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: This study reports a prospect i ve clinical trial comparing a carbon fibre reinforced carbon ( CFRC ) endodontic post with a conventional prefabricated post .  Twenty-seven single rooted maxillary anterior teeth in 18 patients ( nine males and nine females ; age range 18 - 60 years ) were restored either with a CFRC post or a wrought precious alloy control . Cast type III gold alloy cores were used in conjunction with both post groups . The CRFC posts ( n = 16 ) were cemented with a composite luting agent and the conventional posts ( control ) were cemented with zinc phosphate . Four failures were recorded in the CFRC post group at 24 , 29 , 56 and 87 months , compared with one failure in the control group at 84 months . These results suggest that post-retained crowns utilizing a CFRC material and a composite resin luting agent do not perform as well as conventional wrought precious alloy posts Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more OBJECTIVES This retrospective study investigated the clinical effectiveness over up to 8 years of parallel-sided and of tapered glass-fiber posts , in combination with either hybrid composite or dual-cure composite resin core material , in endodontically treated , maxillary anterior teeth covered with full-ceramic crowns . METHODS The study population comprised 192 patients and 526 endodontically treated teeth , with various degrees of hard-tissue loss , restored by the post- and -core technique .  Four groups were defined based on post shape and core build-up material s , and within each group post- and -core restorations were assigned r and omly with respect to root morphology . Inclusion criteria were symptom-free endodontic therapy , root-canal treatment with a minimum apical seal of 4 mm , application of rubber dam , need for post- and -core complex because of coronal tooth loss , and tooth with at least one residual coronal wall . Survival rate of the post- and -core restorations was determined using Kaplan-Meier statistical analysis . RESULTS The restorations were examined clinical ly and radiologically ; mean observation period was 5.3 years . The overall survival rate of glass-fiber post- and -core restorations was 98.5 % . The survival rate for parallel-sided posts was 98.6 % and for tapered posts was 96.8 % . Survival rates for core build-up material s were 100 % for dual-cure composite and 96.8 % for hybrid light-cure composite . CONCLUSIONS For both glass-fiber post design s and for both core build-up material s , clinical performance was satisfactory . Survival was higher for teeth retaining four and three coronal walls PURPOSE In the present prospect i ve study , four different post- and -core systems were evaluated over a period of up to 10 years . MATERIAL S AND METHODS Fifty endodontically treated teeth in 31 patients were r and omized to one of four groups for post- and -core placement : Group 1 received conventional tapered cast posts and cores ( n = 14 ) ; group 2 received ParaPost system prefabricated gold posts with cast cores ( n = 13 ) ; group 3 received ParaPost system cast posts and cores ( n = 13 ) ; and group 4 received Radix-Anchor posts ( n = 10 ) . Clinical and radiologic evaluations were made . RESULTS One post and core in group 2 was functioning well 58 months after placement when the patient died . No posts and cores in groups 1 or 2 had been lost or had any complications , one in group 3 had been lost because of a root fracture after 108 months , and two in group 4 had been lost after 54 and 88 months , respectively , because of loss of retention . The final treatment result for 46 of the 49 remaining posts ( 30 patients ) was successful . The overall failure rate was 6 % . There were no statistically significant differences between the four groups . CONCLUSION If recommended procedures are strictly followed , posts and cores can serve as abutments for fixed single crowns with satisfactory long-term results PURPOSE This controlled clinical trial aim ed to compare the 3-year outcomes of glass fiber posts and composite cores with gold alloy-based posts and cores for the restoration of endodontically treated teeth . MATERIAL S AND METHODS One hundred forty-four patients in need of 205 restorations on endodontically treated teeth were selected and followed for 7 to 37 months ( mean : 21 ± 9 months ) . The teeth were primarily stratified based on the remaining tissue available to restore the tooth core with or without a post . Then , r and omization allocated the teeth to either test group 1 ( prefabricated glass fiber posts ) , test group 2 ( custom-made glass fiber posts ) , or test group 3 ( composite cores without posts ) . The control group consisted of gold alloy-based posts and cores . All posts/cores were covered with all-ceramic single crowns .  Failures were either absolute , such as root fractures or irreparable fractures of the post/core , or relative , such as loss of post retention or reparable fractures of the core . Success and survival probability lifetime curves , corrected for clustering , were drawn for the entire data set . RESULTS The recall rate at 3 years was 97.1 % . Absolute failures consisted of two root fractures and one endodontic failure , while relative failures included three instances of retention loss of the post/core and one post fracture . Because of the low number of events , no statistical tests were performed . The success and survival probabilities over all groups together at 3 years amounted to 91.7 % and 97.2 % , respectively . CONCLUSIONS After being followed for up to 3 years , both cast gold and composite post and core systems performed well clinical ly . Longer follow-up times are needed to detect possible significant differences . Int J Prosthodont 2011;24:363 - 372 Prospect i ve clinical studies comparing the results of different types of restorations of endodontically treated teeth are lacking . This study compared the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite to the  restorations of premolars using amalgam . Premolars with Class II carious lesions were selected and r and omly assigned to one of two experimental groups : ( 1 ) restoration with amalgam or ( 2 ) restoration with fiber posts and composite .  