Location angle of second mesio-buccal canal in maxillary molars of an Indian population: an in vivo retrospective CBCT evaluation and proposal of a new classification.

Background: The current investigation was designed for predicting the location angle of second mesio-buccal root canal in permanent maxillary (first and second) molars with the aid of proposed measuring points and line using cone beam computed tomography in an Indian population. Methods: Three-hundred and twenty-four scans of permanent maxillary (first (n = 162) and second (n = 162)) molars with mesio-buccal 2 root canals and unassociated to the current evaluation were acquired. The maxillary molars were viewed with CSI imaging software. The images were captured and were further assessed using 3D Slicer. The assessment included of measuring the distance between the main mesio-buccal and mesio-buccal 2 canal and the angle at which the MB2 it is located utilizing proposed lines joining the disto-buccal and palatal canals. The data was tabulated for the incidence of various angles where the MB2 is located and MB-MB2 distance was determined. The angles denoted were either positive; I (0.1° to 1.9°), II (2° to 4°), III (>4°) or negative I (-0.1° to -1.9°), II (-2° to -4°), III (>-4°). On the data tabulated a new Banga Vhorkate and Pawar's (BVP's) angular classification for maxillary molars was proposed. Results: The existence of positive angle III was found in 41.35% of maxillary first molars (36 right and 31 left of 162), whereas positive angle II appeared in 41.98% of maxillary second molars (32 right and 36 left of 162). The MB1-MB2 in maxillary 1st molar is seen to be 3.12-3.31 mm and this distance in maxillary 2nd molar is 2.8-3.1 mm. The disto-buccal to palatal canal orifice mean distance was 5.06-5.22 mm in maxillary first molars and 4.9-5.8 mm in maxillary second molars. Conclusion: Accurate diagnosis of the location of second mesio-buccal canal increases the success rate of endodontic treatment and a better prognosis. The new proposed classification may be considerably helpful in the urge to locate the mesio-buccal 2 canal.

Relation between Apical Seal and Apical Preparation Diameter: An In Vitro Study.

BACKGROUND: The current recommendations for the apical preparation diameter, one of the most important mechanical imperatives in the apical third preparation, are to preserve the apical foramen in its original position along with its narrowest diameter to avoid any complication such as tearing, zipping, or transport of the foramen. The aim of our study was to see the correlation between apical seal and apical preparation diameter. MATERIALS AND METHODS: In total, 90 extracted maxillary incisors were randomly allocated into three groups of 30 teeth each according to the apical preparation size: Group 1: finishing file F1 corresponding to size 20 reached the working length, Group 2: prepared up to size 30 corresponding to finishing file F3, and Group 3: prepared up to size 50 corresponding to finishing file F5. After the filling of the root canals, the teeth were isolated and immersed in a dye solution, then cut longitudinally, photographed, and the dye penetration were calculated using a computer software. RESULTS: Comparison of the three different apical preparation sizes showed no statistically significant differences regarding the apical microleakage. CONCLUSION: The most important value of the dye penetration was observed in the group with the largest apical diameter.

Influences of Successive Exposure to Bleaching and Fluoride Preparations on the Surface Hardness and Roughness of the Aged Resin Composite Restoratives.

Background and Objectives: Surfaces of composite restorations are adversely affected upon bleaching and topical fluoride application. Such a procedure is normally carried out in the presence of restorations already serving in a different oral environment, although previous in vitro studies only considered the freshly-prepared composite specimens for assessment. The current study accordingly aimed to evaluate both the surface hardness and roughness of aged composite restoratives following their successive exposure to bleaching and topical fluoride preparations. Materials and Methods: Disc specimens were prepared from micro-hybrid, nano-filled, flowable and bulk-fill resin composites (groups 1-4, n = 60 each). All specimens were subjected to artificial aging before their intermittent exposure to surface treatment with: none (control), bleach or topical fluoride (subgroups 1-3, n = 20). All surface treatments were interrupted with two periods of 5000 thermal cycles. Specimens' surfaces were then tested for both surface hardness (Vickers hardness number (VHN), n = 10) and roughness (Ra, n = 10). The collected VHNs and Ras were statistically analyzed using two-way ANOVA and Tukey's comparisons at α = 0.05 to confirm the significance of differences between subgroups. Results: None of the tested composites showed differences in surface hardness and roughness between the bleached and the non-treated specimens (p > 0.05), but the bleached flowable composite specimens only were rougher than their control (p < 0.000126). In comparison to the control, fluoride treatment not only reduced the surface hardness of both micro-hybrid (p = 0.000129) and flowable (p = 0.0029) composites, but also increased the surface roughness of all tested composites (p < 0.05). Conclusion: Aged composite restoratives provide minimal surface alterations on successive bleaching and fluoride applications. Flowable resin composite is the most affected by such procedures. Although bleaching seems safe for other types of composites, the successive fluoride application could deteriorate the aged surfaces of the tested resin composites.

Evaluation of Antimicrobial Efficacy of Root Canal Sealers against Enterococcus faecalis: A Comparative Study.

AIM: The study aimed to evaluate the efficacy of root canal sealer's antimicrobial activity against Enterococcus faecalis. MATERIALS AND METHODS: Root canal sealers with the brands Endoflas FS, AH Plus, and Tubli-Seal EWT were selected. Enterococcus faecalis organisms' zone of inhibition was measured. Tukey post hoc tests and one-way analysis of variance (ANOVA) were used to compare the data among study groups and within its group. The data were said to be statistically significant with an established p-value less than 0.05. RESULTS: The maximum zone of inhibition (23.20 ± 1.202 mm) was shown by Endoflas FS sealer; AH Plus and Tubli-Seal showed the inhibition zone of (18.42 ± 1.023) and (16.88 ± 0.962) respectively, following Endoflas FS. The ANOVA test showed p < 0.0001, which is highly statistically significant. AH Plus and Endoflas FS showed a statistically significant difference of 0.04 and 0.001 in between groups, and there was no statistically significant difference in the Tubli-Seal group from Tukey post hoc test. CONCLUSION: The study showed that Endoflas FS sealer has a significant antimicrobial effect against E. faecalis. CLINICAL SIGNIFICANCE: In clinical situation, despite perfect che-momechanical root canal preparation, persistence of microorganisms may reinfect the root canal. Therefore, endodontic root canal sealers play a major role in the eradication of bacteria. The polymicrobial nature of endodontic infection plays a main role during the usage of endodontic sealer with antimicrobial agents, which in turn reduces the failure of endodontic treatment.

Retrieval of a metallic obstruction from the root canal of a premolar using Masserann technique.

A metallic obstruction in the root canal blocks canal cleaning and shaping procedures and requires either bypassing or retrieval. Many methods have been recommended to retrieve a metallic obstruction from the root canal. This article describes the retrieval of a metallic obstruction from the root canal of a premolar using Masserann technique to facilitate endodontic retreatment. Masserann technique is said to have limited application in posteriors. However, in this case, the obstruction was successfully retrieved by employing Masserann technique which consisted of using a trephan to cut the dentine and extractor tube to retrieve the obstruction. The retrieved obstruction was found to be a separated H-file. Endodontic retreatment was completed following the detection and negotiation of an extra canal in the same tooth.