This study evaluated the influence of eugenol on the push-out bond strengths of fiber posts cemen... more This study evaluated the influence of eugenol on the push-out bond strengths of fiber posts cemented with different types of resin luting agents. Seventy-two extracted maxillary single-rooted canine teeth were randomly divided into two groups of 36 teeth. Group 1, the control group, was filled with gutta-percha only (i.e., did not receive eugenol), whereas group 2 was filled with a eugenol-containing sealer. All root canals were filled and each group was divided into three subgroups. The posts in each subgroup were cemented with the following materials: subgroup 1 with a 2-step self-etching adhesive system (Clearfil Liner Bond 2V + Panavia F); subgroup 2 with a 1-step self-etching adhesive (Panavia F); and subgroup 3 with a self-adhesive (Clearfil SA Cement). Dislodgement resistance was measured using a universal testing machine. All data were subjected to ANOVA using a factorial design and Tukey test (α = 0.05). The use of the eugenol-containing sealer significantly reduced the push-out bond strength of the fiber post (P < 0.05). The push-out bond strength of Panavia F was significantly higher than those of the other groups filled with the eugenol-containing sealer (P < 0.05). The Panavia F group was less susceptible to the inhibiting effect of eugenol than were the other evaluated groups when the fiber post was cemented in the canals filled with the eugenol-containing sealer.
Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With tec... more Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With technological advancements in metallurgy, manufacturers have attempted to produce instruments with enhanced features. In parallel with these developments, endodontic motors have undergone improvements in terms of torque control and kinematics that are adjustable in different directions. This review presents an overview of the advancements in instrumentation kinematics and the effect of instrumentation kinematics on root canal shaping procedures and instrument performance. The literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords 'kinematics and endodontics' and 'reciprocation and endodontics'. In addition, historical literature was searched using the keyword 'nickel-titanium and endodontics'. Overall, 143 articles were included up to 2015.
Introduction: The purpose of this study was to investigate the incidence of apical crack initiati... more Introduction: The purpose of this study was to investigate the incidence of apical crack initiation and propagation in root dentin after several endodontic procedures. Methods: Sixty intact mandibular premolars were sectioned perpendicular to the long axis at 1 mm from the apex, and the apical surface was polished. Thirty teeth were left unprepared and served as a control, and the remaining 30 teeth were instrumented with ProTaper Universal instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F5. The root canals were filled with the single-cone technique. Gutta-percha was removed with drills of the Rebilda post system (VOCO, Cuxhaven, Germany). Glass fiberreinforced composite fiber posts were cemented using a dual-cure resin cement. The fiber posts were removed with a drill of the post system. Retreatment was completed after the removal of the gutta-percha. Crack initiation and propagation in the apical surfaces of the samples were examined with a stereomicroscope after each procedure. The absence/presence of cracks was recorded. Logistic regression was performed to analyze statistically the incidence of crack initiation and propagation with each procedure. Results: The initiation of the first crack and crack propagation was associated with F2 and F4 instruments, respectively. The logistic regression analysis revealed that instrumentation and F2 instrument significantly affected apical crack initiation (P < .001). Post space preparation had a significant effect on crack propagation (P = .0004). The other procedures had no significant effects on crack initiation and propagation (P > .05). Conclusions: Rotary nickeltitanium instrumentation had a significant effect on apical crack initiation, and post space preparation with drills had a significant impact on crack propagation. (J Endod 2015;41:253-256)
The purpose of the present study is to evaluate smear layer generation and residual debris after ... more The purpose of the present study is to evaluate smear layer generation and residual debris after using self-adjusting file (SAF) or rotary instrumentation and to compare the debris and smear layer removal efficacy of the SAF cleaning/shaping irrigation system against final agitation techniques. One hundred and eight maxillary lateral incisor teeth were randomly divided into nine experimental groups (n = 12), and root canals were prepared using ProTaper Universal rotary files, with the exception of the SAF instrumentation group. During instrumentation, root canals were irrigated with a total of 16 mL of 5% NaOCl. For final irrigation, rotary-instrumented groups were irrigated with 10 mL of 17% EDTA and 10 mL of 5% NaOCl using different irrigation agitation regimens (syringe irrigation with needles, NaviTip FX, manual dynamic irrigation, CanalBrush, EndoActivator, EndoVac, passive ultrasonic irrigation (PUI), and SAF irrigation). In the SAF instrumentation group, root canals were instrumented for 4 min at a rate of 4 mL/min with 5% NaOCl and received a final flush with same as syringe irrigation with needles. The surface of the root dentin was observed using a scanning electron microscope. The SAF instrumentation group generated less smear layer and yielded cleaner canals compared to rotary instrumentation. The EndoActivator, EndoVac, PUI, and SAF irrigation groups increased the efficacy of irrigating solutions on the smear layer and debris removal. The SAF instrumentation yielded cleaner canal walls when compared to rotary instrumentation. None of the techniques completely removed the smear layer from the root canal walls.
