Burak Sagsen

Push‐out bond strength of two new calcium silicate‐based endodontic sealers to root canal dentine

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 randomly 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.

Can intracoronally bleached teeth be bonded safely

INTRODUCTION Our objective was to determine the effects of intracoronal bleaching on the shear bond strength and failure side location of metallic brackets at 2 times (bleaching immediately before bonding and 30 days before bonding). METHODS Sixty freshly extracted mandibular incisors were randomly divided into 3 groups; each group contained 20 teeth. After finishing canal preparation and root canal filling, the root fillings were removed to a level 2 mm apical to the cementoenamel junction. Glass ionomer base (Vitrabond, 3 M Dental Products, St Paul, Minn) was placed approximately 2-mm thick. Bleaching agent (Whiteness Perfect, FGM Dental Products, Joinville, Brazil) was placed into the rest of the cavity for 4 days at 2 times. Shear bond strength of these brackets was measured in megapascals. The adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance (ANOVA), Tukey, and chi-square tests. RESULTS The bond strengths of the group with no bleaching (mean, 20.25 +/- 7.06 MPa) were significantly higher (P >0.001) than those of the group that had bleaching immediately before bonding (mean, 4.85 +/- 3.22 MPa) and the group that had bleaching 30 days before bonding (mean, 8.70 +/- 4.93 MPa). The results of the chi-square comparisons indicated significant differences among the 3 groups. In the group with no bleaching, there was a higher frequency of ARI scores of 2 to 4, indicating cohesive failures in the resin. In the other 2 groups, the failures were mostly adhesive at the resin-enamel interface (ARI scores of 4 and 5). CONCLUSIONS Intracoronal bleaching with carbamide peroxide adversely affected the shear bond strength and changed the site of failure during debonding when bonding was done immediately or 30 days after bleaching.

The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation.

Objective: The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques. Materials and Methods: 120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted. Results: The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05). Conclusions: In conclusion, except the hand file and control group, all experimental groups showed microcrack formations.

Radiographic Assessment of the Technical Quality and Periapical Health of Root-Filled Teeth Performed by General Practitioners in a Turkish Subpopulation

Aim. The aim of this study was to evaluate by means of radiographs the technical quality of root fillings performed by dental practitioners. Methods and Material. Standardized periapical radiographs were made on 484 patients who received endodontic treatment in private practice. A total of 831 endodontically treated teeth with 1448 roots were evaluated for technical quality of the root canal filling and the periapical status of the teeth. Also, the apical status of each root-filled tooth was assessed according to the length, density, and taper of root fillings, and the presence of apical transportation, broken root instruments, and overfilled sealer or gutta-percha material was recorded for each root canal. Results. Of the endodontically treated teeth 26.6% had healthy periapical tissues, while technically good endodontic treatment constituted 12.8%. Based on the treatment success, there was no significant difference between the tooth groups. Statistical analysis of the data did not demonstrate statistically significant differences between the various parameters that were evaluated (P < 0.05). Conclusions. Technical quality of root fillings in a population who received treatment in private practice was poor and was consistent with a low prevalence of apical health. The probable reasons for this failure are multifactorial and may be improved if the operators improve their skills with continuing postgraduate education programs.

The Effect of Peracetic Acid on Removing Calcium Hydroxide from the Root Canals

INTRODUCTION The goal of this study was to evaluate the efficiencies of different irrigation solutions in the removal of calcium hydroxide (CH). METHODS Forty-eight maxillary central incisor teeth were used. Root canals were prepared with the ProTaper system (Dentsply Maillefer, Baillagues, Switzerland). Five milliliters 2% NaOCl, 5 mL 17% EDTA, and 10 mL saline were used for final irrigation. The canals were filled with CH paste. Specimens were randomly divided into 4 experimental groups (n = 10) according to irrigation protocols. Positive and negative control groups (n = 4) were used. Group 1 used 2.5 mL 17% EDTA, group 2 used 2.5 mL 2.5% NaOCl + 2.5 mL 17% EDTA, group 3 used 2.5 mL 1% peracetic acid (PAA), and group 4 used 2.5 mL 0.5% PAA. The specimens were evaluated with scanning electron microscope analysis and scored. Kruskal-Wallis and Student Newman-Keuls post hoc tests were used for statistical analysis. RESULTS In the apical thirds, 1% PAA was superior to the other groups (P < .05); however, there were no significant differences among the other groups (P > .05). In the middle thirds, no significant differences were found among the groups (P > .05). In the coronal thirds, 1% PAA was superior to the other groups. There were significant differences among all the other groups (P < .05). CONCLUSIONS According to the findings of the present study, 1% PAA could be recommended for the removal of CH from the root canals.

