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Aim: To investigate whether a minimally invasive basic root canal preparation technique has an influence on root canal cleanliness in extracted mandibular molar teeth. Methodology: A total of 80 root canals (40 mesio‐buccal and 40 mesio‐lingual) from 40 mandibular molars were included. The teeth were divided equally into four different experimental groups depending on the subsequently root canal preparation technique: Group 1: a basic preparation was performed up to size 20,.04 taper; Group 2: a basic preparation was performed up to size 2,.06 taper; Group 3: a basic preparation was performed up to size 25,.04 taper; and Group 4: a basic preparation was performed up to size 25,.06 taper. After the use of each instrument, each root canal was irrigated with 2.5 mL of 6% sodium hypochlorite for 30 s. Then, 1 mL NaOCl was activated for 20 s using an EDDY sonic tip. Final irrigation was performed using a total of 5 mL of 17% EDTA solution. The roots were then split longitudinally and all root canal thirds were observed through scanning electron microscopy (SEM) to evaluate the presence of superficial debris and smear layer using a scoring system. Data were statistically analysed using the Kruskal–Wallis and Bonferroni tests with a level of significance set at P < 0.05. Results: In all groups, there was significantly more residual debris and smear layer in the apical third (P < 0.05), with no differences between the middle and coronal thirds (P > 0.05). For both the parameters analysed, there was no difference amongst the groups in the middle and coronal thirds (P > 0.05), whilst in the apical third significantly less debris and smear layer was found in specimens from groups 3 and 4 than for groups 1 and 2 (P < 0.05). Conclusion: All basic root canal preparation techniques were associated with less debris and smear layer on the canal walls in the middle and coronal thirds, without differences among them. Even though debris and smear layer were always present in the apical third, an apical size of 25 resulted in significantly cleaner canals walls compared to a size 20. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To compare the cyclic fatigue resistance and bending properties of R‐Pilot and WaveOne Gold (WOG) Glider files, at intracanal temperature (35°C). Methodology: Forty R‐Pilot and 40 WOG Glider files were subjected to a cyclic fatigue resistance test (n = 20), calculating the time to fracture (TTF) in an artificial stainless steel canal. The length of the fractured file tips (FL) was also measured. The fracture surface of fragments was examined with a scanning electron microscope, and the cross‐sectional area of the fractured surfaces was measured. Flexibility of the tested files (n = 20) was determined using 45° bending test. Data were analysed statistically using the Mann–Whitney U‐test at 5% significance level. Results: Time to fracture was significantly higher in the R‐Pilot group compared to the WOG Glider (P < 0.05). There was no significant difference between groups for fracture length. The bending resistance of R‐Pilot files was significantly greater than WOG Glider files (P < 0.05). Conclusions: A significant greater cyclic fatigue resistance was observed for R‐Pilot files compared to WOG Glider instruments, although the bending resistance of WOG Glider files was lower. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To examine the cyclic fatigue resistances of R‐Pilot, HyFlex EDM and PathFile NiTi glide path files in S‐shaped artificial canals. Methodology: Twenty R‐Pilot (12.5/.04), 20 HyFlex EDM (10/.05) and 20 PathFile (19/.02) single‐file glide path files were included. Sixty files (n: 20/each) were subjected to static cyclic fatigue testing using double‐curved canals until fracture occurred (TF). The number of cycles to fracture (NCF) was calculated by multiplying the rpm value by the TF. The length of the fractured fragment (FL) was determined by a digital microcaliper. Six samples of fractured files (n: 2/each) were examined by SEM to determine the fracture mode. The NCF and the FL data were analysed using one‐way anova, post hoc Tamhane and Kruskal–Wallis tests using SPPS 21 software. The significance level was set at 5%. Results: In the double‐curved canal, all the files fractured first in the apical curvature and then in the coronal curvature. The NCF values revealed that the R‐Pilot had the greatest cyclic fatigue resistance, followed by the HyFlex EDM and PathFile in both the apical and coronal curvatures (P < 0.05). Conclusions: R‐Pilot NiTi glide path files, used in a reciprocating motion, had the greatest cyclic fatigue resistance amongst the tested NiTi glide path files in an artificial S‐shaped canal. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate the influence of access cavity designs on the mechanical properties of a single-rooted mandibular first premolar tooth under various static loads using a finite element analysis., Materials and Methods: 3-dimensional FEA designs were modeled according to the access cavity designs: an intact tooth (control), traditional access cavity (TEC-I), traditional access cavity with Class-II mesio-occlusal cavity design (TEC-II), conservative access cavity (CEC), ninja access cavity (NEC), caries-driven access cavity (Cd-EC), buccal access cavity (BEC) and bucco-occlusal access cavity (BOEC). After the simulated access cavity preparations, root canal treatment was simulated and three different static loads which mimicked oblique and vertical mastication forces were applied to the models. The stress distribution and maximum Von Misses stress values were recorded. The maximum stress values were obtained on both enamel and dentin under multi-point vertical loads., Results: The maximum stress values were obtained on both enamel and dentin under multi-point vertical loads. Under all load types, the minimum stress distribution was observed in the control group, followed by CEC, NEC and BEC designs. The highest stress concentration was detected in Cd-EC and TEC-II designs. Under single-point vertical loading, the stress was mostly concentrated in the lingual PCD area, while under multi-point vertical loading, the entire root surface was stress-loaded except for the lingual apical third of the root., Conclusion: Preserving tooth tissue by simulating CEC, NEC and BEC access cavities increased the load capacity of a single-rooted mandibular first premolar following simulated endodontic treatment., (© 2024. The Author(s).)

