human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective : Bacterial leakage and root fractures are the most important reasons of root canal treatment failure . Due to the lack of adhesion of gutta percha to the canal walls , Resilon has been introduced as a root-filling material able to bond to the root walls . Metal posts may predispose the tooth walls to oblique and vertical fracture which usually leads to tooth loss ; whereas , fiber posts may reinforce the remaining tooth structure . The purpose of this study was to compare the effect of Resilon and gutta-percha on the fracture resistance of root canal following restoring with quartz fiber posts . Material s and Methods : Forty-four maxillary incisor root canals were chemo-mechanically prepared , then r and omly divided into three groups : 1-Control group ( n=20 ) , 2-Experimental group ( n=20 ) and a negative control group ( n=4 ) . Root filled teeth were restored with quartz fiber posts and composite resin cores .  Four teeth with a conservative prepared access cavities and without any further post preparation were used as a negative control group . After simulating the clinical situation , specimens were loaded in the Universal Testing Machine for compressive strength test . All data were statistically analyzed by the T-test . Results : The mean compressive strengths for group 1 was 535.8 ± 155.23 N and 645.93 ± 182.98N for group 2 , which were statistically significant ( p-value= 0.047 ) . Conclusion : Root canals filled with Resilon were significantly more resistant than that of gutta-percha , following restoration with quartz fiber posts Background : As per many studies endodontically treated teeth are widely considered to be more susceptible to fracture than vital teeth . Obturation strains and post placement have been a major cause of vertical root fracture . Present study was conducted to compare in vitro fracture resistance after filling with either Gutta-percha or Resilon by lateral condensation techniques in root canals . This study evaluated a new thermoplastic synthetic polymer based on polyester , which contains bioactive and radiopaque filler , Resilon performs every way as Gutta-percha except that it allows the bonding agent to attach to the resin core and the dentin wall thus forming a monoblock . Material s and Methods : In the present study 90 freshly extracted single-rooted human m and ibular premolar teeth endodontically treated , were cut at the cemento-enamel junction , and were r and omly divided into three groups of 30 each as teeth of Group A ( Control ) received no obturation , Group B teeth were obturated using Gutta-percha/AH26 , and Group C teeth were obturated using Resilon/Epiphany obturating kit . Each specimen were mounted in acrylic in a polyvinyl ring and then tested for fracture resistance with the help of an universal testing machine . A compressive force was applied until the root is fractured . The data were subjected to analysis of variance for comparing mean difference of fracture resistance among three groups . Multiple comparisons among these groups were carried out by non-parametric Kruskal – Wallis analysis . A p value of < 0.0001 was considered a statistically significant difference . Results : The results obtain after analysis showed no significant differences in the fracture resistance between the two tested groups of endodontic sealers . Conclusion : Within the limitation of the present in-vitro study , Resilon/Epiphany sealer performs better than Gutta-percha/AH 26 sealer with lateral condensation technique Aim : Comparative assessment of fracture resistance of roots obturated with three hydrophilic systems — novel CPoint system , Resilon/Epiphany system , and EndoSequence BC sealer ; and one hydrophobic gold st and ard gutta-percha/AHPlus system . Material s and Methods : Ninety freshly extracted , human , single-rooted m and ibular premolars were selected . The specimens were decoronated and st and ardized to a working length of 13 mm . The teeth were r and omly divided into six groups ( n = 15 ) . In Group A , teeth were left unprepared and unfilled ( negative control ) . Rest of the groups were prepared by using ProTaper system up to a master apical file F3 ; followed by which Group B was left unobturated ( positive control ) ; Group C , novel CPoint System ; group D , Resilon/Epiphany system , Group E EndoSequence BC sealer , and Group F gutta-percha and AH Plus . Specimens were stored for 2 weeks at 100 % humidity . Each group was then subjected to fracture testing by using a universal testing machine . The force required to fracture each specimen was recorded and the data was