Resistance to vertical root fracture of apicoected teeth using different devices during two root canal irrigation procedures.

The aim of the present work was to measure the fracture resistance of endodontically treated teeth that were apicoected with different procedures. Seventy-two extracted human maxillary anterior teeth were included in this study. The specimens were randomly assigned to three main groups according to the apical surgery procedures and then two subgroups according to the irrigation protocols during root canal treatment and total of six groups were obtained (n = 12). Group 1: served as a control and apical surgery process was not performed in this group. Group 2: apical surgery process was performed with tungsten carbide fissure bur Group 3: apical surgery process was performed with Er:YAG laser. Subgroup a: In this group, the specimens were irrigated with %5 NaOCl. Subgroup b: 15% EDTA solution was filled into the root canal and then agitated using a 1.5 W/100 Hz diode laser. The specimens were filled and mounted in acrylic resin blocks and compression strength test was performed. Statistical analysis was performed using two-way ANOVA. The statistical analysis revealed that there were no statistical significant differences between apical surgery procedures (groups 1, 2, and 3) (p < 0.05). Apical resection procedures did not affect the fracture resistance Significant differences were determined between the subgroups (p < 0.05). Agitation of the EDTA with the diode laser reduced the fracture resistance of the specimens. The different canal irrigation techniques altered resistance to fracture; however, apical surgery procedures did not altered the resistance to fracture when compared with the control group.

The Effect of Diode Laser With Different Parameters on Root Fracture During Irrigation Procedure.

The aim of this study is to compare the effect of a single diode laser application and agitation of EDTA with diode laser with different parameters at different time intervals on root fracture. Ninety mandibular incisors were instrumented except the negative control group. The specimens were divided randomly into 10 groups according to final irrigation procedure: (G1) non-instrumented; (G2) distilled water; (G3) 15% EDTA; (G4) ultrasonically agitated EDTA; (G5) single 1.5W/100 Hz Diode laser; (G6) single 3W/100 Hz Diode laser; (G7) 1.5W/100 Hz Diode laser agitation of EDTA for 20 s; (G8) 1.5W/100 Hz Diode laser agitation of EDTA for 40 s; (G9) 3W/100 Hz Diode laser agitation of EDTA for 20 s; and (G10) 3W/100 Hz Diode laser agitation of EDTA for 40 s. The specimens were filled, mounted in acrylic resin, and compression strength test was performed on each specimen. Statistical analysis was carried out using one way ANOVA and Tukey's post hoc tests (P = 0.05). The statistical analysis revealed that there were statistically significant differences among the groups (P < 0.05). Laser-agitated irrigation with a 3W/100 Hz Diode laser for both 20 s and 40 s decreased the fracture resistance of teeth.

Effect of different post space irrigation procedures on the bond strength of a fiber post attached with a self-adhesive resin cement.

STATEMENT OF PROBLEM: The effects of different post space irrigation procedures on the bond strength of a self-adhesive resin cement to the root canal dentin are still unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effects of alternative post space irrigation procedures on the cement strengths of posts attached with a self-adhesive resin cement. MATERIAL AND METHODS: Forty single-rooted teeth were selected, and after root canal preparation and obturation, post spaces were prepared. The teeth were divided into 4 groups corresponding to the post space irrigation procedure and treated as follows: the distilled water (DW) group (control) received 15 mL of distilled water; the NaOCl+ethylenediaminetetraacetic acid (EDTA) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of distilled water; the chlorhexidine (CHX) group was treated with 15 mL of 2% chlorhexidine solution; and the phosphoric acid (PA) group treatment consisted of etching the walls of the prepared post holes with 35% phosphoric acid. Fiber posts were attached with a self-adhesive resin cement, and specimens were cut horizontally for push-out testing. The statistical evaluation consisted of 1-way ANOVA with the post hoc Tukey honest significant differences test (α=.05). RESULTS: The NaOCl+EDTA treatment yielded a significantly higher bond strength than those used in the other 3 groups (P=.003). No statistically significant differences were found among any of the other groups, as different root regions showed similar bond strength values (P>.05). CONCLUSIONS: The results showed that EDTA in combination with NaOCl could be advantageous for post space irrigation when fiber posts are bonded with a self-adhesive resin cement.

