A comparative evaluation of the vertical root fracture resistance of endodontically treated teeth using different root canal sealers: an in vitro study. Evaluation of Fracture Resistance of Endodontically Treated Teeth Filled with Gutta-Percha and Resilon Obturating Material: An In Vitro Study In vitro fracture resistance of roots obturated with epoxy resin-based, mineral trioxide aggregate-based, and bioceramic root canal sealers. The effect of two different root canal sealers and smear layer on resistance to root fracture. A comparison of root fracture resistance using two root canal sealers. The effect of resin-based sealers on fracture properties of dentine. Effect of dentinal tubules and resin-based endodontic sealers on fracture properties of root dentin. Fracture resistance of roots endodontically treated with a new resin filling material. Resistance to Fracture of Dental Roots Obturated with Different Materials Gutta percha verses resilon: an in vitro comparison of fracture resistance in endodontically treated teeth. Cytotoxicity testing of endodontic sealers: a new method. Push-out bond strength of two new calcium silicate-based endodontic sealers to root canal dentine. Influence of laser irradiation on fiber post retention Final Irrigation Regimens Affect Fracture Resistance Values of Root-filled Teeth. Fracture resistance of roots filled with gutta-percha or RealSeal®. Postoperative pain after endodontic retreatment: single- versus two-visit treatment. Fracture resistance of compromised endodontically treated teeth restored with bonded post and cores: An in vitro study. Post-operative symptoms and healing after endodontic treatment of infected teeth using pulsed Nd:YAG laser. Effect of final irrigation procedures on fracture resistance of root filled teeth: an ex vivo study Resistance to fracture of roots filled with different sealers. Effect of eugenol-containing sealer and post diameter on the retention of fiber reinforced composite posts Fracture resistance of roots obturated with three different materials. Nickel-titanium rotary instrument fracture: a clinical practice assessment. Comparing subcutaneous tissue responses to freshly mixed and set root canal sealers Drying protocol influence on the bond strength and apical sealing of three different endodontic sealers.
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 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 INTRODUCTION The aim of this study was to evaluate the fracture resistance of teeth filled with 3 different endodontic sealers . METHODS Seventy-five single-rooted extracted m and ibular premolars were decoronated to a length of 13 mm . The teeth were r and omly divided into 5 groups ( n = 15 for each group ) . In group 1 , the teeth were left unprepared and unfilled ( negative control ) , and in group 2 , the teeth were left unobturated ( positive control ) . The rest of the roots were prepared by using the ProTaper System up to a master apical file size of F3 : group 3 , bioceramic sealer ( Endosequence BC sealer ) + gutta-percha ; group 4 , mineral trioxide aggregate-based sealer ( Tech Biosealer Endo ) + gutta-percha ; and group 5 , epoxy resin-based sealer ( AH Plus Jet ) + gutta-percha . All root specimens were stored for 2 weeks at 100 % humidity to allow the complete setting of the sealers . Each specimen was then subjected to fracture testing by using a universal testing machine at a crosshead speed of 1.0 mm/min(-1 ) until the root fractured . The force required to fracture each specimen was recorded , and the data were analyzed statistically . RESULTS The fracture values of groups 3 and 5 were significantly higher than those of group 4 ( P < .05 ) . There was no significant difference between groups 3 and 5 ( P > .05 ) . CONCLUSIONS In contrast to Tech Biosealer Endo , Endosequence BC and AH Plus Jet sealer increased the force to fracture in root-filled single-rooted premolar teeth The purpose of this in vitro study was to test the effect of Ketac-Endo ( KE ) and AH 26 on resistance to root fracture and also to evaluate the effect of smear layer .  