Micro-computed tomography analysis of shaping ability of nickel-titanium instruments activated by continuous rotation or adaptive motion.

This study assessed the ability of Twisted File Adaptive (TFA), TruNatomy (TRN) and VDW.Rotate (VR) instruments activated by continuous rotation (CR) and adaptive motion (AM) to shape curved root canals. Thirty mandibular molars with two separate mesial canals 20°-40° curved were collected and scanned using micro-computed tomography (µCT). The canals were then randomly assigned into six groups (n = 10): TRN, VR or TFA instruments activated by CR or AM. TRN groups 17.02, 20.04 and 26.04; VR groups 15.04, 20.05 and 25.06; TFA groups were shaped consecutively using 15K-file, 20.04 and 25.06. After they were shaped, the canals were scanned again. The volume of removed dentin, canal transportation and centring ratio were calculated µCT images. All data were analysed using the Kruskal-Wallis test or one-way analysis of variance (p < 0.05). With both kinematics, the TRN instrument removed the least amount of dentin, the VR-CR and the TFA-AM removed the most (p < 0.05). The transportation and centring ratios among all groups were similar (p > 0.05). The volume of dentin removed, the diameter or design features of the instruments and different kinematics did not affect the centring ratio and the amount of transportation and remained within safe limits. All three instruments activated by either kinematics were found to have similar effectiveness in shaping curved root canals.

A novel one-step multiplex PCR protocol to detect avian haemosporidian parasites in the subgenus Haemoproteus (Kruse, 1890) used to quantify parasite prevalence in domestic pigeons (Columba livia) in Turkey.

Infections of avian haemosporidian parasites are regularly identified by molecular methods including multiplex PCR, which allows researchers to distinguish mixed infections of parasites from multiple genera. Here we extend the utility of a previously designed multiplex PCR by designing a primer set specific to parasites of the subgenus Haemoproteus (genus: Haemoproteus). The updated one-step multiplex PCR protocol we describe here allows for the detection of the genera Plasmodium and Leucocytozoon and the two subgenera (Haemoproteus and Parahaemoproteus) of the genus Haemoproteus. A sensitivity analysis showed that the multiplex PCR could amplify DNA of parasites in the subgenus Haemoproteus at very low levels of infection. We used this multiplex PCR to identify haemosporidian infections in 250 adult domestic pigeons (Columba livia) in Turkey. All samples were also screened by microscopy and a widely used nested PCR to compare with the results of multiplex PCR, to detect low levels of parasitemia, and to identify possible abortive infections. In total, 71 pigeons (28.4%) were found to be infected by all three methods. The multiplex PCR protocol successfully detected and discriminated both subgenera Haemoproteus and Parahaemoproteus infections. We compared our results with previous host species records to assess the host specificity of the parasite lineages we found. Our findings provide novel data on the prevalence of avian haemosporidians in domestic pigeons and demonstrate the utility of the new one-step multiplex PCR protocol for the determination of mixed avian haemosporidian infections. We expect that this protocol will contribute to a better understanding of the distribution, epizootiology, and ecology of avian haemosporidians.

Determination of extracellular traps structures from sheep polymorphonuclear leukocytes to Echinococcus granulosus protoscoleces.

It was aimed to detect extracellular traps structures from sheep polymorphonuclear leukocytes (PMN) after being confronted with Echinococcus granulosus protoscoleces in vitro. Also, the effect of cyst fluid was examined on the development of extracellular traps. At the end of the incubation for 1 h, the extracellular traps augmented with neutrophil elastase, histone (H3) and myeloperoxidase were visualized in the protoscoleces-PMN co-culture microscopically. Some protoscoleces lysed and the chitinous hooks released were surrounded by the extracellular traps. The other protoscoleces were still intact and the extracellular trap structures were observed around them. The relationship between the extracellular DNA contents and the protoscoleces concentration was not found statistically significant (P > 0.05). The extracellular DNA amount in the co-cultures diluted in RPMI-1640 increased with the incubation time (P < 0.05). However, the time-dependent relationship was not found in the co-cultures diluted in the cyst fluid (P > 0.05). The difference in the extracellular DNA amount was detected as statistically significant (P < 0.05) between the two co-culture groups (diluted in RPMI-1640 or the cyst fluid), except for 30 min incubation. To the Author's knowledge, NETosis reaction was firstly observed in sheep PMN after being confronted with protoscoleces in vitro. The cyst fluid had some negative effects on the development of extracellular traps from sheep PMNs at the 1-h incubation time. It should be investigated which molecules are responsible for NETosis inhibition in hydatid cyst fluid. Future studies may clarify whether neutrophils fight with protoscoleces by using their different mechanisms.

