ProTaper Universal System Research Articles

Dentin Sealing of Calcium Silicate-Based Sealers in Root Canal Retreatment: A Confocal Laser Microscopy Study.

The aim of the present in vitro study was to evaluate the intratubular penetration of three bioceramic sealers in root canal retreatment. Here, 30 single-rooted human teeth were instrumented with the Protaper Universal system and filled with gutta-percha and the epoxy-resin-based sealer AH Plus mixed with rhodamine B. After two weeks in a humid environment, they were re-instrumented with Reciproc Blue and divided into three groups according to the endodontic sealer to be used in the re-filling (n = 10): G1: CeraSeal, G2: TotalFill BC Sealer, G3: TotalFill BC Sealer HiFlow. For the filling, a single cone technique was used, and the respective sealers were mixed with fluorescein. The roots were then sectioned at 2, 5, and 8 mm (apical, medial, and coronal measurement points, respectively) from the apex, and the dentinal tubule penetration depth and percentage of penetration around the canal perimeter were evaluated by means of confocal laser scanning microscopy (CLSM). Penetration between groups was compared using the Kruskal−Wallis test, and within each group using the Wilcoxon test. Statistical significance was established at p < 0.05. A non-significant reduction was found in the penetration depths and in a percentage of penetration around the canal perimeter between AH Plus and the tested calcium-silicate-based sealers (p > 0.05). Consequently, this reduction may not affect the three-dimensional seal of the root canal system in a negative manner. The penetration depth and percentage of penetration around the canal perimeter at both the root canal treatment and retreatment were significantly reduced from the coronal to apical points in all groups (p < 0.05).

Effect of 0.2% Chitosan Associated with Different Final Irrigant Protocols on the Fiber Post Bond Strength to Root Canal Dentin of Bovine Teeth: An In-vitro Study

Objective: This in-vitro study investigated the effect of 0.2% Chitosan associated with different final irrigant protocols on the bond strength of fiber posts (FP) to root canal dentin. Methods: Fifty bovine incisors roots were prepared using the ProTaper Universal system, irrigated with 2.5% sodium hypochlorite, and divided into one control group (n=10) with no final irrigant protocol and four experimental groups (n=10), which were defined according to the combination of chelating solution (17% EDTA and 0.2% Chitosan) and irrigant activation/delivery method [conventional irrigation (CI), and passive ultrasonic irrigation (PUI)]. Post spaces were prepared to a depth of 12 mm using #1-5 Largo drills, and the FP were cemented using self-adhesive resin cement. Two slices of 2 mm in thickness from each third were obtained and submitted to the micropush-out test. After testing the push-out strength, the slices were analyzed under a stereomicroscope at 40× magnification for bond failure patterns determination. Statistical analysis was performed using three-way ANOVA followed by Tukey’s test (α = 0.05). Results: The control and 17% EDTA + CI groups exhibited significantly lower bond strength than 0.2% Chitosan + CI, 17% EDTA + PUI, and 0.2% Chitosan + PUI groups in the cervical third (P = 0.00). The cervical third had higher values than the middle and apical thirds in control (P = 0.00), 17% EDTA + PUI (P = 0.00), and 0.2% Chitosan + PUI groups (P = 0.00). Adhesive cement-dentin failure type was predominant in all groups. Conclusion: The use of 0.2% chitosan did not affect the bond strength of FP to root dentin. Passive ultrasonic activation of chelating solutions resulted in an improvement in bonding strength.

Comparative Assessment of Qmix as Endodontic Irrigant on Reversal of Bond Strength in Teeth Subjected to Irradiation: An Scanning Electron Microscope Study

