Penetration of Epiphany, Epiphany self-etch, and AH Plus into dentinal tubules: a scanning electron microscopy study

Introduction

The purpose of this study was to measure the average depth of dentinal tubule sealer penetration in the middle third of teeth obturated with gutta-percha/AH Plus (Dentsply, DeTrey, Konstanz, Germany), Resilon/Epiphany (Pentron Clinical Technologies, Wallingford, CT), and Resilon/Epiphany self-etch (SE) using scanning electron microscopy (SEM).

Methods

The root canals of 36 extracted single-rooted human teeth were prepared and randomly divided into three groups. Obturations were performed with the following filling materials using the lateral compaction technique: group 1, gutta-percha/AH Plus; group 2, Resilon/Epiphany; and group 3, Resilon/Epiphany SE. The specimens were prepared for SEM examination. The average depth of sealer penetration into the dentinal tubules was measured. Data were analyzed by one-way analysis of variance and a post hoc Tukey test.

Results

The mean (± standard deviation) values for the average depth of sealer penetration in the middle third of the roots were 22.07 ± 6.92 μm, 31.56 ± 6.80 μm, and 21.50 ± 9.25 μm for AH Plus, Epiphany, and Epiphany SE, respectively. The average penetration depth of Epiphany was significantly higher than that of Epiphany SE and AH Plus (P < .05). There was no significant difference between the penetration depth of Epiphany SE and AH Plus (P > .05).

Conclusions

It could be concluded that the average penetration for Epiphany into dentinal tubules within the middle third of the roots was significantly deeper than that of Epiphany SE and AH Plus.     

Push-out Bond Strength of Resilon/Epiphany and Resilon/Epiphany Self-Etch to Root Dentin

IntroductionThe present study was designed to investigate the bond strength produced by Epiphany and Epiphany SE to root canal dentin.MethodsA sample of 36 human upper canines was prepared and assigned to experimental groups (n = 12), designated as group 1, Resilon/Epiphany; group 2, Resilon/Epiphany SE; and group 3, AH Plus/gutta-percha. After the filling procedures, each tooth was prepared for push-out assessment by using root slices of 1-mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey test for multiple comparisons were used to compare the results among the experimental groups.ResultsAH Plus/gutta-percha root fillings showed significantly higher push-out bond strength than both Resilon/Epiphany and Resilon/Epiphany SE (P < .05). There was no significant difference between Epiphany/Resilon and Epiphany SE/Resilon (P > .05).ConclusionsUnder the present in vitro conditions, the adhesiveness quality to root dentin promoted by both Epiphany sealers is compromised even when teeth with simple anatomic features were obturated under well-monitored laboratory conditions.     

Effect of Calcium Hydroxide and Double and Triple Antibiotic Pastes on the Bond Strength of Epoxy Resin–based Sealer to Root Canal Dentin

Introduction

The aim of this study was to evaluate the effects of calcium hydroxide (CH) and triple (TAP) and double (DAP) antibiotic pastes on the bond strength of an epoxy resin–based sealer (AH Plus Jet; Dentsply DeTrey, Konstanz, Germany) to the root canal dentin.

Methods

Sixty-four single-rooted human mandibular premolars were decoronated and prepared using the rotary system to size 40. The specimens were randomly divided into a control group (without intracanal dressing) and 3 experimental groups that received an intracanal dressing with either CH, DAP, or TAP (n = 16). The intracanal dressing was removed by rinsing with 10 mL 17% EDTA followed by 10 mL 2.5% sodium hypochlorite. The root canals were then obturated with gutta-percha and AH Plus Jet sealer. A push-out test was used to measure the bond strength between the root canal dentin and the sealer. The data were analyzed using 2-way analysis of variance and Tukey post hoc tests to detect the effect of the independent variables (intracanal medicaments and root canal thirds) and their interactions on the push-out bond strength of the root canal filling material to the root dentin (P = .05).

Results

The push-out bond strength values were significantly affected by the intracanal medicaments (P < .001) but not by the root canal thirds (P > .05). In the middle and apical third, the bond strength of the TAP group was higher than those of the CH and DAP groups (P < .05).

Conclusions

The DAP and CH did not affect the bond strength of the epoxy resin–based sealer. Additionally, the TAP improved the bond strength of the epoxy resin–based sealer in the middle and apical thirds.     

Sealapex Xpress and RealSeal XT Feature Tissue Compatibility In Vivo

Objective

This study evaluated the response of apical and periapical tissues of dogs' teeth with pulp vitality after root canal filling with the endodontic sealers Sealapex Xpress and Real Seal XT.

