title: Fracture resistance of roots prosthetically restored with intra-radicular posts of different lengths. Relationship between crown placement and the survival of endodontically treated teeth. Effect of tooth type and ferrule on the survival of pulpless teeth restored with fiber posts: a 3-year clinical study. Survival of two post systems--five-year results of a randomized clinical trial. Three-year clinical comparison of survival of endodontically treated teeth restored with either full cast coverage or with direct composite restoration. Rigid versus flexible dentine-like endodontic posts--clinical testing of a biomechanical concept: seven-year results of a randomized controlled clinical pilot trial on endodontically treated abutment teeth with severe hard tissue loss.
abstract: The purpose of this study was to assess the fracture resistance of roots that were prosthetically restored with intra-radicular posts  of different lengths . Forty-five bovine incisors were sectioned 17 mm from their apices , endodontically treated and r and omly divided into three experimental groups : GI , fibreglass posts luted at a depth of 12 mm ; GII , 8 mm and GIII , 4 mm . All posts were luted with dual resin cement . Resin composite cores were prepared with st and ardized measurements , and all teeth were restored with metal crowns . The sample s were su bmi tted to the fracture resistance test in a universal testing machine , at an angle of 135 degrees and speed of 0.5 mm min(-1 ) , until fracture occurred . The data , in MPa , were su bmi tted to the analysis of variance ( anova ) followed by Tukey 's test ( alpha = 0.01 ) . No statistically significant difference ( P > 0.01 ) was found between GI ( 129.72 + /- 12.14 ) and GII ( 154.3 + /- 12.08 ) , which presented the highest fracture resistance values . Group GIII ( 100.5 + /- 8.07 ) showed lower fracture resistance ( P < 0.01 ) when compared with GI and GII . Within the limitations of this study , it was concluded that the post lengths influenced the fracture resistance of prosthetically restored roots . These results suggest that it is not necessary to perform excessive intra-radicular post-space preparation to improve the fracture resistance of roots STATEMENT OF PROBLEM Crowns have been considered the restoration of choice for endodontically treated teeth , but their selection has been based primarily on anecdotal evidence . PURPOSE This study tested the hypothesis that crown placement ( coronal coverage ) is associated with improved survival of endodontically treated teeth when preaccess , endodontic , and restorative factors are controlled . MATERIAL AND METHODS A University of Iowa College of Dentistry treatment data base was used to identify permanent teeth that had undergone initial obturation between July 1 , 1985 , and December 31 , 1987 . Study patients were restricted to persons with at least 1 dental visit in each 2-year interval from 1985 to 1996 ; a simple r and om sample of 280 patients ( n = 400 teeth ) was selected . Dental charts , radiographs , and computerized data bases were examined to ascertain variables of interest and to verify study inclusion criteria . Kaplan-Meier survival estimates were generated for the 203 teeth that satisfied study inclusion criteria . Multivariate Cox proportional hazards regression models were developed , with st and ard errors adjusted to account for clustering of teeth within patients . RESULTS When tooth type and radiographic evidence of caries at access were controlled , the final Cox model showed that endodontically treated teeth not crowned after obturation were lost at a 6.0 times greater rate than teeth crowned after obturation ( 95 % confidence interval : 3.2 to 11.3 ) . CONCLUSION Within the limitations of this study , a strong association between crown placement and the survival of endodontically treated teeth was observed . These results may impact treatment planning if long-term tooth retention is the primary goal PURPOSE To determine , in a 3-year clinical trial , whether tooth type and ferrule significantly affect the survival of pulpless teeth restored with fiber posts . METHODS A sample of 87 teeth in 87 patients ( 32 men and 55 women , age ranged from 23 to 78 ) were restored using Snowpost : 34 incisors , 12 canines , 25 premolars and 16 molars . The posts were cemented with RelyXUnicem and the core was made with a resin composite ( Dentocore Automix ) . Every tooth was covered with a metal-ceramic or all ceramic crown . Two experimental groups , according to the presence or absence of ferrule , were defined : A ) 45 teeth with ferrule ( > 2 mm height ) ; and B ) 42 teeth without ferrule ( < 2 mm height ) . Patients were reevaluated every 6 months . RESULTS 14 of the total restorations failed ( 16.1 % ) . The failure modes were caries ( n=4 ) , post fracture ( n=4 ) , root fracture ( n=2 ) , and marginal gap , post cement failure , crown cement failure , and periapical lesion ( n= 1 respectively ) . In Group A the failure observed was 6.67 % and in Group B it was 26.20 % . The