In-vitro Evaluation of the Accuracy of Electronic Apex Locators and Cone Beam Computed Tomography in the Detection of Oblique Root Fractures.

OBJECTIVES: This study aimed to compare the accuracy of cone-beam computed tomography (CBCT) scanning and three different electronic apex locators (EALs) in the detection of simulated oblique root fractures (ORF) in different localizations. METHODS: The study utilized a total of eighty human maxillary incisors, which were categorized into two groups based on the location of the ORF (apical and middle third of the root) formed on the buccal side of the root surface. The measurement of the distance between the incisal edge and the intersection of the ORF with the root canal was conducted using a stereomicroscope. This measurement is referred to as the actual working length (AWL). Additionally, three EALs-Dentaport ZX, EndoRadar Pro, and Propex II-were utilized to determine the electronic working length (EWL). Furthermore, CBCT images were employed to assess the distance, known as the CBCT working length (CWL). The differences were determined by subtracting AWL from EWL and CWL. RESULTS: Based on the accuracy of the devices, there were no significant differences observed among Dentaport ZX, EndoRadar, Propex II, and CBCT measures in both the apical and middle third HRF groups, within the acceptable range of 0.5 mm and 1 mm. CONCLUSION: The accuracy of Dentaport ZX, Propex II, and CBCT was higher in the middle third ORF group compared to the apical third ORF group, with a tolerance of 0.5 mm. However, there were no significant differences seen among the devices.

Comparative evaluation of the accuracy of electronic apex locators and cone-beam computed tomography in detection of root canal perforation and working length during endodontic retreatment.

BACKGROUND: To evaluate the accuracy of the electronic apex locators (EALs), and Cone-Beam Computed Tomography (CBCT) scanning, both in working length (WL) determination and in the detection of root canal perforations in retreatment cases. METHODS: Sixty human mandibular premolars were selected. After crown removal partially and canal access, root canals were instrumented and irrigated. The obturation process utilized gutta-percha and sealer with warm vertical compaction. Two groups were distinguished: one without perforation (Group 1) and the other with an apical third perforation (Group 2). Retreatment included filling removal, apical preparation, and irrigation. Actual working lengths (AWL) were determined using a stereomicroscope. CBCT images were used to measure CBCT working length (CWL), with adjustments for optimal views. Propex II and Dentaport ZX were used to measure electronic working length (EWL). Differences between EWL and AWL, as well as CWL, were analyzed to gauge accuracy. Data underwent Two-way ANOVA analysis. Measurements within ± 0.5 and ± 1 mm tolerance ranges were deemed successful for each device, followed by applying the Pearson Chi-square test. RESULTS: The study reveals no significant inter-group variations in device performance (p > .05). Dentaport ZX missed detecting perforation in two Group 2 (apical perforation) cases. For ± 1 mm tolerance, Propex II displayed the highest success in Group 2 (apical perforation). CONCLUSION: This study demonstrates the comparable performance of Propex II, Dentaport ZX, and CBCT in endodontic retreatment, providing insights into diagnostic reliability.

The effect of the KTP laser on smear layer and temperature change: an in vitro study.

The purpose of this study was to evaluate the effects of potassium-titanyl-phosphate (KTP) laser irradiation on smear layer removal and temperature changes of the root surfaces. Two hundred four extracted single-root human premolars were included. The canals were instrumented and divided into two main groups: group A (smear layer examination n:119) and group B (temperature change examination n:85). Each group was divided into subgroups (n:17) according to the different five laser power settings: A1, B1: 1 W-5.33 J/cm2; A2, B2: 1.5 W-7.52 J/cm2; A3, B3: 2 W-10.3 J/cm2; A4, B4: 3 W-15.5 J/cm2, A5, B5: 4 W-20.1 J/cm2, A6: positive control no laser irradiation-irrigated 2 mL for 2 min 2.5% NaOCl + 2 mL distilled water and A7: negative control groups no laser irradiation irrigated 2 mL for 2 min 17% EDTA + 2 mL for 2 min 2.5% NaOCl + 2 mL distilled water. The temperature elevations were measured with an infrared thermographic camera and smear layer examined by scanning electron microscope. According to Kruskal-Wallis and Tukey's tests, in all groups the highest smear scores were in the apical third. In all areas, there were statistically significant differences between negative control group (17% EDTA) and all other groups (p < 0.05). The highest smear scores were determined in 1 W KTP laser and positive control (2.5% NaOCl) groups. Statistically, in all thirds, the differences the 3 W and 4 W KTP laser groups between each other and all other groups were significant (p < 0.05). After the end of the use of the laser, increase in temperature values in all groups were found to be below 10 °C in 20 s.