Methods

Thirty-eight root canals with vital pulp from dogs' premolars were used. After instrumentation, the canals were filled with Sealapex Xpress and gutta-percha (group SX/GP, n = 16) or Real Seal XT and Resilon cones (group RS/R, n = 22). The animals were killed after 90 days, and the teeth with surrounding tissues were subjected to histotechnical processing. Hematoxylin-eosin–stained sections were examined by conventional light microscopy for a quantitative histopathologic analysis (sealing of apical opening by newly formed mineralized tissue [biological sealing], inflammatory cell infiltrate, root and bone tissue resorption), according to a scoring system. The subsequent sections were evaluated by immunohistochemistry for identification of mineralization markers (osteopontin, alkaline phosphatase, and RUNX2). Data were analyzed by nonparametric Mann-Whitney U test (α = 0.05).

Results

Complete biological sealing was observed in 50% and 22.7% of the specimens of groups SX/GP and RS/R, respectively. Partial biological sealing was observed in 25% and 54.6% and absence of sealing in 25% and 22.7% of the specimens of groups SX/GP and RS/R, respectively. There were no significant differences (P > .05) between the groups for the scores attributed to the histopathologic parameters. Positive staining for osteopontin, alkaline phosphatase, and RUNX2 was observed in both groups, especially in the periodontal ligament.

Conclusions

Sealapex Xpress and RealSeal XT feature tissue compatibility in vivo and allow for sealing of apical opening by deposition of mineralized tissue.     

Push-out Bond Strength of RealSeal SE and AH Plus after Using Different Irrigation Solutions

Introduction

The aim of this investigation was to evaluate the influence of different endodontic irrigants (sodium hypochlorite [NaOCl], chlorhexidine [CHX], and EDTA) on the push-out bond strength of the obturation materials RealSeal SE (SybronEndo, Orange, CA) and AH Plus (Dentsply International Inc, York, PA).

Methods

Two hundred human root canals were prepared and divided into 2 groups according to the filling material (RealSeal SE vs AH Plus). Each group was subdivided into 5 groups according to the irrigation protocol (0.9% saline [control], 3% NaOCl, 3% NaOCl with saline, 17% EDTA, and 2% CHX). After obturation, roots were sliced into 1-mm discs for push-out assessment. Compressive loading was performed using an universal testing machine at a speed of 0.5 mm/min. Two-way analysis of variance and the Kruskal-Wallis test were performed for pair-wise comparisons to assess the differences between the experimental groups.

Results

AH Plus exhibited a significantly higher bond strength than RealSeal SE (mean = 2.53 and 1.53 MPa, respectively; P < .05), except with saline alone (P > .05). Within the AH Plus groups, no significant differences existed between the irrigants and saline alone (P > .05). The bond strength of RealSeal SE with saline alone or with NaOCl and saline did not differ from that of AH Plus with saline alone (P > .05). However, the push-out bond strength of RealSeal SE decreased by approximately half (P < .05 compared with RealSeal SE with saline alone) after rinsing with NaOCl alone, EDTA, or CHX.

Conclusions

The bond strength of RealSeal SE is highly influenced by the irrigant used.     

Influence of endodontic irrigants on resin sealer bond strength to radicular dentin

The present study evaluated the influence of 2% chlorhexidine and 2.5% sodium hypochlorite on the resin sealer/dentin interface bond strength of AH Plus/gutta-percha and Epiphany/Resilon. Seventy-two extracted bovine incisors were randomly distributed into 6 groups according to irrigant and sealers: G(S+AH)=physiologic saline solution+AH Plus/gutta-percha; G(S+Ep)=physiologic saline solution+Epiphany/Resilon; G(H+AH)=2.5% sodium hypochlorite (NaOCl)+AH Plus/gutta-percha; G(H+Ep)=2.5% NaOCl+Epiphany/Resilon; G(C+AH)=2% chlorhexidine (CHX)+AH Plus/gutta-percha; and G(C+Ep)=2% CHX+Epiphany/Resilon. After 7 days at 37°C and 100% humidity, the roots were cut transversally on the long axis of the tooth in 0.8 mm (±0.09)-thick slices; these slices were then subjected to the push-out test. Data were analyzed using a 2-way ANOVA and Tukey tests at 5% significance. The AH Plus/gutta-percha groups showed significantly higher bond strength than the Epiphany/Resilon groups, regardless of the irrigant used (p<0.001). Sodium hypochlorite adversely affected bond strength in the AH Plus group, whereas chlorhexidine did not influence the push-out bond strength of either sealer (p<0.05). Two percent chlorhexidine did not adversely affect the bond strength of the sealers, whereas 2.5% sodium hypochlorite solution damaged AH Plus/gutta-percha bond strength.     

