Aim: To compare and evaluate the root reinforcement potential of four different intraorifice barriers: Mineral trioxide aggregate (MTA), resin-modified glass ionomer cement (RMGIC), fiber-reinforced composite (FRC), and nanohybrid composite (NC). Materials and Methods: Seventy-five mandibular premolars were decoronated to a standardized length, and prepared and obturated with gutta-percha and AH Plus sealer. Except for control specimens, the coronal 3-mm gutta-percha was removed and filled with different materials. The specimens (75) were divided into five groups (n = 15) on the basis of the intraorifice barrier material used. Group 1: MTA, Group 2: RMGIC, Group 3: FRC, Group 4: NC, Group 5: no barrier (control). Fracture resistance of the specimens was tested. Results: Fracture resistance of roots was significantly affected by the type of intraorifice barrier used and the following pattern was observed: RMGIC > FRC > NC > MTA. Conclusion: Intraorifice barriers can be regarded as a viable choice to reduce the occurrence of postendodontic root fractures. Among the four tested materials, RMGIC showed the maximum reinforcement.

Aim: The purpose of this study was to investigate temperature-dependent rheological properties of three endodontic sealers MTA Fillapex (Angelus, Brazil), AH Plus (Dentsply, Germany), and EndoREZ (Ultradent, USA). Materials and Methods: Five samples of each group of endodontic sealers (n = 30) were freshly mixed and placed on the plate of a rheometer (MCR 301, AntonPaar, Physica) and examined at 25^° C and 37^° C temperature, respectively. Rheological properties of the sealers were calculated according to the loss modulus (G"), storage modulus (G'), loss factor (Tan δ), and complex viscosity (ç*) using dynamic oscillatory shear tests. Results: Statistical analysis (Wilcoxon signed-rank test) demonstrated that MTA Fillapex exhibited higher loss modulus (G" > G') and a crossover region. AH Plus and EndoREZ had a higher storage modulus (G' > G") at both temperatures. Loss factor (Tan δ) of MTA Fillapex was the highest compared to AH Plus, followed by EndoREZ. With a temperature change from 25°C to 37°C, MTA Fillapex exhibited a decrease while AH Plus exhibited an increase and, EndoREZ exhibited the least change, in complex viscosity (ç^* ). Conclusions: EndoREZ exhibited better rheological properties compared to the other two test sealers.

Objective: The aim of this study was to evaluate defects caused by torsional fatigue in used hand and rotary nickel-titanium (Ni-Ti) instruments by stereomicroscopic examination. Materials and Methods: One hundred five greater taper Ni-Ti instruments were used including Protaper universal hand (Dentsply Maillefer, Ballaigues, Switzerland), Protaper universal rotary (Dentsply Maillefer, Ballaigues, Switzerland), and Revo-S rotary (MicroMega, Besanηon, France) files. Files were used on lower anterior teeth. After every use, the files were observed with both naked eyes and stereomicroscope at 20Χ magnification (Olympus, Shinjuku, Tokyo, Japan) to evaluate defects caused by torsional fatigue. Scoring was assigned to each file according to the degree of damage. Statistics: The results were statistically analyzed using the Mann-Whitney U test and the Kruskal-Wallis test. Results: A greater number of defects were seen under the stereomicroscope than on examining with naked eyes. However, the difference in methods of evaluation was not statistically significant. Revo-S files showed minimum defects, while Protaper universal hand showed maximum defects. The intergroup comparison of defects showed that the bend in Protaper universal hand instruments was statistically significant. Conclusion: Visible defects in Ni-Ti files due to torsional fatigue were seen by naked eyes as well as by stereomicroscope. This study emphasizes that all the files should be observed before and after every instrument cycle to minimize the risk of separation.

Aim: This study evaluated whether using supplementary files for removing root canal filling residues after ProTaper Universal Retreatment files (RFs) increased the debris extrusion apically. Materials and Methods: Eighty mandibular premolars with single root and canal were instrumented with ProTaper Universal rotary system (SX-F3) and obturated. The samples were divided randomly into four groups (n = 20). Group 1 served as a control; only ProTaper Universal RFs D1-D3 were used, and the extruded debris was weighed. Groups 2, 3, and 4 were the experimental groups, receiving a twofold retreatment protocol: Removal of the bulk, followed by the use of supplementary files. The bulk was removed by RFs, followed by the use of ProTaper NEXT (PTN), WaveOne (WO), and Self-Adjusting File (SAF) for removal of the remaining root filling residues. Debris extruded apically were weighed and compared to the control group. Statistical analysis was performed using one-way analysis of variance (ANOVA) and post hoc Tukey's test. Results: All the three experimental groups presented significant difference (P < .01). The post hoc Tukey's test confirmed that Group 4 (SAF) exhibited significantly less (P < .01) debris extrusion between the three groups tested. Conclusion: SAF results in less extrusion of debris when used as supplementary file to remove root-filling residues, compared to WO and PTN.