Seventy-two human maxillary canine teeth were r and omly divided into six groups ( n = 12 ) and were prepared using six different methods : group 1 : KE , without smear layer ( smear - ) ; group 2 : KE , with smear layer ( smear + ) ; group 3 : AH 26 , smear ( - ) ; group 4 : AH 26 , smear ( + ) ; group 5 ( negative control ) : nonprepared ; group 6 ( positive control ) : prepared but unfilled . After storing 1 week in 100 % humidity at 37 degrees C , the coronal lingual walls and root canal spaces were lowered 2 mm below the buccal walls of the roots . The sample s were placed into acrylic resin blocks so that 10 mm of buccal roots were exposed and were placed in a specially design ed steel pad at an angle of 15 degrees to the long axis of the root . A slowly increasing force was applied at the junction of the buccal wall and root canal space until fracture occurred . The force required to fracture each tooth was recorded as kg and statistically analyzed using one-way analysis of variance and Duncan tests . The results indicated that instrumentation of the root canals significantly weakened the tooth structure to fracture ( p < 0.05 ) . The canals obturated with either sealer were significantly stronger than roots whose canals were instrumented but not obturated ( p < 0.05 ) , and there was no difference between the sealers . The presence or absence of the smear layer did not cause any significant effect on the root fracture resistance of the teeth ( p > 0.05 ) 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 AIM To determine whether resin-based sealer cements are able to strengthen root dentine , as measured by work of fracture ( Wf ) , micro-punch shear strength ( MPSS ) and resistance to vertical root fracture ( VRF ) . METHODOLOGY One hundred and twenty extracted premolar teeth were r and omly assigned amongst four treatments before testing : intact , root canals prepared but unfilled , or root filled using epoxy- or urethane dimethacrylate (UDMA)-based sealer ( plus core material ) . Sample s were then prepared for measuring Wf , MPSS or VRF using st and ard test procedures . Data were analyzed using one-way anova with significance set at P < 0.05 . RESULTS For all three tests , root canals filled using epoxy resin-based sealer were not statistically significantly different compared with UDMA resin ( P = 1 for Wf , P = 0.7 for MPSS and P = 0.12 for VRF ) , or different from both sound and prepared dentine ( P > 0.05 ) . There was also no significant difference between sound dentine and prepared dentine for both Wf ( P = 0.92 ) and resistance to VRF ( P = 1 ) . CONCLUSIONS Neither epoxy nor UDMA resins used as sealer cements enhanced fracture resistance of root dentine when placed within root canals of extracted teeth 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 sample s were prepared for Wf test parallel to dentinal tubules . Wf was compared under ANOVA with statistical significance set at p<0.05 . RESULTS Dentinal tubules influenced the path of cracks through dentin , with micro-cracks initiated in peritubular dentin of individual tubules ahead of the main crack tip . A significant difference ( p<0.001 ) was found between Wf perpendicular to tubule direction ( 254.9 J/m(2 ) ) vs. parallel to tubule direction from inner to outer dentin ( 479.4 J/m(2 ) ) . Neither canal preparation nor obturation using epoxy- or UDMA-based resins as sealer cements substantially influenced fracture properties of root dentin , despite extensive infiltration of dentinal tubules by both sealer cements BACKGROUND The authors evaluated the fracture resistance of endodontically treated teeth filled with either gutta-percha or a new resin-based obturation material .  METHODS The authors prepared and r and omly divided 80 single-canal extracted teeth into five groups : lateral and vertical condensation with gutta-percha , lateral and vertical condensation with the new resin-based obturation material , and a control group with no filling material . The specimens were stored in 100 percent humidity for two weeks , mounted in polyester resin and loaded to failure . RESULTS The authors found statistically significant differences among the experimental groups ( P < .05 ) . The groups with the new material displayed higher mean fracture loads and the gutta-percha groups lower mean fracture load values than the control unfilled group . However , the differences were not significant . The groups with the new material displayed significantly higher mean fracture loads than gutta-percha groups independent of the filling technique used . CONCLUSIONS Filling the canals with the new resin-based obturation material increased the in vitro resistance to fracture of endodontically treated single-canal extracted teeth when compared with st and ard gutta-percha techniques . CLINICAL IMPLICATION S ; If other properties of the new resin-based obturation material compare favorably with those of gutta-percha for filling the root canal , it should be considered as a replacement for gutta-percha , as the results of this study indicate that it could provide enhanced resistance to tooth fracture The aim of this study was to compare the vertical fracture resistance of roots obturated with different  root canal filling material s and sealers .  