The apical sealing ability of a new root canal filling material

PURPOSE: To assess the apical sealing property of a new root canal filling material, Epiphany. METHODS: Seventy extracted maxillary and mandibular single-rooted teeth were used. They were randomly divided into three groups and obturated by lateral condensation with gutta-percha and AH 26/AH Plus sealers and Resilon core material and Epiphany sealer. Apical leakage was measured by the fluid-transport method. RESULTS: The differences in leakage among gutta-percha with AH 26, gutta-percha with AH Plus, and Resilon with Epiphany were statistically significant (P < 0.05). The teeth filled with gutta-percha/AH 26 displayed the most apical leakage. There were no differences between the Resilon/Epiphany and gutta-percha/AH Plus groups (P > 0.05).     

The Effect of Different Final Irrigant Activation Techniques on the Bond Strength of an Epoxy Resin–based Endodontic Sealer: A Preliminary Study

Introduction

The aim of this study was to evaluate whether or not different final irrigation activation techniques affect the bond strength of an epoxy resin–based endodontic sealer (AH Plus; Dentsply DeTrey, Konstanz, Germany) to the root canal walls of different root thirds.

Methods

Eighty single-rooted human mandibular premolars were prepared by using the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) to size F4, and a final irrigation regimen using 3% sodium hypochlorite and 17% EDTA was performed. The specimens were randomly divided into 4 groups (n = 20) according to the final irrigation activation technique used as follows: no activation (control), manual dynamic activation (MDA), CanalBrush (Coltene Whaledent, Altststten, Switzerland) activation, and ultrasonic activation. Five specimens from each group were prepared for scanning electron microscopic observation to assess the smear layer removal after the final irrigation procedures. All remaining roots were then obturated with gutta-percha and AH Plus sealer. A push-out test was used to measure the bond strength between the root canal dentin and AH Plus sealer. The data obtained from the push-out test were analyzed using 2-way analysis of variance and Tukey post hoc tests.

Results

The bond strength values mostly decreased in the coronoapical direction (P < .001). In the coronal and middle thirds, ultrasonic activiation showed a higher bond strength than other groups (P < .05). In the apical third, MDA displayed the highest bond strength to root dentin (P < .05). The majority of specimens exhibited cohesive failures.

Conclusions

The bond strength of AH Plus sealer to root canal dentin may improve with ultrasonic activation in the coronal and middle thirds and MDA in the apical third.     

Root Reinforcement after Obturation with Calcium Silicate–based Sealer and Modified Gutta-percha Cone

Introduction

A root canal obturated with a calcium silicate–based sealer (bioceramic sealer [BCS]) and a modified gutta-percha cone (bioceramic cone [BCC]) might improve the fracture resistance of the root. The objective of this study was to evaluate root reinforcement of a bioceramic cone/sealer (TotalFill; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) by investigating the fracture resistance, push-out bond strength, sealer penetration, and modulus of elasticity (MOE) in comparison with gutta-percha/AH Plus (Dentsply Maillefer, Tulsa, OK) (GP/AH).

An in vitro assessment of the sealing ability of resilon/epiphany using fluid filtration

The aim of this in vitro study was to compare the sealing ability of Resilon/Epiphany to gutta-percha and Roth or AH Plus sealers. Leakage of the obturated roots was measured using the fluid filtration technique. There were eight groups of 12 teeth each. Group 1: obturated with Resilon/Epiphany; group 2: obturated with gutta-percha/Roth, allowed to set for 3 wk; group 3: obturated with gutta-percha/Roth; group 4: obturated with Resilon/Epiphany using a single cone; group 5: obturated with Resilon cones without using primer/sealer (positive control); group 6: obturated with gutta-percha/AH Plus; group 7: same as group 6, but allowed to set for 8 h; and group 8: sealed on the outside with three layers of nail varnish (negative control). The results showed that only the positive control (group 5) leaked significantly more (p < 0.05) than the other groups. There was no effect of time on leakage. Resilon/Epiphany was no better than gutta-percha/Roth or gutta-percha/AH Plus at sealing root canals.     