Veneer Ceramic to Y-TZP Bonding: Comparison of Different Surface Treatments.

PURPOSE: The purpose of this study was to evaluate the effects of various surface-treatment techniques for enhancing the bond strength between veneering ceramic and yttria-stabilized tetragonal zirconia polycrystals (Y-TZP). MATERIALS AND METHODS: Pre-sintered Y-TZP specimens were divided into eight groups (n = 10) according to the surface-treatment technique used: (a) untreated (control); (b) air abrasion with aluminum oxide particles; (c) erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation at different energy intensities (1 to 6 W). All specimens were then sintered and veneered with veneering ceramic according to the manufacturer's instructions. The obtained zirconia-ceramic specimens were immersed in 37°C distilled water for 24 hours before a shear bond strength test using a universal testing device at a 1 mm/min crosshead speed. The average values were calculated. After debonding, the Y-TZP surfaces were examined under a stereomicroscope to determine their fracture pattern, and the surface topography was evaluated with scanning electron microscopy after surface treatments. RESULTS: The bond strength ranged from 13.24 to 20.54 MPa. All surface treatments increased the bond strength between the veneering ceramic and Y-TZP; however, the value for the 6 W irradiation group was significantly different from the values for other groups (p ˂ 0.05). CONCLUSIONS: The present study's findings showed that higher energy densities were needed for the laser irradiation to improve the bond strength between the veneering ceramic and zirconia. CLINICAL IMPLICATION: Y-TZP is commonly used as a core material in fixed restorations. The bond strength between zirconia and the veneering ceramic can be affected by various surface treatments.

Evaluation of Apically Extruded Debris using Two Niti Systems Associated with Two Irrigation Techniques in Primary Teeth.

PURPOSE: The aim of this study was to compare the effects of 2 NiTi file systems [Twisted File Adaptive (TFA) and Reciproc (RP)] and 2 irrigation techniques [Conventional needle irrigation (CNI) and Laser activated irrigation (LAI)] on the amount of apically extruded debris in primary maxillary molars. STUDY DESIGN: Sixty extracted primary maxillary molars were randomly divided into 4 groups. The mesio-buccal roots of teeth in 4 groups were instrumented using TFA with LAI, RP with LAI, TFA with CNI and RP with CNI respectively. Debris extruded during instrumentation was collected into Eppendorf tubes and amounts were determined. The data were analyzed using two-way ANOVA test at 0.05 level of significance. RESULTS: The results indicated all instrumentation and irrigation systems caused a measurable apical extrusion of debris. However, no statistically significant difference in debris extrusion was observed between irrigation techniques or instrumentation systems (P > 0.05). The total amount of debris extruded apically by LAI was greater than that by CNI. CONCLUSIONS: All instrumentation and irrigation techniques caused debris extrusion. However, the optimal laser activation time and power settings should be investigated to ensure minimal extrusion of debris and irrigant due to cavitation and pressure during LAI in root canal treatment.

Effects of dentin surface treatments including Er,Cr:YSGG laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin.

OBJECTIVE: Intra-canal post systems are commonly used to restore root-filled teeth. Bond strengths of the posts can be affected by various surface treatments of the post or the dentin. The aim of this study was to evaluate the effects of dentin surface treatments including erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin. MATERIALS AND METHODS: Forty single-rooted human maxillary incisors were filled and post spaces were prepared. After these procedures, the specimens were divided randomly into four groups according to the dentin surface treatments, as follows: (i) untreated surface (control), (ii) 1W Er,Cr:YSGG laser application, (iii) 2W Er,Cr:YSGG laser application and (iv) 3W Er,Cr:YSGG laser application. Then the posts were cemented into the root canals using dual-cured resin cement. Bonded specimens were cut into 1-mm-thick slices and push-out tests were performed using a universal testing device. All specimens were loaded until fracture and the failure modes were evaluated with a stereomicroscope at 32× magnification. Representative specimens were analyzed by scanning electron microscopy. Data were analyzed using a one-way ANOVA, Tukey and Wilcoxon tests. RESULTS: The bond strength values ranged from 3.22-4.68 MPa. There were no statistically significant differences among the groups, regardless of the different levels. The coronal and middle levels of the post space had significantly higher bond strength values compared with the apical level (p < 0.05). CONCLUSION: Er,Cr:YSGG laser irradiation with different intensities did not increase the bond strength of the fiber posts to the root canal dentin walls.

