Zeliha Yilmaz

Effect of low-surface-tension EDTA solutions on the wettability of root canal dentin

OBJECTIVE This study was conducted to evaluate the effect of reducing the surface tension of ethylenediaminetetraacetic acid (EDTA) solutions on the wettability of root canal dentin. STUDY DESIGN Forty-two extracted teeth were sectioned at the crown, and the apical third and remaining mid-root portion was bisected longitudinally. The root halves were embedded in resin blocks. The experimental groups were treated with 17% EDTA, EDTA-T, and REDTA alone or followed by 2.5% NaOCl. Surface free energies of samples were calculated by measuring contact angles. Surface tension measurements of all solutions were performed with pendant drop method. RESULTS The addition of surfactant to the EDTA solution significantly decreased the surface tension of solutions (P < .01). Combined and single use of experimental solutions and NaOCl significantly decreased the water contact angle and increased the surface free energy of root canal dentin (P < .05). EDTA-T alone or combined with NaOCl also increased surface free energy compared with EDTA solution (P < .05). CONCLUSIONS The use of low-surface-tensioned EDTA compounds alone or in combination with NaOCl increased the wettability of root canal dentin.

Sealing efficiency of BeeFill 2in1 and System B/Obtura II versus single-cone and cold lateral compaction techniques.

OBJECTIVE The objective of this study was to investigate the sealing properties of 2 warm vertical compaction techniques (BeeFill 2in1, System B/Obtura II) in comparison with single-cone and cold laterally compacted gutta-percha. STUDY DESIGN The root canals of single-rooted human teeth were prepared by using Mtwo rotary files and divided into 4 groups (n = 10/group) with respect to the filling technique tested: Group 1, cold laterally compacted gutta-percha + AH-26; Group 2, single-cone tapered Mtwo gutta-percha + AH-26; Group 3, System B/ObturaII + AH-26; Group 4, BeeFill 2in1 + 2seal. The leakage of specimens was measured using a fluid-filtration method after 1 and 2 weeks. The data were analyzed statistically with 2-way repeated measures ANOVA (P = .05). RESULTS After 1 week, the System B/Obtura II group showed the greatest amount of leakage(P < .05) compared with the other test groups that had similar levels of fluid conductance(P < .05). By the end of the second week, the BeeFill group yielded the greatest amount of leakage (P < .05). Compared with their 1-week values, the fluid conductance of all test groups decreased significantly (P < .05). CONCLUSION The apical sealing efficiency of System B/Obtura II and BeeFill were inferior to the other obturation techniques after 2-week fluid conductance testing in vitro.

Microleakage evaluation of roots filled with different obturation techniques and sealers

OBJECTIVE The aim of this study was to compare the apical seal of the Single-cone ProTaper gutta-percha technique and the lateral compaction technique in combination with 3 sealers (AH-26, Apexit, and Sealite-Ultra). STUDY DESIGN Seventy extracted single-root teeth were used. Root canals were prepared with ProTaper rotary instruments. Six groups were formed: (I) Single-cone ProTaper gutta-percha with AH-26; (II) lateral compaction technique with AH-26; (III) Single-cone ProTaper gutta-percha with Apexit; (IV) lateral compaction technique with Apexit; (V) Single-cone ProTaper gutta-percha with Sealite-Ultra; and (VI) lateral compaction technique with Sealite-Ultra. The fluid conductance of each specimen was measured after the 7th and 30th days using a fluid filtration method. RESULTS When lateral compaction was performed, all sealers showed similar levels of leakage (P > .05). Using the single-cone technique, Sealite-Ultra showed more leakage than the others (P < .05). Comparing filling techniques, there was a significant difference only in the Sealite-Ultra groups (P < .05). CONCLUSION Single-cone ProTaper gutta-percha and lateral compaction techniques showed similar sealing effect.

Influence of cement type and thickness on polyfiber post adhesion

Introduction: To evaluate the effect of two different post space diameters and related resin cement film thicknesses on the bond strength of a polyfiber post. Materials and Methods: A total of 48 premolars were randomly divided into two according to the post space diameter: 1.1 mm and 1.5 mm. Then each group was divided into three sub-groups according to luting cement used: RelyX U100, Panavia F2.0/ED primer, Clearfil SA cement. Spirapost was then luted into the canal using luting cements. Two slices were obtained from each root specimen. Push-out tests were performed. Data was analyzed with Kruskal-Wallis and Connover post-hoc and Mann-Whitney U-test (P < 0.05). Results: Push-out bond strength was found to vary significantly according to type of adhesive system and post space diameter size (P < 0.05). The self-adhesive resin cement RelyX U100 had significantly higher bond strengths compared with the other adhesive system (P < 0.05). The self-etch adhesive system (Panavia F2.0) showed significantly lower bond strengths compared with the other systems (P < 0.05). There was a significant interaction between the luting systems and post space diameter (P < 0.05). Conclusion: The increases in post space diameter significantly reduced the bond strength of Spirapost to root dentine for both groups.

Effectiveness of a new canal brushing technique in removing calcium hydroxide from the root canal system: A scanning electron microscope study

Aim: To evaluate the effectiveness of Canal Brush technique removal Ca(OH)2 from the root canal system using Scanning Electron Microscope (SEM). Materials and Methods: Eighteen teeth were instrumented up to #40 and dressed with Ca(OH)2. Ca(OH)2 was removed with master apical file (MAF) (Group 1, n:6) and CanalBrush technique (Group 2, n:6). Six teeth served as positive and negative controls. The roots were splited in the buccolingual direction and prepared for SEM examination. Two examiners evaluated the wall cleanliness then statistical analysis was performed by Mann-Whitney U and Friedman tests. Results: Differences in cleanliness were observed between Group 1 and Group 2 in the apical thirds (P=0.002). In the coronal and middle thirds, there were no differences between the two groups. Conclusions: It is essential to re-instrument the root canal walls using instrumentation techniques while irrigating with NaOCl and EDTA combination. The Canal Brush technique results in the packing effect of the Ca(OH)2 through to the apex.