To investigate the apical extrusion of sodium hypochlorite in immature permanent teeth caused by conventional syringe irrigation (CSI), EDDY, XP-endo Finisher file (XP-F), and a new laser irrigation activation system [shock-wave-enhanced-emission-photo-acoustic-streaming (SWEEPS)]. Three-dimensionally printed forty-nine teeth with immature central incisor morphology were randomly assigned to seven experimental groups, based on the irrigation activation methods and insertion depths (1 mm and 2 mm short of the working length) as follows: CSI-1, CSI-2, EDDY-1, EDDY-2, XP-1, XP-2, and SWEEPS. Prior to the irrigation activation process, samples were placed in metacresol mixed agar gel in Eppendorf tubes. To evaluate NaOCI extrusion into the gel, each sample was digitally photographed, and the area of apical extrusion was analyzed using ImageJ software. To examine potential significant differences between the continuous variables, the Mann-Whitney U test and Kruskal-Wallis H test, were applied (P = .05). The SWEEPS resulted in a greater amount of apical extrusion compared to the CSI method, regardless of the insertion depth (P < 0.001). The SWEEPS resulted in greater apical extrusion scores compared to EDDY-2 (P < 0.001). The EDDY-1 resulted in greater amount of apical extrusion scores compared to EDDY-2 (P < 0.001). This study, the first to show the effect of the novel SWEEPS technology on NaOCI extrusion, found that irrigation activation can cause different levels of apical extrusion depending on the method and distance from the working length. It is crucial to consider the potential occurrence of apical extrusion when applying activation methods to immature teeth., (© 2024. The Author(s).)

This study aimed to compare the syringe-needle irrigation (SNI), passive ultrasonic irrigation (PUI), EDDY, and shock wave-enhanced emission photoacoustic streaming (SWEEPS) techniques regarding calcium hydroxide and double antibiotic paste removal from the root canal in regenerative endodontic treatments. Eighty single-rooted human teeth were decoronated and enlarged up to #100 to stimulate the immature tooth model. Root canals were irrigated with 1.5% sodium hypochlorite followed by saline solution according to the regenerative endodontic treatment protocol. Dressed teeth were divided into 2 main groups regarding the used intracanal medicaments. Calcium hydroxide and double antibiotic paste were introduced to the canals, and teeth were stored for 3 weeks. Each medicament group was divided into 4 subgroups according to the activation techniques. Medicaments were removed using a 17% EDTA solution. Teeth were split longitudinally into two parts. The remaining medicaments were evaluated under a stereo microscope with a scoring system. Data were analyzed with the Kruskal-Wallis and Mann-Whitney U tests. Regardless of the used irrigation activation systems, there was no statistically significant difference between the removal of the CH and DAP from the root canal (P>0.05). While SWEEPS had the highest ability regarding the removal of intracanal medicaments, syringe-needle irrigation had the lowest (P<0.05). There was no statistically significant difference between PUI and EDDY (P>0.05). Complete removal of intracanal medicaments could not be achieved with any techniques. SWEEPS technology was more effective in removing intracanal medicaments in regenerative endodontic treatments compared to the sonic and ultrasonic irrigation activation systems., (© 2024. The Author(s).)

Background: This study aimed to compare the shaping ability of different instruments, TruNatomy Glider (TRN-G), WaveOne Gold Glider (WOG-G), and ProGlider (Pro-G) using micro-computed tomography (micro-CT)., Methods: The mesial canals of 27 mandibular molars with two separate mesial canals and moderate curvature were included in this study [n = 27 mesiobuccal (MB) and mesiolingual (ML) root canal]. According to the manufacturer's instructions, the glide path was created with TRN-G, WOG-G, and Pro-G glide path instruments (n = 9 MB and ML root canal in each group). Micro-CT scanning was performed before and after preparation. Mesiodistal (MD) and buccolingual (BL) transportation and the centering ratio were measured at three levels within the canal (3, 5 and 7 mm). A three-way robust ANOVA was used to compare the parameters., Results: TRN-G showed significantly greater transportation in the MD direction than the other instruments throughout the root canal (overall root canal) (p < 0.05). The best centering ability in the BL direction was shown by the WOG-G, regardless of level within the canal and canal distinction (MB vs. ML) (p < 0.05). There was no significant difference between groups according to the level within the canal and canal parameters (p > 0.05). Whether the root canal was MB or ML did not affect centering or transportation (p > 0.05)., Conclusions: Glide path instruments can be used to shape moderately curved canals with minimal apical transportation and better centering ability. All three tested glide path files can used safely before the shaping file., (© 2023. BioMed Central Ltd., part of Springer Nature.)