The aim of this current study was to compare and evaluate the reversal efficacy of Qmix and chitosan-based irrigation materials quantitatively through the assessment of the push-out bond strength of bioceramic sealer employing universal testing machine and to qualitatively analyze the sealer/dentin interface by scanning electron microscope (SEM) in the teeth subjected to fractioned radiation. Ninety single-rooted straight human maxillary central incisors were randomly divided into six groups (n = 15) where in three groups comprise Chitosan, Qmix, and EDTA/sodium hypochlorite which were not exposed to irradiation while other three groups were challenged with irradiation protocols. Root canals were prepared with ProTaper universal system and all the samples were irrigated according to the final irrigation protocols and obturated with bioceramic sealers. Dentin slices were prepared with 1 mm thickness from each root third for the estimation of bond strength of sealers to dentin. Qualitative assessment of the sealer-dentin interface was done by scanning electron microscopy. Bond strength data were scrutinized by independent t-test and failure modes using the Chi-square test. Significantly lower bond strength (p <0.05) was recorded after irradiation compared with nonirradiated group. To quantify the results irrigation protocols, Qmix had highest bond strength followed by chitosan and EDTA/sodium hypochlorite group irrespective of irradiation status. Bond strength values reduced after irradiation in all root thirds irrespective of the irrigation materials. Scanning electron microscope images revealed traces of repair process for Qmix-based irrigation materials than the chitosan-based materials for both irradiated and nonirradiated specimens. All the irrigation materials employed in this study had good bond strength. The specimen irrigated with Qmix had comparatively higher bond strength than the chitosan-based materials. The teeth subjected to irradiation challenge were associated with a decrease in the push-out bond strength of sealers to intraradicular dentin with formation of more gaps and fewer tags at the sealer/dentin interface. Selection of ideal irrigation protocols still remains a challenge for the clinical practitioners, and this study explored the utilization of novel materials used for irrigation, especially in the teeth subjected to radiation.

Effectiveness of the REvision System and Sonic Irrigation in the Removal of Root Canal Filling Material from Oval Canals: An In Vitro Study.

This study aimed to evaluate the effectiveness of the Endostar REvision system (Poldent, Warsaw, Poland) in the removal of filling materials from oval root canals using sonic irrigation as an additional cleaning method. Thirty human-extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) up to instrument F1 (20/.07), and then filled by the continuous wave vertical compaction technique using pulp canal sealer EWT (Sybron Dental Specialties, Orange, CA, USA). The teeth were randomly divided into two groups (n = 15) according to the instrumentation system and the additional cleaning method, as follows: REvision (30/.08, 25/.06) with EQ-S sonic activation (Meta Biomed, Chungcheongbuk-do, Korea), REvision (30/.08, 25/.06) without additional activation. All specimens were sectioned longitudinally at 3 and 7 mm from the apex, and analyzed using digital microscopy (KEYENCE, Osaka, Japan) to measure the total area of the residual obturation materials, followed by SEM analysis. The data on the percentage of remaining filling material were analyzed by Kruskal–Wallis one-way Analysis of Variance on ranks. None of the retreatment protocols completely removed the filling material from the root canals (p > 0.05); the retreatment technique using sonic activation showed statistically less residual filling materials than the retreatment technique using irrigants without activation at the coronal third (p < 0.05), whilst no significant difference was found between both tested groups at the apical and middle thirds (p > 0.05). The REvision system showed promising results in the removal of filling materials from oval canals.

Effect of hand files, rotary protaper universal and protaper retreatment files on crack formation in dentin

Background: The aim of the study was to compare the effect of hand files, rotary protaper universal files and protaper retreatment files on crack formation in dentin. Methods: Eighty mandibular premolar teeth with single canals are selected and mounted on resin blocks with simulated periodontal ligaments. The teeth were divided into four groups of twenty samples in each group. Un-instrumented group serves as control group while group two and three consists of hand file and rotary protaper universal file system respectively. Group 4 consists of retreatment group consisting of two sub groups of ten samples in each group. Subgroup 4a consist of samples prepared with hand file while subgroup 4b consist of samples prepared with rotary protaper universal system. Thereafter, retreatment is performed with protaper retreatment file system in both the sub groups. All the roots were sectioned perpendicular to the long axis at 4mm from apex using a low speed saw (Isomet) under water cooling. Digital images of each sections were captured at 25X magnification using a digital camera attached to a stereomicroscope and cracks were noted. Results: Although the result is statistically non significant, hand files show less number of cracks as compared to rotary protaper universal file.

