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.

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.

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.

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.

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.

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.

Cyclic fatigue resistance of the WaveOne Gold Glider, ProGlider, and the One G glide path instruments in double-curvature canals.

OBJECTIVES: The aim of this study was to compare the cyclic fatigue resistance of the WaveOne Gold Glider, ProGlider and One G glide path instruments in artificial double-curvature canals. MATERIALS AND METHODS: This study included 15 WaveOne Gold Glider (size 15/0.08), 15 ProGlider (size 16/0.08), and 15 One G (size 16/0.06) nickel titanium files. The files were used in accordance with the manufacturer's instructions until they were broken in artificial double-curvature canals made of stainless steel. The time to fracture was recorded via a digital stopwatch and the number of rotations until fracture was also calculated. The data were statistically analyzed via the Kruskal-Wallis test. RESULTS: The highest average number of rotations until fracture of the files was found for the WaveOne Gold Glider, followed by ProGlider and One G in order. Statistically significant differences were present between all groups of files (p < 0.05). CONCLUSIONS: In our study, the resistance of the WaveOne Gold Glider nickel-titanium (Ni-Ti) file to cyclic fatigue in S-shaped curved canals was found to be higher than that of the ProGlider and One G Ni-Ti files.

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.

Evaluation of Various Pretreatments to Fiber Post on the Push-out Bond Strength of Root Canal Dentin.

INTRODUCTION: The aim of this in vitro study was to compare the effect of different pretreatments (fiber post) with the laser-activated irrigation (LAI) technique (for removal of the smear layer) on root canal dentin in terms of push-out bond strength (PBS) in a fiber post. METHODS: Fifty freshly extracted mandibular single-rooted premolars were prepared, and LAI was applied to all roots (17% EDTA was 5 mL for 120 seconds with an erbium, chromium:yttrium-scandium-gallium-garnet laser [0.50 W, 20 Hz, 25 mJ]). In addition, 50 quartz fiber posts were randomly assigned to 5 groups (n = 10) according to the surface treatments as follows: group S (sandblasting), group N1 and group N2 (neodymium:yttrium-aluminum-garnet laser irradiation [2 W, 200 mJ, 10 Hz, with pulse durations of 180 or 320 microseconds), group HF (9.7% hydrofluoric acid etched), and group C (control with no treatment). Dual-cure resin cement was adhered onto the fiber posts after they were covered with a silane agent, and then the posts were placed into the canal space using a Lentulo spiral. The PBS test was performed after all specimens were transversally sectioned (root slices of 1-mm thickness). Data were analyzed with 1-way analysis of variance/Tukey post hoc test (α = 0.05). RESULTS: The highest PBS value was observed in group S (middle part), and the lowest value was observed in group C (apical part). There were no statistical differences among the groups regardless of the part. Furthermore, when the PBS values of the different parts of dentin were compared within treated groups, significant differences were observed in all groups except group N2 (P < .05). CONCLUSIONS: Within the limitations of this study, it can be concluded that the LAI technique when used with 17% EDTA had a significant effect on the amount of smear layer removed from the root canal dentin, which was also detected in the fracture pattern (adhesive failure [resin-post interface]). However, the various treatments of the fiber post did not improve the PBS of the root dentin.

The Influence of Various Irrigants on the Accuracy of 2 Electronic Apex Locators in Locating Simulated Root Perforations.

INTRODUCTION: The aim of this study was to assess the accuracy of the Dentaport ZX (Morita Co, Kyoto, Japan) and the Rootor (Meta Biomed, Cheongwon-gun, Korea) electronic apex locators (EALs) in detecting root perforations in dry conditions and in the presence of the following irrigation solutions: 2.5% sodium hypochlorite (NaOCl), 0.9% saline solution (NaCl), and 17% EDTA. METHODS: Twenty extracted, single-rooted human teeth were perforated artificially in the middle section. The actual canal lengths (ALs) up to the perforation site were determined, and then the teeth were embedded in an alginate mold. The electronic measurements of the perforations were obtained using a size 20 K-file by each EAL in various conditions. For each tooth, the AL was subtracted from the electronic length of the perforation. Statistical analyses were performed using the Friedman and Wilcoxon signed rank tests at a significance level of P < .05. RESULTS: The most accurate measurements for both EALs were obtained in dry conditions. Among the irrigation solutions in the Dentaport ZX group, EDTA gave the most accurate results, and NaOCl gave the least accurate ones. However, measurements with NaCl were closer to the AL than those obtained with EDTA for the Rootor group. Significant differences were noted among the EALs when the measurements were taken with NaOCl, NaCl, and EDTA (P < .05). CONCLUSIONS: The Dentaport ZX was more accurate compared with the Rootor in the presence of different irrigants. The content of the root canal affected the accuracy of both EALs. The most accurate measurements were obtained in dry canals.

