Coronal Thirds Research Articles

Mandibular second molars' C-shaped canal frequency in the Pakistani subpopulation: A retrospective cone-beam computed tomography clinical study

Introduction: The adequate knowledge of the canal configuration can improve the quality and prognosis of endodontic treatment. The aim of the study was to determine the frequency of C-shaped root canal in the mandibular permanent second molars among a Pakistani subpopulation sample by utilizing cone-beam computed tomography images. Materials and Methods: Cone-beam computed tomographic images of 360 patients with 720 mandibular second molars were analyzed for the presence of C-shaped canal configuration. The root canal system was classified according to Fan's classification at three distinct levels. Unilateral or bilateral presence of C-shaped root canals and the location of the longitudinal groove were assessed. Moreover, the correlation of frequency of C-shaped canal with the gender was measured using the Chi-square test. The data were analyzed using SPSS version 23. Results: Of 720 mandibular second molars of 360 patients, 10% of teeth were found to have C-shaped canals in 48 patients. The most commonly noted C-shaped canal configurations in the coronal and middle third were C1 (41.7%) and C3 (37.5%), respectively, whereas C2 (33.3%) and C4 (33.3%) configurations were commonly found in the apical third. Twenty-four of 48 patients had bilateral C-shaped root canals. Overall, 37.5% of the teeth were right-sided teeth and 62.5% were left-sided teeth. The frequency of C-shaped canals was significantly higher in females as compared to males, 15.6% and 4.2%, respectively (P = 0.03). The longitudinal groove was most commonly located on the lingual surface (66.7%). Conclusions: The frequency of C-shaped canal configuration in the Pakistani subpopulation was 10% in the mandibular second molar teeth.

The mussel-inspired polydopamine surface treatment influences bond strength of glass fiber posts to radicular dentin

The aim of this study was to compare the efficacy of silane and a novel bioinspired polydopamine functionalization on the adhesion strength of glass fiber posts cemented to root dentin. Sixty-four surface treated posts [polydopamine (group 1 = 32) or silane (group 2 = 32)] were cemented in root canals of 64 extracted and decoronated mandibular premolars by using 3 commercial brands of self-adhesive resin cements (subgroups A, B and C) or a total-etch resin cement (subgroup D). The samples were subjected to push-out bond strength testing at 24 h and at 6 months after storage in water. Each sample was subdivided into six slices (three slices of the coronal and three slices of the apical) to determine the push-out bond strength in the coronal and apical third. The mean bonding strength value of the 3 slices both for the coronal and apical third was calculated as megapascals (MPa) and the data were statistically analyzed using post hoc Tukey HSD and Student t tests using four-way ANOVA (P = 0.05). Failure modes were investigated using scanning electron microscopy (SEM). The number of adhesive failures at the dentin-cement interface dropped when polydopamine was used (12–33%). Failure between the post and cement interface also dropped (4–13%) in all the resin cement groups, except the Subgroup C (17%). Polydopamine treatment significantly increased the adhesion strength for all cements compared to silanization at 24 h (P < 0.05), however at 6 months, only for the self-adhesive cements (P < 0.05). Polydopamine surface treatment improves the short-term bond strength of fiber-posts cemented to root canal dentin. The positive effect of polydopamine on long-term bond strength did not appear to be significant for the total-etch resin cement.

Shaping and Centering Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Three Thermally Treated NiTi Endodontic Instrument Systems.

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel–titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. µCT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 °C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey’s test was used for statistical analysis of the data; the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p > 0.05), but demonstrated significantly different resistance to cyclic fatigue (p < 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

Influence of Propolis, Ozone and Photodynamic therapy in root canal disinfection on resin bond strength to radicular dentin.

