Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speck...Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.展开更多
Interface debonding between prostheses and abutments was the most frequent failure mode of resin-bonded fixed partials dentures(RBFPDs) in clinic. The purpose of this study was to investigate the effect of accessory r...Interface debonding between prostheses and abutments was the most frequent failure mode of resin-bonded fixed partials dentures(RBFPDs) in clinic. The purpose of this study was to investigate the effect of accessory retention forms on the bond strength of RBFPDs. Three types of 3D finite element models were constructed.The model of posterior metal plate RBFPD with spoon-shaped occlusal rest seats served as the control. The remaining two types of models based on the control added the retention form design of the pin hole and axial groove respectively. The axial or buccolingual load of 150 N was applied on the prosthesis, first premolar and first molar respectively. The maximum principal stresses of the adhesive layer in different models were calculated. Under the load of the same magnitude, the stress due to the buccolingual load was significantly higher than that due to the axial load in the adhesive layer. The proximal shoulder, occlusal rest seats wall and the proximal margin adjacent to the shoulder were the high risk region where the adhesive layer damaged easily. Compared with the control model, the pin and groove models could slightly decrease the stress in the adhesive layer after the axial loading, while the stress in the adhesive layer drastically decreased after horizontal loading and reduced by 22% and 31% respectively. These results indicate that the horizontal occlusal force has a more serious harm to the debonding of RBFPDs. In addition, the accessory retention forms(e.g. pin and axial groove retention forms) can decrease the stress level in the adhesive layer, which are conducive to increase the load-bearing capacity of RBFPDs.展开更多
A computer-aided design model for a fixed partial denture was constructed and used in a finite element analysis to study the overall load sharing mechanism between the fixed partial denture and oral structures while t...A computer-aided design model for a fixed partial denture was constructed and used in a finite element analysis to study the overall load sharing mechanism between the fixed partial denture and oral structures while the denture base rested on the al- veolar ridge. To investigate the consequences of non-contact conditions, three additional models were generated incorporating a uniform clearance of 0.125 mm, 0.25 mm, and 0.5 mm, respectively. A 100 N static load located at the free end of the prosthesis was applied while the distal portion of the jaw was set fixed. The results show that whilst releasing the ridge almost entirely, the presence of the clearance drastically increased the load on the splinting teeth. A pull-out force on the canine tooth of about 44 N was computed, accompanied by a mesio-distal moment of about 500 N.cm. The combination of which was similar to the tooth extraction maneuver performed by the dentist. In contrast, the second premolar was found to bear a push-in force of almost 115 N. The first molar, though barely solicited in the contact condition, became substantially loaded in non-contact conditions, which validates the choice of sacrificing three teeth to support the denture.展开更多
Background Dental implant technology has developed rapidly in recent years. However, the use of implant-supported fixed bridges with cantilevers has been controversial. The purpose of this study was to evaluate the cl...Background Dental implant technology has developed rapidly in recent years. However, the use of implant-supported fixed bridges with cantilevers has been controversial. The purpose of this study was to evaluate the clinical results of the mandibular anterior implant-supported fixed bridges with a cantilever. Method Thirty-three patients （15 males, 18 females; mean age, 42.6 years; range 20-54 years） with two missing anterior mandibular teeth had single implant-supported fixed bridges with a cantilever. Clinical examination was recorded and radiographs were taken. The mean duration of follow-up was 30 months （15-44 months）. Results All implants survived. Loosening or fracture of the prosthesis was not observed. All patients were satisfied with the treatment. The mean bone resorption values after 12, 24, and 36 months of implant loading were 0.94, 1.18 and 1.35 mm respectively. The changes of gingival papilla height ranged from 0 to 0.5 mm. There was significant difference between 1-year and 2 or 3 years restoration groups regarding the average gingival height changes （P 〈0.05）. Conclusion After careful and precise selection of patients, restoration with a single implant-supported fixed bridge with a cantilever can be recommended if two anterior mandibular teeth are missing.展开更多
目的评价固定局部义齿修复在T-Scan Ⅲ数字化咬合分析系统指导下进行咬合调整的临床疗效。方法选择2018年10月至2020年9月就诊的88例单颗后牙缺失需固定局部义齿修复患者,随机分为咬合纸法组和T-Scan Ⅲ法组,每组44例。口内试戴时,分别...目的评价固定局部义齿修复在T-Scan Ⅲ数字化咬合分析系统指导下进行咬合调整的临床疗效。方法选择2018年10月至2020年9月就诊的88例单颗后牙缺失需固定局部义齿修复患者,随机分为咬合纸法组和T-Scan Ⅲ法组,每组44例。口内试戴时,分别采用传统咬合纸法和T-Scan Ⅲ指导法对修复体进行咬合调整,经抛光、粘接后完成修复,于3、12个月时复诊,采用改良的美国公共卫生署(United States Public Health Service,USPHS)评价系统和患者满意度调查表对修复效果进行评价。结果固定局部义齿修复后3个月时,咬合纸法组和T-Scan Ⅲ法组成功率分别为95.45%和97.73%;修复后12个月时,两组成功率分别为90.91%和95.45%,两个时间点两组成功率差异均无统计学意义(P均>0.05);在修复体咬合接触类型评价中,T-Scan Ⅲ法组Ⅰ类占93.18%,高于咬合纸法组(P<0.05);在对修复后咬合感受满意度调查中,两组分别有68.18%和86.36%的患者表示非常满意,后者较前者高(P<0.05)。结论T-ScanⅢ指导下咬合调整能够获得较好的临床效果,固定局部义齿修复中可以将T-ScanⅢ指导下咬合调整作为一种选择。展开更多
文摘Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.