Crowns of 55 extracted m and ibular premolar teeth were removed to provide root lengths of 13 mm . Five roots were saved as negative control group ( canals unprepared and unfilled ) . Fifty root canals were instrumented and then five roots were saved as positive control group ( canals prepared but unfilled ) . The remaining 45 roots were r and omly divided into three experimental groups ( n = 15 root/group ) and obturated with the following procedures : in group 1 , glass ionomer-based sealer and cone ( ActiV GP obturation system ) ; in group 2 , bioceramic sealer and cone ( EndoSequence BC obturation system ) ; and in group 3 , roots were filled with bioceramic sealer and cone ( Smartpaste bio obturation system ) . All specimens were tested in a universal testing machine for measuring fracture resistance . For each root , the force at the time of fracture was recorded in Newtons . The statistical analysis was performed by using Kruskal-Wallis and post hoc test . There were no significant differences between the three experimental groups . The fracture values of three experimental and negative control groups were significantly higher than the positive control group . Within the limitations of this study , all material s increased the fracture resistance of instrumented roots OBJECTIVE The aim of this study was to evaluate and compare the fracture resistance of endodontically treated teeth filled with gutta percha and Resilon  using lateral and vertical condensation methods . MATERIAL S AND METHODS A total of 75 freshly extracted single-rooted teeth were selected . All sample s were instrumented with profile 4 % Ni-Ti rotary instruments . Sample s were r and omly divided into five groups of 15 sample s each : Group 1 was obturated using lateral condensation with gutta percha and AH -26 sealer . Group 2 was obturated using vertical condensation with gutta-percha and AH-26 . Group 3 was obturated with Resilon and epiphany using lateral condensation technique . Group 4 was obturated with Resilon and epiphany using vertical condensation method . Group 5 received no filling . Restored teeth were subjected to compressive loading in a universal testing machine . RESULTS One-way ANOVA test showed significant difference among the groups ( P < 0.05 ) . The mean and SD values for the groups are as follows : Group 1 - ( 773.3 ± 148.1 ) , Group 2 - ( 769.9 ± 170.5 ) , Group 3 - ( 928.1 ± 135.4 ) , Group 4 - ( 902.6 ± 120.8 ) , and Group 5 - ( 766.0 ± 152.0 ) . It was seen that sample s of Group 3 showed the highest fracture resistance followed by Group 4 , Group 1 , and Group 2 . Group 5 showed the least fracture resistance . CONCLUSION Resilon-epiphany obturated roots using lateral condensation method showed higher fracture resistance  compared with gutta percha-AH 26 groups on vertical loading The purpose of this study was to compare ISO st and ards versus a new technique for in vitro evaluation of cytotoxicity of root canal sealers . The cytotoxicity of AH Plus , Cortisomol , and Sealapex was first recorded according to ISO st and ards on L 929 fibroblasts by the MTT assay . In parallel , 30 single-rooted teeth were cut at the cementum enamel junction ( CEJ ) , and the roots were prepared and sterilized before filling with the lateral condensation using one of three sealers ( n = 10 ) . The apexes of the roots were dipped into 1 ml of minimum essential medium for 1 , 2 , and 30 days renewing the medium every other day . After 24-h contact between the medium and the filled roots , the medium was used to measure the cytotoxicity on L 929 with the MTT assay . ISO st and ards always gave a statistically higher cytotoxicity than the root-dipping technique ( p < 0.0001 ) , whatever the sealer and the exposure time . The ISO st and ards showed statistically significant differences among the sealers ( p < 0.0001 ) . AH Plus was noncytotoxic , Cortisomol showed a high cytotoxicity