analyzed statistically using analysis of variance ( ANOVA ) test and Tukey 's post-hoc test . Results : The hydrophilic obturation systems have shown to exhibit significantly higher fracture resistance as shown by the values in Groups C , D , and E ( P < 0.05 ) when compared with Group F. Within hydrophilic groups there was significant difference between Group D and Groups C and E ( P < 0.05 ) , while Groups C and E had no significant difference ( P > 0.05 ) . Conclusion : In contrast to hydrophobic systems , hydrophilic systems showed higher fracture resistance in a single-rooted premolar AIM The aim of this study was to compare in vitro root fracture resistance following root canal filling with either Ketac-Endo or Roth 's root canal sealer . METHODOLOGY The roots of 40 teeth with single canals were instrumented and placed r and omly into four groups of 10 teeth . The prepared canals were obturated with lateral compaction using gutta-percha and Roth 's 801 sealer , lateral compaction and Ketac-Endo sealer or with a single cone and Ketac-Endo sealer ; the fourth group acted as unfilled controls . The roots were stored for 2 weeks in 100 % humidity prior to being mounted in acrylic resin blocks . A steel tipped rod attached to an Instron testing machine was positioned against the canal opening and a slowly increasing force was applied until root fracture occurred . The results were subjected to statistical analysis using Kruskal-Wallis one-way ANOVA . RESULTS There were no significant differences between the groups in terms of force required to vertically fracture the roots . CONCLUSIONS Under the conditions of this study , the use of Ketac-Endo sealer in conjunction with lateral compaction or single-cone obturation techniques does not increase the fracture resistance of root-filled teeth The aim of this study was to compare the fracture resistance of roots filled with gutta percha ( GP ) and different root canal sealers .  Fifty-five human maxillary central incisors were selected and r and omly divided into three experimental groups ( Groups 1 - 3 ) and two control groups ( Groups 4 and 5 ) . They were Group 1 - 15 root canals filled with an epoxy resin-based sealer ( AH Plus ) and GP , Group 2 -15 root canals filled with a calcium silicate-based sealer ( iRoot SP ) and GP , Group 3 : 15 root canals filled with another calcium silicate-based sealer ( MTA Fillapex ) and GP , Group 4 : five roots were instrumented but not filled , and Group 5 : five roots were neither instrumented nor filled . Compressive loading was carried out using a universal testing machine until fracture occurred . Force applied at time of fracture was recorded as fracture strength of specimen in Newtons . There were no significant differences in fracture strength among the three experimental groups ( p>0.05 ) , whose results were significantly superior to that of Group 4 ( p<0.05 ) . In conclusion , all the root canal sealers used in the present study increased the fracture resistance of instrumented root canals Background : Reinforcement of root canals obturated with Resilon was reported by several investigators , but no studies reported the reinforcement of overtly flared root canals obturated with Resilon material . The aim of this study was to investigate the fracture resistance of overtly flared root canals filled with Resilon as compared to similar root canals filled with gutta-percha ( GP ) . Material s and Methods : Sixty single-rooted premolars were divided r and omly into six groups . Group 1 served as control group . The control group was sub-divided into two groups , a negative group and a positive group . The negative group consisted of root canals that were only cleaned from residual pulpal tissues , however , the positive group had prepared and overtly flared root canals without obturation . Groups 2 and 4 were shaped using 0.04 taper rotary files , while groups 3 and 5 were shaped using 0.06 taper rotary files . Before obturation , the last four groups were further flared coronally with a reverse cone diamond bur . Groups 2 and 3 were obturated with GP and a resin-based sealer , while groups 4 and 5 were obturated with Resilon and Epiphany self-etching primer and Epiphany sealer . Roots were then fixed into a universal testing machine and vertically loaded until fracture . SPSS software ( Release 9.0 for Windows , SPSS , Chicago , USA ) was used to perform the statistical analysis . Results : Fracture resistance measurements showed that there were differences in resistance to fracture among the experimental groups ( ANOVA , P < 0.0001 ) . Mean values of the loading force applied to the negative control group