This systematic review aimed to investigate whether minimally invasive root canal preparation ensures higher fracture resistance compared to conventional root canal preparation in endodontically treated teeth (ETT). A comprehensive search strategy was conducted on the "PubMed, Web of Science, and Scopus" databases, alongside reference and hand searches, with language restrictions applied. Two independent reviews selected pertinent laboratory studies that explored the effect of minimally invasive root canal preparation on fracture resistance, in comparison to larger preparation counterparts. The quality of the studies was assessed, and the risk of bias was categorized as low, moderate, or high. The electronic search yielded a total of 1,767 articles. After applying eligibility criteria, 8 studies were included. Given the low methodological quality of these studies and the large variability of fracture resistance values, the impact of reduced apical size and/or taper on the fracture resistance of the ETT can be considered uncertain. This systematic review could not reveal sufficient evidence regarding the effect of minimally invasive preparation on increasing fracture resistance of ETT, primarily due to the inherent limitations of the studies and the moderate risk of bias., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2023. The Korean Academy of Conservative Dentistry.)

The aim of this study was to evaluate the debridement efficacy of sonic irrigation (EDDY; VDW, Munich, Germany and EndoActivator; Dentsply-Sirona, Ballaigues, Switzerland) and ultrasonically activated irrigation (Irrısafe; Satelec Acteon, Merignac, France) in a simulated canal isthmus connecting curved canals. Transparent resin blocks were produced containing two curved canals connected with an isthmus. The isthmus was then filled with dentin debris. Three irrigant activation cycles were performed and the amount of remaining debris was compared analysing pictures taken after each activation cycle. Data were statistically analysed using one-way ANOVA and post hoc Tukey tests at a significance level of p < 0.05. EDDY showed greater efficiency in removing dentin debris from the simulated isthmus than the other techniques tested. An increase in the activation time enhanced the efficiency of both EDDY and ultrasonically activated irrigation in debris removal., (© 2023 Australian Society of Endodontology Inc.)

This study aimed to evaluate the shaping ability of XP-endo Shaper, TruNatomy and EdgeFile X3 during the preparation of resin-printed mandibular molar mesial root canals. Thirty-three resin-based mandibular mesial roots with two canals, obtained from extracted tooth cone-beam computed tomography (CBCT) image and printed on a three-dimensional (3D) printer, were divided into three experimental groups according to the different nickel-titanium (NiTi) systems used for root canal preparation. The specimens were scanned using CBCT imaging before and after root canal preparation. Then images were registered using a dedicated software and changes in the canal area, volume, untouched canal surface and the maximum and minimum dentine wall wear were calculated. The XP-endo Shaper instruments showed improved shaping ability with lower untouched root canal surface and better preservation of root canal anatomy during the preparation of resin-printed mandibular mesial root canals compared with TruNatomy and EdgeFile X3 systems., (© 2022 Australian Society of Endodontology Inc.)

Objectives: The purpose of this study was to evaluate the influence of endodontic access cavities design on the removal of calcium hydroxide medication of the apical third of mandibular incisor root canal walls and dentinal tubules with different cleaning protocols: EDDY sonic activation, Er,Cr:YSGG laser-activated irrigation, or conventional irrigation with IrriFlex., Materials and Methods: Seventy-eight extracted human mandibular incisors were assigned to 6 experimental groups ( n = 13) according to the endodontic access cavity and cleaning protocol for calcium hydroxide removal: traditional access cavity (TradAC)/EDDY; ultraconservative access cavity performed in the incisal edge (UltraAC.Inc)/EDDY; TradAC/Er,Cr:YSGG; UltraAC.Inc/Er,Cr:YSGG; TradAC/IrriFlex; or UltraAC.Inc/IrriFlex. Confocal laser scanning microscopy images were used to measure the non-penetration percentage, maximum residual calcium hydroxide penetration depth, and penetration area at 2 and 4 mm from the apex. Data were statistically analyzed using Shapiro-Wilk and WRS2 package for 2-way comparison of non-normally distributed parameters (depth of penetration, area of penetration, and percentage of non-penetration) according to cavity and cleaning protocol with the significance level set at 5%., Results: The effect of cavity and cleaning protocol interactions on penetration depth, penetration area and non-penetration percentage was not found statistically significant at 2 and 4 mm levels ( p > 0.05)., Conclusions: The present study demonstrated that TradAC or UltraAC.Inc preparations with different cleaning protocols in extracted mandibular incisors did not influence the remaining calcium hydroxide at 2 and 4 mm from the apex., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2023. The Korean Academy of Conservative Dentistry.)

Background: Teeth may have additional roots and a different number of root canals. Overlooked root canals may cause endodontic failure. The aim of this study was to investigate the prevalence of root canals and the number of roots of premolars in a selected Turkish population., Materials and Methods: A total of 2,570 teeth from 1,438 patients were evaluated. The cone-beam computed tomography scans of 1,055 maxillary and 1,515 mandibular premolars were examined., Results: Type IV root canal morphology was observed most frequently in maxillary first premolars (77%), and the rates of single and double channel formations were very similar (51% and 49%, respectively). Of the second maxillary premolars, 57.4% had Type I morphology, and 89.9% of the teeth were single-rooted, while 68.6% had a single root canal. The most common formation was Type I (85%) among mandibular first premolars, and a single root was observed in 95.6% of these teeth. In addition, 87% of the mandibular first premolars had a single root canal. The second mandibular premolars mostly had Type I (95.4%) formation, and 99.3% of the teeth were single-rooted, while 96.9% had a single root canal., Conclusion: According to our findings, 51% of maxillary first premolars had a single root, 79.4% had two root canals, and 77% had Type IV (77%) formation. Maxillary second premolars mostly had Type I formation. In addition, a single root and single root canal formation were most common. Mandibular first premolars generally had a single root and single root canal formation, but 13% had two root canals, and 6.4% had Type V formation. More than 95% of mandibular second premolars had Type I formation., (© 2023. The Author(s).)

