Comparison of cytotoxic effects of calcium silicate-based materials on human pulp fibroblasts Mehmet.

Background. This study aimed to compare the in vitro cytotoxicity of Theracal LC, BiodentineTM, iRoot BP Plus, and MTA Angelus on human pulp fibroblasts (HPF). Methods. Fifteen discs from each calcium silicate-based material were prepared in sterile Teflon molds. After setting, the fabricated discs were eluated with a culture medium for 24 h. HPF cells were plated onto 24-well plates at 5×103 cells/well, and the cells were exposed to the material eluates. The cell viability was evaluated with MTT assay at three different times (24, 48, and 72 h). Data were statistically analyzed. The apoptotic/necrotic status of HPF cells exposed to material eluates was determined by flow cytometry. Results. The differences between the effects of Theracal LC, BiodentineTM, MTA Angelus, and iRoot BP Plus on HPF cells were found to be statistically significant (P<0.05). Theracal LC was found to be more cytotoxic considering other vital pulp capping materials at 24- (28.3%), 48- (44.9%), and 72-hour (49.2%) intervals. On the other hand, BiodentineTM showed the least cytotoxic effects (97.1%, 130.0%, and 103.7%, respectively) According to flow cytometry results, Theracal LC material increased apoptosis/necrosis ratios compared to the other materials. Conclusion. Based on the results of the present study, BiodentineTM, MTA Angelus, and iRoot BP Plus can be classified as biocompatible materials in vital endodontic treatments. However, the Theracal LC materials should be used carefully due to their cytotoxic effects.

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.

Comparative analysis of three different filling techniques and the effects of experimental internal resorptive cavities on apical microleakage.

OBJECTIVES: The aim of this study was to evaluate the sealing abilities of three different gutta-percha techniques in experimentally defective roots (EDR) and non-defective roots (NR). MATERIALS AND METHODS: Sixty canine teeth were divided into six groups of ten; Group 1, NR + cold lateral condensation (CLC); Group 2, EDR + LC; Group 3, NR + BeeFill; Group 4, EDR + BeeFill; Group 5, NR + Thermafil; and Group 6, EDR + Thermafil. Apical leakage was measured using a computerized fluid filtration meter with a laser system. RESULTS: Statistical analysis revealed that the CLC demonstrated more microleakage in the EDR than in the NR (P < 0.01). Thermafil demonstrated more microleakage in the NR than in the EDR (P < 0.01). No statistically significant differences were found between the BeeFill groups (P > 0.05). CONCLUSIONS: The results of this study indicate that internal resorptive cavities can affect the apical sealing properties of different root canal filling techniques, with Thermafil ensuring the lowest apical microleakage.

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.

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.

Quality of different gutta-percha techniques when filling experimental internal resorptive cavities: a micro-computed tomography study.

The purpose of this ex vivo study was to determine the quality of root fillings in experimental internal resorptive cavities filled using cold lateral condensation (CLC), vertical condensation and Thermafil techniques. Forty-five extracted maxillary canine teeth were selected. After root canal instrumentation, the roots were sectioned horizontally and experimental internal resorption cavities were prepared. The root sections were re-approximated with a luting agent and randomly assigned to three groups (n = 15) to be filled using CLC, vertical condensation and Thermafil, respectively. Assessment of obturation quality in the internal resorptive cavity was performed using a desktop X-ray micro focus computed tomography scanner, and the percentage of gutta-percha (GP), sealer and voiding was calculated for each specimen. Data were statistically analysed using non-parametric tests, with P < 0.05 denoting a statistically significant difference. Vertical condensation filled 96.25 ± 8.31% of the total artificial cavity, and was superior to CLC (63.20 ± 16.87%) and Thermafil (59.26 ± 18.47%). The mean percentage of voids was 3.75 ± 8.31% in the vertical condensation group, 37.09 ± 17.13% in the CLC group and 41.06 ± 18.60% in the Thermafil group. We conclude that obturation of experimental resorption cavities is significantly better when using vertical condensation than when using other GP-based techniques.

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.

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.

Effect of different light sources in combination with a light-transmitting post on the degree of conversion of resin composite at different depths of simulated root canals.

AIM: The aim of this study was to evaluate the degree of conversion (DC) of composite resin at different depths of simulated immature root canals using light-transmitting plastic post (LTPP) and three different light sources. METHODOLOGY: Composite resin was packed into 60 black plastic cylinders 12mm in length with 4mm internal diameters to simulate immature root canals. LTPPs were inserted into half of the simulated canals and the other half acted as controls. Both the simulated canals with LTPPs and the controls were divided into three groups of 10, and each group was cured using either a quartz-tungsten-halogen (QTH), light-emitting diode (LED), or plasma arc (PAC) curing unit. Specimens were sectioned in three horizontally 24h after curing to represent cervical, middle, and apical levels. DC for each section of composite resin was measured using a Fourier transform infrared spectrophotometer, and data were analyzed using three-way anova and Tukey tests. RESULTS: At the cervical level, no significant differences were found between specimens cured using different light sources or between specimens with and without LTPPs (P>0.05). However, DC was significantly higher in specimens with LTPPs than in those without LTPPs at both the middle and apical levels (P<0.05). The mean DC of all specimens with LTPPs was significantly higher than that of specimens without LTPPs (P<0.05). PAC unit showed lower DC than QTH and LED units at both the middle and apical levels; however, the differences were not statistically significant (P > 0.05). CONCLUSIONS: The results of this study suggest that the use of a LTPP increased the DC of composite resin at the middle and apical levels of simulated immature root canals, but that DC was independent of type of light source.

Comprehensive treatment of the infected maxillary lateral incisor with an accessory root.

Rare anatomic anomalies may occur in the dentition and can affect treatment decisions and prognosis. Accurate diagnosis and therapy performed at the highest level can result in predictable success in these cases. This case report shows the clinical and radiographic findings and successful treatment (nonsurgical and surgical) of a combined apical and marginal periodontal inflammatory lesion of a maxillary lateral incisor with an accessory root.