were the highest at 1.81 KN , whereas the mean values for the Resilon groups ( Groups 4 and 5 ) at 1.13 KN and 1.54 KN were found to be higher than the GP groups ( Groups 2 and 3 ) at 0.45 KN and 0.88 KN , respectively . Tukey 's post hoc test showed that there was no statistical difference between the mean values of the negative control group and Group 5 ( P = 0.69 ) . Conclusion : Obturation of overtly flared roots with Resilon material increased the resistance of these teeth to vertical root fracture OBJECTIVE The objective of this study is to evaluate the vertical root fracture resistance of endodontically treated teeth obturated with - Tubli-Seal EWT/Gutta-percha , AH Plus/Gutta-percha , Epiphany SE sealer/Epiphany point . STUDY DESIGN Sixty-five single rooted premolars were decoronated and root length was 14 mm for each specimen . Fifty five teeth were enlarged up to ISO size 40 master apical file with stainless steel K-files using st and ardized preparation and remaining ten teeth were served as negative control . Then teeth were r and omly assigned into different groups depending on sealer used for obturation as follows : Group 1 : Negative control-no instrumentation was performed . Group 2 : Positive control-gutta-percha with out the use of any sealer . Group 3 : Experimental group-gutta-percha and Tubli-Seal EWT root canal sealer . Group 4 : Experimental group-gutta-percha and AH Plus . Group 5 : Experimental group-epiphany SE sealer and epiphany points . After 72 hours , the specimens were embedded in autopolymerizing resin leaving 7 mm of each root exposed and were subjected to fracture testing under universal testing machine at a crosshead speed of 1.0 mm per minute until the root fractured . Results were statistically analyzed using one-way ANOVA and independent t-test . RESULTS Showed that Epiphany SE sealer/Epiphany points showed highest mean fracture resistance and Tubli-Seal EWT group showed the least fracture resistance of all the material s tested . There was no statistically significant difference among experimental groups . CONCLUSION Epiphany SE sealer/Epiphany points demonstrated highest fracture resistance values than the other material s tested and intact tooth had highest resistance against vertical root fracture . CLINICAL SIGNIFICANCE Epiphany SE sealer/Epiphany points may be one of the material s of choice in the endodontic treatment of teeth The aim of this study was to evaluate the influence of the embedment material and periodontal ligament simulation on fracture resistance of bovine teeth . Eighty bovine incisor teeth were r and omized into 8 groups ( n = 10 ) , embedded in acrylic or polystyrene resin using 4 types of periodontal ligament simulation : 1 - -absence of the ligament ; 2 - -polyether impression material ; 3 - -polysulfide impression material ; 4 - -polyurethane elastomeric material . The specimens were stored at 370C and 100 % humidity for 24 hours . Specimens were su bmi tted to tangential load on the palatal surface at 0.5 mm/minute crosshead speed until fracture . The fracture modes were analyzed as follows : 1 - -coronal fracture ; 2 - -cemento-enamel junction fracture ; 3 - -partial root fracture ; 4 - -total root fracture . Statistical analyses by two-way ANOVA and Tukey 's test were applied ( p < 0.05 ) . The results showed that root embedment method and periodontal ligament simulation have a significant effect on fracture resistance . Artificial periodontal ligament modified the fracture modes OBJECTIVE To investigate the role of dentinal tubules in the fracture properties of human root dentin and whether resin-filled dentinal tubules can enhance fracture resistance . MATERIAL S AND METHODS Crack propagation in human root dentin was investigated in 200 microm thick longitudinal sample s and examined by light and scanning electron microscopy . 30 maxillary premolar teeth were prepared for work of fracture ( Wf ) test at different tubule orientations , one perpendicular and two parallel to dentinal tubules . Another 40 single canal premolars were r and omly divided into four groups of 10 each : intact dentin , prepared but unobturated canal , canal obturated with epoxy rein ( AH Plus/gutta percha ) , or with UDMA resin sealer ( Resilon/RealSeal . The 
    Output:
    
agent
Although the majority of the studies reported that the use of root canal sealers increased the fracture resistance of endodontically treated teeth , conflicting evidence was found for the reinforcing effect of resin , glass ionomer , and calcium silicate-based sealers while there was moderate evidence for zinc oxide eugenol-based sealers in favor of no reinforcing effect .