Extrusion of debris during retreatment using various nickel-titanium files in teeth with simulated lateral root perforation.

PURPOSE: To investigate the influence of various nickel-titanium (Ni-Ti) files on debris extrusion during the retreatment of teeth with simulated lateral root perforation, focusing on root resorption. METHODS: Sixty human mandibular premolar teeth were divided into groups with and without perforation and further subdivided based on the retreatment technique. Lateral root perforations were created in one group (Group 1), while the other group had no perforations (Group 2). Two retreatment techniques were compared: Remover (RE)+One RECI (OR) and ProTaper Universal Retreatment (PTUR)+WaveOne Gold (WOG). The weight of the extruded debris was determined. The time of both retreatment procedures was measured. Statistical analyses were performed using a two-way analysis of variance (ANOVA) test (P < 0.05). RESULTS: Teeth with simulated lateral root perforation exhibited higher extrusion of debris during retreatment. In both groups, RE+OR files led to more extruded debris than PTUR+WOG files. However, this difference was statistically significant in Group 2 (P < 0.001). Compared to PTUR+WOG files, RE+OR files showed a statistically significant longer time to remove obturation material (P < 0.001). CONCLUSION: Perforated teeth exhibited significantly higher debris extrusion. While both file systems demonstrated similar debris extrusion in perforated teeth, the RE+OR files significantly increased debris extrusion in non-perforated teeth compared to the PTUR+WOG files.

KTP laser on microleakage of compomer restorations in Class V restorations.

AIM: To evaluate the effects of pulsed KTP (potassium-titanyl-phosphate) laser on decrease of dentinal microleakage of compomer restorations in primary teeth. METHOD: Twenty four primary molars were selected for the study After Class V cavity preparations in buccal and lingual surfaces, teeth were divided into three groups: Group 1: Control, Group 2: 1 WKTP laser Group 3: 1.5 WKTP laser. Then cavities were restored with compomer and teeth were thermocycled to 500 cycles, isolated and immersed in 0.5% basic fuchsin for 24 hours. Teeth were rinsed, dried, and sectioned, and microleakage was assessed by dye penetration at the occlusal and gingival surface of the teeth with stereomicroscope (40X). The data were analyzed with Kruskal-Wallis, Mann-Whitney U and Wilcoxon tests. RESULTS: When the scores of microleakage at the gingival margins of the groups were compared, the differences among the groups were found to be statistically significant (p<0.05). At the occlusal margins of the groups, there were no statistical differences (p>0.05). Comparing the gingival and the occlusal margins in the each group, statistically significant differences existed in the Groups 1 and 3 (p<0.05). CONCLUSIONS: KTP laser is able to seal dentinal tubules and consequently reduce microleakage towards pulp in primary teeth.

Accuracy of different electronic apex locators in determination of minimum Root perforation diameter.

This study aims to evaluate the ability of Raypex 6, Propex Pixi, Dentaport ZX, Apex ID, Propex II and Dr.'s Finder NEO to detect minimum root canal perforation diameter. One hundred single-rooted, extracted human teeth were artificially perforated by 5 burs in different diameters (0.25-1.25 mm) in 5 mm above the apex. Twenty teeth were assigned to each group. The actual canal lengths (AL) were measured under stereomicroscope followed by a measurement of electronic canal length (EL) using each electronic apex locator (EAL). None of the EALs were able to detect the perforation at diameters of 0.50 and 0.25 mm. Although all EALs used in our study were unable to detect perforations at diameters of 0.5 mm and 0.25 mm, they were highly successful in the determination of simulated root perforations at diameters of 1.25, 1 and 0.75 mm.