Aim: To evaluate the shear bond strength of MTA with three different types of adhesive systems- self-adhering flowable composite, etch and rinse adhesive system and self etch adhesive system. Methodology: MTA specimens (n = 60) were prepared using cylindrical acrylic blocks, having a central cavity with 4 mm diameter and 2 mm depth. MTA was mixed and placed in the prepared cavity, and was covered with a moist cotton pellet and temporary filling material. The specimens were divided into 3 groups which were further divided into 2 sub-groups (45 Minutes and 24 hours). After the application of bonding agents composite resin was placed over the MTA surface. The specimens were tested for shear bond strength and readings were statically analyzed. Result: After 24 hrs the mean value of etch and rinse group was significantly higher than self etch and the self adhering composite groups. Among the 45 minutes groups there were no significant difference. Conclusion: In single visit after 45 minutes self adhering flowable can be used successfully as a final restorative material in place of conventional flowable composite without using any alternative adhesive system over MTA.

Aim: The objective of this study was to evaluate the effectiveness of 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and 2% peracetic acid (PAA) in disinfecting Resilon cones and to evaluate topographical changes microscopically under scanning electron microscope (SEM) after rapid chemical disinfection. Materials and Methods: Resilon cones were disinfected in an ultraviolet (UV) light chamber for 20 min and contaminated by immersing in a microbial suspension of Enterococcus faecalis for 30 min. The contaminated cones were then immersed in the 5.25% NaOCl, 2% CHX, and 2% PAA for 1 min, 5 min, and 10 min, separately. The cones were then incubated at 37΀C in thioglycollate broth for 7 days and examined for turbidity. The samples showing turbidity were subcultured on blood agar and incubated at 37΀C for 48 h. Gram staining was done to confirm that the cultured bacteria were E. faecalis. Surface changes of disinfected Resilon cones were evaluated under SEM. Statistical Analysis Used: The data were analyzed statistically using Kruskal-Wallis, analysis of variance (ANOVA), and Mann-Whitney U-test. Result: In eliminating E. faecalis, 5.25% NaOCl was most effective followed by 2% PAA and 2% CHX. Topographic examination of tested Resilon cones revealed some surface deposits after disinfection with 5.25% NaOCl and 2% CHX, whereas 2% PAA caused surface erosion. Conclusion: In disinfecting Resilon cones, 5.25% NaOCl is most effective followed by 2% PAA and 2% CHX.

Aim: Current ex vivo study compared fracture resistance of teeth instrumented using 5 endodontic files, filled with Gutta-percha and AH Plus. Materials and Methods: Sixty freshly extracted, single-rooted mandibular premolars were acquired and decoronated to obtain 15 mm segments. These samples were randomly divided into six groups (n = 10). Group 1 served as the control containing untreated samples (without instrumentation or filling). In Groups 2-6, samples were instrumented using rotary (Universal ProTaper and Revo-S), reciprocating (WaveOne and RECIPROC^; ), and self-adjusting file (SAF), respectively. Following instrumentation, the samples were filled by lateral compaction with Gutta-percha and AH Plus. A week later, after the sealer was completely set, a vertical load was applied to the specimen's canal in each group until fracture. The loads required for fracture were recorded, and statistical analysis was performed. Results: The mean fracture load differed significantly among the groups (P < 0.01; one-way ANOVA). Tukey's post-hoc tests revealed that the fracture resistance was similar in the control and SAF groups (P > 0.05) and was significantly higher than that of the 2 rotary and reciprocating groups (P < 0.01). Conclusion: The samples instrumented by the SAF exhibited a better fracture resistance.