decreasing over time ( p < 0.001 ) , and Sealapex displayed a high cytotoxicity that did not decrease over time ( NS ) . The new technique showed statistically significant differences among the sealers ( p = 0.001 ) , but the differences were so small that they were likely not clinical ly relevant . The high cytotoxicity of Sealapex decreased over time but the cytotoxicity of AH Plus and Cortisomol did not . The results show that the ISO st and ards may strongly over-evaluate the cytotoxicity of the endodontic sealers , emphasize the difference among the sealers , and may clinical ly correspond to a large overfilling . The new technique reduces the discrimination of the test and may clinical ly correspond to a classical filling . Therefore , both methods might be considered as clinical ly relevant , corresponding to classical and overfilling conditions AIM To assess the push-out bond strength of two new calcium silicate-based endodontic sealers in the root canals of extracted teeth . METHODOLOGY Thirty extracted single-rooted central incisors of similar sizes were selected r and omly and distributed to three groups ( n = 10 ) . All canals were instrumented using ProTaper rotary instruments to achieve tapered canal walls . Irrigation was performed using 5 mL 2.5 % NaOCl between each instrument , and the smear layer was removed using 5 mL 17 % EDTA . The canals were filled with three different sealers using a cold lateral compaction technique : group 1 : AH Plus + gutta-percha , group 2 : I Root SP + gutta-percha and group 3 : MTA Fillapex + gutta-percha . Three horizontal sections were prepared at a thickness of 1 mm ± 0.1 in the apical , middle and coronal parts of each root . The test specimens were subjected to the push-out test method using a Universal Test Machine ( Instron , Canton , MA , USA ) that carried 1-mm , 0.5-mm and 0.3-mm plungers for coronal , middle and apical specimens , respectively . The loading speed was 1 mm min(-1 ) . The push-out data were analysed by two-way analysis of variance ( anova ) and the post hoc Holm-Sidak test , with significance set at P < 0.05 . RESULTS In the coronal specimens , there was no significant difference between the sealers . In the middle and apical segments , there was no significant difference between I Root SP and AH Plus groups . However , the I Root SP and AH Plus had significantly higher bond strength values than the MTA Fillapex ( P < 0.05 ) . In terms of root segments , the bond strengths in the middle specimens and the apical specimens were higher compared with the bond strengths in the coronal specimens ( P < 0.05 ) . There were no significant differences between the bond strengths in the middle and apical specimens . CONCLUSION MTA Fillapex had the lowest push-out bond values to root dentine compared with other sealers The purpose of this in vitro study was to compare the bond strength between fiber post and laser-treated root canals . Forty single-rooted bovine teeth were endodontically treated and r and omly divided into four groups of equal size according to the root canal treatment : group 1 conventional treatment ( without laser irradiation ) ; group 2 Nd : YAG laser ( 1.5 W , 10 Hz , 100 mJ ) ; group 3 Er , Cr : YSGG laser ( 0.75 W , 20 Hz ) ; and group 4 Nd : YAG + Er , Cr : YSGG lasers . The fiber posts were cemented with an adhesive system + resin cement , in accordance with the manufacturer ’s instructions . A mini acrylic pipe was fixed on the coronal section of the post using a light-polymerized resin . Specimens were mounted on an acrylic pipe with a self-polymerized resin . Retention forces were determined using a universal testing machine ( 0.5 mm/min ) . Data were analyzed using one-way ANOVA and Tukey tests ( p < 0.05 ) . The post retention force in group 2 was found to be lower than that in the other experimental groups . Fractures were observed at the interface between the dentin and the resin in all groups . High-intensity lasers can be used in conventional endodontic treatment ; however , root canal surface irradiation using the Nd : YAG laser was shown to negatively affect the post retention force INTRODUCTION The purpose of this study was to compare the effect of different final irrigation solutions on fracture resistance values ( FRVs ) of endodontically treated teeth . METHODS Eighty extracted decoronated human incisors were used . Ten r and omly selected roots were used as the negative