Assessment of push-out bond strength of post-surface pretreatment before salinization using hydrogen peroxide, aluminum trioxide, and natural photosensitizers to radicular dentin

ObjectiveThe study aimed to evaluate the effect of different post surface pretreatment methods i.e., 24% hydrogen peroxide (H2O2), riboflavin photosensitizer (RFP), curcumin photosensitizer (CP) and aluminum oxide (Al2O3), and silane only on the bond values of glass fiber post to resin cement Materials and MethodsFifty single-rooted human teeth were obtained and crowns were sectioned coronally to the cementoenamel junction (CEJ). Protaper universal file system was used for canal cleaning and shaping followed by obturation. Post space was prepared and all the posts were then randomly divided into five groups depending on the surface pretreatment used (n = 10). Group 1: 24% H2O2 + silane, Group 2: RFP + silane, Group 3: CP + silane, Group 4: Al2O3 + silane, Group 5: silane only. Post-surface treatment was followed by post-placement using a self-etch dual-cure cement Panavia F 2.0. Acrylic blocks were used to hold the specimens perpendicularly and all the samples were sectioned by slow-speed saw into coronal, middle, and apical third. The universal testing machine determines pushout bond strength and failure mode was analyzed by stereomicroscope. One-way analysis of variance (ANOVA) and Tukey multiple comparison tests were used to analyze data. ResultThe coronal section of group 4 (Al2O3 + silane) displayed the highest PBS (8.23±0.14 MPa). Whereas, an apical third of group 2 (RFP + silane) exhibited the lowest PBS (2.02±0.12 MPa). PBS values in samples in group 1 surface treated with 24% H2O2 + silane displayed comparable outcomes to samples in group 4 at all three levels (p>0.05). Samples in group 2 (RFP + silane) group 3 (CP + silane) and group 5 (Silane Only) demonstrated comparable PBS (p>0.05). ConclusionGlass fiber reinforced post-surface pretreatment method using hydrogen peroxide and aluminum trioxide along with silane improves push-out bond strength at all three levels (coronal, middle, and apical). The use of a silane coupling agent on glass fiber posts alone does not improve bond values. The practice of photosensitizer on post-surface needs to be investigated further.

Shaping Ability of Reciprocating and Rotary Systems After Root Canal Retreatment: a CBCT Study.

The purpose of this in vitro study was to evaluate the shaping ability of reciprocating and continuous rotary systems after root canal retreatment. After preparation and root canal filling, mesial canals of 54 mandibular molars were distributed into 3 groups (n=18), according to the filling material removal and re-instrumentation protocols: WOG group - WaveOne Gold system; PTN group - ProTaper Next system; and PTU group - ProTaper Universal system. Cone-beam computed tomographic (CBCT) images acquisition of the mesial root canals was performed at different moments: (1) before instrumentation (unprepared root canals), (2) after preparation and filling, (3) after filling material removal and (4) re-instrumentation. The apical transportation (AT), centering ability (CA) and change in root canal diameter were assessed by CBCT analysis. The remaining filling material quantification was performed by radiographic examination. The statistical analyses were performed using the 3-way ANOVA, Tukey-Kramer, Kruskal-Wallis and Dunn multiple Comparison tests (p<0.05). The tested instruments did not show full CA (=1.0). PTN group had greater AT at the 5th mm in comparison with the WOG group (p<0.05). After re-instrumentation, WOG group had greater root canal diameter change at the 1st and 5th mm than PTN and PTU groups (p<0.05). There was no significant difference among groups when comparing the amount of remaining filling material after re-instrumentation (p>0.05). The tested systems provided minimal alteration in root canal morphology at the apical portion after root canal retreatment. However, WOG promoted greater change in root canal diameter.

Radicular canal disinfection by photosensitizers activated by photodynamic therapy and Er, Cr: YSGG laser bonded to glass fiber post using different cement types. An Invitro study