Aim: The purpose of this study was to evaluate the sealing ability of mineral trioxide aggregate (MTA) and EndoSequence with chitosan and carboxymethyl chitosan (CMC) as retrograde smear layer removing agents using scanning electron microscopy (SEM). Materials and Methods: Forty human single rooted teeth were taken. Crowns were decoronated and canals were obturated. Apically roots were resected and retrograde cavities were done. Based on the type of retrograde material placed and the type of smear layer removal agent used for retrograde cavities, they were divided into four groups (N = 10): Group I chitosan with EndoSequence, group II chitosan with MTA, group III CMC with EndoSequence, and Group IV CMC with MTA. All the samples were longitudinally sectioned, and the SEM analysis was done for marginal adaptation. Statistical Analysis: Kruskal-Wallis and Mann-Witney analysis tests. Results: SEM images showed the presence of less gaps in group III, i.e., CMC with EndoSequence when compared to other groups with statistically significant difference. Conclusion: Within the limited scope of this study, it was concluded that EndoSequence as retrograde material showed better marginal sealing ability.

Aims: To access the role of ultrasound and color doppler in diagnosing periapical lesions of maxilla and mandible. Settings and Design: This study was conducted in the Department of Conservative Dentistry and Endodontics (Faculty of Dental Sciences), Department of Radiotherapy, and Department of Pathology. Materials and Methods: The study group comprised 30 patients with periapical lesions of endodontic origin in maxilla and mandible requiring endodontic surgery. After thorough clinical and radiographic examination patients were subjected to ultrasound and color doppler examination, where the lesions were assessed for their contents as to cystic or solid. Following which periapical surgery was done and the pathological tissue obtained was subjected to histopathological examination. The results of the ultrasound examination were correlated with histopathological features. The diagnostic validity of ultrasound was assessed by calculating the sensitivity, specificity, positive predictive value, and negative predictive value. Statistical Analysis Used: The statistical analysis was done using statistical package for social sciences (SPSS) version 15.0 statistical analysis software. The values were represented in number (%). Results: Within the limitations of the current study it can be stated that although ultrasound may not establish the definitive diagnosis, it can facilitate the differential diagnosis between cystic and solid granulomatous lesions. However, this technique may have a limited role in detecting periapical lesions present in the region with thick overlying cortical bone. Conclusion: Ultrasound can routinely be recommended as a complimentary method for the diagnosis of periapical lesions of endodontic origin. However, this technique may have a limited role in detecting periapical lesions present in the region with thick overlying cortical bone.

Context: Accidental root canal perforations are among the main complications of endodontic treatment. Aim: This study evaluated the influence of operating microscope (OM) in the marginal adaptation of mineral trioxide aggregate (MTA) (Angelus^® ) and glass ionomer (Vitremer) inserted into cervical perforations. Materials and Methods: Perforations were made in the cervical third of the buccal wall of the root canal in mandibular incisors. Next, the teeth were divided into four groups (N = 10): MG - MTA without OM; VG - Vitremer without OM; MOMG - MTA with OM; VOMG - Vitremer with OM. The perforations were sealed according to the group and the teeth were prepared for analysis by confocal laser scanning microscope. Images of perforation region (1,024Χ) were made and the gap presented by the materials was measured using the Image J program. LEXT OLS4100 three dimensional (3D) measuring laser microscope measured the volumetric misfit. Data of gap were analyzed by Kruskal-Wallis and Dunn's tests. Analysis of variance (ANOVA) and Tukey's tests compared the volumetric misfits. Results: The results showed lower volume and gap in the interface dentin/material in VOMG compared to the other groups (P < 0.05). Conclusion: The use of OM improved the quality of cervical perforations sealed with Vitremer, being indicated in clinical situations of iatrogenic cervical perforations.

Background: The entire effects of different bleaching regimens on the mechanical properties of composite resins have remained unknown. The purpose of this study was to evaluate the effects of different bleaching regimens on the flexural strength (FS) of hybrid composite resins. Materials and Methods: In this in vitro study, 80 bar-shaped specimens of hybrid composite resins were fabricated and randomly divided into four groups, 20 specimens in each group. First group (C) was considered as control. The other groups were treated by home bleaching (HB) agent, in-office bleaching (IB) agent, and the combination regimens (HIB), respectively. The FS was evaluated by three-point bending test by using a Universal Testing Machine. All data were analyzed by using Statistical Package for the Social Sciences (SPSS) software version 18, analysis of variance (ANOVA), and Turkey's post hoc statistical tests (α = 0.05). Results: The maximum mean value of FS was seen in HB group with significant differences to other groups (P < 0.05). Also, the minimum FS was observed in group HIB. Conclusion: Application of different bleaching regimens does not have any adverse effect on the FS of hybrid composite resins. However, the administration of HB regimens seemed to have lesser negative impact on the FS.