log-rank test showed statistically significant differences between both groups . According to the type of tooth , the incisors were the teeth with the highest failure rate ( 73.52 % ) , but Chi-square test showed no statistically significant differences among the four tooth types , perhaps because of the low number of the sample OBJECTIVE To assess the survival rate of two different post systems after 5 years of service with a prospect i ve r and omized controlled trial . METHOD AND MATERIAL S One hundred patients in need of a post were studied . Half of the patients received long glass fiber-reinforced posts , while the other half received long metal screw posts . The posts were assigned r and omly . After at least 5 years ( mean , 61.37 months ) , follow-ups were established . When a complication occurred prior to this recall , the type and time of the complication was documented . Statistical analysis was performed using the log-rank test and Kaplan-Meier analysis . Additionally , a Cox regression was performed to analyze risk factors . RESULTS The survival rate of fiber-reinforced posts was 71.8 % . In the metal screw post group , the survival rate was significantly lower , 50.0 % ( log-rank test , P = .026 ) . Metal posts result ed more often in more unfavorable complications ( eg , root fractures ) ; consequently , more teeth ( n = 17 ) had to be extracted . The Cox regression identified the following risk factors : position of the tooth ( anterior vs posterior teeth ) , degree of coronal tooth destruction , and the post system  ( fiber-reinforced post vs metal screw post )  . Fiber-reinforced restorations loosened in several patients ; in some of these cases ( n = 6 ) , patients did not notice this , leading to the extraction of teeth . CONCLUSION Long metal screw posts should be used with great care in endodontically treated teeth . Besides the selection of the post system , other factors influence the survival of the restoration STATEMENT OF PROBLEM Little information exists regarding the outcome of crown build-ups on endodontically treated teeth restored with metal-ceramic crowns or with only a direct-placed composite . PURPOSE The aim of this study was to evaluate the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite restorations and compare that treatment with a similar treatment of full-coverage with metal-ceramic crowns . MATERIAL AND METHODS Subjects included in this study had one maxillary or m and ibular premolar for which endodontic treatment and crown build up was indicated and met specific inclusion /exclusion criteria . Only premolars with Class II carious lesions and preserved cusp structure were included . Subjects were r and omly assigned to 1 of the following 2 experimental groups : ( 1 ) teeth endodontically treated and restored with adhesive techniques and composite or ( 2 ) teeth endodontically treated , restored with adhesive techniques and composite , and then restored with full-coverage metal-ceramic crowns .  Sixty teeth were included in the first group and 57 in the second . All restorations were performed by one operator . Causes of failure were categorized as root fracture , post fracture , post decementation , clinical and /or radiographic evidence of marginal gap between tooth and restoration , and clinical and /or radiographic evidence of secondary caries contiguous with restoration margins . Subjects were examined for the listed clinical and radiographic causes of failure by 2 calibrated examiners at intervals of 1 , 2 , and 3 years . Exact 95 % confidence intervals for the difference between the 2 experimental groups were calculated . RESULTS At the 1-year recall , no failures were reported . The only failure modes observed at 2 and 3 years were decementations of posts and clinical and /or radiographic evidence of marginal gap between tooth and restoration . There was no difference in the failure frequencies of the 2 groups ( 95 % confidence interval , -17.5 to 12.6 ) . There was no difference between the number of failures caused by post decementations and the presence of marginal gaps observed in the 2 groups ( 95 % confidence intervals , -9.7 to 16.2 and -17.8 to 9.27 ) . CONCLUSION Within the limitations of this study , the results upheld the research hypothesis that the clinical success rates of endodontically treated premolars restored with fiber posts and direct composite restorations after 3 years of service were equivalent to a similar treatment of full coverage with metal-ceramic crowns 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 )
target: Conclusions The most frequently reported failures in the available studies were as follows : fiber post debonding , loss of retention of single crowns , and marginal gaps .
  Less frequently , chippings and fractures were recorded in SCs .
background: Objective The present systematic review aim ed at assessing data from the literature on endodontic and prosthetic complications in endodontically treated teeth restored with fiber posts and single crowns ( SCs ) or fixed dental prostheses ( FDPs ) .