AimTo assess the tensile bond strength (TBS) of conventional glass ionomer cement (GIC) and resin cemented fiber post to radicular dentin when disinfected with different photosensitizers methylene blue photosensitizer (MBP), curcumin photosensitizer (CP), and laser therapy Er, Cr: YSGG laser (ECYL) Material and MethodsSixty carefully extracted, non-traumatic, non-carious, closed apex human mandibular premolars were collected. Periodontal fibers, plaque, or calculi were detached. Decoration of samples was executed up till the cementoenamel junction. Samples were embedded perpendicularly in a heat cure acrylic resin. Canals of all specimens were shaped and cleaned with Protaper universal NiTi system dehydrated with paper points and obturated with gutta-percha. Post space was prepared after the removal of gutta-percha via peso reamers. Post space was disinfected with MBPv100mg/L in group 1; group 2 500 mg/L and group 3 ECL. After sequential photo-irradiation therapies, fiber post was luted with resinous cement and GIC (n = 10 each). After post-cementation, all specimens were subjected to tensile strength in the universal testing machine in Newton. Failure analysis was assessed at 30x magnification.TBS determination was statistically analyzed by one-way variance analysis (ANOVA), followed by the Tukey test (p= 0.05) by parallelizing different groups. ResultsFiber post cemented to radicular dentin with Rely X ARC resin cement and radicular canal disinfected with CP offered the highest TBS (289.25±3.27 N). Similarly, canal space disinfected with MBP and post-luted via Rely X ARC showed the lowest TBS (281.54±4.46 N). Intragroup comparison unveiled that there is no statistical difference between tensile strength sustained by two luting cement (p>0.05). ConclusionRely X ARC resinous cement bared the highest tensile bond strength for a post-dentine-cement bond with different photo-activated canal disinfectants (Methylene blue photosensitizer, Curcumin photosensitizer) and Er, Cr: YSGG then Vidrion C (GIC).

An in vitro comparative assessment of manual hand file, rotary protaper ni-ti, erbium:yttrium-aluminum-garnet laser, canal brush, and ultrasound methods for smear layer removal.

Selection of instruments is important to prevent any complications such as ledge formation and instrument breakage. The main drawback linked with instrumentation is smear layer formation. This study was done for comparison of manual hand file, rotary ProTaper Ni-Ti, erbium:yttrium-aluminum-garnet (Er:YAG) laser, ultrasound, and CanalBrush (CB) methods for smear layer removal. Sixty freshly extracted single-rooted mandibular first premolars extracted for orthodontic treatment purpose were selected and classified into six groups. Group I was negative control in which no final agitation of irrigant was performed. In Group II, solution activation was performed with ProTaper Universal System, in Group III, solution activation was done with canal brush, in Group IV, ultrasound activation was done, in Group V, solution agitation was performed with Er:YAG laser agitation, and in Group VI, canal preparation with hand files was performed. Smear layer score was evaluated after canal preparation with each method. Score 1 was seen in 3 (30%) in Group IV and 6 (60%) in Group V, score 2 was seen in 3 (30%) in Group I, 8 (80%) in Group II, 7 (70%) in Group III, 5 (50%) in Group IV, 3 (30%) in Group V, and 4 (40%) in Group VI. Score 3 was observed in 7 (70%) in Group I, 2 (20%) in Group II, 3 (70%) in Group III, 2 (20%) in Group IV, 1 (10%) in Group V, and 6 (60%) in Group VI. A statistically significant difference was found in smear layer removal score in all groups (P < 0.05) except between Group I versus VI (P > 0.05). Complete removal of the smear layer was not observed in any of the methods used in the study; however, Er: YAG laser was found to be better as compared to other methods.

Effects of sodium hypochlorite on corrosion of the rotary nickel-titanium endodontic instruments - SEM analysis

Introduction/Objective. of this study is to use scanning electron microscopy (SEM) analysis to examine surfaces of new and same sets of Ni-Ti instruments after canal preparations, to check their suspectability to corrosion. Methods. In this study, we used five different endodontic Ni-Ti instruments: K3, Mtwo, ProTaper Universal, HyFlex and BioRaCe. Instruments were analyzed before and after preparation of canals of different curvature, using SEM (150?2000 ?). Results. Corrosion of the working part was observed in 5.5% of new Ni-Ti instruments of the K3 system (apical and middle segment), in 5.5% of Mtwo instruments (apical third), and in 11.1% of ProTaper Universal systems (apical and middle third). Corrosion was not observed on the new instruments of the HyFlex and BioRaCe kits. After instrumentation, disinfection, and sterilization, corrosion was observed in all sets of K3 and ProTaper Universal systems and in all HyFlex instruments of the first group. Corrosion was observed in the HyFlex system in the second group in 16.7% of instruments (apical and middle third) and in the third 83.3% in the apical and 66.7% in the middle segment. In the Mtwo set, corrosion was observed in 16.7% of instruments in the first (apical and middle third), in the second group in 33.3% of instruments in the apical part and 50% in the middle third, while in the third group, corrosion was observed in 16.7% of instruments in the middle third of instruments. Conclusion. Rotary Ni-Ti instruments K3 and ProTaper Universal are susceptible to corrosion in a very high percentage. Ni-Ti systems with post-heat treatment of the working part (HyFlex) are somewhat more resistant to corrosion, while in Ni-Ti systems with electropolished surface (BioRaCe), corrosion is not observed.