Conclusion On the basis of available evidence , the use of root canal sealer increases the fracture resistance of endodontically treated teeth .
Regarding the comparisons among the sealers , no conclusions could be drawn for the superiority of one sealer type to another .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective : Bacterial leakage and root fractures are the most important reasons of root canal treatment failure . Due to the lack of adhesion of gutta percha to the canal walls , Resilon has been introduced as a root-filling material able to bond to the root walls . Metal posts may predispose the tooth walls to oblique and vertical fracture which usually leads to tooth loss ; whereas , fiber posts may reinforce the remaining tooth structure . The purpose of this study was to compare the effect of Resilon and gutta-percha on the fracture resistance of root canal following restoring with quartz fiber posts . Material s and Methods : Forty-four maxillary incisor root canals were chemo-mechanically prepared , then r and omly divided into three groups : 1-Control group ( n=20 ) , 2-Experimental group ( n=20 ) and a negative control group ( n=4 ) . Root filled teeth were restored with quartz fiber posts and composite resin cores .  Four teeth with a conservative prepared access cavities and without any further post preparation were used as a negative control group . After simulating the clinical situation , specimens were loaded in the Universal Testing Machine for compressive strength test . All data were statistically analyzed by the T-test . Results : The mean compressive strengths for group 1 was 535.8 ± 155.23 N and 645.93 ± 182.98N for group 2 , which were statistically significant ( p-value= 0.047 ) . Conclusion : Root canals filled with Resilon were significantly more resistant than that of gutta-percha , following restoration with quartz fiber posts Background : As per many studies endodontically treated teeth are widely considered to be more susceptible to fracture than vital teeth . Obturation strains and post placement have been a major cause of vertical root fracture . Present study was conducted to compare in vitro fracture resistance after filling with either Gutta-percha or Resilon by lateral condensation techniques in root canals . This study evaluated a new thermoplastic synthetic polymer based on polyester , which contains bioactive and radiopaque filler , Resilon performs every way as Gutta-percha except that it allows the bonding agent to attach to the resin core and the dentin wall thus forming a monoblock . Material s and Methods : In the present study 90 freshly extracted single-rooted human m and ibular premolar teeth endodontically treated , were cut at the cemento-enamel junction , and were r and omly divided into three groups of 30 each as teeth of Group A ( Control ) received no obturation , Group B teeth were obturated using Gutta-percha/AH26 , and Group C teeth were obturated using Resilon/Epiphany obturating kit . Each specimen were mounted in acrylic in a polyvinyl ring and then tested for fracture resistance with the help of an universal testing machine . A compressive force was applied until the root is fractured . The data were subjected to analysis of variance for comparing mean difference of fracture resistance among three groups . Multiple comparisons among these groups were carried out by non-parametric Kruskal – Wallis analysis . A p value of < 0.0001 was considered a statistically significant difference . Results : The results obtain after analysis showed no significant differences in the fracture resistance between the two tested groups of endodontic sealers . Conclusion : Within the limitation of the present in-vitro study , Resilon/Epiphany sealer performs better than Gutta-percha/AH 26 sealer with lateral condensation technique Aim : Comparative assessment of fracture resistance of roots obturated with three hydrophilic systems — novel CPoint system , Resilon/Epiphany system , and EndoSequence BC sealer ; and one hydrophobic gold st and ard gutta-percha/AHPlus system . Material s and Methods : Ninety freshly extracted , human , single-rooted m and ibular premolars were selected . The specimens were decoronated and st and ardized to a working length of 13 mm . The teeth were r and omly divided into six groups ( n = 15 ) . In Group A , teeth were left unprepared and unfilled ( negative control ) . Rest of the groups were prepared by using ProTaper system up to a master apical file F3 ; followed by which Group B was left unobturated ( positive control ) ; Group C , novel CPoint System ; group D , Resilon/Epiphany