extended dissection.Patients were evaluated pre-operatively and 12-month post-operatively with the American Urological Association symptom score,post-void residual urine,and maximum flow rate.Results:Despite the previously failed minimally invasive procedures,urethroplasty with lower lip buccal graft and laterally extended dissection resulted in favorable outcomes(success rateZ94%).The meanstandard deviation of American urological association symptom score improved from pre-operative levels at the 12-month post-operative follow-up(25.823.97 to 10.885.57);so did postvoid residual urine(71.1274.98 mL to 15.0028.30 mL),and maximum flow rate(7.881.72 mL/s to 25.825.59 mL/s)with all statistically significant(p<0.05).Conclusion:The current study showed that female urethroplasty with buccal graft could be highly successful in experienced hands.An anterior approach could be superior to the posterior one due to higher mechanical support and lower sacculation rate.A laterally extended incision may improve visualization and better graft placement by providing wider working space.The results should be evaluated in the future studies with larger sample size.展开更多
文摘Since the last two decades, restorative dentistry has been witnessing an increased acceptance of the use of the well-known all-ceramic materials for the fabrication of single dental restorations, such as inlays, onlays, crowns, anterior and posterior fixed partial dentures (PFPDs). These restorations certainly offer the potential for better biocompatibility coupled with superior aesthetic qualities, especially when compared with the conventional prostheses made from porcelain that is fused with metal ceramic restorations. However, brittleness and extreme sensitivity of all-ceramic materials to micro-like defects or cracks that are inherently present, or may grow, in their microstructure during different laboratory fabrication steps, during necessary clinical adjustments, or from post-placement chewing activity, remain major shortcomings of these dental restorations. In fact, many researchers are of the opinion that the improved mechanical properties can significantly improve the lifetime of all-ceramic restorations and result in enhanced reliability. Therefore, efforts of researchers, as well as manufacturers, have been directed towards the improvement of the mechanical properties in order to overcome such limitations. This article reviews the characterization of the most important mechanical properties that can delineate the behavior of all-ceramic dental materials upon loading. These include fracture mechanics, the brittle nature of ceramics, the relationship between microstructural features and fracture behavior, sources of cracks and flaws that may initiate a fracture and the effect of different fabrication procedures and/or clinical adjustments on the mechanical behavior of dental ceramics are also reviewed and discussed.
文摘目的评价3D打印白硅钙石(bredigite,BRT)骨支架材料在大鼠Onlay骨移植中的效果。方法通过3D打印技术制备骨BRT支架材料作为实验组,β⁃磷酸三钙(β⁃tricalcium phosphate,β⁃TCP)骨支架材料作为对照组,通过扫描电镜(scanning electron microscopy,SEM)、X射线衍射(X⁃ray diffraction,XRD)、力学测试和体外降解测试实验对其进行表征观察。建立SD大鼠颅骨Onlay骨移植的动物模型,根据移植物的不同,分为自体骨移植组(Auto组)、β⁃TCP组及BRT组。术后12周获取标本行大体观察、micro⁃CT扫描检测分析、组织学HE染色。结果SEM观察显示,BRT有规则的多孔结构,XRD衍射峰较为锐利。与β⁃TCP组(11.29±1.30)MPa相比,BRT支架材料(46.80±3.44)MPa具有更好的力学强度(P<0.001);在体外第35天时,BRT降解率为27.18%±1.41%,并且在降解过程中释放钙、镁、硅离子。micro⁃CT及组织学染色实验结果提示,Auto组有一定程度的骨吸收,β⁃TCP和BRT组均有一定新骨生成。micro⁃CT和组织学定量结果,BRT组新生骨组织占比分别为16.83%±2.11%和19.08%±2.17%,均高于β⁃TCP组(8.48%±1.85%,10.81%±1.33%)(P<0.05)。结论3D打印BRT骨支架材料促进Onlay骨移植中的骨再生。
文摘Objective:To describe the outcome of female anterior wall(pubic side)onlay urethroplasty with buccal mucosal graft using laterally extended surgical dissection in patients with previously failed minimally invasive techniques.Methods:From January 2016 to April 2018,17 symptomatic patients with previously failed minimally invasive procedures were enrolled in the study.The diagnosis of urethral stricture was confirmed based on a combination of patients’symptoms,post-void residual urine,video-urodynamics,and cystoscopy.Urethroplasty with lower lip mucosal graft was performed using the modified laterally extended dissection.Patients were evaluated pre-operatively and 12-month post-operatively with the American Urological Association symptom score,post-void residual urine,and maximum flow rate.Results:Despite the previously failed minimally invasive procedures,urethroplasty with lower lip buccal graft and laterally extended dissection resulted in favorable outcomes(success rateZ94%).The meanstandard deviation of American urological association symptom score improved from pre-operative levels at the 12-month post-operative follow-up(25.823.97 to 10.885.57);so did postvoid residual urine(71.1274.98 mL to 15.0028.30 mL),and maximum flow rate(7.881.72 mL/s to 25.825.59 mL/s)with all statistically significant(p<0.05).Conclusion:The current study showed that female urethroplasty with buccal graft could be highly successful in experienced hands.An anterior approach could be superior to the posterior one due to higher mechanical support and lower sacculation rate.A laterally extended incision may improve visualization and better graft placement by providing wider working space.The results should be evaluated in the future studies with larger sample size.