control group . The remaining roots were prepared by the ProTaper system ( Dentsply Maillefer , Ballaigues , Switzerl and ) up to F2 . Ten prepared roots were selected as the positive control . The other prepared roots were divided into 6 ( n = 10 ) groups according to the final irrigation solution used : 5 mL saline , 17 % EDTA , EDTA with a surfactant ( REDTA ) , chlorhexidine , QMix ( Dentsply Tulsa Dental Specialties , Tulsa , OK ) , and BioPure MTAD ( Dentsply Tulsa Dental Specialties ) . In all groups , the final irrigation was performed for 1 minute except for the BioPure MTAD group ; in this group , it was applied for 5 minutes according to the manufacturer 's instructions . The specimens were filled with a single gutta-percha cone and AH 26 sealer ( Dentsply , De Trey , Konstanz , Germany ) . After being stored under 37 ° C and 100 % humidity for a week , the specimens were loaded in a vertical direction at 1 mm/min speed until they were vertically fractured . The results were analyzed by the Kruskal-Wallis and Siegel Castellan tests . RESULTS The negative control group showed the highest FRV . There were statistically significant differences between the negative and positive control groups ( P < .05 ) . Specimens irrigated with REDTA and QMix showed a higher FRV compared with the positive control group ( P < .05 ) . Specimens exposed to chlorhexidine and BioPure MTAD showed a lower FRV compared with the negative control group ( P < .05 ) . CONCLUSIONS Root canal preparation weakens the tooth . The final irrigation regimen has an impact on the FRV . A short time exposure to irrigation solutions ( REDTA and QMix ) that include surfactants probably contributed to the higher FRV , instead of a long time exposure as done with BioPure MTAD AIM To evaluate the vertical root fracture resistance of maxillary central incisors filled with different  root filling material s and sealers . METHODOLOGY Forty maxillary central incisor root canals were instrumented and divided r and omly into four groups . Each group was filled using lateral compaction , with gutta-percha and AH Plus , gutta-percha and RealSeal ( ® ) sealer , RealSeal ( ® ) cone and RealSeal ( ® ) sealer , or RealSeal ( ® ) cone and AH Plus , respectively . The roots were loaded vertically by a conical spreader tip inserted into the canal and attached to an Instron testing machine until root fracture occurred . The load at fracture and the pattern of fracture were recorded . Mechanical properties of both core material s were tested under compressive loading . Results were analysed statistically by two-way analysis of variance and post hoc Tukey 's tests . An independent sample t-test was used to compare the mechanical properties of the filling material s. RESULTS Load at fracture of roots  filled with gutta-percha and AH Plus ( 255 ± 74 N ) and gutta-percha and RealSeal ( ® ) sealer ( 237 ± 38 N ) was significantly greater than those filled using the RealSeal ( ® ) system ( 163 ± 29 N ) and RealSeal ( ® ) cone with AH Plus sealer ( 134 ± 17 N ) . Most fracture lines were in a bucco-lingual direction . In compressive tests of the core material s , RealSeal ( ® ) had greater flow in response to load than gutta-percha , suggesting more efficient transmission of forces to the canal wall in the fracture tests . CONCLUSIONS The lower fracture resistance of roots filled using RealSeal ( ® ) is probably the result of more efficient transmission of forces within the canal , rather than a direct effect of the material itself OBJECTIVE The purpose of this clinical study was to determine the effect of 1- or 2-visit root canal treatment on the postoperative pain in the retreatment cases . STUDY DESIGN Two hundred eighteen cases that required retreatment were included in the study . Obturated and unfilled canal space and the status of periapical tissues were evaluated according to the PAI index . The patients were subcategorized in regard to the presence or the absence of preoperative pain . Approximately half of each category was treated in 1 appointment . After removing the previous root canal obturation material s and biomechanic preparation of root canals , the teeth in the 1-visit group were obturated at the first appointment by using AH 26 sealer and laterally compacted gutta-percha , and those in the 2-visit group were medicated with calcium hydroxide-chlorhexidine combination and then closed with a temporary filling