Efficacy of Orange Oil, Lemon Oil and Xylene as Solvents in Removing Gutta Percha from Curved Root Canals: An In-vitro Study

Introduction: Root Canal Treatment (RCT) is the most common and effective treatment for saving natural tooth. Despite of modern technology and progress in the materials, failures in endodontic treatment still remains. Microbial infection majorly bacteria in the root canal is the prime cause of reinfection in root canal treatment. Endodontic instruments, solvents, lasers are the different techniques that can be used for removing gutta percha from the root canal. Aim: To compare the efficacy of orange oil, lemon oil, and xylene as solvents in removing gutta percha from curved root canals. Materials and Methods: In this in-vitro study, 24 freshly extracted teeth which includes incisors, premolars and molars having curved root will be taken. Then RCT would be performed in all the extracted teeth by using cold lateral compression obturation method. Then all teeth would be divided in three groups (n=8). After one month, the Gutta Percha (GP) would removed by ProTaper Universal system. First group will use orange oil as solvent, second group will use lemon oil as solvent and the third group will use xylene as a solvent. The micro-Computed Tomography (CT) images prior to the application of solvent and after application of solvent will be taken and would be evaluated to check the percentage of filling material remaining. Results: The expected outcome is orange oil and lemon oil to act as a better root canal solvent as compared to xylene. Conclusion: The determination and comparison of the efficacy of orange oil, lemon oil and xylene as GP solvents from this planned study will help the clinicians during re-RCT treatment.

INCIDENCE OF APICAL ROOT CRACK FORMATION AFTER ROTARY ROOT CANAL INSTRUMENTATION AT DIFFERENT INSTRUMENTATION LENGTHS USING PROTAPER UNIVERSAL, PROTAPER NEXT AND PROTAPER GOLD FILES - AN IN-VITRO STUDY

Aim: To evaluate the incidence of apical root crack formation after root canal preparation using ProTaper Universal (PTU), ProTaper Next (PTN) and ProTaper Gold (PTG) rotary file systems and compare the crack formation at various instrumentation lengths. Subjects and Methods: One hundred single rooted extracted mandibular premolar teeth were mounted in acrylic resin blocks after simulating periodontal ligament. The teeth were divided into four groups. Group I was instrumented using PTU, group II using PTN and group III using PTG rotary files, while group IV was left untreated, serving as a negative control group. Each group was subdivided into three subgroups: A, B and C instrumented till root canal length (RCL), RCL-1 and RCL+1. Root apex was sectioned horizontally 1-2mm from apical foramen and was stained with 1% methylene blue dye followed by stereomicroscopic evaluation to determine apical root cracks. The data was analyzed using chi-square, Shapiro Wilkinson and Cramers phi test. The significance level was set at P&lt;0.05. Result: Significant difference was seen in percentage of cracks after instrumentation with PTU and PTG, while no significant difference with PTU and PTN. Specimen instrumented upto RCL-1 showed less cracks as compared to those instrumented upto RCL and RCL+1. Conclusion: PTG produced least number of cracks followed by PTN and PTU. Moreover, instrumentation at RCL-1 reduced the crack formation.

Shaping Ability of Three Ni-Ti Rotary Systems in Curved Root Canals of Extracted Teeth

Aims. The purpose of this study was to compare the effects of 3 different rotary Ni-Ti instruments used to prepare curved root canals on the root canal curvature by using Digora system. Methods. Mesiobuccal canals of 30 mandibular first molars with curvature between 20-40 degrees were divided into 3 equal groups according to Ni-Ti rotary system need for root canal preparation: Alpha, RaCe and ProTaper system. Root canal curvatures from both buccal and proximal view were measured before and after instrumentation by using Digora system and image analysis software according Schneider's technique. Results. The result indicated that ProTaper system showed significantly greater decrease in curvature in the mesio-distal view and in the bucco-lingual view (p&lt;.05). Conclusion. The current study concluded that the rotary Ni-Ti RaCe system better maintained the original root canal curvature than the rotary Ni-Ti Alpha System and ProTaper Universal Systems. It may be better to use the rotary Ni-Ti RaCe system to prepared curved canal in order to maintained the original root canal curvature.