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.

Comparison of Smear Layer Removal Ability of QMix with Different Activation Techniques.

INTRODUCTION: To evaluate the effectiveness of QMix solution (Dentsply Tulsa Dental Specialties, Tulsa, OK) on the smear layer using the following irrigation activation techniques: the EndoActivator (EA) system (Dentsply Tulsa Dental Specialties), photon-initiated photoacoustic streaming (PIPS), and an Er:YAG laser with an endodontic fiber tip. METHODS: Sixty-four extracted single-rooted human teeth were decoronated and the canals instrumented with ProTaper (Denstply Maillefer, Ballagues, Switzerland) up to size F4. The canals were irrigated with 5.25% sodium hypochlorite and a saline solution for 1 minute each. The specimens were then divided randomly into 4 experimental and 4 control groups (n = 8) according to the final irrigation activation technique. These groups included group 1, 2.5 mL QMix; group 2, QMix + EA; group 3, QMix + PIPS; and group 4: QMix + Er:YAG. Laser activated distilled water was used as control groups 5, 6, 7, and 8. Teeth were split longitudinally, and specimens were observed under a scanning electron microscope. Images were taken at the coronal, middle, and apical thirds of the teeth at a magnification of 1000× and were scored in the presence of the smear layer. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The highest scores were found in the apical third of all groups (P < .05). The QMix + Er:YAG group removed the smear layer more effectively than the nonactivated QMix group in the apical third (P < .05). The QMix + EA group removed the smear layer significantly in all thirds of the teeth when compared with the nonactivated QMix group (P < .05). The QMix + PIPS group showed a significantly better effect than the QMix group in the coronal third (P < .05). CONCLUSIONS: The EA and Er:YAG laser enhanced the smear layer removal ability of QMix in the apical thirds of the canals. QMix removed more smear layer in the coronal thirds when activated with the PIPS technique.

Efficacy of Laser-Activated Irrigants in Calcium Hydroxide Removal from the Artificial Grooves in Root Canals: An Ex Vivo Study.

OBJECTIVE: The aim of this study was to investigate the efficacy of an erbium chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with different irrigation solutions [sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), QMix 2in1, and peracetic acid] in removing calcium hydroxide (CH) from artificial grooves created in root canals. BACKGROUND DATA: CH has to be removed totally before the root canal filling. Any CH residue on the dentin walls may affect the dentinal bond strength and the penetration of sealers into the dentin tubules, and may increase apical leakage. In addition, such a remnant could react chemically with sealers and, possibly, influence physical properties. Therefore, complete removal of CH placed inside the root canals is recommended, using various products and techniques. METHODS: The root canals of 160 extracted single-rooted mandibular premolars were prepared with ProTaper Universal rotary instruments up to size F4. The roots were split longitudinally along the length of the instrumented canals, and a standardized groove was prepared in the apical part of one segment. CH powder mixed with distilled water was placed into the grooves, and the root halves were then reassembled. The roots were randomly divided into two main groups according to the selected irrigation techniques (needle and laser activation) and then each main group was divided into four subgroups according to the final irrigation (NaOCl, EDTA, QMix 2in1, and peracetic acid) protocols used. After irrigation, the roots were disassembled and digital images were taken using a stereomicroscope. Measurements of residual CH were performed as percentages of the overall groove surface area with image analysis software. The data obtained were analyzed using one way analysis of variance and Tukey's honest significant difference tests. Statistical significance was set at p < 0.05. RESULTS: Significantly less residual CH was obtained in the laser-activated groups than in the needle-irrigated groups (p < 0.05). According to both main groups' data, NaOCl left significantly more CH than the other groups (p < 0.05). However, there was no significant difference among the EDTA, QMix 2in1, and peracetic acid groups. CONCLUSIONS: None of the techniques removed the CH dressing completely. Laser-activated irrigation was significantly more effective than needle irrigation.