system , Group E EndoSequence BC sealer , and Group F gutta-percha and AH Plus . Specimens were stored for 2 weeks at 100 % humidity . Each group was then subjected to fracture testing by using a universal testing machine . The force required to fracture each specimen was recorded and the data was analyzed statistically using analysis of variance ( ANOVA ) test and Tukey 's post-hoc test . Results : The hydrophilic obturation systems have shown to exhibit significantly higher fracture resistance as shown by the values in Groups C , D , and E ( P < 0.05 ) when compared with Group F. Within hydrophilic groups there was significant difference between Group D and Groups C and E ( P < 0.05 ) , while Groups C and E had no significant difference ( P > 0.05 ) . Conclusion : In contrast to hydrophobic systems , hydrophilic systems showed higher fracture resistance in a single-rooted premolar AIM The aim of this study was to compare in vitro root fracture resistance following root canal filling with either Ketac-Endo or Roth 's root canal sealer . METHODOLOGY The roots of 40 teeth with single canals were instrumented and placed r and omly into four groups of 10 teeth . The prepared canals were obturated with lateral compaction using gutta-percha and Roth 's 801 sealer , lateral compaction and Ketac-Endo sealer or with a single cone and Ketac-Endo sealer ; the fourth group acted as unfilled controls . The roots were stored for 2 weeks in 100 % humidity prior to being mounted in acrylic resin blocks . A steel tipped rod attached to an Instron testing machine was positioned against the canal opening and a slowly increasing force was applied until root fracture occurred . The results were subjected to statistical analysis using Kruskal-Wallis one-way ANOVA . RESULTS There were no significant differences between the groups in terms of force required to vertically fracture the roots . CONCLUSIONS Under the conditions of this study , the use of Ketac-Endo sealer in conjunction with lateral compaction or single-cone obturation techniques does not increase the fracture resistance of root-filled teeth The aim of this study was to compare the fracture resistance of roots filled with gutta percha ( GP ) and different root canal sealers .  Fifty-five human maxillary central incisors were selected and r and omly divided into three experimental groups ( Groups 1 - 3 ) and two control groups ( Groups 4 and 5 ) . They were Group 1 - 15 root canals filled with an epoxy resin-based sealer ( AH Plus ) and GP , Group 2 -15 root canals filled with a calcium silicate-based sealer ( iRoot SP ) and GP , Group 3 : 15 root canals filled with another calcium silicate-based sealer ( MTA Fillapex ) and GP , Group 4 : five roots were instrumented but not filled , and Group 5 : five roots were neither instrumented nor filled . Compressive loading was carried out using a universal testing machine until fracture occurred . Force applied at time of fracture was recorded as fracture strength of specimen in Newtons . There were no significant differences in fracture strength among the three experimental groups ( p>0.05 ) , whose results were significantly superior to that of Group 4 ( p<0.05 ) . In conclusion , all the root canal sealers used in the present study increased the fracture resistance of instrumented root canals Background : Reinforcement of root canals obturated with Resilon was reported by several investigators , but no studies reported the reinforcement of overtly flared root canals obturated with Resilon material . The aim of this study was to investigate the fracture resistance of overtly flared root canals filled with Resilon as compared to similar root canals filled with gutta-percha ( GP ) . Material s and Methods : Sixty single-rooted premolars were divided r and omly into six groups . Group 1 served as control group . The control group was sub-divided into two groups , a negative group and a positive group . The negative group consisted of root canals that were only cleaned from residual pulpal tissues , however , the positive group had prepared and overtly flared root canals without obturation . Groups 2 and 4 were shaped using 0.04 taper rotary files , while groups 3 and 5 were shaped using 0.06 taper rotary files . Before obturation , the last four groups were further flared coronally with a reverse cone diamond bur . Groups 2 and 3 were obturated with GP and a resin-based sealer , while groups 4 and 5 were obturated with Resilon and Epiphany self-etching primer and Epiphany sealer . Roots were then fixed into a universal testing machine and vertically loaded until fracture . SPSS software ( Release 9.0 for Windows , SPSS , Chicago , USA ) was used to perform the statistical analysis . Results : Fracture resistance measurements showed that there were differences in resistance to fracture among the experimental groups ( ANOVA , P < 0.0001 ) . Mean values of the loading force applied to the negative control group were the highest at 1.81 KN , whereas the mean values for the Resilon groups ( Groups 4 and 5 ) at 1.13 KN and 1.54 KN were found to be higher than the GP groups ( Groups 2 and 3 ) at 0.45 KN and 0.88 KN , respectively . Tukey 's post hoc test showed that there was no statistical difference between the mean values of the negative control group and Group 5 ( P = 0.69 ) . Conclusion : Obturation of overtly flared roots with Resilon material increased the resistance of these teeth to vertical root fracture OBJECTIVE The objective of this study is to evaluate the vertical root fracture resistance of endodontically treated teeth obturated with - Tubli-Seal EWT/Gutta-percha , AH Plus/Gutta-percha , Epiphany SE sealer/Epiphany point . STUDY DESIGN Sixty-five single rooted premolars were decoronated and root length was 14 mm for each specimen . Fifty five teeth were enlarged up to ISO size 40 master apical file with stainless steel K-files using st and ardized preparation and remaining ten teeth were served as negative control . Then teeth were r and omly assigned into different groups depending on sealer used for obturation as follows : Group 1 : Negative control-no instrumentation was performed . Group 2 : Positive control-gutta-percha with out the use of any sealer . Group 3 : Experimental group-gutta-percha and Tubli-Seal EWT root canal sealer . Group 4 : Experimental group-gutta-percha and AH Plus . Group 5 : Experimental group-epiphany SE sealer and epiphany points . After 72 hours , the specimens were embedded in autopolymerizing resin leaving 7 mm of each root exposed and were subjected to fracture testing under universal testing machine at a crosshead speed of 1.0 mm per minute until the root fractured . Results were statistically analyzed using one-way ANOVA and independent t-test . RESULTS Showed that Epiphany SE sealer/Epiphany points showed highest mean fracture resistance and Tubli-Seal EWT group showed the least fracture resistance of all the material s tested . There was no statistically significant difference among experimental groups . CONCLUSION Epiphany SE sealer/Epiphany points demonstrated highest fracture resistance values than the other material s tested and intact tooth had highest resistance against vertical root fracture . CLINICAL SIGNIFICANCE Epiphany SE sealer/Epiphany points may be one of the material s of choice in the endodontic treatment of teeth The aim of this study was to evaluate the influence of the embedment material and periodontal ligament simulation on fracture resistance of bovine teeth . Eighty bovine incisor teeth were r and omized into 8 groups ( n = 10 ) , embedded in acrylic or polystyrene resin using 4 types of periodontal ligament simulation : 1 - -absence of the ligament ; 2 - -polyether impression material ; 3 - -polysulfide impression material ; 4 - -polyurethane elastomeric material . The specimens were stored at 370C and 100 % humidity for 24 hours . Specimens were su bmi tted to tangential load on the palatal surface at 0.5 mm/minute crosshead speed until fracture . The fracture modes were analyzed as follows : 1 - -coronal fracture ; 2 - -cemento-enamel junction fracture ; 3 - -partial root fracture ; 4 - -total root fracture . Statistical analyses by two-way ANOVA and Tukey 's test were applied ( p < 0.05 ) . The results showed that root embedment method and periodontal ligament simulation have a significant effect on fracture resistance . Artificial periodontal ligament modified the fracture modes OBJECTIVE To investigate the role of dentinal tubules in the fracture properties of human root dentin and whether resin-filled dentinal tubules can enhance fracture resistance . MATERIAL S AND METHODS Crack propagation in human root dentin was investigated in 200 microm thick longitudinal sample s and examined by light and scanning electron microscopy . 30 maxillary premolar teeth were prepared for work of fracture ( Wf ) test at different tubule orientations , one perpendicular and two parallel to dentinal tubules . Another 40 single canal premolars were r and omly divided into four groups of 10 each : intact dentin , prepared but unobturated canal , canal obturated with epoxy rein ( AH Plus/gutta percha ) , or with UDMA resin sealer ( Resilon/RealSeal . The 
    Output:
    