material . One week after the initial appointment , patients were asked about the occurrence of postoperative pain . The level of discomfort was rated as no pain , mild pain , moderate pain , or severe pain ( flare-up ) . Data were statistically analyzed using the chi-squared and Fischer exact tests . RESULTS Eight patients from the 1-visit group and 2 patients from the 2-visit group had flare-ups . There was a statistical difference between the groups ( P < .05 ) . Two-visit root canal treatment was more effective in completely eliminating pain than 1-visit treatment of previously symptomatic teeth ( P < .05 ) . CONCLUSIONS Two-visit endodontic treatment with intracanal medication was found to be effective in reducing postoperative pain of previously symptomatic teeth and decreased the number of flare-ups in all retreatment cases STATEMENT OF PROBLEM It is unclear which post and core system performs best when bonded to severely compromised endodontically treated teeth . PURPOSE The purpose of this study was to investigate the fracture resistance and mode of failure of severely compromised teeth restored with 3 different adhesively bonded post and core systems . MATERIAL AND METHODS Thirty extracted endodontically treated maxillary anterior teeth were r and omly divided into 3 groups , CPC , gold cast post and core ; TPC , titanium prefabricated post/composite resin core ; and FPC , quartz fiber reinforced post/composite resin core . All posts were adhesively cemented . All cores resembled a central incisor preparation with no remaining tooth structure above the finish line . Cast gold crowns were fabricated and cemented adhesively . The specimens were aged with thermocycling and cyclic loading . Two specimens per group were r and omly selected for micro-computed tomographic imaging before and after aging . Failure was induced with a universal testing machine . The mode of failure was characterized by the interface separation . Data were analyzed with 1-way ANOVA ( α=.05 ) followed by post hoc tests ( Bonferroni ) . RESULTS A statistically significant difference was found among the 3 groups ( P=.002  ) . CPC was significantly different than TPC ( P=.008 ) or FPC ( P=.003 ) . The primary mode of failure  for CPC and TPC  was root fracture , and for FPC post debonding . CONCLUSIONS Severely compromised endodontically treated teeth restored with bonded gold cast post and cores showed significantly higher fracture resistance Forty-four teeth in 38 patients , diagnosed with chronic apical periodontitis , were endodontically treated . Root canals were shaped using a step-back technique with 5 % NaOCl and 3 % H2O2 as irrigants . In half of the teeth the canal terminus was irradiated with pulsed Nd : YAG laser ( 1 W , 15 pps , 1 s ) . All canals were then obturated with laterally condensed gutta-percha points and sealer , and final radiographs were obtained . Occurrence of spontaneous pain was recorded 1 day after treatment . Percussion pain was recorded after 1 week , and then at 3 and 6 months after treatment . Radiographic follow-up was performed at 3 and 6 months . Percussion pain was significantly less ( P < 0.05 ) in the laser-treated group than in the control group , both 1 week and 3 months after treatment . Other differences between the groups were not significant . These results suggested that the clinical application of pulsed Nd : YAG laser might be advantageous for the treatment of infected root canals AIM To evaluate the effect of chlorhexidine ( CHX ) on fracture resistance of roots treated with different concentrations of ethylenediaminetetraacetic acid ( EDTA ) . METHODOLOGY One hundred and twenty intact single-rooted premolar teeth were sectioned below the cementum-enamel junction to st and ardize the length of the teeth to 12 mm . The canals of one hundred specimens were instrumented with ProTaper Universal rotary instruments up to size F4 and were r and omly divided into five groups ( n = 20 ) according to the final irrigating solutions : Group 1 : distilled water ( DW ) ; Group 2 : 5 % EDTA and 2.5 % NaOCl ; Group 3 : 17 % EDTA and 2.5 % NaOCl ; Group 4 : 5 % EDTA , 2.5 % NaOCl , DW and 2 % CHX ; Group 5 : 17 % EDTA and 2.5 % NaOCl , DW and 2 % CHX . Root canals were filled with gutta-percha and epoxy resin-based root canal sealer using a single-cone technique . Twenty teeth served as negative controls and were not instrumented nor root filled ( Group 6 ) . All