Influence of filling materials on the bonding interface of thin-walled roots reinforced with resin and quartz fiber posts

Introduction

A common complication during the restoration of severely destroyed teeth is the loss of coronal root dentine. The aim of this study was to evaluate the influence of different sealers on the bonding interface of weakened roots reinforced with resin and fiber posts.

Methods

Sixty extracted maxillary canines were used. The crowns were removed, and the thickness of root dentine was reduced in the experimental (n = 40) and positive control (n = 10) groups. The specimens of experimental group were assigned to four subgroups (n = 10) according to the filling material: gutta-percha + Grossmann’s sealer, gutta-percha + AH Plus (Dentsply De Trey Gmbh, Konstanz, Germany), gutta-percha + Epiphany (Pentron Clinical Technologies, Wallingford, CT), and Resilon (Resilon Research LLC, Madison, CT) + Epiphany. In the negative control group (n = 10), canals were not filled. After post space preparation, the roots were restored with composite resin light-activated through a translucent fiber post. After 24 hours, specimens were transversally sectioned into 1-mm-thick slices. Push-out test and scanning electron microscopic (SEM) analyses of different regions were performed. Data from push-out test were analyzed by using Tukey post hoc multiple comparison tests. The percentage of failure type was calculated. Data from SEM analysis were compared by Friedman and Kruskal-Wallis tests (α = 0.05).

Results

The mean bond strength was significantly higher in the negative control group as compared with the other groups (P < .05). In all groups, the most frequent type of failure was adhesive. Overall, apical and middle regions presented a lower density of resin tags than the coronal region (P < .05).

Conclusions

The push-out bond strength was not affected by sealer or region. The canal region affected significantly the resin tag morphology and density at the bonding interface.     

An in vitro evaluation of the apical sealing ability of a new resin-based root canal obturation system

The purpose of this study was to assess the apical sealing ability of the new resin-based Epiphany-Resilon root canal filling system, and to compare this with the sealing abilities of different pairings of AH plus, gutta-percha, Epiphany, and Resilon. Seventy extracted human single-rooted teeth were used. All teeth were instrumented using a set of ProTaper rotary instruments. The canal spaces were filled with different combinations of core and sealer using lateral condensation, as follows: group 1, AH Plus + gutta-percha; group 2, AH Plus + Resilon; group 3, Epiphany + Resilon; group 4, Epiphany + gutta-percha. Apical leakage quantity was measured with the computerized fluid filtration meter. Statistical analysis indicated that Epiphany gutta-percha combination had the least amount of microleakage than all the other groups; AH Plus gutta-percha combination proved to have second least amount of microleakage among the groups. AH Plus-Resilon combination demonstrated the greatest amount of microleakage. There were a significant difference between Epiphany gutta-percha and AH Plus-Resilon combinations (p < 0.05). It was found that there were no significant differences between Epiphany-Resilon combination and all the other groups (p > 0.05).     

Comparison between gutta-percha and resilon removal using two different techniques in endodontic retreatment

This study compared the remaining filling material and working time when removing gutta-percha/AH 26 and Resilon/Epiphany from root filled extracted teeth. The root fillings were removed using chloroform and two different rotary systems (K3 and Liberator files). The amount of residual filling material on the canal walls was imaged and measured using image analyzer software. The group filled with Resilon/Epiphany and retreated with K3 files demonstrated the least residual filling material on the walls (p < 0.05). There was no statistically significant difference between the gutta-percha/AH26 and Resilon/Epiphany groups when the Liberator files were used (p > 0.05). In the groups filled with Resilon/Epiphany, the filling was removed faster than groups filled with gutta-percha/AH 26 (p < 0.05). K3 rotary system was faster than Liberator to remove both gutta-percha and Resilon (p < 0.05). Resilon/Epiphany was effectively removed with K3 or Liberator rotary files.     

Push-out bond strengths: the Epiphany-Resilon endodontic obturation system compared with different pairings of Epiphany, Resilon, AH Plus and gutta-percha