Background: Manual or mechanized instruments can be used for root canal preparation. Manual instrumentation using K-files is widely used in primary teeth, but there are many limitations. Mechanized root canal preparation can lead to easy access to all canals, decrease instrumentation time, and result in more funnel-shaped root canals, resulting in a more predictable uniform paste fill., Aim: This study aimed to evaluate the shaping ability and instrumentation time of VDW.ROTATE™ and EdgeTaper Platinum™ during the preparation of resin-printed primary molars. Hand K-files were used as a reference for comparison., Design: Sixty-six resin-based maxillary second primary molars, obtained from extracted tooth cone-beam computed tomography (CBCT) image and printed on a three-dimensional printer, were divided into three groups: VDW.ROTATE™, EdgeTaper Platinum™, and K-files. The specimens were scanned using CBCT imaging before and after root canal preparation. Images were registered using a dedicated software, and changes (Δ) in the canal area, volume, and untouched canal surface were calculated. Instrumentation time was evaluated. Data were statistically analyzed using the SPSS program., Results: There was no significant difference among the tested file systems for Δ canal volume and area (p > .05). VDW.ROTATE™, however, showed significantly lower untouched canal surface area than other systems in all roots (p < .001). The VDW.ROTATE™ was found to be significantly faster (6.47 ± 0.39 min) than EdgeTaper Platinum™ (7.71 ± 0.73 min) and K-files (8.22 ± 0.72 min), (p < .05)., Conclusions: The shaping ability and the instrumentation time were directly influenced by the root canal instrumentation system used during the preparation of resin-printed primary molars, with VDW.ROTATE™ being the faster system and associated with the lower amount of untouched canal surface area., (© 2022 BSPD, IAPD and John Wiley & Sons Ltd.)

The aim of this study was to examine the effectiveness of different irrigation activation methods on smear layer removal and tubular penetration. One hundred-five distal roots of mandibular molar teeth in total; 50 for smear removal efficiency (n = 10) analysis using scanning electron microscopy (SEM), and 55 roots were used to examine tubular penetration using confocal laser scanning microscope (CLSM). Five different irrigation activation methods were used in this study; conventional needle irrigation (CNI), sonic irrigation device of EDDY, passive ultrasonic irrigation (PUI), PIPS and SWEEPS techniques, which are two different laser irrigation activation methods. The obtained data were statistically analyzed and the significance level was determined as p < 0.05. At the apical level, the cleanest canal walls were observed when laser methods PIPS and SWEEPS were used, while in the middle third, there was no difference in smear removal efficiencies between all groups except for the CNI (p > 0.05). Penetration depths and percentages increased from apically to coronally in all groups. The PUI and EDDY generally showed similar penetration depths and percentages to the CNI, except at the coronal root level (p > 0.05). In all groups, when PIPS was used, it showed greater penetration depth and percentage (p < 0.05). PIPS and SWEEPS techniques showed lowest and similar smear scores compared to PUI and EDDY in the apical area where access and effectiveness of the irrigation solution are difficult., (© 2022. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