Reciproc versus Twisted file for root canal filling removal: assessment of apically extruded debris.

PURPOSE: The aim of this study was to evaluate the amount of apically extruded debris during endodontic retreatment with different file systems. MATERIALS AND METHODS: Sixty extracted human mandibular premolar teeth were used in this study. Root canals of the teeth were instrumented and filled before being randomly assigned to three groups. Guttapercha was removed using the Reciproc system, the Twisted File system (TF), and Hedström-files (H-file). Apically extruded debris was collected and dried in pre-weighed Eppendorf tubes. The amount of extruded debris was assessed with an electronic balance. Data were statistically analyzed using one-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests. RESULTS: The Reciproc and TF systems extruded significantly less debris than the H-file (p<0.05). However, no significant difference was found between the Reciproc and TF systems. CONCLUSION: All tested file systems caused apical extrusion of debris. Both the rotary file (TF) and the reciprocating single-file (Reciproc) systems were associated with less apical extrusion compared with the H-file.

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.

Shaping ability of reciprocating single-file and full-sequence rotary instrumentation systems in simulated curved canals.

OBJECTIVE: The purpose of this study was to evaluate the shaping ability of three nickel-titanium systems in simulated curved canals. MATERIALS AND METHODS: Sixty simulated canals were prepared to apical size 25 with Reciproc, S5, and twisted file (TF) instruments. Standardized pre and postoperative images were taken using a digital camera, were superimposed and aberrations were recorded. Material removal was measured at five points: The canal orifice, halfway to the orifice, beginning of the curve, the apex of the curve, and end-point. The data were analyzed using Kolmogorov-Smirnov, analysis of variance, and Tukey tests. RESULTS: The mean total width of the prepared canals in the Reciproc group was greater than the TF and S5 groups at halfway to the orifice, the beginning of the curve, the apex of the curve, and the end-point (P < 0.05). Mean absolute transportation was always <0.16 mm; however, significant differences occurred between the three systems at the orifice, halfway to the orifice, and the beginning of the curve (P < 0.05). TF created minimal absolute transportation at halfway to the orifice and the beginning of the curve, and greater absolute transportation at the orifice compared with the Reciproc and S5 instruments. However, the difference between the S5 and TF groups was not statistically significant at halfway to the orifice (P > 0.05). CONCLUSIONS: Under the conditions of the study, Reciproc produced widest canal shapes. TF provided more centered apical preparation and maintained the original canal shape well.

Pulp tissue dissolution capacity of QMix 2in1 irrigation solution.

OBJECTIVE: The aim of this study was to evaluate the tissue dissolution efficacy of four root canal irrigation solutions (sodium hypochlorite [NaOCl], chlorhexidine gluconate [CHX], Octenidine [OCT], and QMix 2in1) on bovine pulp tissue. MATERIALS AND METHODS: Fifty bovine pulp tissue samples, each weighing 6.55 mg, were prepared and randomly divided into four experimental groups and one control group (n = 10) according to the dissolution irrigants used: (1) 5.25% NaOCl group; (2) 2% CHX group; (3) OCT group; (4) QMix 2in1 group; and (5) control group (saline solution). These samples were then placed into special bovine dentin reservoir models and immersed for 1 h with each test solution (0.1 mL of each) at room temperature. The pulp samples were then blotted dry and weighed again. The percentage of weight loss was calculated. Statistically analyzed with one-way analysis of variance and post-hoc Tukey tests (P = 0.05). RESULTS: Saline solution did not dissolve the bovine pulp tissue. All groups, except OCT, dissolved pulp samples more effectively than the control group (P < 0.05). The highest tissue dissolution was observed in 5.25% NaOCl group (P < 0.05). No statistically significant difference was found between the tissue-dissolving effect between QMix 2in1 and those of 2% CHX. CONCLUSIONS: Within the limitations of this in vitro study, NaOCl exhibited the best tissue-dissolving effect out of all solutions tested. CHX and QMix 2in1 were able to dissolve pulp tissue but less than NaOCl. OCT and saline solutions could not exhibit significantly tissue-dissolving effectiveness. This study shown that QMix 2in1 has little capacity to dissolve pulp tissue therefore used alone is not sufficient for this purpose.