The aim of the present study was to assess post space disinfection using different irrigants and their effect on radicular dentin bond to SERC. Forty single rooted mandibular 2nd premolars were collected and disinfected. All samples were decoronated maintaining root length of 12 mm and embedded vertically in acrylic resin. Shaping of the canal was performed using reciprocating system. Canals were dried using paper points and obturated with gutta percha via lateral condensation. Peso-reamers were used to create post space up to 10 mm. The post space was irrigated with 1% NaOCl before being randomly allocated into four groups (n = 10) according to different methods of canal disinfection. Samples in group 1 were subjected to photoactivated disinfection (PAD), group 2 irrigated with ethanol based propolis group 3 disinfected using ozone and group 4 irrigated with 2.25 % NaOCl with 17 % EDTA and ECL. GFP was fitted using SERC. Each sample was cut into 1 mm from coronal, middle and apical and subjected to pushout bond strength (PBS) via universal testing machine. Fracture analysis were confirmed by stereomicroscope at 40x magnification. For comparison of means, Analysis of variance (ANOVA) and Tukey multiple comparison test was used maintaining the level of significance at p < 0.05. The highest PBS at all three levels were found in group 4, canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL. Whereas, the lowest PBS was observed in group 1. Inter group comparison, prosthetic space disinfected with propolis extract showed no significant difference to group 4 canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL at all three levels (p > 0.05). Intra group comparison in all experimental groups showed no significant difference was noted in coronal and middle thirds of group 1, group 2 and group 3 respectively (p > 0.05). 2.5 % NaOCl with EDTA and ECL treatment (group 4) remains the gold standard when used as a final canal irrigant. Propolis can be used as potential irrigant for canal disinfectant provided if the composition becomes standardized.

Comparison of Cone Beam Computed Tomography and Digital Radiography in Detecting Separated Endodontic Files and Strip Perforation

The separation of endodontic files and strip perforation are among procedural intraoperative complications which may ultimately lead to the failure of root canal treatment. The aim of the present study was to compare the diagnostic potential of cone beam computed tomography (CBCT) and digital periapical radiographs in detecting separated rotary files and strip perforation in filled canals. Fifty human mandibular molars were selected for this study. The teeth were randomly divided into two groups based on endodontic errors (i.e., file separation and strip perforation). In each group, 25 of 50 mesial canals were randomly chosen for simulating the errors, while the other 25 canals were considered as the control group. In group one, a simulation of the separation of rotary files was performed using ProTaper F2 files. Strip perforation of the root canals in group two was achieved by number 2 and 3 Gates Glidden drills in the coronal third of the root canals. Digital periapical radiographs in two different horizontal angles and high-resolution CBCT scans were obtained from the teeth mounted on a dry human mandible with simulated soft tissue covering. Three experienced observers who were unaware of the study groups evaluated the digital periapical and CBCT image sets in two separate readings. Intraobserver and interobserver agreements, as well as accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated and compared. Intraobserver and interobserver agreements ranged from poor to excellent and poor to good, respectively. The accuracy, sensitivity, specificity, PPV, and NPV for digital radiography in detecting separated files were 0.950, 0.813, 0.957, 0.929, and 0.880, respectively. The same values for CBCT were 0.747, 0.667, 0.900, 0.833, and 0.783, respectively. For the diagnosis of strip perforation, these values were 0.855, 0.800, 0.909, 0.889, and 0.833 for periapical radiography and 0.955, 1.000, 0.920, 0.926, and 1.000 for CBCT. In conclusion, CBCT was superior for diagnosing strip perforation of the filled root canals, while digital periapical radiographs performed better in the detection of separated rotary files.

Effects of a Novel NiTi Thermomechanical Treatment on the Geometric Features of the Prepared Root Canal System.

Objectives: This study aimed to compare the ex vivo performance of two rotary nickel–titanium (NiTi) systems with similar designs but manufactured from martensitic and austenitic alloys, the One Curve (OC) and One Shape (OS) rotary endodontic files, respectively. Methods: Forty separate mesial canals of 20 extracted mandibular molars were scanned using micro-computed tomography (CT), which were divided into 2 groups and instrumented with OC and OS, respectively. Post-instrumentation micro-CT scans were evaluated using validated computer algorithms to compare changes in canal thickness, surface area, structure model index (SMI) scores, volume of removed dentin, percentage of untreated canal surface, percentage of curvature straightening, and the amount of canal transportation. Results: Both files led to significant changes in the basic root canal geometry, with no preparation errors and no statistically significant differences. However, OC treatment resulted in significantly less curvature straightening (17.30%; 10.77%) (independent samples t test, p < 0.05) and less apical transportation (55.11 µm; 33.15 µm) (Mann–Whitney U, test p < 0.05) compared to OS treatment. Transportation values in the middle and coronal thirds were statistically similar (independent sample t-test, p > 0.05). OC treatment produced significantly less straightening and less apical transportation than OS.