To investigate the efficacy of a new laser irrigation activation system [shock wave-enhanced emission photo-acoustic streaming (SWEEPS)] in terms of postoperative pain after primary root canal treatment compared with other techniques, namely photon-induced photo-acoustic streaming (PIPS), sonic system with EDDY, passive ultrasonic system (PUI), and manual dynamic activation (MDA). Two hundred patients with symptomatic irreversible pulpitis in mandibular premolar teeth were enrolled and randomly allocated to five different irrigation activation groups (n = 40) after chemo-mechanical root canal preparation. For irrigation activation, the SWEEPS and PIPS tips were attached to the Er-YAG laser system in the respective groups, while the Irrisafe tip was used in the PUI group and the EDDY tip in the sonic group. In the MDA group, irrigation was agitated with the master gutta-percha cone. At postoperative hours 8, 24, and 48 and on day 7, pain intensity was evaluated using the 10-mm Visual Analog Scale (VAS) and analgesic intake was recorded. The Kruskal-Wallis test was used to analyze the VAS scores, and pain prevalence and analgesic intake were examined with the Pearson's chi-square test at the 5% significance level. The PIPS and SWEEPS groups had the lowest level and prevalence of pain when compared to the remaining groups (P < 0.001). The PUI, sonic and MDA groups did not differ in terms of pain scores at hours 8 and 48 (P > 0.05). On day 7, the highest score and pain prevalence were recorded in the MDA group (P < 0.001). There was no difference between the groups in terms of analgesic intake (P > 0.05). Laser-activated irrigation systems provided lower postoperative pain scores and levels compared to the other activation systems. The MDA group had the highest pain scores and incidence at the end of the seventh day., (© 2022. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Introduction: This study aimed to evaluate the shaping ability of TruNatomy (Dentsply Maillefer, Ballaigues, Switzerland), VDW.ROTATE (VDW GmbH, Munich, Germany) and ProTaper Gold (Dentsply Maillefer, Ballaigues, Switzerland) during the preparation of resin-printed mandibular molar mesial root canals., Materials and Methods: Thirty-three printed resin-based mandibular mesial roots with two canals were obtained from extract tooth cone-beam computed tomography (CBCT) image. The printed teeth were divided into three groups ( n = 11) according to the system used for root canal preparation: TruNatomy, VDW.ROTATE, and ProTaper Gold. The specimens were scanned using CBCT imaging before and after root canal preparation. Then images were registered using a dedicated software and changes in the canal area, volume, untouched canal surface, and the maximum and minimum dentin wall wear were calculated., Statistical Analysis Used: Data were statistically analyzed using Shapiro-Wilk for normality, one-way ANOVA, and Tukey or Kruskal-Wallis H tests with alpha set at 5%., Results: No differences were observed for changes in the canal area, volume, untouched canal surface area, and minimum dentine wall wear parameters for the whole canal length ( P > 0.05). The mean of untouched canal surface area for the TruNatomy, VDW.ROTATE, and ProTaper Gold was 40%, 44%, and 44%, respectively. The maximum dentine wall wear was significantly lower in the ProTaper Gold group than in the TruNatomy and VDW.ROTATE groups ( P < 0.05)., Conclusions: TruNatomy, VDW.ROTATE, and ProTaper Gold systems showed similar shaping ability in printed resin-based mandibular mesial roots without clinically significant errors. A large amount of untouched canal surface area was observed for all systems., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Journal of Conservative Dentistry.)

This study aimed to evaluate and compare the dynamic cyclic fatigue, torsional and bending resistance of two novel RACE EVO (FKG Dentaire SA, La Chaux de Fonds, Switzerland) and R-Motion (FKG) nickel−titanium instruments with traditional RaCe (FKG) instruments. RACE EVO, R-Motion and RaCe instruments with a size of 25 and taper of 0.06 were used. A dynamic cyclic fatigue test was used to assess the time to fracture. The fractured surfaces were further analyzed using scanning electron microscopy at ×350 and ×3000 magnifications. A torsional resistance test was performed to measure the maximum torsional strength and angle of rotation. Phase transformations with temperature were evaluated using differential scanning calorimetry. The results were statistically analyzed with a Kruskal−Wallis test at a 5% significance level. R-Motion had the highest time to fracture and the lowest torsional and bending resistance, whereas RaCe had the lowest time to fracture and the highest torsional and bending resistance (p < 0.05). In relation to the angle of rotation, RACE EVO instruments had the highest deformation capacity followed by R-Motion and RaCe instruments (p < 0.05). The greater cyclic fatigue resistance and lower torsional and bending resistance results indicate that the novel R-Motion and RACE EVO instruments are less rigid and more flexible than RaCe instruments.

In this paper, a new powerful deep learning framework, named as DENTECT, is developed in order to instantly detect five different dental treatment approaches and simultaneously number the dentition based on the FDI notation on panoramic X-ray images. This makes DENTECT the first system that focuses on identification of multiple dental treatments; namely periapical lesion therapy, fillings, root canal treatment (RCT), surgical extraction, and conventional extraction all of which are accurately located within their corresponding borders and tooth numbers. Although DENTECT is trained on only 1005 images, the annotations supplied by experts provide satisfactory results for both treatment and enumeration detection. This framework carries out enumeration with an average precision (AP) score of 89.4% and performs treatment identification with a 59.0% AP score. Clinically, DENTECT is a practical and adoptable tool that accelerates the process of treatment planning with a level of accuracy which could compete with that of dental clinicians.

The aim of this study was to assess the effectiveness of irrigation activation techniques on postoperative pain (PP) in mandibular premolar teeth with irreversible pulpitis after single-visit endodontic treatment. A total of 160 patients with symptomatic irreversible pulpitis were included in this prospective randomized clinical study. Four different activation methods were used in mandibular premolar teeth. In group 1, teeth were irrigated with side-port endodontic needles (NI) without any agitation; in groups 2 and 3, sonic activation was performed using EDDY and EndoActivator (EA), respectively; and in group 4, passive ultrasonic irrigation (PUI) was used. Patients' analgesic intake-as well as pain intensity during and after treatment-were recorded at 8, 24, 48 h and 7 days. The data relating to age, sex and analgesic intake was evaluated using the Chi-square test and the preoperative pain and PP intensity at different time intervals was evaluated with the Kruskal-Wallis test at a 5% significance level. Highest PP was recorded at 8 h, pain intensity decreased in all groups by the time. Pain in the NI group was found higher than that of EDDY group at 24 h (P < 0.05). EA and PUI had caused mild pain and had similar pain scores at 24 h. (P > 0.05). No statistically difference was found among the groups with regard to analgesic intake (P > 0.05). Although there were slight differences in PP levels between the groups at 24 h, pain levels decreased in all groups after 24 h. Activation of the irrigation solution did not make any difference in terms of PP after 24 h.