specimens were embedded in self-curing acrylic resin and loaded vertically at 0.5 mm min-1 until fracture occurred . The data were evaluated statistically using one-way anova test followed by Holm-Sidak 's multiple comparison test ( P < 0.05 ) . RESULTS Group 1 ( only DW ) had the lowest vertical fracture strength , followed by Group 3 ( 17 % EDTA and 2.5 % NaOCl ; P < 0.05 ) . Group 6 ( negative control group ) had the highest fracture resistance . Final irrigation with CHX following irrigation with 17 % EDTA or 5 % EDTA and 2.5 % NaOCl ( groups 4 and 5 ) significantly increased the fracture resistance of roots ( P < 0.05 ) . However , the difference between Group 4 and Group 5 was not significant ( P > 0.05 ) . CONCLUSIONS Intracanal CHX rinse of EDTA/NaOCl-treated root dentine enhanced the fracture resistance of roots filled with AH Plus 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 : Fiber reinforced composite ( FRC ) posts are cemented with resin cements . It is reported that using resin cements in canals sealed with eugenol-containing sealers reduces the post retention . However , there is controversy on the subject . Aims : The aim was to investigate the influence of eugenol-containing sealers and the amount of dentin removal from root canal with different post diameters on retention of FRC posts . Setting s and Design : It was an in vitro study Material s and Methods : The roots of sixty teeth were cut with 14 mm distance from the apex and were instrumented to the working-length of 13 mm . The teeth were r and omly distributed into 2 groups ( n = 30 ) . Following storage in normal saline for 7 days , the sample s in both the groups were further divided into 3 subgroups ( n = 10 ) . Canals in the experimental subgroups ( I , II , III ) were obturated by gutta-percha and eugenol-containing sealer ; and in the control subgroups ( IV , V , VI ) without any sealer . After storage in normal saline for 7 days , the post space was prepared by # 3 , # 2 , and # 1 drills of DT Light-Post system . Post was cemented with Panavia-F2.0 resin-cement . A composite core was built for each sample . All sample s were thermo cycled for 1000 cycles . The sample s were tested for post retention with a mechanical testing machine . Statistical Analysis : Data were analyzed by two-way ANOVA and Tukey-HSD test . Results : There was not a significant difference in retention between FRC posts # 1 and # 2 ( P > 0.05 ) . Post # 3 was more retentive than posts # 1 and # 2 ( P < 0.05 ) . ZOE sealer significantly reduced the retention of posts ( P = 0.024 ) , however , increasing post-space diameter significantly increased post retention in canals coated with ZOE sealer ( P = 0.002 ) . Conclusions : Eugenol-containing sealer reduced the retention of FRC posts cemented with resin cement . Removing more dentin from root-canals treated with eugenol-containing sealer for placing larger diameter posts caused an increase in post retention OBJECTIVE The aim of this study was to compare the fracture resistance of roots obturated with different material s. STUDY DESIGN Sixty root canals were instrumented and divided into 4 equal groups ( n = 15 each ) . The root canals in group 1 were filled with AH26 sealer and gutta-percha , in group 2 with Resilon and Epiphany , and in group 3 with Ketac-Endo Aplicap and gutta-percha .  Fifteen root canals had no obturation . The force required to fracture was recorded . The data was analyzed with analysis of variance and Duncan test . RESULTS The mean force of fracture for group 1 was significantly higher than for the other 3 groups ( P < .05 ) . There was significant difference between group 2 and group 3 ( P < .05 ) . Group 2 and group 3 were not significantly different from the control group ( P > .05 ) . CONCLUSION The use of AH26 + gutta-percha increased the fracture resistance of instrumented root canals compared with Resilon + Epiphany and Ketac-Endo Aplicap + gutta-percha AIM To prospect ively determine the incidence of nickel-titanium rotary instrument fracture in an endodontic clinical practice setting . METHODOLOGY Eleven second year endodontic residents , using four nickel-titanium rotary instrument systems ( ProFile , ProTaper , GTRotary and K3Endo )  according to the recommendations of the manufacturers , instrumented 3181 canals in 1403 teeth of 1235 patients , in a dental school post-graduate endodontic clinic , in 1 year . The incidence of