Evaluation of resin sealer penetration of dentin following different final rinses for endodontic irrigation using confocal laser scanning microscopy.

The aim of the study was to assess the depth of sealer penetration into dentinal tubules following different final rinses and indirectly evaluate precipitation of irrigating solutions. Methods: 52 extracted maxillary incisors were prepared to size 40/04 with 6% sodium hypochlorite irrigating solution. Following power analysis, teeth were randomly divided into 4 groups (n=13) according to final rinse. Group 1 - 17% EDTA, Saline and 2% Chlorhexidine solution; Group 2 - SmearOFF™; Group 3 - Qmix® ; and Group 4 - saline control. Obturation was performed with gutta percha and resin sealer mixed with rhodamine-B-isothiocyanate dye using warm vertical compaction. Teeth were sectioned into apical, middle, and coronal thirds using Buehler diamond saw at 3, 6 and 9mm from the apex. Sections were examined under confocal laser scanning microscopy, and images were exported to Image J software to measure the maximum depth of sealer penetration circumferentially. Data were analysed using a generalised linear model and post hoc multiple comparisons with significance set at P<0.05. Group 3 had the highest depth of penetration. There were statistically significant differences between Groups 2 and 3 and control for all sections, Group 1 and control in apical section only. Conclusion: Recently developed final rinses produced higher sealer penetration and more patent dentinal tubules than using EDTA and chlorhexidine sequentially.

In Vitro Evaluation of Different Irrigation Protocols on Intracanal Smear Layer Removal in Teeth with or without Pre-Endodontic Proximal Wall Restoration.

To investigate the influence of pre-endodontic coronal wall restoration on smear layer removal during different root canal irrigation strategies, single-root premolars were prepared with a mesio-occlusal cavity. Half were left untreated (G1), while the mesial walls of the remaining half were reconstructed using a resin composite (G2). The specimens were divided into control (ctrl) groups, which used the conventional needle irrigation method, and four experimental subgroups according to irrigation strategy: Sonic activation using the Endoactivator, sonic activation using the EQ-S, mechanical activation using the XP-Endo finisher, and ultrasonic activation using the EndoUltra. Smear layer removal was assessed through SEM and the results were statistically analyzed. At the coronal and middle thirds, no significant difference (p > 0.05) was detected for G1 and G2, except for the control subgroups (G1ctrl vs G2 ctrl) at the middle third. At the apical third, the smear layer removal was significantly greater for G2 than G1. In G1, both at the middle and apical level, EQ-S and EndoUltra showed greater smear layer removal (p < 0.05) compared to the others G1 subgroups. In G2, at the apical level, the EQ-S and EndoUltra were the most effective in smear layer removal. Pre-endodontic coronal wall restoration may improve the smear layer removal during root canal irrigation.

Comparative Analysis of the Smear Layer Removal Capability between EndoVac and Endoactivator Endodontic Irrigation Systems at the Root Canal System and Isthmus: A Micro-Computed Tomography Analysis

The aim of this comparative study is to analyze the efficacy of EndoVac and Endoactivator endodontic irrigation systems for removing the endodontic smear layer present in the coronal, middle, and apical root third of the root canal system (RCS) and the isthmus from mesial roots from the first lower molar teeth using micro-computed tomography (micro-CT) analysis. The study was performed on 40 mesial roots that were randomly assigned to the following groups: Group A, EndoVac endodontic irrigation system (EV) (n = 10); Group B, Endoactivator endodontic irrigation system (EA) (n = 10); Group C, Root canal systems performed with F2 ProTaper Gold endodontic rotary system but not irrigated (Positive control) (n = 10); Group D, Root canal systems not performed or irrigated (Negative control) (n = 10). The samples were exposed to micro-CT analysis and the mesial roots were segmented using an advanced image segmentation technique based on partial differential equations (ROI: 10 × 10 × 10 mm) and the root canal systems and isthmus were reconstructed at a resolution of 25 microns per voxel. The EA study group showed statistically significant different residual endodontic smear layer volume (0.48 ± 0.24 mm3) compared to the EV study group (0.18 ± 0.15 mm3) (p = 0.016). The EV endodontic irrigation system performed a higher smear layer removal at coronal and middle root thirds, compared to the EA endodontic irrigation system; however, the EA endodontic irrigation system performed a higher smear layer removal at the apical root third, compared to the EV endodontic irrigation system.

