Sezer Demirbuga

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.

The Effects of Mtwo, R-Endo, and D-RaCe Retreatment Instruments on the Incidence of Dentinal Defects during the Removal of Root Canal Filling Material

INTRODUCTION The aim of this study was to compare the incidence of dentinal defects after retreatment procedures with different nickel-titanium rotary retreatment files. METHODS One hundred-eighty mandibular premolars were randomly assigned to 6 groups (n = 30 teeth per group). One group was left unprepared, and the remaining 5 groups were prepared with K-files (Dentsply Maillefer, Ballaigues, Switzerland) and filled with gutta-percha and AH plus sealer (Dentsply Maillefer, Ballaigues, Switzerland). Of these 5 groups, 1 group was left filled and received no further treatments; in the other groups, removal of the filling material was performed with Mtwo R (VDW, Munich, Germany), D-RaCe (FKG Dentaire, La Chaux-de-Fonds, Switzerland), R-Endo instruments (Micro-Mega, Besançon, France), or Hedström files (Dentsply Maillefer). Roots were then sectioned 3, 6, and 9 mm from the apex and observed under a microscope. The presence of dentinal defects was noted. Chi-square tests were performed to compare the incidence of dentinal defects between the groups. A Pearson correlation test was performed to check the correlation between defects and root level or remaining dentin thickness. RESULTS No defects were observed in the unprepared group. Dentinal defects were detected in all retreatment groups. Retreatment groups showed significantly more defects than the filled but no retreatment group (P < .05). There was no significant difference in the occurrence of defects between retreatment groups (P > .05). There was no correlation between the appearance of defects and level of the root or remaining dentin thickness. CONCLUSIONS Under the experimental conditions, all retreatment techniques used in this study created defects in the root dentin.

Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular first and second molars in Turkish individuals

Objective: The aim of this study was to investigate the root and canal morphology of mandibular first and second molars in a Turkish population by using cone beam computed tomography (CBCT). Study design: CBCT images of mandibular first (n = 823) and second molar (n = 925) teeth from 605 Turkish patients were analyzed. The root canal configurations were classified according to the method of Vertucci. Results: The majority of mandibular molars (95.8% of first molars, 85.4% of second molars) had two separate roots; however, three roots were identified in 2.06% of first molars and 3.45% of second molars. C-shaped canals occurred 0.85% of first molars and 4.1% of second molars. Three canals were found in 79.9% of first molars and 72.8% of second molars. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal. The most common root morphology of first and second molars is the two rooted morphology with three canals. Both the mesial and distal roots showed wide variations in canal anatomy with type IV and type I canal configuration predominating in the mesial and distal roots, respectively. Conclusion: Vertucci type I and IV canal configurations were the most prevalent in the distal and mesial roots, respectively, of both the mandibular first and second permanent molar teeth. Key words:Cone-beam CT, Turkish, mandibular molars, root and canal morphology.

The effect of a new-generation flowable composite resin on microleakage in Class V composite restorations as an intermediate layer.

Aim: To evaluate the effect of application a new-generation bulk-fill flowable composite resin as an intermediate material between composite resin and dental substrates on micro-leakage in Class V composite restorations. Materials and Methods: A total of 144 Class V cavities were prepared in 72 human molars. Specimens were then randomly distributed among three groups according to adhesive system applied (Group 1: Clearfil SE Bond; Group 2: Adper Easy One; Group 3: Adhesive 200T), and each group was divided into three subgroups according to liner material used (Group A: No liner-control group; Group B: Aelite Flo LV, low viscosity microhybrid composite; Group C: Smart dentin replacement). All cavities were restored using resin composite (Aelite LS, low shrinkage posterior composite). Specimens were stained with 0.5% basic fuchsin and evaluated dye penetration. Results: There was no significant difference in dye penetration was found between the control and the experimental groups. Conclusions: Micro-leakage is not affected by the application of either conventional or new-generation flowable composite resin as an intermediate material between composite resin and dental substrates.

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.

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.

Effect of resin infiltration on enamel surface properties and Streptococcus mutans adhesion to artificial enamel lesions

UNLABELLED Authors would like to add ACKNOWLEGMENT in this article, page 30, between CONCLUSION and REFERENCES as below. ACKNOWLEGMENT This research was supported by Erciyes University Scientific Research Project Department.