In Vitro Fracture Resistance of Endodontically Treated Roots Filled with a Bonded Filling Material or Different Types of Posts

AIM This study aimed to compare the fracture resistance of roots filled with a bonded material, fiber posts, or titanium post systems. METHODS Canals in the first group were filled with AH Plus and gutta-percha cones, and roots in the second group were filled with Epiphany sealer and Resilon cones. The root fillings (60 roots) were removed up to 4 mm from the canal apex to obtain 10-mm-deep post spaces, and posts were cemented. The groups were as follows: AH Plus control group, Epiphany control group, AH Plus fiber post group, AH Plus titanium post group, Epiphany fiber post group, and Epiphany titanium post group. Fracture tests were performed by using an Instron testing machine. The force was applied at a 45° axial angle with a constant speed of 1 mm/min. For each sample, the force at which fracture occurred was recorded in units of newtons. Statistical analysis was carried out by using analysis of variance test. RESULTS There was no statistically significant difference between all groups (P > .05). CONCLUSIONS Titanium posts, fiber posts, and Epiphany root canal filling systems were found to have no reinforcing effect on endodontically treated roots.

Evaluation of the resin cement thicknesses and push-out bond strengths of circular and oval fiber posts in oval-shapes canals

PURPOSE The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts. MATERIALS AND METHODS Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done. RESULTS No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the coronal, middle and apical specimens (P<.05). CONCLUSION In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength.

Comparison of the effect of MTAD and conventional irrigation agents on apical leakage and push-out bond strength of root canal filling

The aim of this study was to evaluate the effect of MTAD (a mixture of tetracycline isomer, an acid, and a detergent) and conventional irrigation agents on the apical leakage and push-out bond strength of root canal filling and to correlate the apical leakage and push-out bond strength. Root canals of 120 maxillary central incisors were prepared with a ProTaper file up to F3 and distributed to six groups. Saline, 1% NaOCl, 17% EDTA, 17% EDTA/1% NaOCl, and 2% chlorhexidine (CHX) solutions were used between each file change, and 5 mL of the same irrigating solution was used for the final flush. In the MTAD group, the root canals were irrigated with 1.3% NaOCl between each file and 5 mL of MTAD for the final flush. All the root canals were filled with AH Plus sealer and gutta-percha cones. Apical leakage was evaluated using a fluid transport system. After the apical leakage test, each tooth was prepared for the push-out assessment. The statistical analysis revealed that the irrigation solutions had no effect on the apical leakage of the root canal fillings (p = 0.258). The root fillings of the groups irrigated with MTAD showed significantly lower push-out bond strength values than the other groups (p < 0.001). These commonly used irrigating solutions did not affect the apical leakage of the root canal sealer. MTAD reduced the bond strength of the root canal sealer to the root canal dentin.

In vitro antimicrobial efficiency of different root canal sealers against Enterecoccus faecalis

Objective: The antibacterial effectiveness of four different sealers AH Plus, EndoRez, mineral trioxide aggregate (MTA) Fillapex, iRoot SP against Enterococcus faecalis was evaluated by time kill assay method in vitro . Materials and Methods: Four sealers are used in this study: An epoxy resin-based sealer, AH Plus (Dentsply, Maillefer, Switzerland), a polymethacrylate resin-based sealer, EndoRez (Ultradent, South Jordan, UT) and two calcium silicate-based sealers, MTA Fillapex (Angelus Solucxoes Odontologicas, Londrina, Brazil), iRoot SP (Innovative BioCreamix Inc., Vancouver, Canada). Each sealer was mixed according to manufacturers instructions. Five mg of each sealer was added to sterile tubes separately and evaluated at 20 min, 24 h, 7 days, and 30 days. Two tubes were used as positive and negative. Results: At the 20 th min AH Plus and iRoot SP were bactericidal, MTA Fillapex, and EndoRez were ineffective at the 20 th min. At the 1 st day MTA Fillapex was ineffective and rest of the sealers was bacteriostatic. At the 7 th day, only MTA Fillapex showed bactericidal effect, AH Plus, iRoot SP and EndoRez were bacteriostatic. At the 30 th day, MTA Fillapex was still bactericidal, AH Plus, iRoot SP, and EndoRez were still bacteriostatic. Conclusion: All root canal sealers tested were effective against E. faecalis . Fresh iRoot SP and fresh AH Plus had bactericidal action against E. faecalis . EndoRez has bacteriostatic behavior against E. faecalis . MTA Fillapex was the only sealer that could be bacteriocidal at 7 th and 30 th day.

Effects of physical and morphological properties of roots on fracture resistance.

Objective: The aim of this study was to determine how physical and morphological properties affect the fracture resistance of roots, and which criteria are important for root specimen standardization in fracture resistance studies. Materials and Methods: Seventy-five freshly extracted human canine teeth were selected. Crowns were sectioned from the cement-enamel junction and the root lengths were set at 16 mm. Then they were prepared up to ProTaper F3 file. Each root was numbered and data were obtained by measuring mesiodistal and buccolingual dimensions, volume, weight, and density. Tests for fracture strength were performed using an Instron Testing Machine (Instron Corp. MA, USA). The force was applied axially, angled at 45 degrees with a constant speed of 1 mm/min. For each sample, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically using linear regression analysis. Results: Volume and weight of the roots had more effect than mesiodistal or buccolingual dimensions on root fracture resistance. Conclusions: In root fracture resistance studies, volume or weight of the roots must be standardized when distributing roots to groups.