Effects of post surface treatments including Er:YAG laser with different parameters on the pull-out bond strength of the fiber posts.

This study aims to evaluate the effects of Er:YAG laser irradiation under different power settings on the pull-out bond strengths of fiber-reinforced composite posts. The crowns of single-rooted 60 teeth were removed by separation and the root canals were cleaned and shaped. Root canals were filled and post spaces were prepared. Sixty fiber posts were divided into five groups according to surface treatment methods as follows: an untreated control group, a sandblasting-coated group, and three groups undergoing surface preparation with Er:YAG laser under three different power settings (150, 300, and 450 mJ at 10 Hz for 60 s at 100-µs pulse duration). After root canal procedures, fiber posts were cemented to the root canal. After all of the specimens were set, pull-out tests were performed using a universal testing machine at a crosshead speed of 2 mm/min. The data were analyzed using one-way ANOVA and Tukey post-hoc test (p < 0.05). The pull-out strength values ranged between 5.26 and 6.76 Mpa. The lowest values were observed in the groups without surface treatment. Surface treatment applied by 4.5-W Er:YAG laser increased the pull-out bond strength compared to the control group (p < 0.05). 4.5-W Er:YAG laser irradiation increased the pull-out bond strength of fiber posts to resin cement.

Effect of citric acid irrigation on the fracture resistance of endodontically treated roots.

OBJECTIVE: The aim of this study was to evaluate the effect of citric acid irrigation on root fracture in different concentrations and at various time exposures on root fracture. MATERIALS AND METHODS: Forty-eight human mandibular incisors with similar dimensions were selected. The specimens were decoronated, then divided into 6 groups as follows: A group without instrumentation and filling (G1) and the 5 other groups with canal preparation and irrigation of distilled water (G2), 10% citric acid for 1 min (G3), 50% citric acid for 1 min (G4), 10% citric acid for 10 min (G5), and 50% citric acid for 10 min (G6). In the experimental groups, the canals were obturated and subjected to the strength test. Statistical analysis was performed using Kruskal-Wallis test (P = 0.05). RESULTS: G6 showed the highest fracture resistance (629.97 N), and G3 showed the lowest fracture resistance (507.76 N). However, there was no statistically significant difference among the groups. CONCLUSIONS: The results of this study suggest that use of citric acid is safe in terms of fracture resistance.

Effect of agitation of EDTA with 808-nanometer diode laser on removal of smear layer.

INTRODUCTION: Near-infrared diode lasers can be used for several applications, which range from disinfection to smear layer removal in endodontics. This study evaluated the efficacy of agitation of 15% EDTA with an 808-nm diode laser on removal of the smear layer. METHODS: Sixty extracted human maxillary central incisor teeth were instrumented up to ProTaper F4 (Dentsply Maillefer, Ballagues, Switzerland) and then randomly divided into 6 groups (n = 10 for each group) according to the different final irrigating protocols as follows: 5% sodium hypochlorite for 120 seconds performed with the NaviTip (Dentsply Maillefer, Ballaigues, Switzerland) (control group); 15% EDTA for 120 seconds performed with the NaviTip; and agitation of 15% EDTA with an 808-nm diode laser for 10, 20, 30, and 40 seconds. Specimens were observed under a scanning electron microscope, and open dentinal tubules were counted using Adobe Photoshop software (Adobe Systems, San Jose, CA). The data were analyzed with 1-way analysis of variance and Tukey post hoc tests (P = .05). RESULTS: The number of open dentinal tubules was higher in the middle thirds than in the apical thirds. The differences between the apical and middle thirds were statistically significant (P < .05). Statistically significant differences were also found between the control group and the other groups in both the middle and apical thirds of the root canals (P < .05). CONCLUSIONS: The results indicated that agitation of 15% EDTA with an 808-nm diode laser for 20 seconds was effective in removing the smear layer in the apical thirds of root canals.