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Background/purpose: Calcium hydroxide and mineral trioxide aggregate (MTA) are used for inducing a calcific barrier at an open tooth root (apexification). The purpose of this study was to compare the efficacy of calcium hydroxide and MTA for apexification of immature permanent teeth., Methods: Medline, Cochrane, EMBASE, and Google Scholar were searched until November 24, 2015, using the keywords apexification, permanent teeth, MTA, and calcium hydroxide., Results: Of 216 studies identified, four studies were included. There were no differences in the clinical success rate [pooled odds ratio (OR) = 3.03, 95% confidence interval (CI): 0.42-21.72, p = 0.271], radiographic success rate (pooled OR = 4.30, 95% CI: 0.45-41.36, p = 0.206), or apical barrier formation rate (pooled OR = 1.71, 95% CI: 0.59-4.96, p = 0.322) between calcium hydroxide and MTA groups. The time required for apical barrier formation was significantly less in the MTA group (pooled difference in means = -3.58, 95% CI: from -4.91 to -2.25, p < 0.001)., Conclusion: While both materials provide similar success rates, the shorter treatment time with MTA may translate into higher overall success rates because of better patient compliance., (Copyright © 2016. Published by Elsevier B.V.)

The aim of this study was to investigate the effect of sodium ascorbate (Sa) on degree of conversion (DC) and bond strength (BS) of RealSeal SE to sodium hypochlorite (NaOCl) treated root dentin. Two hundreds simulated canals were prepared and irrigated with Distilled water(DW), 1.3% NaOCl (1.3% N), 5.2% NaOCl (5.2% N), MTAD, 17% EDTA (EDTA), 10% Sa, 1.3% NaOCl/MTAD (N-M), 1.3% NaOCl/Sa/MTAD(N-Sa-M), 5.2% NaOCl/EDTA(N-E), and 5.2% NaOCl/Sa/EDTA (N-Sa-E) respectively. They were subsequently bulk filled with RealSeal SE and analyzed with micro-Raman spectroscopy and universal testing machine for DC and BS respectively. One-way ANOVA and post hoc Tukey's test showed DC of 1.3% N, 5.2% N, N-M and N-E were significantly lower (p<0.01) than other six groups. BS of DW, Sa, N-M were significantly lower than 1.3% N, 5.2% N, MTAD, EDTA, N-Sa-M and N-E (p<0.01), and group N-Sa-E achieved the highest BS among all groups (p<0.01). NaOCl negatively affected DC and BS of RealSeal SE, which could be reversed with 10% Sa.

Introduction: Recently, a methacrylate-based obturation system, Resilon/RealSeal SE, has been developed to replace gutta-percha and traditional sealers. As a resin-based material, degree of conversion (DC) is one of the most important characteristics. The aim of this study was to investigate the time-dependent change of DC of RealSeal SE as well as the influence of canal moisture and root canal depth on it., Methods: DC of RealSeal SE, either self-cured or dual-cured (n = 8 in each group), was calculated according to the Raman spectra obtained at different times after mixing. Thirty extracted teeth with single canal were instrumented and divided randomly into 2 groups in terms of different canal drying methods. In the ethanol group, excess distilled water in root canal was removed with paper points followed by 95% ethanol. In the paper points group, root canals were blot-dried with paper points until the last one appeared dry. DC of RealSeal SE was calculated from serial cross sections (2, 5, and 8 mm from the apex) obtained 1 week after obturation with Resilon/RealSeal SE., Results: Significant increase in DC of RealSeal SE was observed in 1 week (P < .01), with little change afterwards (P > .05). DC of sealer in ethanol group was significantly higher than in paper points group (P < .01). However, DCs of RealSeal SE at different levels of tooth sections were not significantly different (P > .05)., Conclusions: Both self-cured and dual-cured RealSeal SE achieved stable DC after 1 week. Root canal moisture was a critical factor in determining DC of RealSeal SE., (Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate the efficacy of the ProTaper Universal rotary retreatment system for gutta-percha (GP) removal from root canals., Methodology: Root canals of 60 extracted human maxillary anterior teeth were prepared and filled with laterally condensed GP and AH Plus sealer. Teeth were divided into three groups: group A--GP removal completed with the ProTaper Universal rotary retreatment system and with further canal repreparation accomplished with ProTaper Universal rotary instruments; group B--GP removal was completed using Gates Glidden drills and Hedström files with chloroform as a solvent, followed with further canal repreparation with ProTaper Universal rotary instruments; group C--the same as group B for GP removal with further canal preparation with stainless steel K-flex files (Kerr). The operating time was recorded. Teeth were rendered transparent for the evaluation of the area of remaining GP/sealer in bucco-lingual and mesial-distal directions. Statistical analysis was performed by using repeated measures analysis of variance and anova. Results The ProTaper Universal technique (group A) resulted in a smaller percentage of canal area covered by residual GP/sealer than in groups B and C, with a significant difference between groups A and C (P < 0.05). Mean operating time for group A was 6.73 min, which was significantly shorter (P < 0.05) than group B (10.86 min) and group C (13.52 min)., Conclusions: In this laboratory study all test techniques left GP/sealer remnants within the root canal. The ProTaper Universal rotary retreatment system proved to be an efficient method of removing GP and sealer from maxillary anterior teeth.