Shear bond strength of resin-modified glass ionomer cement bound to mineral trioxide aggregate after various disinfection protocols.

This study compared the effects of 3 different cavity disinfection protocols (CDP) on the shear bond strength (SBS) of resin-modified glass ionomer cement (RM-GIC) to mineral trioxide aggregate (MTA). One hundred eighty standard holes were prepared and filled with MTA. They then divided into 3 main groups based on the chosen time intervals (15 min, 24 h, and 72 h). Main groups were divided into 3 subgroups based on the CDP [chlorhexidine gluconate (CHX), ozone, laser, and control]. RM-GIC was applied on MTA after CDP for all groups. A universal testing device was then used for test and the data was statistically analysed. CHX showed significantly lower SBS values except ozone and laser than the control (p < 0.05). There were no statistically significant differences among the time intervals. As a result, CHX decreased the bond strength between the MTA and RM-GIC while ozone and laser had no negative effect.

In Vitro Comparison of the Accuracy of Cone-Beam Computed Tomography Scanning and Electronic Apex Locators in Detection of Simulated Root Perforations in Different Localizations.

INTRODUCTION: This study aimed to compare the accuracy of cone-beam computed tomographic (CBCT) scanning and 2 different electronic apex locators (EALs) in the detection of simulated root canal perforations in different localizations. METHODS: Eighty human mandibular premolars were prepared and divided into 2 groups according to the localization of the perforation area, having a 1-mm diameter. The distance between the occlusal edge and the beginning of the perforation was measured under a stereomicroscope (actual working length) using 2 EALs (Propex II [Dentsply Maillefer, Ballaigues, Switzerland] and Dentaport ZX [J. Morita, Tokyo, Japan]) (electronic working length) and CBCT images (CBCT working length). The calculations were made by subtracting the actual working length from the electronic working length and the CBCT working length to determine the differences. RESULTS: In the apical third perforation group, there was a significant difference between Dentaport ZX and CBCT imaging. There was no significant difference between Dentaport ZX and Propex II and Propex II and CBCT measurements. In the middle third perforation group, Propex II was significantly more successful than CBCT imaging. In addition, there was no significance between the accuracy of Propex II in detecting the perforation area between the apical third perforation group and the middle third perforation group. CBCT imaging was more accurate in detecting the perforation area in the apical third perforation group than in the middle third perforation group. CONCLUSIONS: In cases in which the root canal perforation was in the apical third of the root, both the EAL and CBCT imaging were successful in determining the perforation area, whereas the success rate of all devices used in this study decreased when the perforation area was in the middle third of the root.

The state of additive manufacturing in dental research - A systematic scoping review of 2012-2022.

Background/purpose: Additive manufacturing (AM), also known as 3D printing, has the potential to transform the industry. While there have been advancements in using AM for dental restorations, there is still a need for further research to develop functional biomedical and dental materials. It's crucial to understand the current status of AM technology and research trends to advance dental research in this field. The aim of this study is to reveal the current status of international scientific publications in the field of dental research related to AM technologies. Materials and methods: In this study, a systematic scoping review was conducted using appropriate keywords within the scope of international scientific publishing databases (PubMed and Web of Science). The review included related clinical and laboratory research, including both human and animal studies, case reports, review articles, and questionnaire studies. A total of 187 research studies were evaluated for quantitative synthesis in this review. Results: The findings highlighted a rising trend in research numbers over the years (From 2012 to 2022). The most publications were produced in 2020 and 2021, with annual percentage increases of 25.7% and 26.2%, respectively. The majority of AM-related publications in dentistry research originate from Korea. The pioneer dental sub-fields with the ost publications in its category are prosthodontics and implantology, respectively. Conclusion: The final review result clearly stated an expectation for the future that the research in dentistry would concentrate on AM technologies in order to increase the new product and process development in dental materials, tools, implants and new generation modelling strategy related to AM. The results of this work can be used as indicators of trends related to AM research in dentistry and/or as prospects for future publication expectations in this field.

Effects of three different irrigating solutions and KTP laser irradiation on apical leakage: an electrochemical study.