The aim of this study was to investigate the effects of different post and core systems, CAD/CAM crown placement on fracture strength of endodontically treated mandibular premolar teeth. One hundred forty single-rooted premolar teeth were randomly divided into a control group and six experimental groups as follows: control group (Group 1); FiberSite post luting with Clearfil DC Core Plus (Group 2); RelyX Fiber post luting and core build up with Clearfil DC Core Plus (Group 3); RelyX Fiber post luting with Clearfil DC Core Plus and core build up with Filtek Bulk Fill Posterior (Group 4); specimens that received CAD/CAM crowns after the same procedures performed in Groups 2, 3, and 4, respectively (Groups 5, 6, and 7). Fracture strength tests were performed, and the failure modes were recorded. Data were statistically analyzed using one-way ANOVA and post hoc Tukey tests. The highest fracture resistance was observed in the control group and among the experimental groups in Group 4. Groups 3 and 5 showed similar fracture resistance followed by Group 2. The lowest fracture resistances were seen in the samples of Groups 6 and 7. While the fracture strength of Group 2 increased after the crown placement (Group 5), the fracture strength of Group 3 and Group 4 decreased (P < 0.05). While the specimens in Groups 1, 2, 3, and 4 predominantly showed favorable failure, unfavorable failure was more frequent in Groups 5, 6, and 7.

Objectives: This study aims to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium (NiTi) rotary files at body temperature., Materials and Methods: In total, 80 VDW.ROTATE (25/0.04), TruNatomy (26/0.04), 2Shape (25/0.04), and HyFlex CM (25/0.04) NiTi rotary files ( n = 20 in each group) were subjected to static cyclic fatigue testing at body temperature (37°C) in stainless-steel artificial canals prepared according to the size and taper of the instruments until fracture occurred. The number of cycles to fracture (NCF) was calculated, and the lengths of the fractured fragments were measured. The data were statistically analyzed using a 1-way analysis of variance and post hoc Tamhane tests at the 5% significance level ( p < 0.05)., Results: There were significant differences in the cyclic fatigue resistance among the groups ( p < 0.05), with the highest to lowest NCF values of the files as follows: VDW.ROTATE, HyFlex CM, 2Shape, and TruNatomy. There was no significant difference in the lengths of the fractured fragments among the groups. The scanning electron microscope images of the files revealed typical characteristics of fracture due to cyclic fatigue., Conclusions: The VDW.ROTATE files had the highest cyclic fatigue resistance, and the TruNatomy and 2Shape files had the lowest cyclic fatigue resistance in artificial canals at body temperature., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported., (Copyright © 2020. The Korean Academy of Conservative Dentistry.)

The aim of the present study was to evaluate the effect of environmental temperature, heat-treatment*** and design on the cyclic fatigue resistance of OneShape (OS), OneShape new generation (OSNG) and One Curve (OC) NiTi rotary single-file instruments. Cyclic fatigue testing of NiTi instruments was performed in an artificial canal with a 5-mm radius of curvature and a 60° angle of curvature located 5 mm from the tip of the instrument. During the experiment 3 different temperatures were used in a thermostatic bath with electronic and infrared controls: 0°, 20° and 35 °C. Sixty OneShape, 60 OneShape new generation and 60 One Curve instruments were rotated in the artificial canal until fracture occurred and the number of cycles to fracture (NCF) and the length of the fractured fragment (FL) was recorded. Data were analyzed by one-way ANOVA test at the 5% significance level. Fatigue resistance was significantly higher as the environmental temperature decreased, with differences ranging from 61 to 791%. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested (P < 0.05). There was no significant difference with respect to the length of the fractured file fragments for all the instruments tested at all the temperatures tested (P > 0.05). Within the limitation of the present study, fatigue resistance of the files was significantly increased when the environmental temperature decreased. OC instruments were significantly more resistant to cyclic fatigue than OS and OSNG instruments at all the temperatures tested.

Background. This study examined the effects of changes in temperature and environmental conditions on the cyclic fatigue resistance of Reciproc Blue, HyFlex EDM, WaveOne Gold, and Twisted File Adaptive. Methods. Forty-five Reciproc Blue (25/.08), 45 HyFlex EDM (25/.08), 45 WaveOne Gold (25/.07), and 45 Twisted File Adaptive (25/.08) files were tested for cyclic fatigue at room temperature (20°C) in air and water and at body temperature (35°C) in water. All the instruments were rotated in artificial canals made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius of curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds, using a digital chronometer. Mann-Whitney U test was used for the statistical analysis of data, with SPSS 21.0. Results. Cyclic fatigue resistance was significantly higher in all the groups in water at an ambient temperature of 20°C compared with air and water at temperatures of 20°C and 35°C, respectively (P<0.05). The intragroup analysis revealed that HyFlex EDM had the highest cyclic fatigue resistance, followed by Reciproc Blue, WaveOne Gold, and Twisted File Adaptive in both air and water at 20°C (P<0.05). HyFlex EDM exhibited the highest cyclic fatigue resistance in water at 35°C, whereas there was no significant difference between the other groups (P>0.05). Conclusion. Within the limitations of the present study, an increase in the ambient temperature significantly decreased the cyclic fatigue resistance of the tested NiTi files., (© 2019 Gündoğar et al.)