Scanning electron microscopic analysis of interaction between 2% lidocaine hydrochloride (with adrenaline) with 3% sodium hypochlorite and 2% chlorhexidine on root canal dentin after Chemomechanical instrumentation: An in vitro study

Introduction: To investigate the effect of resultant precipitate formed on interaction between 2% lidocaine hydrochloride (with adrenaline) (LA) with 3% sodium hypochlorite (NaOCL) and 2% chlorhexidine (CHX) on root canal dentin after chemomechanical preparation using scanning electron microscopy (SEM). Methods: Thirty six mandibular premolars were decoronated, and the root length was standardized. All specimens were randomly distributed into the following three groups: Group I (control): 2% LA mixed with sterile water. Group II: 2% LA with 3% NaOCL, Group III: 2% LA with 3% CHX. In all groups mechanical instrumentation with rotary files was done. Teeth samples were sectioned into three parts, split and SEM analysis of root canal wall was done at cervical. Middle, and apical root thirds. Results: SEM images revealed patent dentinal tubules with no precipitate occlusion in group I and group III, whereas there was occlusion of dentinal tubules with a precipitate in group II at all the three root levels studied. Conclusions: The precipitate formed on the interaction between 2% LA solution with 3% NaOCL tends to occlude the dentinal tubules at the coronal, middle, and apical root thirds. The chemomechanical rotary instrumentation procedure did not effectively remove the precipitate from all the three root levels of the specimens studied. LA/sterile water group and LA/CHX group did not result in any precipitate formation on root canal dentin.

Push-out Bond Strength of Two Types of Dental Post Luted with Two Types of Cement at Two Different Root Levels.

ObjectiveEndodontically treated teeth may require posts for retaining the core and replacing the coronal structures that have been lost. The objective of this study was to evaluate and compare the push-out bond strength between different types of post cemented with different types of luting cement at different types of root level.Materials and MethodsIn this in-vitro study, a total of 48 single-rooted permanent human teeth were decoronated, and the roots were treated endodontically. Following post space preparation, the sample was divided into four groups (n= 12 each) based on the types of post and cement. Two different types of post [GC everStick®POST (ES) and Parapost® Fiber LuxTM (PF)], and two different types of cement [G-CEMTM (G), and RelyXTM Unicem (R)] were used according to the manufacturer’s instructions. All roots were sectioned at the coronal and middle thirds with a thickness of 3±0.1mm. The Push-out bond strength (PBS) test was performed using a universal testing machine at a cross-head speed of 0.5mm/ min. The bond strength values were recorded, and the data were analyzed using the SPSS program. Apart from descriptive statistics, three-way ANOVA was used for the interaction of the independent variables (post, cement, and root level). For differences between the groups, the Mann-Whitney U test was used. A P-value of less than 0.05 was considered significant for all analyses.ResultsPush-out bond strength of samples at the middle level (11.38±10.31 MPa), with PF posts (11.18±9.98 MPa), and of those luted with RelyXTM Unicem cement (13.26±8.73 MPa) was higher than that of their counterparts. The PBS means of RelyXTM Unicem cement at both root levels were much higher than PBS means of G-CEMTM cement. Three-way ANOVA test revealed a significant effect for each variable with a higher effect of cement (Sum of Squares= 1310.690; P< 0.001). No significant difference (P= 0.153) was found between the coronal and middle parts and between ES and PF posts (P= 0.058). However, a highly significant difference (P< 0.001) was found between RelyXTM Unicem and G-CEMTM cements.ConclusionThe type of cement had a significant effect on push-out bond strength with RelyXTM Unicem which had higher values than G-CEMTM. However, the type of post and root level had no significant effect on PBS, although Parapost® Fiber LuxTM and middle root level had higher values than their counterparts.

Evaluation of Recombinant Human Platelet-Derived Growth Factor or Enamel Matrix Derivative Plus Calcium Hydroxide for Pulp Capping: A Randomized Controlled Human Clinical Trial.