The effect of various backfilling techniques on the fracture resistance of simulated immature teeth performed apical plug with Biodentine

AIM To evaluate the fracture resistance of simulated immature teeth that had been backfilled using different materials after using Biodentine as the apical plug material. DESIGN Seventy-five single-rooted teeth were divided into five groups (n = 15). The 15 teeth in group 1 served as a negative control group and received no treatment. The remaining 60 teeth were instrumented to a #6 Peeso reamer to obtain a standard internal diameter of 1.5 mm. The apical 4 mm of 60 teeth was filled with Biodentine. The backfilling was then performed on each group as follows: group 2--no backfilling (positive control), group 3--gutta-percha, group 4--fiber post, and group 5--Biodentine. Specimens were then subjected to fracture testing. The force required to fracture each specimen was recorded, and the data were statistically analyzed. RESULTS The mean fracture values of groups 1 and 4 were significantly higher than groups 2, 3, and 5 (P < 0.05). The values of groups 3 and 5 were significantly higher than group 2 (P < 0.05). CONCLUSIONS The backfilling with fiber post after an apical Biodentine plug provided the highest fracture resistance among all experimental groups.

Comparing the shear bond strength of direct and indirect composite inlays in relation to different surface conditioning and curing techniques

Objective: The aim of this study was to test the null hypothesis that different surface conditioning (etch and rinse and self-etch) and curing techniques (light cure/dual cure) had no effect on the shear bond strength of direct and indirect composite inlays. Materials and Methods: A total of 112 extracted human molar teeth were horizontally sectioned and randomly divided into two groups according to restoration technique (direct and indirect restorations). Each group was further subdivided into seven subgroups (n = 8) according to bonding agent (etch and rinse adhesives Scotchbond multi-purpose plus, All-Bond 3, Adper Single Bond and Prime Bond NT; and self-etch adhesives Clearfil Liner Bond, Futurabond DC and G bond). Indirect composites were cemented to dentin surfaces using dual-curing luting cement. Shear bond strength of specimens was tested using a Universal Testing Machine. Two samples from each subgroup were evaluated under Scanning electron microscopy to see the failing modes. Data was analyzed using independent sample t-tests and Tukey′s tests. Results: Surface conditioning and curing of bonding agents were all found to have significant effects on shear bond strength (P < 0.05) of both direct and indirect composite inlays. With direct restoration, etch and rinse systems and dual-cured bonding agents yielded higher bond strengths than indirect restoration, self-etch systems and light-cured bonding agents. Conclusions: The results of the present study indicated that direct restoration to be a more reliable method than indirect restoration. Although etch and rinse bonding systems showed higher shear bond strength to dentin than self-etch systems, both systems can be safely used for the adhesion of direct as well as indirect restorations.

The effect of pre-heating silorane and methacrylate-based composites on microleakage of Class V restorations

Objective: This study compared the effects of 4 different temperatures (4°C, 25°C, 37°C, 60°C) on the microleakage of silorane and methacrylate-based composites in Class V cavities. Materials and Methods: Standard Class V cavities were prepared at the buccal and lingual surfaces of human molars. The specimens were randomly divided into 2 groups according to the composite resin used (Group I: Filtek Silorane Adhesive System and Filtek Silorane composite; Group II: Clearfil SE Bond and Aelite LS Posterior composite) and into 4 subgroups according to temperature treatment (Group A: Refrigeration at 4°C; Group B (control): Storage at room temperature (25°C); Group C: Heated to 37°C and Group D: Heated to 60°C using Calset). Specimens were dyed with 0.5% basic fuchsin, sectioned, and evaluated at 25x magnification. Statistical analysis was performed using Mann-Whitney U and Kruskal-Wallis tests at P Results: Filtek Silorane and Aelite LS Posterior showed similar microleakage values ( P >0.05). Differences in temperature did not significantly affect microleakage values for Filtek Silorane ( P >0.05); however, microleakage values of Aelite LS Posterior composite varied according to temperature treatment, with heating resulted in significantly less microleakage than cooling (between Groups IID and IIA and Groups IIC and IIA) ( P Conclusion: Pre-heating was shown to reduce microleakage values of Aelite LS Posterior composite, but did not significantly alter the microleakage values of Filtek Silorane composite.