Evaluation of fracture strength of different restoration techniques applied to C-shaped 3D model teeth.

The aim of this study is to investigate the effect of different restoration methods applied to model teeth with a C-shaped root canal configuration on fracture strength. A total of 76 artificial tooth models were made using images of a molar tooth with a C-shaped root canal anatomy. The teeth were randomly divided into seven groups and different restorations, such as resin composite (2), bundled fiber post and resin composite (3), vertical fiber post and resin composite (4), horizontal fiber post and resin composite (5), woven fiber post and resin composite (6) and composite endocrown (7) were applied to the different groups except control group (1). The artificial teeth were embedded in acrylic blocks and subjected to fracture tests. The data were analyzed using one-way analysis of variance, Monte Carlo Pearson Chi-square, Pearson Chi-square, and Fisher's exact test (P < 0.05). All groups differed in terms of fracture strength (P = 0.001). The highest fracture strength observed in group 6, and there was a significant difference between group 6 and group 4 based on a least significant difference pairwise comparison test. In terms of fracture type, the highest reparability percentage (100%) observed in group 7. The fracture strength values of endocrown restorations and woven fiber-reinforced resin composite restorations were found to be as high as those of the intact models. Considering also fracture restorability, endocrown restorations may be recommended for teeth with C-shaped root canal anatomy. The usage of the 3D tooth models in the studies offer a valuable opportunity in terms of the standardization of the samples, particularly in teeth with anatomical variations. This study shows that using of this technology, homogeneous groups can be created and experimental studies can be improved.

The effects of root canal perforation repair materials on the bond strength of fiber posts.

INTRODUCTION: This study aimed to evaluate the effect of calcium hydroxide and bioceramics used in perforation repair on the bonding strength of fiber posts via a push-out test. METHODOLOGY: This study used 106 extracted single-rooted human mandibular premolar teeth. Root canal preparations were performed with a rotary file system and perforations were created in the middle third of each tooth. The samples were randomized into two main experimental groups, one with calcium hydroxide and one without. Each group had four subgroups in which different bioceramic cements were applied (n = 11) and a control group (n = 9). The root canals perforations were repaired using MTA, Biodentine, Bioaggregate, and Endosequence BC root repair material. A fiber post was applied to each tooth and a push-out test was performed. The samples were examined at 40× magnification with a digital microscope in order to identify fracture type. RESULTS: Bonding strength was calculated in MPa. A statistical analysis showed that the calcium hydroxide had no effect on the bonding strength of the fiber posts. A comparison of the perforation repair materials revealed that Biodentine in the calcium hydroxide group and Bioaggregate in both groups decreased the bonding strength compared to the other materials (p < 0.05). The most common failure type was adhesive failure between the dentin and resin cement (38.16%). CONCLUSIONS: The use of different perforation repair materials can affect the bonding strength of fiber posts. Therefore, the choice of perforation repair material should be made on an individual basis.

Physical properties of MTA, BioAggregate and Biodentine in simulated conditions: A micro-CT analysis.

The aim of this study was to evaluate the physical properties of calcium-silicate based cements as retrograde filling in different pH and blood conditions using micro-CT. Eighty-four teeth were obturated and after root-end resection, 3 mm-deep root-end cavity was ultrasonically prepared. The samples were divided into four test groups (n=21). Cements were freshly prepared and analyzed with micro-CT before and after exposed. The test groups were exposed for four days to environments containing acid, alkali, or blood. An acidic pH significantly reduced the volume of all materials after four days and differed from the other environments. Biodentine has the highest percentage of loss in volume and density after treatment in an acidic environment. Porosity formation in the acidic medium was observed in Biodentine amongst all materials. The three-dimensional structures of all materials changed after exposed to an acidic pH, while fewer changes were observed in the structures of materials treated with blood and alkali.