Objective: The aim of this study was to evaluate the sealing ability of Resilon after retreatment., Study Design: Sixty-six single-rooted mandibular premolars were enlarged to apical size 45 and then obturated with Resilon. The roots were randomly divided into 3 groups (n = 22/group). In group 1 no further treatment was done. Groups 2 and 3 were reinstrumented to apical size 60 using K-files and ProFile, respectively. In each group, 4 samples were kept for environmental scanning electron microscopy (ESEM) analysis. The remaining roots from groups 2 and 3 were refilled with Resilon. Sixteen roots from each group were then evaluated for microleakage; two roots served as controls. Data were analyzed statistically by Kruskall-Wallis test., Results: There were no significant differences between the experimental groups (P > .05). The ESEM showed new attachment of resin tags on the dentin surface of retreated roots., Conclusion: Resilon can be used for retreatment, but it still allowed microleakage.

Purpose: To evaluate the clinical effect of repair of lateral root canal perforation with mineral trioxide aggregate (MTA)., Methods: 18 teeth with root canal perforation were selected. The root canals were shaped and cleaned, and then obturated with gutta-percha before or after MTA was used to repair the perforation., Results: The postoperative X-ray films showed that the perforation of 17 teeth was repaired well, except one tooth with large and infected perforation. 10 cases showed a little over-filling of MTA. 16 patients were recalled and declared their teeth to be asymptomatic. The recall radiographs indicated that the apical radiolucent areas of teeth with pre-existing apical lesion decreased apparently or disappeared completely. No new radiolucency was found., Conclusions: MTA is effective in treatment of teeth with root canal perforation, even though the material is over-filled. Supported by 2004 Key Clinical Project of Medical Systems Affiliated to Ministry of Health and Natural Science Foundation of Guangdong Province (Grant No.5300624).

Objective: To compare the sealing ability and fracture resistance of roots endodontically treated with bonded and unbonded filling materials., Methods: One hundred and fifteen straight mandibular premolar teeth with single canal were divided randomly into 6 experimental groups, with 15 samples each, and 3 control groups. The sealing ability was evaluated using a glucose quantitative microleakage mode and fracture resistance was tested by universal testing machine., Results: The microleakage results showed that the bonded filling material had the lowest value while the unbonded filling material had the highest value in all groups. There were significant differences in microleakage value among the groups (P < 0.01), but no significant difference was noted in the fracture resistance among the testing groups (P = 0.7016)., Conclusions: Bonded filling material enhanced the sealing ability but could not reinforce the fracture resistance of endodontically treated teeth.

Objective: To synthesize a new resin root canal filling material (NRCFM) and evaluate its stability in water and artificial saliva., Methods: The new root canal filling material was made of thermoplastic elastomer (TPE), ethylene vinyl acetate (EVA) and activity fillers. The NRCFM's stability in water and artificial saliva with different pH values was assessed using gravimetric analysis, ICP and FE-SEM., Results: NRCFM1 and NRCFM2 were successfully made. Gravimetric evaluation showed that the changes in mass over 30 days different solution medium for NRCFM1 and NRCFM2 were comparable to that of GP (P > 0.05) and significantly different from Resilon (P < 0.001). ICP showed slight changes in Si concentration for NRCFM1 and NRCFM2, Zn for GP, Na and Si for Resilon in the alkaline artificial saliva (pH 9.5). GP and Resilon showed release of Zn and Na respectively in distilled water whereas NRCFM1 and NRCFM2 were stable. FE-SEM micrographs showed that there were slight changes on the surface topography of NRCFM1 and NRCFM2., Conclusions: The new resin root canal filling material NRCFM1 and NRCFM2 had good stability in different experimental solutions.

A new dimethacrylate monomer 9,9'-bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl] fluorene (3) with a molecular weight of 634 was synthesized in 51.4% yield by addition of a glycidyl ether group to 9,9'-bis(4-hydroxyphenyl) fluorene (1) by the reaction of compound 1 with epichlorohydrin, and then introducing the methacrylate moiety by the reaction of the epoxy group with methacrylic acid. The structure of monomer 3 was confirmed by FT-IR, (1)H-NMR, mass spectra and elemental analysis.