Ebru Özsezer Demiryürek

Effect of different surface treatments on the push-out bond strength of fiber post to root canal dentin

OBJECTIVE The purpose of this study was to evaluate the effects of different surface treatments on the bond strength of a fiber post to dentin. STUDY DESIGN Sixty extracted human maxillary incisor teeth were manually shaped with K-files using the step-back technique. ISO size 45 files were used as master apical files. Post spaces were prepared and then the root canals were subjected to one of the following 5 surface treatments: irrigation with 5% sodium hypochlorite (NaOCl); treatment with ethanol, ethyl acetate, and acetone-based cleansing agent (Sikko Tim); irrigation with 17% EDTA; etching with 37% orthophosphoric acid for 15 seconds; and etching with 10% citric acid for 15 seconds. Fiber posts were luted using self-etching/self-priming dual polymerized resin cement. From the coronal part of each root, 3 slides of 0.6-mm thickness were obtained. A push-out bond strength test was performed by a universal testing machine at a crosshead speed of 0.5 mm/min. Dentin surfaces were examined under scanning electron microscopy (SEM) after different surface treatments. Data were analyzed with a one-way analysis of variance (ANOVA) and Tukey HSD test. RESULTS ANOVA revealed that canal surface treatment affected the bond strength (P < .001). The highest bond strength was obtained in the Sikko Tim group. The results also showed that surface treatment methods increased the bond strength to dentin when compared with the control group. CONCLUSIONS Sikko Tim group was the more effective surface treatment agent compared with EDTA, orthophosphoric acid, citric acid, and control groups; however, it could not remove the smear layer and sealer remnants effectively on radicular dentin surfaces. Removal of the smear layer and opening of dentinal tubules are not recommended when a self-etching/self-priming adhesive system is used.

Effects of Three Canal Sealers on Bond Strength of a Fiber Post

INTRODUCTION This study evaluated the effects of three different endodontic sealers on the bond strength of a fiber post cemented with adhesive resin cement. METHODS Forty-eight extracted maxillary central incisors were prepared with the step-back technique and randomly divided into four groups (n=12 for each group): group 1, control group (gutta-percha points only, no sealer); group 2, resin-based sealer (AH plus; Dentsply De Trey GmbH, Konstanz, Germany); group 3, zinc oxide-eugenol-based sealer (Endofill; Produits Dentaires SA, Vevey, Switzerland); and group 4, calcium hydroxide-based sealer (Sealapex; Kerr, Romulus, MI). The roots were obturated with gutta-percha using the cold lateral compaction technique. Fiber posts were cemented into the prepared post spaces with the adhesive resin cement Panavia F 2.0 (Kuraray Medical, Okayama, Japan). A push-out test was performed in a universal machine, and failure modes were observed. Morphologic changes of the root canal dentin surfaces were examined with scanning electron microscopy (SEM). RESULTS One-way analysis of variance revealed that sealers have significant effects on bond strength (p<0.05). The control group had the highest mean push-out bond strength. No statistical difference was detected between the eugenol-based sealer group and the resin-based sealer group (p>0.05). The root surfaces were covered with the smear layer and debris in all the groups after post space preparation in SEM analysis. However, some of the dentin tubules were partially open in the control and calcium hydroxide-based sealer groups after the application of the resin monomer. CONCLUSION The results of this study showed that the type of canal sealer and chemomechanical preparation of the root canals affect the bond strength of a fiber post cemented with resin cement.

A comparative scanning electron microscopy evaluation of smear layer removal from teeth with different irrigation solutions and lasers.

The aim of this study was to evaluate the efficacy of smear layer removal from teeth following root canals using lasers (Er:YAG and Nd:YAG), NaOCl, 17% EDTA, and MTAD by scanning electron microscopy (SEM). Root canals were irrigated with 3 mL of 5.25% NaOCl after each file. Teeth were randomly divided into five groups. In the final irrigation, canals were irrigated with 5.25% NaOCl (Group 1, control), 17% EDTA (Group 2), or BioPure MTAD (Group 3). Laser groups were irradiated with Er:YAG laser (1.8 W, 120 mJ, 15 Hz) (Group 4) or Nd:YAG laser (1 W, 100 mJ, 15 Hz) (Group 5). The smear layer at the apical, middle, and coronal thirds of each root canal was imaged using SEM. Smear layer removal by EDTA was the most effective in all regions. The difference between EDTA and MTAD was statistically significant in the coronal and middle (p < 0.05), but not the apical (p > 0.05), regions. The difference between the control and laser groups was not statistically significant (p > 0.05). In all regions, the difference between 17% EDTA-MTAD and the control-laser groups was statistically significant (p < 0.05). Although improvement was observed in removal of the smear layer using alternative materials and techniques, application of a combination of EDTA and NaOCl remains an effective technique.

Endodontic treatment of a taurodontic premolar with five canals.