3D Micro-CT Analysis of Void and Gap Formation in Curved Root Canals.

OBJECTIVE: This study used microcomputed tomography (micro-CT) to compare the volumes of voids and gaps in curved root canals instrumented and filled using various techniques. METHODS: Twenty extracted mandibular first molars with two curved mesial root canals were used. Root canals were instrumented using a self-adjusting file (SAF) or Revo-S file system. For standardization, mesiobuccal canals were instrumented with SAF and mesiolingual canals were instrumented with Revo-S in each root. The canals were divided into four experimental groups (n=10 in each). The canals were then filled via cold lateral compaction (CLC) or a thermoplasticized injectable technique (TT) using gutta-percha and AH Plus root canal sealer. The roots were scanned with a micro-CT, and the volumes of the voids and gaps were calculated using three-dimensional (3D) micro-CT images. Data were analyzed using unpaired t- and Kruskal-Wallis tests. A value of P<0.05 was considered significant. RESULTS: None of the tested techniques provided void- or gap-free fillings. Nevertheless, the SAF showed more gap formation than the Revo-S, and TT showed higher gap formation in all experimental groups. These differences, however, were not statistically significant (P>0.05). CONCLUSION: The SAF and Revo-S rotary file systems yielded comparable results. No statistically significant difference was found between the results of the various instrumentation and filling techniques.

Determination of trace elements in rat organs implanted with endodontic repair materials by ICP-MS.

To investigate the levels of seven elements using an inductively coupled plasma-mass spectrometry (ICP-MS) method in rat organs after the implantation of Micro Mega Mineral Trioxide Aggregate (MM-MTA), Bioaggregate (BA) and Biodentine (BD) materials. MM-MTA, BA and BD were implanted into the subcutaneous tissue of 15 Wistar albino rats; three control animals had no operation. After 45 days, the rats were sacrificed and their brains, kidneys and livers were removed. The ICP-MS analysis was used to determine trace elements. Data were analysed using the Kruskal-Wallis and Connover post hoc tests. There was no significant difference between the control groups and the MM-MTA, BA and BD groups according to the concentration of aluminum, calcium, arsenic and lead in the rats' organs. Beryllium was not detected in all tissue samples. Chromium levels of these materials were higher than the control group in brain and kidney samples (P = 0.038 and P = 0.037); magnesium levels were higher than the control group in kidney and liver samples (P = 0.030 and P = 0.008). MM-MTA, BA and BD were nontoxic according to trace element levels in brain, kidney and liver samples of rats. Further investigation is required to understand the systemic effects of these materials.

Comparative evaluation of root canal preparations of maxillary first molars with self-adjusting file, reciproc single file, and revo-s rotary file: A micro-computed tomography study.

This study was aimed to use micro-computed tomography (µ-CT) to evaluate the canal shaping properties of three nickel-titanium instruments, Self-Adjusting File (SAF), Reciproc, and Revo-S rotary file, in maxillary first molars. Thirty maxillary molars were scanned preoperatively by using micro-computed tomography (µ-CT) scans at 13,68 µm resolution. The teeth were randomly assigned to three groups (n = 10). The root canals were shaped with SAF, Reciproc, and Revo-S, respectively. The shaped root canals were rescanned. Changes in canal volumes and surface areas were compared with preoperative values. The data were analyzed using Kruskal-Wallis and Conover's post hoc tests, with p < .05 denoting a statistically significant difference. Preoperatively canal volumes and surface area were statistically similar among the three groups (p > .05). There were statistically significant differences in all measures comparing preoperative and postoperative canal models (p = 0.0001). These differences occurred after instrumentation among the three experimental groups showed no statistically significant difference for volume (p > .05). Surface area showed the similar activity in buccal canals in each of the three techniques whereas no statistically significant difference was detected among surface area, the SAF, and the Revo-S in the palatal (P) canal. Each of three shaping system showed the similar volume activity in all canals, but SAF and Revo-S provided more effectively root planning in comparison with Reciproc in P canal.

Biocompatibility of a new epoxy resin-based root canal sealer in subcutaneous tissue of rat.