One hundred and nine teeth were included in Group 1 and 110 in Group 2 . Patients were recalled after 1 , 3 and 5 years . No statistically significant difference was found between the proportion of failed teeth in the two experimental groups . Significant differences were observed between the proportion of root fractures ( p=0.029 ) and caries ( p=0.047 ) , with more root fractures and less caries observed in the teeth restored with amalgam at the five-year recall . Within the limits of this study , it can be concluded that restorations with fiber posts and composite were found to be more effective than amalgam in preventing root fractures but less effective in preventing secondary caries INTRODUCTION This is the first clinical long-term pilot study that tested the biomimetic concept of using more flexible , dentine-like ( low Young modulus ) glass fiber-reinforced epoxy resin posts ( GFREPs ) compared with rather rigid , stiff ( higher Young modulus ) titanium posts ( TPs ) in order to improve the survival rate of severely damaged endodontically treated teeth . METHODS Ninety-one subjects in need of postendodontic restorations in teeth with 2 or less remaining cavity walls were r and omly assigned to receive either a tapered TP ( n = 46 ) or a tapered GFREP ( n = 45 ) . The posts were adhesively luted using self-adhesive resin cement . The composite core build-ups were prepared ensuring a circumferential 2-mm ferrule . The primary endpoint was a loss of restoration for any reason . To study group differences , the log-rank test was calculated ( P < .05 ) . Hazard plots were constructed . RESULTS After 84 months of observation ( mean = 71.2 months ) , 7 restorations failed ( ie , 4 GFREPs and 3 TPs ) . The failure modes were as follows : GFREP : root fracture ( n = 3 ) , core fracture ( n = 1 ) and TP : endodontic failure ( n = 3 ) . No statistical difference was found between the survival rates ( GFREPs = 90.2 % , TPs = 93.5 % , P = .642 ) . The probability of no failure was comparable for both post material s ( risk ratio ; 95 % confidence interval , 0.965 - 0.851/1.095 ) . CONCLUSIONS When using self-adhesive luted prefabricated posts in severely destroyed abutment teeth with 2 or less cavity walls and a 2-mm ferrule , postendodontic restorations achieved high long-term survival rates irrespective of the post material used ( ie , glass fiber vs titanium ) 
    Output:
    
agent
The results of this study did not show significant differences for root fracture incidence between metal- and fiber posts .
***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: This study reports a prospect i ve clinical trial comparing a carbon fibre reinforced carbon ( CFRC ) endodontic post with a conventional prefabricated post .  Twenty-seven single rooted maxillary anterior teeth in 18 patients ( nine males and nine females ; age range 18 - 60 years ) were restored either with a CFRC post or a wrought precious alloy control . Cast type III gold alloy cores were used in conjunction with both post groups . The CRFC posts ( n = 16 ) were cemented with a composite luting agent and the conventional posts ( control ) were cemented with zinc phosphate . Four failures were recorded in the CFRC post group at 24 , 29 , 56 and 87 months , compared with one failure in the control group at 84 months . These results suggest that post-retained crowns utilizing a CFRC material and a composite resin luting agent do not perform as well as conventional wrought precious alloy posts Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more OBJECTIVES This retrospective study investigated the clinical effectiveness over up to 8 years of parallel-sided and of tapered glass-fiber posts , in combination with either hybrid composite or dual-cure composite resin core material , in endodontically treated , maxillary anterior teeth covered with full-ceramic crowns . METHODS The study population comprised 192 patients and 526 endodontically treated teeth , with various degrees of hard-tissue loss , restored by the post- and -core technique .  Four groups were defined based on post shape and core build-up material s , and within each group post- and -core restorations were assigned r and omly with respect to root morphology . Inclusion criteria were symptom-free endodontic therapy , root-canal treatment with a minimum apical seal of 4 mm , application of rubber dam , need for post- and -core complex because of coronal tooth loss , and tooth with at least one residual coronal wall . Survival rate of the post- and -core restorations was determined using Kaplan-Meier statistical analysis . RESULTS The restorations were examined clinical ly and radiologically ; mean observation period was 5.3 years . The overall survival rate of glass-fiber post- and -core restorations was 98.5 % . The survival rate for parallel-sided posts was 98.6 % and for tapered posts was 96.8 % . Survival rates for core build-up material s were 100 % for dual-cure composite and 96.8 % for hybrid light-cure composite . CONCLUSIONS For both glass-fiber post design s and for both core build-up material s , clinical performance was satisfactory . Survival was higher for teeth retaining four and three coronal walls PURPOSE In the present prospect i ve study , four different post- and -core systems were evaluated over a period of up to 10 years . MATERIAL S AND METHODS Fifty endodontically treated