This in vivo study assessed calcium hydroxide's effect as a matrix carrier for recombinant human platelet-derived growth factor (rhPDGF) and enamel matrix protein (EMD) on pulp tissue healing following pulp capping. Intact premolar sites (n = 18) were included. Coronal access and pulpotomy were performed, and each tooth was exposed to the oral cavity for 1 hour before pulp capping was performed. Teeth were randomly assigned to one of the following pulp-capping groups (n = 6 each): Group 1 (CaOH2 only); Group 2 (CaOH2+EMD); and Group 3 (CaOH2+rhPDGF). Coronal access cavities were then sealed. Immediate preoperative, postoperative, and 4-month follow-up radiographs were taken. At 4 months, teeth were extracted atraumatically and histomorphometric and micro-CT analyses were performed. Group 1 showed formation of thin, uneven, highly porous dentin-like structure with tunnel defects (average thickness: 0.18 to 0.19 mm). Lack of continuity of the newly formed tissue and interrupted communication tunnels were seen between the pulpal space and pulp-capping material. Group 2 showed formation of highly dense, nonporous, even-thickness dentin-like structure obliterating multiple areas of the pulp space (average thickness: 0.9 to 0.94 mm). Abundant odontoblast lacunae were present in the pulp and structure. Group 3 showed formation of an inconsistent, uneven dentin-like structure that appeared highly porous (average thickness: 1.04 to 1.05 mm). It was without tunneling, and abundant odontoblastic lacunae were present. No statistically significant differences were found between Groups 2 and 3, but both were richer in newly formed dentin-like structure with more thickness than Group 1 (P < .05). Addition of EMD to CaOH2 can result in multiple root canal calcifications, mostly in the coronal and apical thirds of the canals. The calcified tissue does not appear to resemble secondary dentin in form, shape, amount, or density. Addition of rhPDGF to CaOH2 may not cause root canal calcifications. The newly formed structure differs from secondary dentin in degree of mineralization, porosity, and density.

Influence of different posts’s composition and shape on bond strength to radicular dentin

Aim The goal of this in vitro study was to evaluate the bond strength to radicular dentin of a new post in combination with two different luting resin materials and comparing it with a well known translucent post available on the market. Materials and methods A pilot study was conducted on 30 single-rooted extracted teeth, in order to study the link between the dentine-cement interface on the one hand and the post-cement interface on the other hand. Push out bond strength test was perfomed on two types of cement: Kuraray Panavia (Japan) and Gradia Core (GC Tokyo Japan) in combination with two types of fiber posts: Edelweiss post (Edelweiss Dentistry Products GmbH, Wolfurt, Austria) and GC Fiber Post (GC Gradia Core Tokyo Japan). Results According to the results of this study, the GC Post / Gradia Core group recorded push-out forces significantly higher than those of the groups in which the new post was used (p <0.05). Conclusion Within the limits of this in vitro study, it can be concluded that the highest values of adhesive strength in the push-out test were achieved by GC post/Gradia Core GC. Regarding the area of root that can produce the best push out bond strength, it clearly resulted that the coronal third of the root was the best substrate to lute posts.

The Effect of Earlier Bone Grafting, Prior to Orthodontic Treatment, on SWAG Ratings of Graft Outcomes.

To compare the outcomes between 2 groups of patients with complete clefts treated with early secondary alveolar bone grafting (ABG) at 2 centers (5-7 years, before orthodontic intervention) and to a third group of patients treated at one of those centers (center 1) who had received later secondary ABG (8-10 years, after orthodontic intervention). Blind retrospective analysis of cleft site radiographs using Americleft Standardized Way to Assess Grafts (SWAG) scale. A total of 99 patients with complete clefts from 2 North American cleft/craniofacial centers. Secondary ABG representing 2 protocols: early grafting at a mean age of 6.6 years prior to any orthodontic intervention, and later grafting at a mean age of 10.2 years following pregrafting orthodontic intervention. Using occlusal radiographs, the SWAG scale from 0 (failed graft) to 6 (ideal) was used. Six trained, calibrated raters scored each radiograph twice, with the average of the 2 ratings used as the final score. Reliability was assessed using the weighted κ statistic. The significance of differences between groups was determined using the Kruskal-Wallis test and Dunn test for pairwise comparisons. Inter-rater reliability of SWAG method was good (0.631). Intra-rater reliability was excellent (0.817). There was a tendency for improved total graft outcome in the early grafted group from center 1 compared to the later grafted group with improvement being significantly different in only the coronal third of the early, preorthodontic grafted group. However, the difference was not statistically significant for the graft overall.