OBJECTIVE: The objective was to evaluate the subcutaneous biocompatibility of two root canal sealers. MATERIALS AND METHODS: Thirty female rats were distributed into two groups of 15 animals. Each received subcutaneous dorsal implants: Silicone tubes filled with AH Plus or Obtuseal. After the 11(th), 14(th), and 45(th) days, tissues were collected for biopsy and fixed and processed for histologic evaluation. Observations of the cellular inflammatory components, such as lymphocytes and macrophages, were made. The data were analyzed using Kruskal-Wallis and Connover tests (P < 0.05). RESULTS: By the 7(th) day, lymphocyte infiltration increased in both groups (P = 0.0104). However, macrophage infiltration increased only in the AH Plus group (P = 0.0011). By the 14(th) and 45(th) days, lymphocyte and macrophage infiltrations were reduced. At the end of the experimental period, no statistically significant differences were found between the AH Plus group and the Obtuseal group (P > 0.05). CONCLUSION: After 45 days, Obtuseal yielded a satisfactory tissue reaction; it was biocompatible when tested in subcutaneous rat tissue. On the basis of the obtained results, it was concluded that Obtuseal root canal sealer caused a satisfactory tissue reaction as AH plus, because it was biocompatible when tested in the subcutaneous tissue of rats.

Retreatment of flat-oval root canals with a self-adjusting file: an SEM study.

This study evaluated the efficacy of the Self-Adjusting File (SAF) in removing the root filling remnants and smear layer left in oval shaped root canals after using R-Endo retreatment files, by using scanning electron microscopy (SEM). Forty eight maxillary premolars were prepared and the SAF was used in all of the teeth to remove debris and smear layer. Sixteen teeth were used as control and the other 32 teeth were obturated and randomly assigned to two groups according to the retreatment procedures: R-Endo retreatment files and R-Endo retreatment files+SAF. Then, all roots were split longitudinally for SEM evaluation. Using SEM pictures, the number of dentinal tubules and the surface area covered by filling remnants were evaluated. None of the techniques removed root filling remnants and smear layer completely. Additional use of SAF after the retreatment procedures may improve root canal cleanliness in the coronal and middle thirds of oval root canals.

3D analysis of D-RaCe and self-adjusting file in removing filling materials from curved root canals instrumented and filled with different techniques.

The aim of this study was to compare the efficacy of D-RaCe files and a self-adjusting file (SAF) system in removing filling material from curved root canals instrumented and filled with different techniques by using microcomputed tomography (micro-CT). The mesial roots of 20 extracted mandibular first molars were used. Root canals (mesiobuccal and mesiolingual) were instrumented with SAF or Revo-S. The canals were then filled with gutta-percha and AH Plus sealer using cold lateral compaction or thermoplasticized injectable techniques. The root fillings were first removed with D-RaCe (Step 1), followed by Step 2, in which a SAF system was used to remove the residual fillings in all groups. Micro-CT scans were used to measure the volume of residual filling after root canal filling, reinstrumentation with D-RaCe (Step 1), and reinstrumentation with SAF (Step 2). Data were analyzed using Wilcoxon and Kruskal-Wallis tests. There were no statistically significant differences between filling techniques in the canals instrumented with SAF (P = 0.292) and Revo-S (P = 0.306). The amount of remaining filling material was similar in all groups (P = 0.363); all of the instrumentation techniques left filling residue inside the canals. However, the additional use of SAF was more effective than using D-RaCe alone.

Comparison of different retreatment techniques and root canal sealers: a scanning electron microscopic study.

The aim of this study was to evaluate the effectiveness of two retreatment techniques, in terms of the operating time and scanning electron microscopy (SEM) results, in removing three different root canal sealers from root canals that were previously filled with gutta-percha. Sixty extracted single-rooted human premolars were divided into three groups and filled with iRoot SP, MM Seal, and AH Plus sealers, along with gutta-percha, through a lateral compaction technique. Root canal fillings of the samples were removed by ESI ultrasonic tips or R-Endo files. The time to reach the working length was recorded. Longitudinally sectioned samples were examined under SEM magnification. Each picture was evaluated in terms of the residual debris. Data were statistically analyzed with the Kruskall-Wallis test. No statistically significant differences were found in terms of operating time (p>0.05). Significant differences in the number of debris-free dentinal tubules were found among the root canal thirds, but this finding was not influenced by the experimental group (p<0.05). Resin sealer tags were observed inside the dentinal tubules in the MM Seal group. Under the conditions of this study, it may be established that there was no difference among the sealers and retreatment techniques.