Effects of dentin moisture on the push-out bond strength of a fiber post luted with different self-adhesive resin cements.

Objectives This study evaluated the effects of intraradicular moisture on the pushout bond strength of a fibre post luted with several self-adhesive resin cements. Materials and Methods Endodontically treated root canals were treated with one of three luting cements: (1) RelyX U100, (2) Clearfil SA, and (3) G-Cem. Roots were then divided into four subgroups according to the moisture condition tested: (I) dry: excess water removed with paper points followed by dehydration with 95% ethanol, (II) normal moisture: canals blot-dried with paper points until appearing dry, (III) moist: canals dried by low vacuum using a Luer adapter, and (IV) wet: canals remained totally flooded. Two 1-mm-thick slices were obtained from each root sample and bond strength was measured using a push-out test setup. The data were analysed using a two-way analysis of variance and the Bonferroni post hoc test with p = 0.05. Results Statistical analysis demonstrated that moisture levels had a significant effect on the bond strength of luting cements (p < 0.05), with the exception of G-Cem. RelyX U100 displayed the highest bond strength under moist conditions (III). Clearfil SA had the highest bond strength under normal moisture conditions (II). Statistical ranking of bond strength values was as follows: RelyX U100 > Clearfil SA > G-Cem. Conclusions The degree of residual moisture significantly affected the adhesion of luting cements to radicular dentine.

Final Irrigation Regimens Affect Fracture Resistance Values of Root-filled Teeth.

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 randomly selected roots were used as the negative control group. The remaining roots were prepared by the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) 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 manufacturers 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.

Efficacy of rotary Ni-Ti retreatment systems in root canals filled with a new warm vertical compaction technique

The aim of this study was to compare the efficacy of Mtwo, ProTaper retreatment files and Hedström files for the retreatment of root canals filled with BeeFill 2 in1 and cold lateral compaction techniques. 63 single-rooted human teeth were prepared with Mtwo rotary files to size 35/.04 and assigned into three groups (n=21/group). (1) BeeFill 2 in1/2Seal, (2) BeeFill 2 in1/AH26 and (3) laterally-compacted gutta-percha/AH26. The specimens were subgrouped according to the file system used to remove root fillings (n=7/subgroup): 1. Mtwo retreatment file, 2. ProTaper retreatment file, 3. Hedström file. Roots were split longitudinally and photographed. The time required for removal of root canal fillings and the areas of residual root filling materials were compared statistically (p<0.05). The maximum amount of remnant was observed in the Mtwo group for removal of BeeFill 2 in1/AH26. ProTaper retreatment files required less time to remove root filling material than Mtwo retreatment files and Hedström files (p<0.05). Among the tested removal systems, ProTaper retreatment files may offer the best efficiency-speed combination.

The Effect of Temperature and pH Variations on the Surface Tension of EDTA Solutions

INTRODUCTION Surface tension of a liquid is one of the major factors that affect the wetting of a solid. The reduction in surface tension could improve the contact of irrigants with the dentinal walls of the root canal system. This in vitro study was conducted to evaluate the effect of pH and temperature variations on the surface tension of EDTA solutions. METHODS Three solutions, 17% EDTA, REDTA, and EDTA-T, were prepared and adjusted to have a pH of 5.5, 7.5, and 10.5. The surface tension of the test solutions was measured at 22 °C by the pendant drop technique, and the measurement was repeated after heating the solution at 37 °C. Differences among the experimental groups were statistically analyzed using three-way analysis of variance followed by the Bonferroni test for pair-wise comparison. RESULTS The results of this study showed that there were significant differences in the surface tension values of solutions depending on the pH and temperature (P < .001). The surface tension level of the EDTA solution dramatically decreased when surfactant was added to the EDTA solution in both pH and temperature variations (P < .001). The increased temperature significantly altered the surface tension value at a pH of 5.5 of all EDTA solutions, at a pH of 7.5 of EDTA and REDTA solutions, and at a pH of 10.5 of only REDTA solution (P < .01). CONCLUSIONS It was concluded that the surface tension of EDTA with and without surfactant is influenced by pH and temperature.

Influence of different final irrigation regimens and various endodontic filling materials on vertical root fracture resistance

AIM The aim of this study was to evaluate the influence of different endodontic materials and final irrigation regimens on vertical root fracture (VRF) resistance. MATERIALS AND METHODS Eighty human teeth were prepared then assigned into two groups (n = 40) according to the final irrigations. G1: 5 mL, 5.25% sodium hypochlorite (NaOCl), G2: 5 mL, 2% chlorhexidine gluconate (CHX). Each group was assigned into four subgroups according to the obturation system used (n = 10): A: iRoot SP/single gutta-percha cone (SGP), B: Only iRoot SP, C: Mineral trioxide aggregate (MTA)-Fillapex/SGP, D: AH26/SGP. The specimens were embedded in acrylic molds and subjected to compressive loading at a rate of 1 mm min until VRF occurred. Data were analyzed via three-way ANOVA tests. RESULTS The statistically significant difference was found among groups (P < 0.05). The G1A and G1B and G1D revealed significantly higher-VRF values than G1C (P = 0.023). The roots filled with MTA-Fillapex revealed lower-VRF values than the other subgroups (P < 0.05). Groups irrigated with NaOCl had significantly lower-VRF values than the groups irrigated with CHX (P < 0.05). CONCLUSION Final irrigation regimens could alter VRF resistance of root canals filled with different obturation technique and root canal sealers.