Evaluation of apical root defects during canal instrumentation with two different nickel-titanium (NiTi) systems by optical coherence tomography (OCT) scan

Background/purposeCanal instrumentation with rotary nickel-titanium (NiTi) instruments might weaken the dentinal wall. This study aims to investigate the apical root defects during canal instrumentation with two NiTi rotary systems by using optical coherence tomography (OCT) scans. Materials and methodsTwenty mandibular incisors were selected and divided into two groups instrumented using HyFlex CM (HCM) and ProTaper Universal (PTU) systems. OCT scans were taken immediately after canal instrumentation with file #25, #30 and #40. Each cross-sectional reconstructed image of 1, 2 and 3 mm from the apex was examined, root cracks were scored, and dentin thickness was measured at 12 sites. The risk sites with dentin thickness less than 0.30 mm were recorded. ResultsIn HCM group, no cracks were observed after instrumentation with file #30/.06, while in PTU group, root cracks were found in 6 teeth with a total score of 9 after using F3 (#30/.09) (P < 0.05). After file #40, 8 teeth with cracks had a score of 14 in PTU group, while one tooth was observed crack with a score of 1 in HCM group (P < 0.05). The number of risk sites in PTU group was 49 (13.16%), which was significantly more than the 28 (7.78%) in HCM group (P < 0.05) when canals were instrumented with file #30. ConclusionWithin the limitations of this study, when the canals of mandibular incisors were instrumented with size #30 and #40 files, OCT scans showed less root defects in HCM group.

En-face optical coherence tomography analysis of gold and silver nanoparticles in endodontic irrigating solutions: An in vitro study.

Optical coherence tomography (OCT) is a non-invasive, non-radioactive optical diagnostic method based on low-coherence interferometry, which achieves images with different orientation. In dentistry, its major advantage is represented by the localization and characterization of the smallest defects in hard dental tissues, dental materials and of the smallest details in dental anatomy (supplementary canals, recesses, isthmuses, or intra-radicular connections). The aim of the present in vitro study was to evaluate using c-scan en-face optical coherence tomography, the optical opacity, and the distribution inside the root canal lumen of several extracted human teeth of silver and gold nanoparticles from special irrigating solutions used in endodontic treatment. Twelve root canals from 5 human teeth were instrumented using the ProTaper Universal system after initial negotiation with hand K-files ISO no. 10 and rotary nickel-titanium PathFile instruments. An initial c-scan OCT analysis was performed for each sample to confirm that the root canal lumen was empty from radiopaque materials (Group 1). Teeth were first irrigated with NanoCare Plus (Group 2) and then with NanoCare Gold (Group 3) and C-scans were repeated after each irrigation method. The OCT investigation started at the tooth apex, at a depth of 1 mm from its tip. Subsequently, 100 slices of 10 microns were obtained from each root canal. Images were captured and then analyzed with ImageJ software to calculate the level of grey inside the root canal lumen. The highest values of grey were obtained in the samples irrigated with NanoCare Gold after NanoCare Plus (Group 3). The present study proved that both nanoparticles inserted in root canal irrigants were evidenced through OCT imagistic analysis due to their optical opacity, which allowed their highlighting in an empty root canal lumen, after the endodontic treatment was performed and the root canal was cleaned and shaped using specific protocols.

Microscopic Assessment of Dentinal Defects Induced by ProTaper Universal, ProTaper Gold, and Hyflex Electric Discharge Machining Rotary File Systems - An in vitro Study.