AIM: To assess the bond strength of the new resin-based Epiphany-Resilon root canal filling system, and to compare this with bond strengths of different pairings of AH Plus, gutta-percha, Epiphany and Resilon. METHODOLOGY: A total of 65 extracted human single-rooted teeth were used. All teeth were instrumented using a set of ProTaper rotary instruments. Irrigation was performed with 15 mL of 1.25% NaOCl between each instrument and the smear layer was removed during and after instrumentation with 5 mL of 17% EDTA. The canal spaces were filled with different combinations of core and sealer using lateral condensation, as follows: group 1, AH Plus + gutta-percha; group 2, AH Plus + Resilon; group 3, Epiphany + Resilon; group 4, Epiphany + gutta-percha; group 5 (control), gutta-percha only. Cylinders of root dentine 1.13 (0.06)-mm long were prepared from the coronal sections of the 65 teeth. The test specimens were subjected to the push-out test method. After adhesion testing, the remaining sections were examined under a stereomicroscope at x 25 magnification to determine the nature of bond failure. The values of bond strength were analyzed by one-way analysis of variance (ANOVA) and the post hoc Tukey's test, with significance set at P < 0.05. RESULTS: The respective mean push-out test values for groups 1-5 were: 2.000 +/- 0.369, 1.380 +/- 0.154, 1.706 +/- 0.340, 2.857 +/- 0.523 and 0.078 +/- 0.027 MPa. Significant difference (P < 0.001) occurred between the groups. Multiple paired comparisons (Tukey's test) revealed that group 4 (Epiphany + gutta-percha) had significantly (P < 0.001) greater bonding strength than all the other groups; group 1 (AH Plus + gutta-percha) had significantly (P < 0.05) greater bonding strength than group 2 (AH Plus + Resilon); and group 5 (control) had significantly (P < 0.05) lower bonding strength than all the other groups. Inspection of the surfaces revealed the bond failure to be mainly adhesive to dentine for all groups. CONCLUSIONS: The Epiphany-Resilon combination (group 3) was not superior to that of the AH Plus-gutta percha combination (group 1).     

The Effect of Different Irrigating Solutions on Bond Strength of Two Root Canal–filling Systems

The bond strength of ActiV GP root canal filling system and gutta-percha/AH plus sealer when used after final rinse with different irrigation protocols was evaluated in this study. Forty roots were randomly divided into four groups (n = 10) according to the final irrigation regimen: group 1, 5 mL 17% EDTA; group 2, 5 mL 17% EDTA followed by 5 mL 2% chlorhexidine gluconate (CHX); group 3, 5 mL MTAD; and group 4, 5 mL MTAD followed by 5 mL 2% CHX. Each group was further subdivided into two subgroups (n = 5): in subgroup a, the root canals were filled using warm gutta-percha and AH plus sealer, and in subgroup b, the root canals were filled using the ActiV GP obturation system. Two-millimeter thick horizontal sections from the coronal and midthirds of each root were sliced for the push-out bond strength measurement. EDTA/CHX/ActiV GP (2.46 ± 1.02 MPa) yielded significantly the highest mean bond strength value. The significantly lowest bond strength was recorded for EDTA/ActiV GP (1.12 ± 0.72 MPa). It was concluded that the bond strength of ActiV GP was improved by using 2% CHX in the final irrigation after 17% EDTA, whereas CHX did not enhance the effect of MTAD on the bond strength of the material. The bond strength of gutta-percha/AH plus was adversely affected by MTAD and MTAD/CHX.     

In Vitro Fracture Resistance of Roots Obturated with Epoxy Resin–based,Mineral Trioxide Aggregate–based,and Bioceramic Root Canal Sealers

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 mandibular premolars were decoronated to a length of 13 mm. The teeth were randomly 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.     

Biocompatibility of a Self-adhesive Gutta-percha–based Material in Subcutaneous Tissue of Mice

Introduction

The purpose of this study was to evaluate the biocompatibility of a self-adhesive gutta-percha material and compare it with that of conventional gutta-percha.

Methods

Standard quantities of bioactive gutta-percha and conventional gutta-percha were directly inserted subcutaneously into the dorsal connective tissue of 30 BALB/c mice according to ISO 10993-6. After 7, 21, and 63 days each, 10 animals were euthanized, and the materials and surrounding tissue were removed. Tissue samples were subjected to histological processing resulting in 5-μm-thick slices stained with hematoxylin-eosin and Gomori trichrome stain. A grade ranging from I–IV was used to classify the inflammatory reaction. The Mann-Whitney U test with Bonferroni correction was used to compare the grade of inflammation induced by the materials at each time point. Qualitative evaluation of biocompatibility over time was also performed.

Results

Bioactive gutta-percha was more biocompatible than conventional gutta-percha at each time interval (P < .05). Tissue exposed to bioactive gutta-percha reached “no inflammation” (grade I) at the 21-day interval, whereas it took 63 days for the conventional gutta-percha to reach the “slight inflammation” level (grade II).

Conclusions

Bioactive gutta-percha presented good tissue reaction at all time points. It may serve as an alternative to gutta-percha in terms of biocompatibility.     

