This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-roote...This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.展开更多
The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the roo...The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.展开更多
Purpose: This study was aimed to evaluate the effect of restorative materials and glass fiber post on the fracture resistance of endodontically treated premolars. Material and Methods: Fifty extracted single rooted lo...Purpose: This study was aimed to evaluate the effect of restorative materials and glass fiber post on the fracture resistance of endodontically treated premolars. Material and Methods: Fifty extracted single rooted lower premolars were used in this in vitro study and divided into 5 groups: sound teeth (control group);mesial-occlusal-distal (MOD) preparation + endodontic treatment + composite restoration;MOD preparation + endodontic treatment + glass fiber post + composite restoration;MOD preparation + endodontic treatment + amalgam restoration;MOD preparation + endodontic treatment + glass fiber post + amalgam restoration. The specimens were loaded on a universal testing machine at the crosshead speed of1 mm/min until fracture. The data were analyzed using two-way ANOVA test. Results: The mean loads at fracture were 860.11 N, 801.79 N, 761.39 N, 737.14 N and 707.85 N respectively. There were no statistically significant differences (P > 0.05) in the fracture resistance of teeth restored with composite and amalgam, as well as restored with or without glass fiber post. Conclusions: The type of restorative material and the usage of glass fiber post do not have visible influence on the fracture resistance of the endodontically treated mandibular premolars.展开更多
文摘This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading.Fifty extracted single-rooted mandibular premolars were randomized into five groups.Each group was prepared according to numbers of residual walls ranged from 0 to 4.Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts.In no-post groups,gutta percha point 2 mm below cemento-enamel junction was removed.Composite resin was adapted to the well and used to shape the core directly.Each tooth was restored with a complete metal crown.Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles.Then a quasi-statically load was applied in a universal testing machine 306 to the long axis with a crosshead speed of 1 mm？min21until fracture.Data were analyzed with one-way analysis of variance and pairwise comparison（P,0.05）.No specimens failed during dynamic loading.The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant（P,0.05）.Placement of fiber posts had a significant effect when fewer than two walls remained（P,0.05）,but it had no significant influence in groups with two,three or four walls（P.0.05）.Fiber post did not change failure mode,and the fracture pattern was mainly favorable.More dentin walls need to be retained in clinic.When no less than two walls remained,a fiber post is not always necessary.
基金supported by a grant from a program of research and development of Hubei Province (No. 2008-BCC 001)
文摘The aim of this study is to investigate the influence of different posts on the fracture mechanics of endodontically-treated teeth with open apex. Forty-eight human maxillary anterior teeth were collected, and the root was transversely sectioned 12 mm under the cementoenamal junction （CEJ）. These samples were then randomly divided into two groups, i.e., minor diameter open apex root （group A） and major diameter open apex root （group B）, with mineral trioxide aggregate （MTA） placed into the apical 4 mm in the root canals. Subsequently, both groups were respectively further divided into three subgroups as follows： fiber-post （subgroup 1）, metal post （subgroup 2） and non-post （subgroup 3） group. Teeth were restored with a composite resin crown and tested by using a universal testing machine at the rate of 1 mm/min cross-head. Values of the maximum fracture resistance and failure patterns were recorded and compared among all subgroups. In addition, the changes of MTA properties were carefully examined via X-ray photography. Our results indicate that （1） In group A, the mean value of fracture resistance for teeth restored with fiber posts were statistically higher than that with either metal post or non-post; （2） In group B, there was no statistically significant difference in the mean value of fracture resistance among three subgroups; （3） No statistical significance in the mean value of fracture resistance was found between group A and group B; （4） The failure modes of most samples （58%） were irreparable; （5） MTA in two teeth developed cracks after loading tests. In conclusion, endodontically-treated teeth restored with fiber posts are more resistant to fracture than those restored with either metal posts or non-post, and most of the fracture modes are catastrophic in nature.
文摘Purpose: This study was aimed to evaluate the effect of restorative materials and glass fiber post on the fracture resistance of endodontically treated premolars. Material and Methods: Fifty extracted single rooted lower premolars were used in this in vitro study and divided into 5 groups: sound teeth (control group);mesial-occlusal-distal (MOD) preparation + endodontic treatment + composite restoration;MOD preparation + endodontic treatment + glass fiber post + composite restoration;MOD preparation + endodontic treatment + amalgam restoration;MOD preparation + endodontic treatment + glass fiber post + amalgam restoration. The specimens were loaded on a universal testing machine at the crosshead speed of1 mm/min until fracture. The data were analyzed using two-way ANOVA test. Results: The mean loads at fracture were 860.11 N, 801.79 N, 761.39 N, 737.14 N and 707.85 N respectively. There were no statistically significant differences (P > 0.05) in the fracture resistance of teeth restored with composite and amalgam, as well as restored with or without glass fiber post. Conclusions: The type of restorative material and the usage of glass fiber post do not have visible influence on the fracture resistance of the endodontically treated mandibular premolars.