The aim of the present study was to compare the cyclic fatigue resistances of HyFlex EDM (HEDM), WaveOne Gold (WOG), Reciproc Blue (RB), and 2Shape (TS) NiTi systems having different metallurgic properties. HEDM, WOG, RB, and TS instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 45°, and 90° angles of curvatures and a radius of curvature of 5 mm until fracture occurred, and the time to fracture (TTF) was recorded in seconds. Also, number of cycles to fracture was calculated (NCF). Data were statistically analyzed using Kruskal-Wallis and t test. The statistical significance level was set at P < 0.05. When comparing the TTF of all the instruments tested in the artificial canal with 45° curvature, RB had statistically the highest cyclic fatigue resistance followed by HEDM and TS (P < 0.05), while the WOG showed the lowest cyclic fatigue resistance (P < 0.05). In artificial canal with 90° curvature, RB showed a significantly higher cyclic fatigue resistance than the other tested files (P < 0.05), while there was no significant difference among the TS, WOG and HEDM groups (P > 0.05). When the NCF values were taken into consideration, HEDM reported a significantly higher cyclic fatigue resistance than TS in both canal curvatures analyzed (P < 0.05). Within the limitations of the present study, RB NiTi files showed statistically higher cyclic fatigue resistance in artificial canals with 45° and 90° than the other NiTi files tested.

Background. The aim of this study was to compare the cyclic fatigue resistance of 2Shape, Twisted File (TF) and EndoSequence Xpress (ESX) nickel-titanium rotary files at intracanal temperature (35°C). Methods. Twenty 2Shape TS1 (25/.04), 20 TF (25/.04) and 20 ESX (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°C). All the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (NCF) for each file was calculated. Kruskal-Wallis test with Bonferroni correction was performed to statistically analyze data using SPSS 21.0. Statistical significance was set at P<0.05. Results. NCF values revealed that the 2Shape had significantly the highest cyclic fatigue resistance, followed by TF and ESX at intracanal temperature (P<0.05). The difference was significant between the TF and ESX groups (P<0.05). There was no significant difference among the 2Shape, TF and ESX files with respect to the lengths of the fractured file fragments (P>0.05). Conclusion. Within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2Shape files at the intracanal temperature is higher than that of TF and ESX files.

Introduction: The purpose of this article was to compare the cyclic fatigue resistance of Reciproc and Reciproc Blue files (VDW GmbH, Munich, Germany) that were used to prepare root canals of mandibular molar teeth with or without a glide path., Methods: Sixty Reciproc R25 and 60 Reciproc Blue R25 files were used. The Reciproc and Reciproc Blue groups were divided into 3 subgroups (ie, as received condition, used without a glide path, and used with a glide path). All the instruments were rotated in a stainless steel artificial canal with an inner diameter of 1.5 mm, a 60° angle of curvature, and a radius of curvature of 5 mm until fracture occurred. The number of cycle to fracture was calculated, and the length of the fractured segments was measured. The Kruskal-Wallis test was performed to statistically analyze the data using SPSS 21.0 software (IBM Corp, Armonk, NY) at a 5% significance level., Results: The cyclic fatigue resistance of as received condition Reciproc Blue files was found to be higher than as received condition Reciproc files (P < .05). Reciproc Blue files used for root canal preparation showed higher cyclic fatigue resistance than Reciproc files used for root canal preparation (P < .05). There was no statistically significant difference between Reciproc and Reciproc Blue files used with a glide path and without a glide path (P > .05). There was no statistically significant difference in the mean length of the fractured fragments of the instruments (P > .05)., Conclusions: Within the limitations of this in vitro study, it was concluded that creating a glide path using ProGlider files had no effect on the cyclic fatigue resistance of RPC and RPC Blue files., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The purpose of this study was to investigate the amount of apically extruded debris by Reciproc Blue (REC Blue; VDW, Munich, Germany), HyFlex EDM (HEDM; Coltene/Whaledent, Altstätten, Switzerland), and XP-endo Shaper (XPS; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) files during root canal preparation at body temperature., Methods: Sixty extracted single-rooted mandibular premolar human teeth were randomly assigned to 3 groups (n = 20). The canals were instrumented using 1 of the following instruments: REC Blue, HEDM, or XPS. Apically extruded debris during instrumentation was collected into preweighed Eppendorf tubes. All the procedures were performed at 35°C. The amount of extruded debris was calculated by subtracting the weight value of the tooth-free apparatus from the postpreparation weight value. The data were analyzed using the Kruskal-Wallis test at a 5% significance level., Results: All the instruments tested caused extrusion of some debris from the apical foramen. XPS extruded significantly less debris from the apex than REC Blue (P < .05). The difference among the HEDM group and the other groups was not significant (P > .05)., Conclusions: Within the limitations of this in vitro study, the amount of apically extruded debris registered for the different files tested was REC Blue > HEDM > XPS, with a statistical difference only between XPS and REC Blue., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to evaluate the effect of a commercially available irrigant, the Qmix 2 in 1, on the push out bond strength of Endosequence BC which is a bioceramic based root canal sealer., Material and Methods: Sixty extracted maxillary central incisors were prepared with Protaper Next rotary instrument up to X4 (# 40). The specimens were randomly divided into four groups of equal sample size (n=15), according to the final irrigation regimen as follows: Group 1: 2.5% sodium hypochloride (NaOCl) (control), Group 2: 17% ethylenediaminetetraacetic acid (EDTA), Group 3: 2% Chlorhexidine (CHX), Group 4: QMix 2 in 1. After rinsing, teeth were obturated using gutta-percha with Endosequence BC sealer. Slices were obtained from coronal, middle, and an apical section of the root canal. Push-out test was performed to evaluate the bond strength between the root canal dentin and the sealer. Data was statistically analyzed., Results: The push-out bond strength of the root canal sealer was significantly affected by the type of irrigation solution. Highest bond strengths were found in canals irrigated with Qmix solution, and these results were regardless of anatomical section of the root canal (p< 0.05)., Conclusion: Final irrigation of the root canals with QMix had a positive effect on the bond strength of Endosequence BC sealer throughout the root canal., Competing Interests: Conflict of Interest: The authors have no conflicts of interest to declare.