We compared the effects of 6 different rotary systems on transportation, canal curvature, centeri... more We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging. Methods: Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20 -40 were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), Pro-Taper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05. Results: The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation. Conclusions: The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change. (J Endod 2013;-:1-5)
This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using con... more This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using cone-beam computed tomography (CBCT) and panoramic images rendered from CBCT images. In addition, the findings of the imaging techniques were compared. We evaluated 300 CBCT images to determine the type of DI, the presence of an impacted tooth near the DI, and the presence of apical pathosis. The McNemar test was used to compare the prevalence of DI according to CBCT and panoramic images rendered from CBCT images. The presence of DI was lower on panoramic images rendered from CBCT images (3% of the patients) compared with on CBCT images (10.7% of the patients) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). According to the CBCT images, the distribution of teeth with DI was as follows: maxillary lateral incisors (75%), maxillary central incisors (6.8%), mandibular premolars (4.6%), mesiodens (9%), maxillary canines (2.3%), and mandibular canines (2.3%). Type I DI was the most commonly observed type of invaginatus (65.9%), followed by type II (29.5%) and type III (4.6%). All patients with type III DI and 25% of the patients with type II DI had apical pathosis at the time of referral, but periapical lesions were not observed in teeth with type I DI. In total, 13.6% of DI cases had impacted teeth. CBCT can be recommended as an effective diagnostic device for identifying DI because it provides an accurate representation of the external and internal dental anatomy.
New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel-titanium (NiTi) alloys/treat... more New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel-titanium (NiTi) alloys/treatments. The purpose of this study was to compare the cyclic fatigue resistance of these new instruments with that of Revo-S instruments. Four groups of 20 NiTi endodontic instruments were tested in steel canals with a 3 mm radius and a 60° angle of curvature. The cyclic fatigue of the following NiTi instruments with a tip size 25 and 0.06 taper that were manufactured with different alloys was tested: ProTaper Next X2 (M-Wire), OneShape (conventional NiTi), Revo-S Shaping Universal (conventional NiTi) and HyFlex 25/0.6 (controlled memory NiTi wire). A one-way anova and post-hoc Tukey&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s test (α = 0.05) revealed that the HyFlex files had the highest fatigue resistance and the Revo-S had the least fatigue resistance among the groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001).
Introduction: The purpose of this study was to compare the cyclic fatigue resistance of coronal f... more Introduction: The purpose of this study was to compare the cyclic fatigue resistance of coronal flaring instruments. Methods: Three groups of nickeltitanium (NiTi) endodontic coronal flaring instruments were tested in steel canals with a 3-mm curvature radius and 60 (n = 18) and 45 of curvature (n = 18). The cyclic fatigue of the following NiTi instruments was tested: ProTaper Sx (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex 25.08 (Coltene-Whaledent, Allstetten, Switzerland), and Revo-S SC1 (Micro-Mega, Besancon, France). The length and diameter of the fractured fragment and the total area of the fractured surface of each instrument were measured. The data were then statistically analyzed using a 1-way analysis of variance and the post hoc Tukey test (a = .05). Results: At the 60 of curvature, Revo-S had the highest fatigue resistance, HyFlex had the second highest fatigue resistance, and ProTaper Universal had the least fatigue resistance. At the 45 of curvature, the Revo-S and HyFlex showed superior cyclic fatigue resistance compared with the Pro-Taper. The length of the fracture fragment of the Pro-Taper instrument was longer than that of the other groups at the 60 of curvature. At the 45 of curvature, the length of the fracture fragment of the ProTaper and HyFlex instruments was longer than that of Revo-S. The mean diameter and surface area of the HyFlex instruments in the fractured part was higher than that of other groups at both angles of curvature. Conclusions: The Revo-S SC1 and HyFlex 25.08 instruments showed better cyclic fatigue resistance than the ProTaper Sx instrument. (J Endod 2014;-:1-4)
The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinician... more The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinicians should be careful not to purchase counterfeit products.
Background/purpose: The aim of this retrospective study was to analyze the morphology of root can... more Background/purpose: The aim of this retrospective study was to analyze the morphology of root canal systems of mandibular incisors using cone-beam computed tomographic (CBCT) images. Materials and methods: A total of 374 mandibular incisors' images obtained from CBCT of 101 patients were included in the study. The following information was recorded: (1) the age and sex of the patient, (2) the tooth type, (3) the number of roots, (4) the root canal configuration, and (5) the bilateral/unilateral diversity in root number and the configuration of the root canals. The configuration of the root canals was categorized using Vertucci's classification as the main reference. Statistical analysis was carried out using Chi-square and Spearman's rank correlation tests (P Z 0.05). Results: Overall, 52.4% (n Z 196) of the teeth had one root canal (Type I), and 47.6% (n Z 178) had two root canals with different root canal configurations. The rate of complex root canal configurations was higher in males than in females (P < 0.001). Conclusion: Almost one of two mandibular incisors had complex root canal systems. The CBCT may be recommended as an effective diagnostic device for identifying complex root canal configurations. The prevalence of complex root canal configuration was higher in males than in females.