teeth in 31 patients were r and omized to one of four groups for post- and -core placement : Group 1 received conventional tapered cast posts and cores ( n = 14 ) ; group 2 received ParaPost system prefabricated gold posts with cast cores ( n = 13 ) ; group 3 received ParaPost system cast posts and cores ( n = 13 ) ; and group 4 received Radix-Anchor posts ( n = 10 ) . Clinical and radiologic evaluations were made . RESULTS One post and core in group 2 was functioning well 58 months after placement when the patient died . No posts and cores in groups 1 or 2 had been lost or had any complications , one in group 3 had been lost because of a root fracture after 108 months , and two in group 4 had been lost after 54 and 88 months , respectively , because of loss of retention . The final treatment result for 46 of the 49 remaining posts ( 30 patients ) was successful . The overall failure rate was 6 % . There were no statistically significant differences between the four groups . CONCLUSION If recommended procedures are strictly followed , posts and cores can serve as abutments for fixed single crowns with satisfactory long-term results PURPOSE This controlled clinical trial aim ed to compare the 3-year outcomes of glass fiber posts and composite cores with gold alloy-based posts and cores for the restoration of endodontically treated teeth . MATERIAL S AND METHODS One hundred forty-four patients in need of 205 restorations on endodontically treated teeth were selected and followed for 7 to 37 months ( mean : 21 ± 9 months ) . The teeth were primarily stratified based on the remaining tissue available to restore the tooth core with or without a post . Then , r and omization allocated the teeth to either test group 1 ( prefabricated glass fiber posts ) , test group 2 ( custom-made glass fiber posts ) , or test group 3 ( composite cores without posts ) . The control group consisted of gold alloy-based posts and cores . All posts/cores were covered with all-ceramic single crowns .  Failures were either absolute , such as root fractures or irreparable fractures of the post/core , or relative , such as loss of post retention or reparable fractures of the core . Success and survival probability lifetime curves , corrected for clustering , were drawn for the entire data set . RESULTS The recall rate at 3 years was 97.1 % . Absolute failures consisted of two root fractures and one endodontic failure , while relative failures included three instances of retention loss of the post/core and one post fracture . Because of the low number of events , no statistical tests were performed . The success and survival probabilities over all groups together at 3 years amounted to 91.7 % and 97.2 % , respectively . CONCLUSIONS After being followed for up to 3 years , both cast gold and composite post and core systems performed well clinical ly . Longer follow-up times are needed to detect possible significant differences . Int J Prosthodont 2011;24:363 - 372 Prospect i ve clinical studies comparing the results of different types of restorations of endodontically treated teeth are lacking . This study compared the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite to the  restorations of premolars using amalgam . Premolars with Class II carious lesions were selected and r and omly assigned to one of two experimental groups : ( 1 ) restoration with amalgam or ( 2 ) restoration with fiber posts and composite .  One hundred and nine teeth were included in Group 1 and 110 in Group 2 . Patients were recalled after 1 , 3 and 5 years . No statistically significant difference was found between the proportion of failed teeth in the two experimental groups . Significant differences were observed between the proportion of root fractures ( p=0.029 ) and caries ( p=0.047 ) , with more root fractures and less caries observed in the teeth restored with amalgam at the five-year recall . Within the limits of this study , it can be concluded that restorations with fiber posts and composite were found to be more effective than amalgam in preventing root fractures but less effective in preventing secondary caries INTRODUCTION This is the first clinical long-term pilot study that tested the biomimetic concept of using more flexible , dentine-like ( low Young modulus ) glass fiber-reinforced epoxy resin posts ( GFREPs ) compared with rather rigid , stiff ( higher Young modulus ) titanium posts ( TPs ) in order to improve the survival rate of severely damaged endodontically treated teeth . METHODS Ninety-one subjects in need of postendodontic restorations in teeth with 2 or less remaining cavity walls were r and omly assigned to receive either a tapered TP ( n = 46 ) or a tapered GFREP ( n = 45 ) . The posts were adhesively luted using self-adhesive resin cement . The composite core build-ups were prepared ensuring a circumferential 2-mm ferrule . The primary endpoint was a loss of restoration for any reason . To study group differences , the log-rank test was calculated ( P < .05 ) . Hazard plots were constructed . RESULTS After 84 months of observation ( mean = 71.2 months ) , 7 restorations failed ( ie , 4 GFREPs and 3 TPs ) . The failure modes were as follows : GFREP : root fracture ( n = 3 ) , core fracture ( n = 1 ) and TP : endodontic failure ( n = 3 ) . No statistical difference was found between the survival rates ( GFREPs = 90.2 % , TPs = 93.5 % , P = .642 ) . The probability of no failure was comparable for both post material s ( risk ratio ; 95 % confidence interval , 0.965 - 0.851/1.095 ) . CONCLUSIONS When using self-adhesive luted prefabricated posts in severely destroyed abutment teeth with 2 or less cavity walls and a 2-mm ferrule , postendodontic restorations achieved high long-term survival rates irrespective of the post material used ( ie , glass fiber vs titanium ) 
    Output:
    