An In Vitro Evaluation Study of the Geometric Changes of Root Canal Preparation and the Quality of Endodontic Treatment.

Introduction The geometry of root canals differs in different parts, especially in the apical region, and it is affected by different preparation techniques. The aim of this study was to evaluate the geometric changes of root canal preparation by general dentists regardless of the endodontic instrumentation systems and to study the quality of endodontic treatment by evaluating the untouched areas after mechanical preparation and the smear layer removal. Materials and Methods 100 extracted maxillary canines were collected for the in vitro study from 10 dentists, and the dentists were asked to treat the teeth endodontically. The teeth then were separated and examined under an optical microscope to evaluate the root canal final diameter and the untouched areas. Then, the teeth were examined under a scanned electronic microscope to evaluate the smear layer in coronal, middle, and third parts of the canal. Statistical significance was set as P < 0.05. Results The mean diameter of the root canal after instrumentation in the coronal and middle thirds was 2.50 ± 1.12 and 1.75 ± 1.24 mm, respectively, and the untouched area percentage observed in the apical thirds was 71%. For smear layer removal, it was better in the coronal and middle thirds than in the apical (P < 0.05). Conclusion The changes in the diameter of the root canal, the percentage of untouched areas after mechanical preparation, and the percentage of smear layer were observed in a higher percent in the apical third than in the coronal and middle thirds, and this raises the question of changing the technique of processing the root canal, especially in the apical third.

Debris and Smear Layer Removal from Oval Root Canals Comparing XP-Endo Finisher, EndoActivator, and Manual Irrigation: A SEM Evaluation.

Objective This study aimed to assess and compare XP-Endo Finisher (XP) cleaning efficiency with respect to the amount of remaining debris and smear layer versus Max-I-Probe needle (CI), EndoActivator device (EA), and combination of XP-Endo Finisher file with EndoActivator device (XP+EA) in oval root canals. Materials and Methods This in vitro study was performed on 36 extracted single root/canal mandibular premolars. Radiographic images were taken in buccolingual and mesiodistal projections to evaluate the shape of the root canal and determine whether it met exclusion criteria. All teeth were decoronated and prepared using Reciproc (R40). The samples were divided randomly into four groups: CI, EA, XP, and XP + EA. The root canals were irrigated with 5 mL of 17% EDTA and 2.5% NaOCl, respectively. Apart from the CI group, both solutions were activated by using the tested techniques for 1 minute. The teeth were split longitudinally, and the best visible identified sections of the roots were used as the representing samples for scanning electron microscope (SEM) evaluation. Each half was divided into the following three parts: 1 mm from the anatomic apex and a standardized photomicrograph with 500x and 1500x magnifications for debris and smear layer were obtained. A five-grade scoring system was utilized to quantify the results at the coronal, middle, and apical regions. Statistical analysis was performed by using the Kruskal–Wallis and Mann–Whitney U tests. Results Group differences in debris and smear layer scores were found statistically significant for all locations as well as for overall assessment, except for the coronal third. Intragroup comparison of debris and smear layer in CI, EA, and XP had the minimum score at the middle third, with no significant difference compared with the coronal and apical thirds. XP + EA had less debris and smear layer score at the coronal third, significantly different from apical third. CI and EA had less debris and smear layer compared with XP and XP + EA at all locations with a significant difference at the middle and apical third ( p < 0.05). Conclusion EA and CI showed less debris and smear layer than XP and XP + EA in the middle and apical third. The use of the XP in conjunction with the present irrigation protocol failed to have debris-free dentin surface in the apical portion of most of the root canals.

Influence of sodium hypochlorite/etidronic acid combination and SmearOFF on push-out bond strength of fiber posts to root dentin.