Taurodontism is a morpho-anatomical abnormality in the shape of a tooth. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cemento-enamel junction are the characteristic features. Special care is required in all aspects of endodontic treatment of a taurodontal tooth, including identifying the orifice, canal exploration, cleaning, shaping and obturation of the root canal. This case report describes the successful endodontic treatment of a taurodontic mandibular second premolar with five root canals.

The Effects of Endodontic Access Cavity Preparation Design on the Fracture Strength of Endodontically Treated Teeth: Traditional Versus Conservative Preparation

Introduction: The aim of this study was to compare the fracture strengths of mandibular molar teeth prepared using traditional endodontic cavity (TEC) and conservative endodontic cavity (CEC) methods and restored using SDR (Dentsply Caulk, Milford, DE) and EverX Posterior (GC Dental, Tokyo, Japan) base composite materials. Methods: A hundred mandibular first molar teeth were randomly divided into 5 groups. In group 1 (the control group), samples were kept intact. In group 2, TECs were prepared, and the samples were restored with EverX Posterior and composite resin. In group 3, CECs were prepared, and the samples were restored with EverX Posterior and composite resin. In group 4, TECs were prepared, and the samples were restored with SDR and composite resin. In group 5, CECs were prepared, and the samples were restored with SDR and composite resin. This load was applied on the samples at 1‐mm/min speed using a 6‐mm round‐head tip until fracture. The forces resulting in fracture were recorded in newton units. The data were analyzed using Kruskal‐Wallis and Pearson correlation tests at a 5% significance level. Results: The fracture strengths of the samples in the control group were significantly higher than the experimental groups (P < .05). There was no statistically significant difference in the endodontic access cavities prepared used the TEC and CEC methods and restored using the same composite base material (P > .05). Conclusions: CEC preparation did not increase the fracture strength of teeth with class II cavities compared with TEC preparation. The fracture strength of teeth restored with the SDR bulk‐fill composite was higher than that of teeth restored with EverX Posterior. HIGHLIGHTSThe effect of traditional and conservative access cavity preparation and base material selection on fracture strength of endodontically treated teeth was evaluated.The fracture strengths of the samples in the control group were significantly higher than those in the experimental groups did (P < .05).There was no statistically significant difference in the endodontic access cavities prepared used the TEC and CEC methods and restored using the same composite base material (P > .05).

Pyrosequencing Analysis of Cryogenically Ground Samples from Primary and Secondary/Persistent Endodontic Infections

Introduction This study aimed to characterize the microbial communities of primary and secondary/persistent endodontic infections using high‐throughput pyrosequencing from the pulverized samples. Methods The roots of 20 extracted human teeth with primary endodontic infection and 20 teeth with secondary/persistent endodontic infection were collected. The outer surfaces of the roots were disinfected, and whole roots were cryopulverized. 16S amplicon pyrosequencing data from the DNA extracted from the pulverized root powders were obtained, and microorganism abundance and diversity were calculated. Data were analyzed using statistical and bioinformatic methods. Results Pyrosequencing analysis resulted a total of 2,606,128 sequences from 40 samples. A total of 15 phyla, 160 genera, and 368 species were detected. No significant difference between primary and secondary/persistent endodontic infections was found regarding the diversity and richness of operational taxonomic units at the phyla, genera, and species levels (P > .005). Conclusions The present study revealed that the microbial diversity of secondary/persistent endodontic infections did not differ than those of primary endodontic infections. A new archaeal species, Candidatus Nitrosoarchaeum limnia, was detected in root canals of 1 patient with primary endodontic infection for the first time. HighlightsMicrobial community profiles of endodontic infections were investigated.Cryopulverized samples were used to represent microbial community structure.Microbial diversity was similar in primary and secondary/persistent infections.Candidatus Nitrosoarchaeum limnia was reported for the first time in a root canal sample.

Comparison of the antimicrobial activity of direct pulp-capping materials: Mineral trioxide aggregate-Angelus and Biodentine.

Purpose: To compare the antimicrobial activity of the tricalcium silicate-based Biodentine (BD) and mineral trioxide aggregate (MTA)-Angelus cement with the aid of agar diffusion test. Materials and Methods: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecium were inoculated in the Brucella liquid medium and were incubated at 37°C for 24 h. Thereafter, 100 >μl of the liquid culture of bacteria inoculated in the Mueller-Hinton agar with spread plate technique. Petri plates were dried in room temperature. For every microorganism, 3 petri plates were prepared (12 in total). In the medium, in every petri plate, 2 holes with 5 mm diameter and 2 mm depth were made. Afterward, BD and MTA-Angelus were filled into these holes under aseptic conditions according to the instructions of the manufacturing company. Then, the plates were kept in the incubator at 37°C for 24 h, and the diameters of the inhibition zones were measured with a digital caliper. Results: Inhibition zones formed by BD against E. coli and S. aureus were significantly larger than the zones formed by MTA-Angelus (P < 0.05). However, the inhibition zones formed by MTA-Angelus against P. aureus and E. faecium were larger than the zones formed by BD (P < 0.05). Conclusion: Within the limits of the present study, tricalcium silicate-based MTA-Angelus and BD have antimicrobial activity against E. coli, S. aureus, P. aureus, and E. faecium.