This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding ... more This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding instruments. Five types of nickel-titanium rotary pathfinding instruments were used in steel canals with a 90° curvature and a curvature radius of 3 mm (n = 10) and 5 mm (n = 10). The cyclic fatigue of the following instruments was tested at 4 mm from the tip: PathFile (#16 and a .02 taper; Dentsply Maillefer, Ballaigues, Switzerland), G-File (#12 and a .03 taper; Micro-Mega, Besançon Cedex, France), Scout Race (#15 and a .02 taper; FKG Dentaire, La Chaux-de-Fonds, Switzerland), HyFlex GPF (#15 and a .02 taper; Coltene-Whaledent, Allstetten, Switzerland), and ProGlider (#16 with a mean taper of .04125 and a .02 at the first 4 mm from the tip, Dentsply Maillefer). The length of the fractured parts was measured, and the number of cycles to fracture (NCF) was calculated. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (α = .05). After Bonferroni correction, the new P value was set as .005. The difference in the cyclic fatigue of all the files at both curvatures was statistically significant (P values from .0035 to less than .0001). The ranking of the instruments from the highest to the lowest NCF was as follows: HyFlex GPF, G files, ProGlider, PathFile, and Scout Race. The length of the fractured part of the instruments was similar in all the groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). All the tested instruments had a lower NCF at a curvature radius of 3 mm when compared with a curvature radius of 5 mm (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .0001). Within the limitations of this study, the cyclic fatigue resistance of the HyFlex GPF instrument was the highest, and the curvature radius had a significant effect on the fatigue resistance.
The aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (D... more The aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (Discus Dental, Culver City, CA), and Self-Adjusting File (SAF) (Re-Dent-Nova, Ra&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;nana, Israel) irrigation systems in removing calcium hydroxide (Ca[OH]2) from simulated root canal irregularities. The root canals of 88 extracted single-rooted teeth were prepared using ProTaper rotary instruments (Dentsply Maillefer, Ballagiues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and Ca(OH)2 medicament was placed into the root canals using a Lentulo spiral. The roots were randomly divided into 4 experimental groups and 2 control groups according to the different irrigation systems used: conventional syringe irrigation, continuous passive ultrasonic irrigation (PUI), EndoVac irrigation, and SAF irrigation. Each group was then divided into 2 subgroups (n = 10) according to the irrigation protocol: subgroup 1: 10 mL 2.5% NaOCl and subgroup 2: 10 mL 17% EDTA + 10 mL 2.5% NaOCl. The amount of remaining medicament was evaluated under a stereomicroscope at 30× magnification using a 4-grade scoring system. The influences of the different Ca(OH)2 medicament removal methods and irrigation protocols were statistically evaluated using 2-way analysis of variance and Tukey post hoc tests. In the NaOCl-irrigated groups, PUI removed significantly more Ca(OH)2 medicament than the other techniques (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). There was no significant difference among the other groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). In the EDTA/NaOCl-irrigated groups, the SAF and PUI removed significantly more Ca(OH)2 than the other techniques (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). The use of the SAF system with the combination of EDTA and NaOCl enhanced Ca(OH)2 removal when compared with the use of only NaOCl irrigation with the SAF. Continuous PUI and SAF were more effective than EndoVac, and conventional syringe irrigation in the removal of the Ca(OH)2 medicament from an artificial standardized groove in the apical part of the root canal.
Introduction: The purpose of this study was to compare the in vitro amount of apically extruded d... more Introduction: The purpose of this study was to compare the in vitro amount of apically extruded debris with new endodontic rotary nickel-titanium instruments. Methods: Sixty mandibular premolars were instrumented up to size 25 using ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Pro-Taper Next (Dentsply Maillefer), Twisted File Adaptive (SybronEndo, Orange, CA), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) rotary systems. The apically extruded debris was collected and dried in preweighed Eppendorf tubes. The amount of extruded debris was assessed with an electronic balance. The total time required to complete root canal shaping with the different instruments was also recorded. The significance level was set at P = .05. Results: The instrumentation time with the ProTaper Universal rotary system was significantly longer than with all the other instruments (P < .05). The Twisted File Adaptive and ProTaper Next systems extruded significantly less debris than the ProTaper Universal and HyFlex systems (P < .05). Conclusions: The ProTaper Next and Twisted File Adaptive instrumentation systems were associated with less debris extrusion compared with the ProTaper Universal and HyFlex systems. (J Endod 2014;40:1638-1641
The aims of the present study were to evaluate the effect of various irrigating solutions on the ... more The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions. The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083). Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .0083). There were no significant differences among the other groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups. Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid.
This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using con... more This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using cone-beam computed tomography (CBCT) and panoramic images rendered from CBCT images. In addition, the findings of the imaging techniques were compared. We evaluated 300 CBCT images to determine the type of DI, the presence of an impacted tooth near the DI, and the presence of apical pathosis. The McNemar test was used to compare the prevalence of DI according to CBCT and panoramic images rendered from CBCT images. The presence of DI was lower on panoramic images rendered from CBCT images (3% of the patients) compared with on CBCT images (10.7% of the patients) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). According to the CBCT images, the distribution of teeth with DI was as follows: maxillary lateral incisors (75%), maxillary central incisors (6.8%), mandibular premolars (4.6%), mesiodens (9%), maxillary canines (2.3%), and mandibular canines (2.3%). Type I DI was the most commonly observed type of invaginatus (65.9%), followed by type II (29.5%) and type III (4.6%). All patients with type III DI and 25% of the patients with type II DI had apical pathosis at the time of referral, but periapical lesions were not observed in teeth with type I DI. In total, 13.6% of DI cases had impacted teeth. CBCT can be recommended as an effective diagnostic device for identifying DI because it provides an accurate representation of the external and internal dental anatomy.