Background. This study compared the cyclic fatigue resistance, bending resistance and cross-sectional areas of Reciproc Blue (RPC Blue), WaveOne Gold (WOG), and Genius File (GF) NiTi rotary systems. Methods. Forty RPC Blue R25 (25/.08), 40 WOG Primary (25/.07) and 40 GF (25/.04) files were used in the present study. Flexibility of the files was determined by 45° bending test. The instruments were also subjected to cyclic fatigue resistance, calculating the number of cycles to fracture (NCF) in an S-shaped artificial stainless steel canal. Also the cross-sectional areas of the files were measured at D5 level. The length of the fractured file tips was measured. The fracture surface of all the fragments was examined with a scanning electron microscope. Data was statistically analyzed using one-way ANOVA and post hoc Tukey tests. Results. In both the apical and coronal curvatures, the NCF of the GF was significantly higher than that of the RPC Blue and WOG files. There was no significant difference between the GF, WOG and Reciproc Blue files with respect to the lengths of the fractured file fragments in either the apical or coronal curvature. The bending resistance of the GF was signif-icantly higher than that of the RPC Blue and WOG files. The RPC Blue had the largest cross-sectional area, and the GF had the smallest cross-sectional area. Conclusion. Within the limitations of the present study, the GF NiTi system exhibited the highest cyclic and bending re-sistance among the experimental groups.

Introduction: The purpose of this study was to compare the cyclic fatigue resistances of Reciproc Blue (VDW, Munich, Germany), HyFlex EDM (Coltene/Whaledent, Altstätten, Switzerland), WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland), and OneShape (Micro Mega, Besancon, France) single-file NiTi systems., Methods: Thirty Reciproc Blue R25 (25/.08), 30 HyFlex EDM (25/.∼), 30 WaveOne Gold Primary (25/.07), and 30 OneShape (25/.06) instruments were included in this study. All the instruments were rotated in artificial canals, which were made of stainless steel with an inner diameter of 1.5 mm, a 60° angle of curvature, and radii of curvatures of 5 mm until fracture occurred, and the time to fracture was recorded in seconds using a digital chronometer. The data were analyzed statistically using Kruskal-Wallis and post hoc Dunn tests via SPSS 21.0 software (SPSS Inc, Chicago, IL). The statistical significance level was set at 5%., Results: The HyFlex EDM file (3456.33 ± 633.37) file had the statistically highest fatigue resistance, and the OneShape file (1221.63 ± 812.4) had the least fatigue resistance (P < .05). The mean number of cycles to fracture of the Reciproc Blue file (2875.89 ± 105.35) file was statistically higher than the WaveOne Gold file (1737.00 ± 376.32) (P < .05). There was no statistically significant difference (P > .05) in the mean length of the fractured fragments of the files (P > .05)., Conclusion: Within the limitations of the present in vitro study, it was found that cyclic fatigue resistance of HyFlex EDM files was higher than the cyclic fatigue resistances of OneShape, Reciproc Blue, and WaveOne Gold files., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Data mining of digital dental records provides possibilities for analysing the variation between dentists when diagnosing caries. A total of 71,317 male and 82,302 female subjects visited the health centres in Vantaa and Kemi during the 'digital era' (1994-2005). As subjects were classified as 'new patients' at the first examination, all re-examinations of the same subjects thereafter by the same dentist produced 'old patients'. A mean number of decayed surfaces (DS) was counted as a function of the age of the subject during the follow-up. The significance of the difference between old and new patients was determined by the Mann-Whitney test for each age cohort at the cross sections, and for the whole follow-up. Caries was seen to affect new patients more than the old ones in both health centres after the age of 20 years. The mean DS values were the same, reaching about 1 for new and old patients at the age of 15 years. The mean DS had a peak for new patients in both health centres at the age of 25 years and another peak around 45-50 years in Kemi. With a few exceptions there was a significant difference between the DS values of new and old patients at most cross sections and for the whole follow-up time. Evidently dentists examine new patients more carefully than their old patients. After the age of 18 years patients may have changed their dentists because they have finished the free-of-charge treatment period.