Objective: The effect of 10% ascorbic acid, 10% tannic acid, and 10% gallic acid on the dentinal tubular penetration of Resilon and Real Seal SE on sodium hypochlorite-treated root canal dentin was evaluated. Materials and Methods: Fifty human premolars were decoronated to attain 14-mm root length and divided into five groups of 10 teeth each. Biomechanical preparation was done with rotary instruments. Group I specimens were irrigated with saline and 17% ethylenediaminetetraacetic acid (EDTA). Specimens from groups II, III, IV, and V were irrigated with 5.25% sodium hypochlorite and 17% EDTA. Specimens from groups III, IV, and V underwent additional irrigation with antioxidants-10% ascorbic acid, 10% tannic acid, and 10% gallic acid, respectively. Following obturation with Resilon and Real Seal SE, scanning electron microscope (SEM) analysis was done to note the maximum dentinal tubular penetration at the cervical, middle, and apical thirds of each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA), Post hoc and Dunnett's test. Results: Maximum dentinal tubular penetration of Resilon and Real Seal SE was obtained following irrigation with 10% gallic acid. Conclusion: 10% gallic acid was superior among the antioxidant irrigants that enabled the increased dentinal tubular penetration of Resilon and Real Seal SE.

Aims: To compare and evaluate the bonding ability of resin composite (RC) to three different liners: TheraCal LC ^TM (TLC), a novel resin-modified (RM) calcium silicate cement, Biodentine ^TM (BD), and resin-modified glass ionomer cement (RMGIC) using an universal silane-containing adhesive and characterizing their failure modes. Materials and Methods: Thirty extracted intact human molars with occlusal cavity (6-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into three groups of 10 samples each based on the liner used as Group A (TLC), Group B (BD), and Group C (RMGIC). Composite post of 3 mm diameter and 3 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS) analysis was performed at a cross-head speed of 1 mm/min. Statistical Analysis Used: Statistical analysis was performed with one-way analysis of variance (ANOVA) and post hoc test using Statistical Package for the Social Sciences (SPSS) version 20. Results: No significant difference was observed between group A and group C (P = 0.573) while group B showed the least bond strength values with a highly significant difference (P = 0.000). The modes of failure were predominantly cohesive in Groups A and B (TLC and BD) while RMGIC showed mixed and adhesive failures. Conclusions: Hence, this present study concludes that the bond strength of composite resin to TLC and RMGIC was similar and significantly higher than that of BD following application of universal adhesive.

Aim: The aim of this study was to evaluate the surface roughness of three composites with three different polishing systems. Materials and Methods: Composite specimens were made from the Teflon mold with a standardized cavity size (6 mm diameter and 3 mm height). Group I - Filtek Z350XT (Nano clusters), group II - T-Econom plus (Microhybrid), group III - G-aenial Flo (True Nano). The samples were cured for 30 s from both sides with the matrices in place. The 60 samples were divided into 3 groups (N = 20), which accounted for 40 surfaces, (n = 20 Χ 2 = 40) in each groups. Each group were subdivided into four subgroups based on the type polishing material, subgroup A - Control, subgroup B - Astrobrush, subgroup C - Astropol, and subgroup D - Soflex spiral wheel. The samples of all groups except group A (control) were finished and polished according to the manufacture's instruction. Results: After polishing, the roughness (Ra) of the resin composite of all the specimens were measured using a profilometer. Soflex spiral wheel (group D) significantly had the least roughness (Ra) value as compared to the other groups. Conclusion: Among the three resin composites tested, G-aenial Flo exhibited least Ra value due to its reduced filler size and its uniform distribution.

Context: Incipient carious lesions are characterized by subsurface dissolution due to more fluoride ions in the 50-100 microns of the tooth's outer surface. Aims: To determine an optimal power setting for 810 nm aluminum gallium arsenide laser for caries inhibition. Materials and Methods: Fifty-four caries-free extracted teeth were sectioned mesiodistally. The samples were divided into 18 groups for each power setting being evaluated. Each group had six samples. The laser used is 810 nm aluminum gallium arsenide laser with power setting from 0.1 watts to 5 watts. Laser fluorescence based device was used to evaluate the effect of irradiation. Statistical Analysis Used: Paired "t" test, one-way analysis of variance (ANOVA), Tukey's post hoc test, and the Pearson's correlation test. Results: The paired t-test showed that there is minimum divergence from the control for 3.5 watts. Tukey's post hoc test also showed statistically significantly results for 3.5 watts. The Pearson's correlation test showed that there was negative correlation between the watts and irradiation. Conclusions: The power setting that gave statistically significant results was 3.5 watts.