instrument fracture was determined based on the number of instruments used . When fracture occurred , data were collected concerning the type , size , taper and prior use of the fractured instruments , the length and location of the fragment within the root canal and the curvature of the canal . RESULTS The overall incidence of instrument fracture was 0.39 % . The incidence of fracture for ProFile , ProTaper , GTRotary and K3Endo files was 0.28 % , 0.41 % , 0.39 % and 0.52 % , respectively . There was no statistically significant difference between instrument systems . The percentage of teeth in which instruments fractured was 1.9 % ( 0.28 % for anterior teeth , 1.56 % for pre-molars and 2.74 % for molars ) . A total of 26 instruments fractured , of which 23 had tapers of 0.06 or greater . Most of the fragments were located in the apical third of the root canal , and both the median and mode amongst the fragment lengths were 2 mm . CONCLUSIONS The low incidence of nickel-titanium rotary instrument fracture supports the continued use of these instruments in root canal treatment INTRODUCTION : The purpose of this study was to compare the subcutaneous tissue responses of freshly mixed or set endodontic root canal sealers ( i.e. RoekoSeal , AH26 , AH Plus ) in Wistar Albino rats . MATERIAL S AND METHODS : Seventy-two male albino rats weighing 200 - 250 g were used . The animals were r and omly divided into six groups of 12 rats each . Root canal sealers were implanted in subcutaneous tissue in both freshly mixed and set conditions . The animals were sacrificed after 7 , 14 , and , 60 days . After histological preparation and Hematoxylin and Eosin ( H&E ) staining , the specimens were evaluated for capsule thickness , severity and extent of inflammation , and necrosis . Results were statistically analyzed using Multivariate ANOVA test . RESULTS : Differences between set and freshly mixed root canal sealers were significant ( P=0.014 ) , but not significant between test material s and controls , except for capsule thickness and extent of inflammation between control and AH26 ( P=0.019 and P=0.006 respectively ) . The interaction between the type of material and setting condition was significant for capsule thickness and severity of inflammation in AH26 specimens at 14 and 60 days ( P=0.001 ) . CONCLUSION : Based on the results of this study assessing the biocompatibility , both set and freshly mixed states can be used . [ Iranian Endodontic Journal 2009;4(4):152 - 7 The aim of this study was to evaluate the influence of drying protocol s ( DP ) on the apical sealing ( AS ) and on the bond strength ( BS ) of teeth filled with different  sealers .  The root canals of one hundred and fifty-six roots of maxillary canines were prepared with Reciproc rotary files ( R50 ) . The teeth were r and omly divided into four groups ( n = 39 ) , according to the DP : GI-paper points ; GII-70 % isopropyl alcohol + aspiration with NaviTip points ; GIII-95 % ethanol + paper points ; GIV-EndoVac + paper points . Each group was divided into subgroups , according to the sealer used : AH Plus , Sealapex and MTA Fillapex , using a single-cone technique . Evaluation of AS and BS was performed with fluid filtration ( FF ) and push-out ( PO ) methods , respectively . The PO test consisted of sectioning the roots , and subjecting a single slice from each third to testing and analysis for failure type . The data was su bmi tted to two-way and three-way variance analysis ( ANOVA ) and Tukey ( α = 5 % ) . The AS showed no drying protocol influence . The FF results revealed a statistically significant difference between MTA and Sealapex ( p < 0.05 ) sealers . The BS test values showed that there was no statistical significant difference among the canal thirds ( p > 0.05 ) , but that there was such a difference among the sealers ( p < 0.05 ) , among the protocol s ( p < 0.05 ) , and in the interaction between sealers and protocol s ( p < 0.05 ) . AH Plus revealed the highest BS values among the sealers ; the highest BS results for the sealers occurred with the specimens used with isopropyl alcohol , compared with ethanol and EndoVac
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 .
Objective The purpose of this study was to systematic ally review and critically analyze the published data of in vitro studies testing the effect of root canal sealers on the fracture resistance of endodontically treated teeth .