Effect of propolis as a root canal irrigant on bond strength to dentin

Purpose The purpose of this in vitro study was to evaluate the effect of propolis on bond strength to dentin of a self-etch adhesive when used as a final irrigant. Methods 126 human third molars were sectioned 3 mm below the occlusal level and then randomly divided into 7 groups (n = 18). The exposed dentin surfaces were treated with irrigation solutions as follows: Group 1: 5.25% NaOCl; Group 2: 5.25% NaOCl followed by 17% EDTA; Group 3: 5.25% NaOCl followed by Tubulicid Plus (Temrex, Freeport, NY, USA); Group 4: 5.25% NaOCl followed by MTAD; Group 5: 5.25% NaOCl followed by 20% propolis; Group 6: 5.25% NaOCl followed by 2% CHX; Group 7: distilled water (control). Irrigated specimens were bonded using Clearfil SE Bond (Kuraray, Osaka, Japan) with Tygon (Saint-Gobain, Saint-Gobain Performance Plastics, France), tubes for microshear bond strength testing. Data was analyzed using a one-way ANOVA and Tukey test. Results Among the tested groups, although the lowest bond strength values were detected in Group 1 (11.25 ± 1.97), a significant statistical difference was detected only between this group and Group 4 (18.70 ± 1.82) and Group 5 (16.75 ± 3.70) (p = 0.0012). Conclusions 20% propolis solution as a final irrigant was found to have a favorable effect on the dentin bond strength of the tested self-etch adhesive to coronal dentin when compared with other irrigation solutions.

EFFICACY OF PROTAPER NEXT AND PROTAPER UNIVERSAL RETREATMENT SYSTEMS IN REMOVING GUTTA-PERCHA IN CURVED ROOT CANALS DURING ROOT CANAL RETREATMENT

Purpose: The aim of this study was to compare the cleanliness of root canal walls after retreatment using ProTaper Next (PTN), ProTaper Universal Retreatment (PTR) nickel-titanium (NiTi) systems and Hedström hand files in curved mesial canals of mandibular molar teeth and the time required for gutta-percha and sealer removal. Materials and Methods: Ninety mandibular molar teeth with curved mesial roots were instrumented up to #35.04 with Mtwo NiTi rotary instruments and obturated using the continuous wave of condensation technique. Removal of gutta-percha and sealer was performed using one of the following: PTN and PTR NiTi systems and Hedström hand files. Samples were placed on the VistaScan phosphor plates in the mesio-distal direction and the radiographs were taken. The digital radiographs were analyzed using AutoCAD software. Also, the total time required for gutta-percha removal was calculated by a chronometer. Results: The total retreatment time was significantly shorter in the PTN and PTR groups compared with the manual group (p<0.05). There was a significant difference between the groups according to the total residual gutta-percha and sealer (p<0.05). The PTN and PTR groups left significantly less gutta-percha and sealer remnant than the manual group (p<0.001). Conclusion: Within the limitations of this study, the PTN and PTR groups showed less residual gutta-percha and sealer than the manual group. The NiTi rotary systems were significantly faster than the manual group in the time required for gutta-percha and sealer removal.

Comparison of the Effectiveness of Different Techniques for Supportive Removal of Root Canal Filling Material

Objective: To compare the cleanliness of oval cross-sectioned root canals after using different supportive techniques for removal of root canal filling material as part of retreatment process. Methods: One hundred mandibular canine teeth with flat oval cross-sectioned canals were instrumented up to #40.06 and obturated using the warm vertical compaction technique. Removal of the gutta-percha and sealer was performed using the D-RaCe nickel-titanium retreatment instruments. The roots were randomly divided into four groups of 25 teeth, and the activation processes were applied: XP-endo Finisher (XP), EndoActivator (EA) and IrrıSafe (IS). Conventional needle irrigation (CI) was used as the control group. The teeth were sectioned, and digital images were captured. The photographs were analysed using AutoCAD software regarding the area of residual root filling. Kruskal–Wallis and post hoc Dunn’s tests were performed for statistical analysis. Results: There was significantly less gutta-percha and sealer remnant in the XP group than in the other groups (P<0.05). The CI group contained significantly more gutta-percha and sealer remnant than the other groups (P<0.05). The apical third of the CI group had significantly more residual gutta-percha and sealer when compared to that of the other groups (P<0.05). Conclusion: Within the limitations of this study, the amount of gutta-percha and sealer in the XP group was lower than that in the EA, IS, and CI groups.