Background:Biomechanical preparation of root canal can damage root dentin leading to the formation of dentinal cracks which can eventually lead to fracture and failure of the treatment.Aim:The aim was to investigate the incidence of dentinal defects in root canals prepared with ProTaper Universal, ProTaper Gold, and Hyflex electric discharge machining (EDM) rotary file systems using handheld USB digital microscope.Materials and Methods:One hundred and fifty extracted mandibular premolar teeth with single canal were randomly divided into five groups (n = 30). Group 1: unprepared (negative control). Group 2: canal preparation done with nickel–titanium hand files (positive control), Group 3: canals prepared with ProTaper Universal rotary system, Group 4: canal preparation done with ProTaper Gold rotary system, and Group 5: canals prepared with Hyflex EDM rotary system. The specimens were sliced at 3 mm, 6 mm, and 9 mm from the apex with a slow-speed saw under water cooling. Digital images of each section were captured at ×40 magnification with the aid of a microscope. Two independent evaluators assessed the images for the presence of dentinal defects. The number of dentinal defects was recorded and Chi-square test was used for statistical analysis (P < 0.05).Results:The number of specimens presenting dentinal defects was as follows: Group 3; ProTaper Universal – 9/30 (30.0%), Group 4; ProTaper Gold – 2/30 (6.7%), and Group 5; Hyflex EDM – 1/30 (3.3%). No defects were detected in the negative and positive control groups (Group 1 and Group 2).Conclusion:ProTaper Universal showed the highest percentage of defects in comparison to ProTaper Gold and Hyflex EDM.

Obturation Quality of Chitosan-Modified Glass Ionomer Cement in Root Canals (In Vitro Study)

Background: Many materials are used for root canal obturation but all of them possess certain drawbacks. In the present study compared the obturation quality of Glass ionomer cement containing chitosan root canal filling material with other regularly used materials by using dye penetration. Material and Methods: Thirty-six human roots were chosen for this study. After de-coronation of the teeth and separation of the desired roots, they were instrumented by the Protaper Universal system from S1-F4 and then divided into three major groups: Group 1, filled with experimental material (glass ionomer cement/Chitosan); group 2, filled with gutta-percha with zinc oxide eugenol sealer; group 3, filled with gutta-percha with AH26. The evaluation was performed by radiographs post-obturation and by dye leakage test.Results: There was no significant difference between root canal obturation materials.Conclusions: The use of glass ionomer cement with chitosan root canal filling material improves the obturation quality of root canals.

Influence of adjunctive photodynamic therapy (curcumin) on the extrusion bond strength of radicular dentin to contemporary root canal sealers

ObjectiveThe aim was to compare Photodynamic therapy (PDT) as an adjunct to NaOCl and EDTA on the extrusion bond strength (EBS) of AH Plus (AH), Sealapex (SA) and MTA Fillapex (MF) root canal sealers. Materials and methodRoot canal treatment for human teeth (n = 60) using protaper universal system was performed followed by irrigation with NaOCl/ EDTA. Samples were divided (n = 30) based on disinfection technique, NaOCl/EDTA and NaOCl/EDTA with PDT (Curcumin-PS-CP) as an adjunct. Specimens were divided in three subgroups (n = 10) based on sealers used (Gp 1-Na-E-AH, Gp 2-Na-E-PDT-AH, Gp 3-Na-E-SA, Gp 4-Na-E-PDT-SA, Gp 5-Na-E-MF & Gp 6-Na-E-PDT-MF). Canals were dried and obturated followed by sectioning at coronal and middle third. EBS testing was performed using a universal testing machine (UTM) and modes of failure were assessed. Analysis of variance (ANOVA) and Tukey multiple comparison tests were used to compare the means of EBS. (p < 0.05). ResultsSealers showed a significant influence on EBS, as Gp 1 (Co: 9.21 ± 0.62, Mid: 8.54 ± 0.55) and Gp 2 (Co: 7.11 ± 0.68, Mid: 7.30 ± 0.37) showed higher EBS than Gp 3 (Co: 5.21 ± 0.63, Mid: 4.36 ± 0.83) and Gp 4 (Co: 5.39 ± 0.72, Mid: 4.46 ± 0.74). Gp 5 (Co: 9.04 ± 0.13, Mid: 8.14 ± 0.91) and Gp 6 (Co: 8.67 ± 0.42, Mid: 8.07 ± 0.07) exhibited higher EBS than Gp 3 and Gp 4 specimens. Adjunctive use of PDT for AH sealer (Gp 2) showed decreased EBS compared to Gp 1 specimens. EBS remained comparable for both MTA-Fillapex and Sealapex with and without PDT. ConclusionAH Plus (Gp 1 and 2) and MTA-Fillapex (Gp 5 and 6) sealers displayed better EBS compared to Sealapex (Group 3 and 4). Adjunctive Application of PDT (CP) did not show a significant improvement in bond strength of sealers to root dentin.