Aim: The purpose of this study was to evaluate the effect of phytic acid, ethylenediaminetetraacetic acid (EDTA), and chitosan solutions on the microhardness of human radicular dentin. Materials and Methods: Thirty dentin specimens were randomly divided into three groups of 10 specimens each according to the irrigant used: G1 - 1% phytic acid, G2 - 17% EDTA, and G3 - 0.2% chitosan. A standardized volume of each chelating solution was used for 3 min. Dentin microhardness was measured before and after application at the cervical, middle, and apical levels with a Vickers indenter under a 200-g load and a 10-s dwell time. The results were analyzed using one-way analysis of variance (ANOVA) and Student's t test. Results: Microhardness of the radicular dentin varied at the cervical, middle, and apical levels. EDTA had the greatest overall effect, causing a sharp percentage reduction in dentin microhardness with a significant difference from phytic acid and chitosan (P = 0.002). However, phytic acid and chitosan differed insignificantly from each other (P = 0.887). Conclusion: All tested chelating solutions reduced microhardness of the radicular dentin layer at all the levels. However, reduction was least at the apical level. EDTA caused more reduction in dentin microhardness than chitosan while phytic acid reduced the least.

Aim: The aim of this study was to compare the efficacy of hand file, nickel titanium rotary instrument, and two reciprocating instruments for removing gutta-percha and sealer from the root canals. Materials and Methods: Eighty-eight mandibular premolar teeth were used. The root canals were shaped and filled with gutta-percha and a resin-based sealer. The specimens were divided into four groups according to the technique by which the root filling material was removed: Group 1 - Wave One; Group 2 - Reciproc; Group 3 - ProTaper; and Group 4 - Gates-Glidden burs and stainless steel hand file. Then teeth were split longitudinally and photographed. The images were transferred to a computer. The ratio of remaining filling material to the root canal periphery was calculated with the aid of ImageJ software. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney tests. Results: A significant difference was found among all groups (P < 0.001). The WaveOne group demonstrated significantly less remaining filling material. The greatest amount of filling material was found in specimens where gutta-percha was removed with Gates-Glidden burs and stainless steel hand file. Conclusion: The reciprocating files were found to be significantly more effective in removing the filling material from the canal walls compared to the rotational file and hand file.

Aim: The aim of this clinical study was to assess the influence of irrigation needle gauge on endodontic irrigation flow rates. Settings and Design: In vivo assessment. Materials and Methods: Five specialist endodontists performed intracanal irrigation procedures on 50 mesiobuccal canal of mandibular first molars using three different irrigation needle gauges. Data of time taken for irrigation was recorded by an irrigation testing system and analyzed using independent sample "T" test and one-way analysis of variance (ANOVA) test. The level of significance was set at P < 0.05. Statistical Analysis Used: The following tests were used for the statistical analysis: Independent sample "T" test, one-way ANOVA test, and post hoc multiple comparison was carried out using Tukey's honest significant difference (HSD) test using Statistical Package for the Social Sciences (SPSS) version 16 for Windows. Results: The average flow rate of 26 gauge was 0.27 mLs⁻¹ , of 27 gauge was 0.19 mLs⁻¹ , and of 30 gauge was 0.09 mls⁻¹ . There was statistical significance among the gauges (P < 0.001). 26 gauge had highest flow rate when compared with other groups followed by 27 gauge and 30 gauge respectively. The operator variability for flow rate of three endodontic irrigation needle gauges (26 gauge, 27 gauge, and 30 gauge) was found to be not significant. Conclusions: Needle gauge has significant influence on endodontic irrigation flow rate.

The use of Projector Endodontic Instrument Guidance System (PEIGS) during endodontic treatment of grossly mutilated tooth facilitates projection of canal orifices from the floor of the pulp chamber to the cavosurface, providing direct visualization and access to the projected canals. Alternatives, such as hypodermic needles as sleeves, were tried successfully with similar outcome. The aim of this case report is to describe a simpler, easily available, economical, yet an effective alternative technique to conventional PEIGS during the pre-endodontic management of grossly destructed tooth. These case reports demonstrate the use of greater tapered gutta-percha points that are easily available and more economical than PEIGS for the successful management of a badly destructed tooth.