Effectiveness of different irrigation systems on smear layer removal: A scanning electron microscopic study.

OBJECTIVES: To evaluate effectiveness of the apical negative pressure irrigation (EndoVac), passive ultrasonic irrigation (PUI), and conventional needle irrigation (CI) systems on smear layer (SR) removal. MATERIALS AND METHODS: Sixty single-rooted canines were prepared using NiTi rotary files and subjected to different irrigation regimens: EndoVac with NaOCl (Group 1) or NaOCl/EDTA (Group 2); PUI with NaOCl (Group 3) or NaOCl/EDTA (Group 4); CI with NaOCl (Group 5) or NaOCl/EDTA (Group 6). The roots were split longitudinally. SEM images were taken to evaluate the amount of residual SR. RESULTS: In Groups 1, 3, and 5, there was no removal of SR (P > 0.05). The coronal thirds within Groups 2, 4, and 6 were cleaned completely, but the middle and the apical thirds was achieved partially or completely (P > 0.05). CONCLUSION: Regardless of which irrigation system was used, the use of NaOCl alone failed to remove the SR. In NaOCl/EDTA combination groups, the SR was removed partially or completely and no statistical significance. This study demonstrated that in order to remove the SR should be used EDTA solution for final irrigation in the root canal, regardless of the technique in each of the three.

Antibacterial and mechanical properties of propolis added to glass ionomer cement.

OBJECTIVE: To investigate whether adding ethanolic extracts of propolis (EEP) might influence the antibacterial and mechanical (shear-peel band strength [SPBS]) properties of conventional glass ionomer cement (GIC) used in orthodontic band cementation. MATERIALS AND METHODS: The cement was divided into four groups: one using the original composition and three with 10%, 25%, and 50% EEP added to the liquid and then manipulated. An antimicrobial assay, broth-dilution method was used to determine the antibacterial capacity of the GIC containing EEP. Eighty teeth were used for the mechanical assay, and an Instron testing machine was used to evaluate the SPBS. Kolmogorov-Smirnov and Kruskal-Wallis tests were used for statistical analyses. RESULTS: GIC with the addition of 25% and 50% EEP activated inhibition of Streptococcus mutans (ATCC 25175) growth, but this effect did not occur in the group to which 10% EEP was added or in the control GIC group. There was no significant difference between the groups in terms of SPBS (P > .05). CONCLUSIONS: The addition of EEP may increase antibacterial properties without negatively modifying the mechanical properties of conventional GIC.

Efficacy of self-adjusting file and passive ultrasonic irrigation on removing calcium hydroxide from root canals.

The aim of this study was to evaluate the efficiencies of the self-adjusting file (SAF) system, passive ultrasonic irrigation (PUI), and conventional irrigation (CI) in removing calcium hydroxide (CH) from root canals. Fifty-one mandibular premolars were used. After root canals were instrumented and filled with a CH paste, 45 teeth were randomly assigned to three experimental groups according to CH removal technique: SAF system, PUI, or CI. The remaining 6 teeth served as positive and negative controls. All samples were evaluated by scanning electron microscopy (SEM) and scored. None of the techniques removed CH completely. However, results at coronal, middle and apical thirds showed that PUI technique was significantly more effective than SAF and CI in removing CH dressing residues from root canal walls.

Endodontic treatment of hypertaurodontism with multiple bilateral taurodontism.

The term taurodontism is derived from the Latin word tauros, for "bull," and the Greek term odus, for "tooth," or "bull tooth." Taurodontism is a morpho-anatomical developmental anomaly, which is seen infrequently in teeth only. It is characterized by a deficiency in the constriction at the cement-enamel junction, with lengthened pulp chambers and apical displacement of the pulpal floor. This gives the tooth a quadrilateral or cylindrical look. This report presents a case of multiple bilateral taurodontism and the successful endodontic treatment of the tooth that had hypertaurodontism. A male patient was referred to the endodontic clinic with decayed left maxillary first molar. Hypertaurodontism was confirmed after clinical and radiographic examination. Panaromic X-rays revealed that all of the patient's molar teeth were taurodontic. Taurodontism offers challenges to the practitioner during shaping and disinfection and at the time of filling the root canals.