OBJECTIVE: The purpose of this study was to evaluate the effect of three different irrigating solutions (17% EDTA, 10% citric acid and 2.5% NaOCl) and KTP laser irradiation on apical leakage using an electrochemical method. MATERIALS AND METHODS: Sixty extracted single-rooted human teeth with mature apices were instrumented up to a size 35 K-file. After using each file and before proceeding to the next, canals were irrigated with 2 ml of 2.5% NaOCl. All teeth were then randomly divided into four groups. In group 1, the root canals were irrigated with a final flush of 17% EDTA. In group 2, the root canals were irrigated with a final flush of 10% citric acid. In group 3, the root canals were irradiated with KTP laser at 1 W, 4.45 J/cm(2). In group 4, the root canals were irrigated with a final flush of 2.5% NaOCl. The root canals were then filled using the cold lateral condensation method. Apical leakage was evaluated using an electrochemical method over a period of 10 days. Data were analysed using Tukey HSD and Friedmann tests with p = 0.05 as the level for statistical significance. RESULTS: The 17% EDTA and 10% citric acid groups had statistically less apical leakage than the 2.5% NaOCl group at days 7, 8, 9 and 10 (p < 0.05); however, no significant differences were found between the tested groups at the other time intervals (p > 0.05). No significant difference was found between the KTP laser group and other groups tested at all time intervals (p > 0.05). CONCLUSION: All groups were unable to eliminate apical leakage. However, final irrigation with 17% EDTA and 10% citric acid following root canal preparation reduced postobturation apical leakage compared with 2.5% NaOCl irrigation. When KTP laser and the other three irrigants were compared, no significant difference was found.

The efficacy of two rotary NiTi instruments and H-files to remove gutta-percha from root canals.

OBJECTIVE: The aim of this study was to evaluate the efficacy of R-Endo® and K3® rotary nickel-titanium instruments compared with manual instrumentation with H-files, with use of a solvent, for removal of gutta-percha during retreatment. STUDY DESIGN: Forty five freshly extracted human single-rooted teeth, each with one root canal, were instrumented with K-files and filled using cold lateral compaction of gutta-percha and AH 26® sealer. The teeth were randomly divided into three groups of 15 specimens each. Removal of gutta-percha was performed with the following devices and techniques: Group 1 (H-files), Group 2 (R-Endo®), and Group 3 (K3®). The specimens were rendered transparent for the evaluation of the area of remaining gutta-percha/sealer in buccolingual and mesiodistal directions. Statistical analysis as performed by using one-way ANOVA and Kruskal-Wallis tests (p=0.05). RESULTS: All retreatment techniques used in this study left some filling material inside the root canal. Images in buccolingual and mesiodistal directions showed no significant differences between the groups (p>0.05). CONCLUSIONS: Under the experimental conditions, the remaining filling material after retreatment was similar for each group.

Microleakage beneath orthodontic brackets in high field magnetic resonance imaging (MRI) AT 1.5 & 3 Tesla.

OBJECTIVES: The aim of the present study was to evaluate the effects of 1.5 T and 3 T MRI on the adhesion between the orthodontic brackets and the teeth by evaluating the microleakage between the enamel, adhesive and brackets interfaces. METHODS: 58 extracted human premolars which were received a standard bracket bonding procedure were randomly divided into three groups; control group (n = 20; no MRI), 1.5 T MRI group (n = 19; 20 min MRI exposure of 1.5 T) and 3 T MRI group (n = 19; 20 min MRI exposure of 3 T). The teeth were kept in distiled water for 2 weeks, and thereafter subjected to 500 thermal cycles. Then, specimens were sealed with nail varnish, stained with 0.5% basic fuchsin for 24 h, sectioned and photographed under a stereomicroscope. Microleakage was scored with regard to the adhesive-enamel and bracket-adhesive interfaces at the occlusal and gingival levels. Statistical analysis was accomplished by Kruskal-Wallis and Bonferroni-Dunn tests. RESULTS: All of the groups exhibited statistically similar microleakage scores in the adhesive-enamel interface along occlusal margins (p>0.05, p = 0.331). The mean microleakage scores along gingival margins in the 3 T MRI group was significantly higher compared to the control group both in the adhesive-enamel and bracket-adhesive interfaces (p<0.05, p = 0.019 and p = 0.020 respectively). The microleakage scores along the gingival margins were also significantly higher than the occlusal margins in the 3 T MRI group (p<0.05, p = 0.029). CONCLUSIONS: 3 T MRI may weaken the adhesion between the enamel and the stainless steel orthodontic brackets.