The aim of the present study was to evaluate crack formation after flaring root canals with Gates... more The aim of the present study was to evaluate crack formation after flaring root canals with Gates Glidden drills and ProTaper Universal (SX; Dentsply Maillefer, Ballaigues, Switzerland), Endoflare (MicroMega, Besançon, France), Revo-S (MicroMega), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) flaring instruments. One-hundred eight mandibular molars were selected. Eighteen teeth were left unprepared to serve as negative controls; the experimental groups consisted of the mesiobuccal and mesiolingual root canals of the remaining 90 teeth, which were instrumented with the following coronal flaring instruments: Gates Glidden drills and ProTaper Universal SX, Endoflare, Revo-S SC1, and HyFlex 25.08 instruments. All roots were then sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the cementoenamel junction. The sections were inspected under a stereomicroscope, and any crack formations were recorded. The data were analyzed using the chi-square test (P = .05). The Gates Glidden drills resulted in a higher rate of crack formation than that noted in the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). Flaring of the root canals using the ProTaper Universal, Endoflare, Revo-S, and HyFlex instruments resulted in crack formation similar to that of the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). The use of the Gates Glidden drills resulted in the formation of the most cracks. However, the results for the ProTaper Universal, Endoflare, Revo-S, and HyFlex flaring instruments were similar to those of the control group in terms of crack formation.
The aim of this study was to determine the effect of photon-induced photoacoustic streaming (PIPS... more The aim of this study was to determine the effect of photon-induced photoacoustic streaming (PIPS) technique at different power settings on extrusion of irrigating solution. Root canal preparation was performed up to a #30 file on 64 extracted single-rooted mandibular premolar teeth, which were then divided into four groups. Each group was irrigated with one of the following irrigation methods: (a) irrigation with conventional irrigation open-ended needles, (b) continuous ultrasonic irrigation, (c) 0.3 W PIPS, or (d) 0.9 W PIPS. Apical extrusion of irrigating solution was evaluated using a modified model. The net weight of the extruded irrigating solution was measured for each group, and the resulting data were analysed statistically using Kruskal-Wallis at a 95 % confidence level (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Although the 0.9 W PIPS group resulted in the largest quantity of irrigation solution, the ultrasonic group was the smallest. However, the difference between these groups was not statistically significant at the 95 % level of confidence (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). PIPS at both 0.3 W and 0.9 W resulted similar solution extrusion to the conventional irrigation or ultrasonic irrigation.
To investigate the incidence of cracks in root dentin after rotary instrumentation and filling wi... more To investigate the incidence of cracks in root dentin after rotary instrumentation and filling with cold lateral condensation (CL), single-cone obturation (SC), and warm vertical compaction (WV) and retreatment of each filling system. One-hundred sixty mandibular incisors were selected. Twenty teeth were left unprepared and served as a control, and the remaining 140 teeth were instrumented. Twenty teeth were assigned to an only prepared group. The remaining 120 teeth were assigned to three root canal filling groups and three retreatment groups (n = 20), as follows: CL, WV, SC, and retreatment of each filling system. All the roots were sectioned perpendicular to the long axis at 2, 4, 6, and 8 mm from the apex, and the sections were then observed under a stereomicroscope. The absence/presence of cracks and vertical root fractures were recorded, and the data were analyzed with a Pearson&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s chi-square test (P = 0.05). No complete vertical root fractures were observed in the unprepared and only prepared groups. However, vertical fractures were observed in the filling and retreatment groups. There were significantly more cracks in the retreatment after WV group than the other groups, with the exception of the retreatment after SC, WV, and CL resulted in significantly more cracks than the only prepared and SC. The filling techniques (except SC) caused more cracks than preparation only. The SC caused fewer cracks compared to the other filling techniques. The retreatment following the different filling techniques (except CL) caused more cracks than the original fillings.
This study evaluated the mineral contents of root-canal dentin after treatment with different irr... more This study evaluated the mineral contents of root-canal dentin after treatment with different irrigation activation protocols. One hundred and eight maxillary lateral incisor teeth were randomly divided into eight experimental groups and one control group. Root canals were prepared using ProTaper rotary files, with the exception of the Self-Adjusting File (SAF) group. Canals were irrigated with 2 mL of 5% sodium hypochlorite (NaOCl) at each instrument change, and received a final flush with 10 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 10 mL of 5% NaOCl for 1 min. The control group was irrigated with distilled water. Group I (GI): Needle syringe irrigation; Group II (GII): NaviTip FX; Group III (GIII): CanalBrush; Group IV (GIV): Manual dynamic activation with gutta-percha; Group V (GV): Passive ultrasonic irrigation; Group VI (GVI): EndoActivator; Group VII (GVII): EndoVac; Group VIII (GVIII): SAF. The level of elemental composition was analyzed by a scanning electron microscopy and an energy-dispersive spectrometer (EDS) system. The results were then statistically analyzed by one-way ANOVA and Tukey tests. Ca/P ratio was changed after treatment with SAF and EndoActivator. The Ca, P, Mg, and S level changes were not statistically significant (P &amp;amp;amp;amp;amp;amp;gt; 0.05). Final irrigation activation protocols did not alter the mineral level of root dentin surface.