Unusual root canal morphology of the maxillary second molar: a case report.

Introduction. This clinical case report presents the successful endodontic treatment of a maxillary second molar that has a mandibular molar-like anatomy with no palatal root and with each of its roots containing two separate root canals. Cone-beam computed tomography (CBCT) was used to confirm this unusual anatomy. Methods. A 34-year-old male patient was referred to the Department of Endodontics at Inonu University's Faculty of Dentistry because of severe pain in his right maxillary second molar. Clinical and radiographic examinations identified unusual roots and root canals anatomy, and CBCT was planned in order to understand the nature of these variations. Cleaning and shaping procedures were performed using the crown down technique with Sybron Endo (Glendora, CA, USA) rotary instruments, and endodontic treatment was completed with gutta-percha cones and AH Plus resin sealers using the cold lateral compaction technique. Conclusions. The maxillary second molar exhibits aberrations and variations in terms of the numbers and configurations of its roots and root canals, and CBCT can be a useful imaging technique in endodontics.

Heat conductive properties of set root canal sealers.

OBJECTIVE: The aim of this study was to examine the thermal conductivity of five different root canal sealers in vitro. MATERIALS AND METHODS: Sealapex, AH Plus, AH 26, Endomethasone and RoekoSeal root canal sealers were examined. These materials were prepared in accordance with the manufacturer's instructions and applied to standard molds. Three samples of each material were prepared. The samples were kept for 5 days under 37°C conditions. Measurements were taken using a heat conduction unit (P.A. Hilton Ltd. Stockbridge, Hants, UK). The thermal conductivity coefficient was calculated for each sample using the Fourier equation. Coefficients were analyzed statistically by the Kruskal-Wallis test. RESULTS: Significant differences were found for thermal conductivity between some materials (p < 0.05). The conductivity coefficient of AH Plus was found to be higher than those of the other materials (p < 0.05). No statistically significant differences were found between AH 26 and RoekoSeal (p > 0.05) and the conductivity coefficients of these sealers were found to be lower than those of the other materials (p < 0.05). No statistically significant differences were found between Sealapex and Endomethasone (p > 0.05) and the conductivity coefficients of these sealers were found to be lower than that of AH Plus but higher than those of RoekoSeal and AH26 (p < 0.05). CONCLUSIONS: The results showed that root canal sealers functioned as thermal insulators and had different heat-conductive properties that depended on their composition.

Evaluation of bacterial microleakage of root canals irrigated with different irrigation solutions and KTP laser system.

OBJECTIVE: The aim of this study was to evaluate bacterial microleakage of the root canals irrigated with different irrigation solutions and the potassium-titanyl-phosphate (KTP) laser system and filled with gutta-percha and AH26 root canal sealer. In addition, the effect of the irrigation solutions on dentin surface was evaluated with a scanning electron microscope (SEM). BACKGROUND DATA: A few studies have reported that KTP laser has the capacity to remove the smear layer. Many researchers have demonstrated that propolis has a bactericidal effect. Both are important effects on root canal treatments. MATERIALS AND METHODS: One hundred and twenty single-root single-canal mandibular premolar teeth were used for this study. The root canals were prepared by Dentaport Root ZX and ProTaper rotary instruments with the crown-down technique. The specimens were randomly divided into five groups of 20 teeth each. Each group was irrigated with 17% ethylenediaminetetraacetic acid (EDTA), 20% propolis, 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine gluconate (CHX), and KTP laser, respectively. A total of 20 teeth were used as controls-10 positive controls and 10 negative controls-which were irrigated with distilled water. The root canals were filled with gutta-percha and AH-26. The external surfaces of specimens were covered with three layers of nail varnish except the apical third. The teeth were inserted into Eppendorf plastic tubes and suspended in glass bottles containing sterile broth. All specimens were inoculated every 5 days with Enterococcus faecalis. The contamination onset time was continuously recorded, as turbidity was the first indication of contamination in a period of 30 days. RESULTS: All statistical analysis was performed using the SPSS for Windows version 15.0 software. A χ(2) test was computed and the statistical significance was set at p<0.05. The controls behaved as expected. CONCLUSIONS: This study showed that different irrigation solutions and KTP laser allowed microleakage of E. faecalis.