Stabilization of autotransplanted teeth using thermoplastic retainers.

OBJECTIVE: Different fixation techniques have been used for stabilization of autotransplanted teeth. Because rigid or extended fixation periods can cause complications such as ankylosis and disturbances of pulpal revascularization, our aim was to evaluate an alternative technique, a removable splint, for improving the success rate of autotransplanted molar teeth. STUDY DESIGN: In 44 patients, (20 male and 24 female patients), 45 transplanted teeth were analyzed. These cases were followed for 31 to 47 months after operation. Transplanted teeth were evaluated after use of a thermoplastic retainer for 1 month, in terms of success rate and dissatisfaction with this apparatus. The primary stability, ankylosis, and root resorption were also analyzed. RESULTS: To date, 1 transplant was extracted after 6 months due to unpreventable periapical root inflammation, and 2 transplants were extracted after one year due to external root resorption. Although 2 ankylosed transplants were still functional after an average follow-up period of three years, with no dissatisfaction by the patients, these cases were treated as failures because of the probable risk for external root resorption. The remaining 40 (88.8 % success rate) transplants remained asymptomatic and functioning for a mean follow-up period of 37 months. In the assessment of dissatisfaction with the thermoplastic retainer, 36 (81.8 %) patients had no or little dissatisfaction, 4 (9 %) patients had very appreciable or excessive dissatisfaction, and 4 (9 %) patients had moderate dissatisfaction. CONCLUSIONS: A thermoplastic retainer for use after autotransplantation of third molar teeth is a reasonable and useful method and a good alternative to conventional rigid or semi-rigid splints. This technique was especially useful in autotransplanted teeth that had poor stability, i.e., in cases in which it is conventionally advised to use long-term rigid or semi-rigid splints.

Evaluation of the shear bond strength of zirconia to a self-adhesive resin cement after different surface treatment.

OBJECTIVES: The aim of this study was to evaluate the SBS of pre-sintered and sintered zirconia to a selfadhesive resin cement after various treatment (air abrasion and the Nd:YAG laser irradiation at varying power levels -1 W, 2 W and 3 W). MATERIAL AND METHODS: Ninety-nine zirconia specimens were prepared and divided into 3 groups: control (with no surface treatment); and pre-sintered and sintered groups with surface treatment. Surface treatment was applied before sintering in the pre-sintered group and after sintering in the sintered group. After following all protocols, a resin cement was layered on the zirconia surface. Shear bond strength was measured using a universal testing machine. The results were subjected to the statistical analysis. The surface topography and phase transformation of zirconia were evaluated using the atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses after surface treatment. RESULTS: The laser irradiation (3 W, 1 W and 2 W) of the pre-sintered zirconia surface resulted in the highest SBS values (p < 0.001), while the lowest SBS values were obtained with airborne particle abrasion of the pre-sintered and sintered zirconia surfaces. CONCLUSIONS: Laser irradiation increased the SBS of pre-sintered zirconia to a resin cement. Surface treatment with air abrasion had a lesser effect on the SBS values.

Effects of different glide path techniques on the amount of extruded debris and preparation times during root canal preparation.

Background. This study purposed to compare the effect of new single glide path files on extruded apical debris and total preparation times during root canal preparation with the WaveOne Gold system. Methods. Thirty-six extracted human lower molar teeth with mesiobuccal canal curvature angles of 25‒35° were randomly splited to three groups. In group 1, the glide path was created with WaveOne Gold Glider (WGG) file at working length (WL); in group 2, the glide path was created with ProGlider file (PG); in group 3, the glide path was not performed. In all the groups, the root canals were shaped with WaveOne Gold Primary (WOG) reciprocating files at WL. Apically extruded debris during instrumentation was picked up into pre-weighed Eppendorf tubes. The weight of the dry extruded debris was calculated by subtracting the pre- and post-instrumentation weights of the tubes in each group. The total time elapsed during the canal preparation was calculated with a chronometer. The data were analyzed using one-way ANOVA and post hoc Tukey tests. Results. The WGG/WOG group extruded significantly fewer debris than the WOG and PG/WOG groups (P<0.05). There was no significant difference between the WOG and PG/WOG groups (P>0.05). The WGG/WOG and PG/WOG groups were significantly faster than the WOG group. Conclusion. The amount of debris extruded apically significantly diminished when conventional WGG was implemented before using WOG. The total preparation time significantly diminished when the WOG file was used in combination with reciprocating and rotary glide path preparation techniques.