This study evaluated the influence of eugenol on the push-out bond strengths of fiber posts cemen... more This study evaluated the influence of eugenol on the push-out bond strengths of fiber posts cemented with different types of resin luting agents. Seventy-two extracted maxillary single-rooted canine teeth were randomly divided into two groups of 36 teeth. Group 1, the control group, was filled with gutta-percha only (i.e., did not receive eugenol), whereas group 2 was filled with a eugenol-containing sealer. All root canals were filled and each group was divided into three subgroups. The posts in each subgroup were cemented with the following materials: subgroup 1 with a 2-step self-etching adhesive system (Clearfil Liner Bond 2V + Panavia F); subgroup 2 with a 1-step self-etching adhesive (Panavia F); and subgroup 3 with a self-adhesive (Clearfil SA Cement). Dislodgement resistance was measured using a universal testing machine. All data were subjected to ANOVA using a factorial design and Tukey test (α = 0.05). The use of the eugenol-containing sealer significantly reduced the push-out bond strength of the fiber post (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The push-out bond strength of Panavia F was significantly higher than those of the other groups filled with the eugenol-containing sealer (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The Panavia F group was less susceptible to the inhibiting effect of eugenol than were the other evaluated groups when the fiber post was cemented in the canals filled with the eugenol-containing sealer.
Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With tec... more Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With technological advancements in metallurgy, manufacturers have attempted to produce instruments with enhanced features. In parallel with these developments, endodontic motors have undergone improvements in terms of torque control and kinematics that are adjustable in different directions. This review presents an overview of the advancements in instrumentation kinematics and the effect of instrumentation kinematics on root canal shaping procedures and instrument performance. The literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords &#39;kinematics and endodontics&#39; and &#39;reciprocation and endodontics&#39;. In addition, historical literature was searched using the keyword &#39;nickel-titanium and endodontics&#39;. Overall, 143 articles were included up to 2015.
Introduction: The purpose of this study was to investigate the incidence of apical crack initiati... more Introduction: The purpose of this study was to investigate the incidence of apical crack initiation and propagation in root dentin after several endodontic procedures. Methods: Sixty intact mandibular premolars were sectioned perpendicular to the long axis at 1 mm from the apex, and the apical surface was polished. Thirty teeth were left unprepared and served as a control, and the remaining 30 teeth were instrumented with ProTaper Universal instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F5. The root canals were filled with the single-cone technique. Gutta-percha was removed with drills of the Rebilda post system (VOCO, Cuxhaven, Germany). Glass fiberreinforced composite fiber posts were cemented using a dual-cure resin cement. The fiber posts were removed with a drill of the post system. Retreatment was completed after the removal of the gutta-percha. Crack initiation and propagation in the apical surfaces of the samples were examined with a stereomicroscope after each procedure. The absence/presence of cracks was recorded. Logistic regression was performed to analyze statistically the incidence of crack initiation and propagation with each procedure. Results: The initiation of the first crack and crack propagation was associated with F2 and F4 instruments, respectively. The logistic regression analysis revealed that instrumentation and F2 instrument significantly affected apical crack initiation (P < .001). Post space preparation had a significant effect on crack propagation (P = .0004). The other procedures had no significant effects on crack initiation and propagation (P > .05). Conclusions: Rotary nickeltitanium instrumentation had a significant effect on apical crack initiation, and post space preparation with drills had a significant impact on crack propagation. (J Endod 2015;41:253-256)
The purpose of the present study is to evaluate smear layer generation and residual debris after ... more The purpose of the present study is to evaluate smear layer generation and residual debris after using self-adjusting file (SAF) or rotary instrumentation and to compare the debris and smear layer removal efficacy of the SAF cleaning/shaping irrigation system against final agitation techniques. One hundred and eight maxillary lateral incisor teeth were randomly divided into nine experimental groups (n = 12), and root canals were prepared using ProTaper Universal rotary files, with the exception of the SAF instrumentation group. During instrumentation, root canals were irrigated with a total of 16 mL of 5% NaOCl. For final irrigation, rotary-instrumented groups were irrigated with 10 mL of 17% EDTA and 10 mL of 5% NaOCl using different irrigation agitation regimens (syringe irrigation with needles, NaviTip FX, manual dynamic irrigation, CanalBrush, EndoActivator, EndoVac, passive ultrasonic irrigation (PUI), and SAF irrigation). In the SAF instrumentation group, root canals were instrumented for 4 min at a rate of 4 mL/min with 5% NaOCl and received a final flush with same as syringe irrigation with needles. The surface of the root dentin was observed using a scanning electron microscope. The SAF instrumentation group generated less smear layer and yielded cleaner canals compared to rotary instrumentation. The EndoActivator, EndoVac, PUI, and SAF irrigation groups increased the efficacy of irrigating solutions on the smear layer and debris removal. The SAF instrumentation yielded cleaner canal walls when compared to rotary instrumentation. None of the techniques completely removed the smear layer from the root canal walls.