基金National Natural Science Foundation of Chinagrant number:10902010,11120101001,and 10925208
文摘Interface debonding between prostheses and abutments was the most frequent failure mode of resin-bonded fixed partials dentures(RBFPDs) in clinic. The purpose of this study was to investigate the effect of accessory retention forms on the bond strength of RBFPDs. Three types of 3D finite element models were constructed.The model of posterior metal plate RBFPD with spoon-shaped occlusal rest seats served as the control. The remaining two types of models based on the control added the retention form design of the pin hole and axial groove respectively. The axial or buccolingual load of 150 N was applied on the prosthesis, first premolar and first molar respectively. The maximum principal stresses of the adhesive layer in different models were calculated. Under the load of the same magnitude, the stress due to the buccolingual load was significantly higher than that due to the axial load in the adhesive layer. The proximal shoulder, occlusal rest seats wall and the proximal margin adjacent to the shoulder were the high risk region where the adhesive layer damaged easily. Compared with the control model, the pin and groove models could slightly decrease the stress in the adhesive layer after the axial loading, while the stress in the adhesive layer drastically decreased after horizontal loading and reduced by 22% and 31% respectively. These results indicate that the horizontal occlusal force has a more serious harm to the debonding of RBFPDs. In addition, the accessory retention forms(e.g. pin and axial groove retention forms) can decrease the stress level in the adhesive layer, which are conducive to increase the load-bearing capacity of RBFPDs.
文摘A computer-aided design model for a fixed partial denture was constructed and used in a finite element analysis to study the overall load sharing mechanism between the fixed partial denture and oral structures while the denture base rested on the al- veolar ridge. To investigate the consequences of non-contact conditions, three additional models were generated incorporating a uniform clearance of 0.125 mm, 0.25 mm, and 0.5 mm, respectively. A 100 N static load located at the free end of the prosthesis was applied while the distal portion of the jaw was set fixed. The results show that whilst releasing the ridge almost entirely, the presence of the clearance drastically increased the load on the splinting teeth. A pull-out force on the canine tooth of about 44 N was computed, accompanied by a mesio-distal moment of about 500 N.cm. The combination of which was similar to the tooth extraction maneuver performed by the dentist. In contrast, the second premolar was found to bear a push-in force of almost 115 N. The first molar, though barely solicited in the contact condition, became substantially loaded in non-contact conditions, which validates the choice of sacrificing three teeth to support the denture.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 81100781）.
文摘Background Dental implant technology has developed rapidly in recent years. However, the use of implant-supported fixed bridges with cantilevers has been controversial. The purpose of this study was to evaluate the clinical results of the mandibular anterior implant-supported fixed bridges with a cantilever. Method Thirty-three patients （15 males, 18 females; mean age, 42.6 years; range 20-54 years） with two missing anterior mandibular teeth had single implant-supported fixed bridges with a cantilever. Clinical examination was recorded and radiographs were taken. The mean duration of follow-up was 30 months （15-44 months）. Results All implants survived. Loosening or fracture of the prosthesis was not observed. All patients were satisfied with the treatment. The mean bone resorption values after 12, 24, and 36 months of implant loading were 0.94, 1.18 and 1.35 mm respectively. The changes of gingival papilla height ranged from 0 to 0.5 mm. There was significant difference between 1-year and 2 or 3 years restoration groups regarding the average gingival height changes （P 〈0.05）. Conclusion After careful and precise selection of patients, restoration with a single implant-supported fixed bridge with a cantilever can be recommended if two anterior mandibular teeth are missing.
文摘目的评价固定局部义齿修复在T-Scan Ⅲ数字化咬合分析系统指导下进行咬合调整的临床疗效。方法选择2018年10月至2020年9月就诊的88例单颗后牙缺失需固定局部义齿修复患者,随机分为咬合纸法组和T-Scan Ⅲ法组,每组44例。口内试戴时,分别采用传统咬合纸法和T-Scan Ⅲ指导法对修复体进行咬合调整,经抛光、粘接后完成修复,于3、12个月时复诊,采用改良的美国公共卫生署(United States Public Health Service,USPHS)评价系统和患者满意度调查表对修复效果进行评价。结果固定局部义齿修复后3个月时,咬合纸法组和T-Scan Ⅲ法组成功率分别为95.45%和97.73%;修复后12个月时,两组成功率分别为90.91%和95.45%,两个时间点两组成功率差异均无统计学意义(P均>0.05);在修复体咬合接触类型评价中,T-Scan Ⅲ法组Ⅰ类占93.18%,高于咬合纸法组(P<0.05);在对修复后咬合感受满意度调查中,两组分别有68.18%和86.36%的患者表示非常满意,后者较前者高(P<0.05)。结论T-ScanⅢ指导下咬合调整能够获得较好的临床效果,固定局部义齿修复中可以将T-ScanⅢ指导下咬合调整作为一种选择。