Human pulp tissue dissolution ability of different extracts of Sapindus mukorossi: An in vitro study.

Objective: Due to the many negative properties of sodium hypochlorite used in current root canal treatment, interest in biocompatible natural agents is increasing day by day. The aim of this study was to evaluate whether various extract solutions of Sapindus mukorossi have dissolution effects on human pulp tissues. Methods: Primarily powder extracts were obtained by extracting fruit shells of S. mukorossi in different solvents (ethanol, methanol, buthanol and distilled water). The test solutions were prepared and randomly separated into six groups with 10 samples in each group: ethanol extract, methanol extract, butanol extract, distilled water extract of S. mukorossi, sodium hypochlorite (NaOCl) and the control group. Among these, S. mukorossi extracts were separated into two subgroups, depending on their concentration level (50 µg/mL and 100 µg/mL). The pulp tissues of freshly extracted human molars were used for dissolution test. The weights of the pulpal tissues were measured and recorded for two times after the samples were placed in the solutions. Statistical analysis for all descriptive statistics was performed using SPSS 22 (P < 0.05). Results: Our results showed that maximum percent yield of preparation was obtained in methanol extract of S. mukorossi. Among all of the groups, the best dissolution capacity was seen in the NaOCl group (positive control group). Among S. mukorossi groups, the best tissue solvent solution was found in SMM group at 50 µg/mL and SMB group at 100 µg/mL. Conclusion: The different extracts of S. mukorossi had a capacity to dissolve pulp tissue but this capacity was less than NaOCl. Therefore, further studies will enable the creation of a commercial solution for clinical use by increasing the effectiveness of S. mukorossi while combining it with other endodontic irrigation solutions.

Antibacterial activity of silver nanoparticles activated by photodynamic therapy in infected root canals.

BACKGROUND: Root canal disinfection includes mechanical, chemical and biological struggle against microorganisms (MOs). Photodynamic therapy (PDT) and nanoparticle (NP) agents may be proposed as an alternative for use against intracanal infections due to their ability to disrupt biofilm and prevent bacterial adhesion to dentin. The use of NP agents in combination with light/photosensitizer (PS) agents increases the efficiency of PDT in root canal disinfection. OBJECTIVES: The aim of the study was to evaluate the effect of light application - PDT - on the antibacterial activity of the combination of a PS agent (toluidine blue O -TBO) and an NP agent (silver nanoparticles - AgNPs) for the disinfection of the root canals inoculated with Enterococcus faecalis (E. faecalis). MATERIAL AND METHODS: In this study, concentrations of 20 ppm of TBO and 10 ppm of AgNPs, which showed the highest antibacterial activity against E. faecalis in the TBO/AgNPs combination, were used according to the preliminary studies. After instrumentation, 120 human, single-rooted, straight-canal mandibular premolars of a standard length of 13 mm were contaminated with bacteria, and experimental procedures were conducted against 21-day-old mature biofilm. The teeth were randomly divided into 5 main experimental groups: TBO/light; AgNPs; TBO/AgNPs; AgNPs/light; and TBO/AgNPs/light. Then, these main groups were divided into 2 subgroups each, according to the 2 application time periods (30 s and 60 s) (n = 10). The remaining 20 teeth constituted positive and negative control groups. The data was analyzed with the Kolmogorov-Smirnov test, one-way analysis of variance (ANOVA), Tukey's honestly significant difference (HSD) test, and the Bonferroni correction. RESULTS: The NaOCl group provided a bacterial reduction that was higher than in all other groups in a statistically significant manner. Light application on the TBO/AgNPs combination was the group that provided the highest bacterial reduction after NaOCl. CONCLUSIONS: The photoactivation of the TBO/AgNPs combination led to an increase in the effect of PDT, and it has the potential to be used as an adjunct for disinfection of the root canal system.