We compared the effects of 6 different rotary systems on transportation, canal curvature, centeri... more We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging. Methods: Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20 -40 were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), Pro-Taper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05. Results: The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation. Conclusions: The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change. (J Endod 2013;-:1-5)
This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using con... more This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using cone-beam computed tomography (CBCT) and panoramic images rendered from CBCT images. In addition, the findings of the imaging techniques were compared. We evaluated 300 CBCT images to determine the type of DI, the presence of an impacted tooth near the DI, and the presence of apical pathosis. The McNemar test was used to compare the prevalence of DI according to CBCT and panoramic images rendered from CBCT images. The presence of DI was lower on panoramic images rendered from CBCT images (3% of the patients) compared with on CBCT images (10.7% of the patients) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). According to the CBCT images, the distribution of teeth with DI was as follows: maxillary lateral incisors (75%), maxillary central incisors (6.8%), mandibular premolars (4.6%), mesiodens (9%), maxillary canines (2.3%), and mandibular canines (2.3%). Type I DI was the most commonly observed type of invaginatus (65.9%), followed by type II (29.5%) and type III (4.6%). All patients with type III DI and 25% of the patients with type II DI had apical pathosis at the time of referral, but periapical lesions were not observed in teeth with type I DI. In total, 13.6% of DI cases had impacted teeth. CBCT can be recommended as an effective diagnostic device for identifying DI because it provides an accurate representation of the external and internal dental anatomy.
New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel-titanium (NiTi) alloys/treat... more New files (ProTaper Next/HyFlex/OneShape) are made from novel nickel-titanium (NiTi) alloys/treatments. The purpose of this study was to compare the cyclic fatigue resistance of these new instruments with that of Revo-S instruments. Four groups of 20 NiTi endodontic instruments were tested in steel canals with a 3 mm radius and a 60° angle of curvature. The cyclic fatigue of the following NiTi instruments with a tip size 25 and 0.06 taper that were manufactured with different alloys was tested: ProTaper Next X2 (M-Wire), OneShape (conventional NiTi), Revo-S Shaping Universal (conventional NiTi) and HyFlex 25/0.6 (controlled memory NiTi wire). A one-way anova and post-hoc Tukey&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s test (α = 0.05) revealed that the HyFlex files had the highest fatigue resistance and the Revo-S had the least fatigue resistance among the groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001).
Introduction: The purpose of this study was to compare the cyclic fatigue resistance of coronal f... more Introduction: The purpose of this study was to compare the cyclic fatigue resistance of coronal flaring instruments. Methods: Three groups of nickeltitanium (NiTi) endodontic coronal flaring instruments were tested in steel canals with a 3-mm curvature radius and 60 (n = 18) and 45 of curvature (n = 18). The cyclic fatigue of the following NiTi instruments was tested: ProTaper Sx (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex 25.08 (Coltene-Whaledent, Allstetten, Switzerland), and Revo-S SC1 (Micro-Mega, Besancon, France). The length and diameter of the fractured fragment and the total area of the fractured surface of each instrument were measured. The data were then statistically analyzed using a 1-way analysis of variance and the post hoc Tukey test (a = .05). Results: At the 60 of curvature, Revo-S had the highest fatigue resistance, HyFlex had the second highest fatigue resistance, and ProTaper Universal had the least fatigue resistance. At the 45 of curvature, the Revo-S and HyFlex showed superior cyclic fatigue resistance compared with the Pro-Taper. The length of the fracture fragment of the Pro-Taper instrument was longer than that of the other groups at the 60 of curvature. At the 45 of curvature, the length of the fracture fragment of the ProTaper and HyFlex instruments was longer than that of Revo-S. The mean diameter and surface area of the HyFlex instruments in the fractured part was higher than that of other groups at both angles of curvature. Conclusions: The Revo-S SC1 and HyFlex 25.08 instruments showed better cyclic fatigue resistance than the ProTaper Sx instrument. (J Endod 2014;-:1-4)
The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinician... more The cyclic fatigue resistance of the counterfeit instruments was very low. As a result, clinicians should be careful not to purchase counterfeit products.
Background/purpose: The aim of this retrospective study was to analyze the morphology of root can... more Background/purpose: The aim of this retrospective study was to analyze the morphology of root canal systems of mandibular incisors using cone-beam computed tomographic (CBCT) images. Materials and methods: A total of 374 mandibular incisors' images obtained from CBCT of 101 patients were included in the study. The following information was recorded: (1) the age and sex of the patient, (2) the tooth type, (3) the number of roots, (4) the root canal configuration, and (5) the bilateral/unilateral diversity in root number and the configuration of the root canals. The configuration of the root canals was categorized using Vertucci's classification as the main reference. Statistical analysis was carried out using Chi-square and Spearman's rank correlation tests (P Z 0.05). Results: Overall, 52.4% (n Z 196) of the teeth had one root canal (Type I), and 47.6% (n Z 178) had two root canals with different root canal configurations. The rate of complex root canal configurations was higher in males than in females (P < 0.001). Conclusion: Almost one of two mandibular incisors had complex root canal systems. The CBCT may be recommended as an effective diagnostic device for identifying complex root canal configurations. The prevalence of complex root canal configuration was higher in males than in females.