The aim was to evaluate the effects of different irrigation protocols on the bonding ability of fiber posts on root canal dentin through push-out test and the dentin tubule penetration of luting cement by confocal laser scanning microscope (CLSM). Forty-eight single-rooted premolars were divided into six groups (n=8) based on post space irrigation protocols: Saline 0.85%; Etidronate 18% (HEBP); EDTA 17%; NaOCl 5.25%+EDTA 17%; NaOCl 2.5%/HEBP 9% combination; SmearOFF. Two specimens per group were assessed with CLSM. The push-out test and the failure analysis were performed. Whilst EDTA had the highest bond strength at the coronal and middle thirds, it was not statistically significant compared to saline, HEBP, and NaOCl/HEBP at the middle third (p>0.05). Cement/dentin adhesive failures were predominant (41.9%) and the intratubular fluorescence intensity was significant among the groups (p<0.05). EDTA resulted in highest bond strength values and dentinal penetration.

Surgical restorative treatment of periodontal disease related to external cervical root resorption: A case report

The occurrence of external cervical root resorption (ECRR) is rare. Herein, we report a case of extensive ECRR in the coronal third of the distal root of a mandibular right molar with food impaction and periapical radiolucency. The distal root was perforated and damaged due to delayed treatment. The resorptive defect was debrided, and the defect was restored with conventionally setting restorative glass-ionomer cement. Postoperative follow-up revealed complete healing.

Quantitative analysis of SmearOFF and different irrigation activation techniques on removal of smear layer: A scanning electron microscope study.

The aim of this study was to evaluate the effectiveness of SmearOFF solution on smear layer removal by using different irrigation activation techniques. One hundred and twenty mandibular premolars were decoronated, and instrumented with Reciproc up to size 50. Then, the specimens were divided into 6 groups according to the final irrigation activation technique: Group 1: SmearOFF + Conventional syringe irrigation (CSI); Group 2: SmearOFF + Sonic activation (SA); Group 3: SmearOFF + Passive ultrasonic activation (PUA); Group 4:17% EDTA + CSI; Group 5:17% EDTA + SA, and Group 6:17% EDTA + PUA. Teeth were split longitudinally, and specimens were observed under scanning electron microscope. Images were taken from the coronal, middle, and apical thirds of the teeth with 1,000× magnification and analyzed using ImageJ program to calculate total open dentinal tubule areas. Three-way ANOVA test was applied to reveal any significant differences among solutions, activation techniques and root thirds. There was no statistically significant difference among the groups in terms of irrigation solutions (p > .05). There was a statistically significant difference between PUA and CSI groups (p < .05). However, no significant difference was observed between PUA and SA, or between SA and CSI (p > .05). All experimental procedures were most effective in the middle region of the root, followed by cervical and apical thirds (p < .05). PUA showed higher efficacy in smear layer removal compared with CSI. SmearOFF and 17% EDTA showed similar results. The best results in removing smear layer were obtained in the middle region of the root.

Comparison of cleaning effectiveness of single rotary file OneShape and reciprocating F2 Protaper with Protaper Universal sequence: A SEM analysis

AimThis in vitro study intend to compare the cleaning effectiveness of Protaper universal sequence with reciprocating F2 Protaper and single rotary file One shape. Materials and method30 extracted human 1st mandibular molars were chosen for the analysis. Three NiTi file systems were used for mechanical preparation, ProTaper full sequence in rotary motion, single F2 Protaper file used in reciprocating motion, and One shape single file used in a circular motion. Irrigation was carried out after each instrument use using 5 ml of 5% NaOCl followed by normal saline. The root canal surface was evaluated at three different areas (coronal, middle and apical thirds) using Scanning Electron Microscopy. Debris and the Smear layer were evaluated. Data were analyzed statistically using the Friedman test and Kruskal–Wallis test (p ≤ 0.05). ResultsA statistically significant difference (p ≤ 0.05) was observed in the debris score of the Protaper universal group when the 3 thirds of the root were compared. Intergroup comparisons confirmed a statistically significant difference at the coronal and apical third of the roots when debris scores were evaluated. Intragroup comparison for the smear layer demonstrated a statistically significant difference (p ≤ 0.05) at all the 3 levels of the radicular canal for the 3 groups studied. Intergroup comparisons revealed a statistically significant difference (p ≤ 0.05) in the middle and apical 1/3rd when the smear layer was evaluated. ConclusionThe Protaper full sequence group provided better results than Single F2 ProTaper and One shape groups when debris and smear layer removal was investigated.