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The aim was to compare Photodynamic therapy (PDT) as an adjunct to NaOCl and EDTA on the extrusion bond strength (EBS) of AH Plus (AH), Sealapex (SA) and MTA Fillapex (MF) root canal sealers.Root canal treatment for human teeth (n = 60) using protaper universal system was performed followed by irrigation with NaOCl/ EDTA. Samples were divided (n = 30) based on disinfection technique, NaOCl/EDTA and NaOCl/EDTA with PDT (Curcumin-PS-CP) as an adjunct. Specimens were divided in three subgroups (n = 10) based on sealers used (Gp 1-Na-E-AH, Gp 2-Na-E-PDT-AH, Gp 3-Na-E-SA, Gp 4-Na-E-PDT-SA, Gp 5-Na-E-MF & Gp 6-Na-E-PDT-MF). Canals were dried and obturated followed by sectioning at coronal and middle third. EBS testing was performed using a universal testing machine (UTM) and modes of failure were assessed. Analysis of variance (ANOVA) and Tukey multiple comparison tests were used to compare the means of EBS. (p < 0.05).Sealers showed a significant influence on EBS, as Gp 1 (Co: 9.21 ± 0.62, Mid: 8.54 ± 0.55) and Gp 2 (Co: 7.11 ± 0.68, Mid: 7.30 ± 0.37) showed higher EBS than Gp 3 (Co: 5.21 ± 0.63, Mid: 4.36 ± 0.83) and Gp 4 (Co: 5.39 ± 0.72, Mid: 4.46 ± 0.74). Gp 5 (Co: 9.04 ± 0.13, Mid: 8.14 ± 0.91) and Gp 6 (Co: 8.67 ± 0.42, Mid: 8.07 ± 0.07) exhibited higher EBS than Gp 3 and Gp 4 specimens. Adjunctive use of PDT for AH sealer (Gp 2) showed decreased EBS compared to Gp 1 specimens. EBS remained comparable for both MTA-Fillapex and Sealapex with and without PDT.AH Plus (Gp 1 and 2) and MTA-Fillapex (Gp 5 and 6) sealers displayed better EBS compared to Sealapex (Group 3 and 4). Adjunctive Application of PDT (CP) did not show a significant improvement in bond strength of sealers to root dentin.

Comparative Evaluation of Dentinal Microcrack Formation before and after Root Canal Preparation Using Rotary, Reciprocating, and Adaptive Instruments at Different Working Lengths—A Micro–computed Tomographic Study

IntroductionThis study aimed to compare root dentinal microcrack formation after root canal shaping using rotary, reciprocating, and adaptive instruments at different working lengths using micro–computed tomographic imaging. MethodsOne hundred eighty extracted mature mandibular molar mesial roots with 2 separate canals were selected. The mesial roots were resected at the cementoenamel junction and randomly divided into 4 groups (n = 45) based on the nickel-titanium file system used: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Gold (Dentsply Maillefer), Twisted File Adaptive (SybronEndo, Orange, CA), and Reciproc Blue (VDW, Munich, Germany). Each of the 4 groups were then subdivided into 3 groups (n = 15) depending on the working length used for root canal preparation (ie, instrumentation 1 mm short, flush, and 1 mm beyond the major apical foramen). The roots were imaged with micro–computed tomographic scanning before and after root canal preparation. The cross-sectional images generated were screened to detect the presence of new microcracks. ResultsThe ProTaper Universal system significantly increased the number of postinstrumentation microcracks at all working lengths (P ≤ .05). No significant increase (P > .05) in postinstrumentation microcracks was observed in the ProTaper Gold, Twisted File Adaptive, or Reciproc Blue groups. ConclusionsRotary instrumentation induced a higher number of dentinal microcracks compared with reciprocating and adaptive instruments. Instrumentation at different working lengths did not significantly influence the formation of dentinal microcracks.