This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding ... more This study compared the cyclic fatigue resistance of current nickel-titanium rotary path-finding instruments. Five types of nickel-titanium rotary pathfinding instruments were used in steel canals with a 90° curvature and a curvature radius of 3 mm (n = 10) and 5 mm (n = 10). The cyclic fatigue of the following instruments was tested at 4 mm from the tip: PathFile (#16 and a .02 taper; Dentsply Maillefer, Ballaigues, Switzerland), G-File (#12 and a .03 taper; Micro-Mega, Besançon Cedex, France), Scout Race (#15 and a .02 taper; FKG Dentaire, La Chaux-de-Fonds, Switzerland), HyFlex GPF (#15 and a .02 taper; Coltene-Whaledent, Allstetten, Switzerland), and ProGlider (#16 with a mean taper of .04125 and a .02 at the first 4 mm from the tip, Dentsply Maillefer). The length of the fractured parts was measured, and the number of cycles to fracture (NCF) was calculated. The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (α = .05). After Bonferroni correction, the new P value was set as .005. The difference in the cyclic fatigue of all the files at both curvatures was statistically significant (P values from .0035 to less than .0001). The ranking of the instruments from the highest to the lowest NCF was as follows: HyFlex GPF, G files, ProGlider, PathFile, and Scout Race. The length of the fractured part of the instruments was similar in all the groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). All the tested instruments had a lower NCF at a curvature radius of 3 mm when compared with a curvature radius of 5 mm (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .0001). Within the limitations of this study, the cyclic fatigue resistance of the HyFlex GPF instrument was the highest, and the curvature radius had a significant effect on the fatigue resistance.
The aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (D... more The aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (Discus Dental, Culver City, CA), and Self-Adjusting File (SAF) (Re-Dent-Nova, Ra&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;nana, Israel) irrigation systems in removing calcium hydroxide (Ca[OH]2) from simulated root canal irregularities. The root canals of 88 extracted single-rooted teeth were prepared using ProTaper rotary instruments (Dentsply Maillefer, Ballagiues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and Ca(OH)2 medicament was placed into the root canals using a Lentulo spiral. The roots were randomly divided into 4 experimental groups and 2 control groups according to the different irrigation systems used: conventional syringe irrigation, continuous passive ultrasonic irrigation (PUI), EndoVac irrigation, and SAF irrigation. Each group was then divided into 2 subgroups (n = 10) according to the irrigation protocol: subgroup 1: 10 mL 2.5% NaOCl and subgroup 2: 10 mL 17% EDTA + 10 mL 2.5% NaOCl. The amount of remaining medicament was evaluated under a stereomicroscope at 30× magnification using a 4-grade scoring system. The influences of the different Ca(OH)2 medicament removal methods and irrigation protocols were statistically evaluated using 2-way analysis of variance and Tukey post hoc tests. In the NaOCl-irrigated groups, PUI removed significantly more Ca(OH)2 medicament than the other techniques (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). There was no significant difference among the other groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). In the EDTA/NaOCl-irrigated groups, the SAF and PUI removed significantly more Ca(OH)2 than the other techniques (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). The use of the SAF system with the combination of EDTA and NaOCl enhanced Ca(OH)2 removal when compared with the use of only NaOCl irrigation with the SAF. Continuous PUI and SAF were more effective than EndoVac, and conventional syringe irrigation in the removal of the Ca(OH)2 medicament from an artificial standardized groove in the apical part of the root canal.
Introduction: The purpose of this study was to compare the in vitro amount of apically extruded d... more Introduction: The purpose of this study was to compare the in vitro amount of apically extruded debris with new endodontic rotary nickel-titanium instruments. Methods: Sixty mandibular premolars were instrumented up to size 25 using ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Pro-Taper Next (Dentsply Maillefer), Twisted File Adaptive (SybronEndo, Orange, CA), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) rotary systems. The apically extruded debris was collected and dried in preweighed Eppendorf tubes. The amount of extruded debris was assessed with an electronic balance. The total time required to complete root canal shaping with the different instruments was also recorded. The significance level was set at P = .05. Results: The instrumentation time with the ProTaper Universal rotary system was significantly longer than with all the other instruments (P < .05). The Twisted File Adaptive and ProTaper Next systems extruded significantly less debris than the ProTaper Universal and HyFlex systems (P < .05). Conclusions: The ProTaper Next and Twisted File Adaptive instrumentation systems were associated with less debris extrusion compared with the ProTaper Universal and HyFlex systems. (J Endod 2014;40:1638-1641
The aims of the present study were to evaluate the effect of various irrigating solutions on the ... more The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions. The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083). Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .0083). There were no significant differences among the other groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups. Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the NaOCl-irrigated groups. However, the precipitate was not observed in specimens in the groups irrigated with 17% EDTA, 7% maleic acid, and 10% citric acid.
This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using con... more This study assessed the presence, characteristics, and type of dens invaginatus (DI) by using cone-beam computed tomography (CBCT) and panoramic images rendered from CBCT images. In addition, the findings of the imaging techniques were compared. We evaluated 300 CBCT images to determine the type of DI, the presence of an impacted tooth near the DI, and the presence of apical pathosis. The McNemar test was used to compare the prevalence of DI according to CBCT and panoramic images rendered from CBCT images. The presence of DI was lower on panoramic images rendered from CBCT images (3% of the patients) compared with on CBCT images (10.7% of the patients) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). According to the CBCT images, the distribution of teeth with DI was as follows: maxillary lateral incisors (75%), maxillary central incisors (6.8%), mandibular premolars (4.6%), mesiodens (9%), maxillary canines (2.3%), and mandibular canines (2.3%). Type I DI was the most commonly observed type of invaginatus (65.9%), followed by type II (29.5%) and type III (4.6%). All patients with type III DI and 25% of the patients with type II DI had apical pathosis at the time of referral, but periapical lesions were not observed in teeth with type I DI. In total, 13.6% of DI cases had impacted teeth. CBCT can be recommended as an effective diagnostic device for identifying DI because it provides an accurate representation of the external and internal dental anatomy.