A novel polyurethane-based root canal-obturation material and urethane-acrylate-based root canal sealer-part 2: evaluation of push-out bond strengths

We have developed a visible-light curable urethane-acrylate/tripropylene glycol diacrylate (UA/TPGDA) oligomer to serve as a root canal sealer and a zinc oxide/thermoplastic polyurethane (ZnO/TPU) composite to serve as a root canal obturation material. The purpose of this study was to compare the push-out bond strengths of the following 8 groups of materials: (1) Tubliseal + gutta-percha (TB/GP); (2) Tubliseal + Resilon (TB/R); (3) Epiphany + gutta-percha (EP/GP); (4) Epiphany + Resilon (EP/R); (5) EndoREZ sealer + EndoREZ cone (ES/EC); (6) EndoREZ sealer + ZnO/TPU (ES/PU); (7) UA/TPGDA + EndoREZ cone (UA/EC); and (8) UA/TPGDA + ZnO/TPU (UA/PU). Eighty 1-mm-thick root slices prepared from extracted human permanent molars were randomly divided into 8 groups with 10 specimens in each group. Root slices were filled with the above obturation materials, and then push-out test was performed with a universal testing machine. The results showed that the UA/EC and UA/PU groups had significantly higher bond strengths than the other groups.     

Radiographic Identification of Separated Instruments Retained in the Apical Third of Root Canal–filled Teeth

Introduction

The aim of the study was to compare the diagnostic ability to radiographically detect separated stainless steel (SS) versus nickel-titanium (NiTi) instruments located at the apical third of filled root canals with either AH 26 (Dentsply DeTrey GmbH, Konstanz, Germany) or Roth sealer (Roth International Ltd, Chicago, IL).

Methods

Sixty single-rooted extracted human teeth with 1 straight root canal were instrumented to a size 25 apical diameter. In 40 teeth, apical 2-mm segments of SS (n = 20) or NiTi (n = 20) files were intentionally fractured in the apical part of the root canal. The remaining 20 teeth without fractured files served as a control group. Subsequently, the root canals were filled using laterally condensed gutta-percha and either AH 26 sealer (AH) or Roth sealer (Roth). All teeth were radiographed using conventional Kodak film (Eastman Kodak Co, Rochester, NY) and a charge-coupled device digital sensor. The evaluation of the images for the presence of a fractured instrument was performed independently by 2 blinded observers. The data were statistically analyzed using McNemar and Fisher exact tests.

Results

The kappa values were 0.76 and 0.615 for the first and second observers, respectively, and 0.584 between the observers. There were no significant differences in the diagnostic ability between digital and conventional radiography or the different root canal sealers (AH vs Roth, P > .05). The sensitivity to detect fractured SS was significantly higher than NiTi (P < .05).

Conclusions

It may be difficult to radiographically detect a retained separated instrument. It is easier to radiographically detect fractured SS than NiTi instruments retained at the apical third of the root canal.     

Thermocompaction decreases long-term push-out bond strength of methacrylate-based sealers

Abstract

Purpose. The purpose of this study was to evaluate the immediate and long-term bond strengths to root dentin of Epiphany/Resilon and AH Plus/gutta-percha fillings, after using either lateral condensation or Tagger’s hybrid thermomechanical compaction techniques. Materials and methods. Eighty human single-rooted teeth were used. The root canals were prepared by means of hand crown-down technique up to a #45 K-file and irrigation with 1% sodium hypochlorite was performed. Samples were randomly divided into eight (n = 10) experimental groups divided according to filling material (gutta-percha/AH Plus and Resilon/Epiphany), obturation technique (Lateral compaction and Tagger’s hybrid thermomechanical compaction) and storage time (24 h and 6 months). During storage, the samples were kept at 37°C and 100% humidity. After the two experimental periods, each root was sectioned perpendicular to its long axis into three serial slices and push-out tests were carried out using a universal testing machine. Statistical significant differences were set by ANOVA and Tuckey post-hoc (p < 0.05). Results. Using thermocompaction technique, the samples filled with Epiphany/Resilon decreased significantly the bond strength after a 6 months storage-period (p < 0.05) and the ones filled with AH Plus/gutta-percha presented a tendency to lower values of the push-out test, although not statistically significant. For both materials, dentin bond strength of the specimens filled by means of lateral condensation remained stable throughout the experimental periods. Conclusion. Under the limitations of the current study, it can be concluded that the thermocompaction technique and the storage time can in?uence push-out bond strength when used with methacrylate-based sealers.