The aim of the present study was to evaluate crack formation after flaring root canals with Gates... more The aim of the present study was to evaluate crack formation after flaring root canals with Gates Glidden drills and ProTaper Universal (SX; Dentsply Maillefer, Ballaigues, Switzerland), Endoflare (MicroMega, Besançon, France), Revo-S (MicroMega), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) flaring instruments. One-hundred eight mandibular molars were selected. Eighteen teeth were left unprepared to serve as negative controls; the experimental groups consisted of the mesiobuccal and mesiolingual root canals of the remaining 90 teeth, which were instrumented with the following coronal flaring instruments: Gates Glidden drills and ProTaper Universal SX, Endoflare, Revo-S SC1, and HyFlex 25.08 instruments. All roots were then sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the cementoenamel junction. The sections were inspected under a stereomicroscope, and any crack formations were recorded. The data were analyzed using the chi-square test (P = .05). The Gates Glidden drills resulted in a higher rate of crack formation than that noted in the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). Flaring of the root canals using the ProTaper Universal, Endoflare, Revo-S, and HyFlex instruments resulted in crack formation similar to that of the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). The use of the Gates Glidden drills resulted in the formation of the most cracks. However, the results for the ProTaper Universal, Endoflare, Revo-S, and HyFlex flaring instruments were similar to those of the control group in terms of crack formation.
The aim of this study was to determine the effect of photon-induced photoacoustic streaming (PIPS... more The aim of this study was to determine the effect of photon-induced photoacoustic streaming (PIPS) technique at different power settings on extrusion of irrigating solution. Root canal preparation was performed up to a #30 file on 64 extracted single-rooted mandibular premolar teeth, which were then divided into four groups. Each group was irrigated with one of the following irrigation methods: (a) irrigation with conventional irrigation open-ended needles, (b) continuous ultrasonic irrigation, (c) 0.3 W PIPS, or (d) 0.9 W PIPS. Apical extrusion of irrigating solution was evaluated using a modified model. The net weight of the extruded irrigating solution was measured for each group, and the resulting data were analysed statistically using Kruskal-Wallis at a 95 % confidence level (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Although the 0.9 W PIPS group resulted in the largest quantity of irrigation solution, the ultrasonic group was the smallest. However, the difference between these groups was not statistically significant at the 95 % level of confidence (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). PIPS at both 0.3 W and 0.9 W resulted similar solution extrusion to the conventional irrigation or ultrasonic irrigation.
To investigate the incidence of cracks in root dentin after rotary instrumentation and filling wi... more To investigate the incidence of cracks in root dentin after rotary instrumentation and filling with cold lateral condensation (CL), single-cone obturation (SC), and warm vertical compaction (WV) and retreatment of each filling system. One-hundred sixty mandibular incisors were selected. Twenty teeth were left unprepared and served as a control, and the remaining 140 teeth were instrumented. Twenty teeth were assigned to an only prepared group. The remaining 120 teeth were assigned to three root canal filling groups and three retreatment groups (n = 20), as follows: CL, WV, SC, and retreatment of each filling system. All the roots were sectioned perpendicular to the long axis at 2, 4, 6, and 8 mm from the apex, and the sections were then observed under a stereomicroscope. The absence/presence of cracks and vertical root fractures were recorded, and the data were analyzed with a Pearson&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s chi-square test (P = 0.05). No complete vertical root fractures were observed in the unprepared and only prepared groups. However, vertical fractures were observed in the filling and retreatment groups. There were significantly more cracks in the retreatment after WV group than the other groups, with the exception of the retreatment after SC, WV, and CL resulted in significantly more cracks than the only prepared and SC. The filling techniques (except SC) caused more cracks than preparation only. The SC caused fewer cracks compared to the other filling techniques. The retreatment following the different filling techniques (except CL) caused more cracks than the original fillings.
This study evaluated the mineral contents of root-canal dentin after treatment with different irr... more This study evaluated the mineral contents of root-canal dentin after treatment with different irrigation activation protocols. One hundred and eight maxillary lateral incisor teeth were randomly divided into eight experimental groups and one control group. Root canals were prepared using ProTaper rotary files, with the exception of the Self-Adjusting File (SAF) group. Canals were irrigated with 2 mL of 5% sodium hypochlorite (NaOCl) at each instrument change, and received a final flush with 10 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 10 mL of 5% NaOCl for 1 min. The control group was irrigated with distilled water. Group I (GI): Needle syringe irrigation; Group II (GII): NaviTip FX; Group III (GIII): CanalBrush; Group IV (GIV): Manual dynamic activation with gutta-percha; Group V (GV): Passive ultrasonic irrigation; Group VI (GVI): EndoActivator; Group VII (GVII): EndoVac; Group VIII (GVIII): SAF. The level of elemental composition was analyzed by a scanning electron microscopy and an energy-dispersive spectrometer (EDS) system. The results were then statistically analyzed by one-way ANOVA and Tukey tests. Ca/P ratio was changed after treatment with SAF and EndoActivator. The Ca, P, Mg, and S level changes were not statistically significant (P &amp;amp;amp;amp;amp;amp;gt; 0.05). Final irrigation activation protocols did not alter the mineral level of root dentin surface.
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