Variations in the Root Form and Root Canal Morphology of Permanent Mandibular canine.

BACKGROUND: Mandibular canines are recognized as usually having one root and one root canal in most cases. However, many investigators have reported the anatomical variations associated with mandibular canines. Thus; the objective of this study is to determine the number of roots and morphology of the root canal system of permanent mandibular canine in a Nepalese population. METHODS: Cone Beam Computerized Tomography images of 390 patients in a Nepalese population were selected, and a total of 780 mandibular canines were analyzed. The number of root and the canal configurations were investigated. Data were analyzed with descriptive analysis and Chi-square tests using the Statistical Package for the Social Sciences (SPSS) software version 20 (SPSS Inc, Chicago, IL, USA). RESULTS: Out of the 780 mandibular canines, 741(95%) were single-rooted canines while only 39 (5%) were double-rooted canines. The most common type of Vertucci in single-rooted canines was Type I (1-1) in the percentage of 85.6% and the least type was Type IV (1-2) in the percentage of (2.5%). The Chi-square tests showed no significant association between gender and number of roots (P = 0.87) and gender and root canal configuration in single-rooted canine (P = 0.52). CONCLUSIONS: All mandibular permanent canines were single rooted but 5.2% of the permanent mandibular canines had two roots.

Spectrophotometric analysis evaluating apical microleakage in retrograde filling using GIC, MTA and biodentine: an in-vitro study.

BACKGROUND: The present study compares the apical microleakage of three different root-end filling materials in which the retrograde cavity is prepared by two different burs. METHODS: Eighty extracted single rooted maxillary and mandibular premolars were taken. Root canal treatment was completed. Apical 3 mm of all the teeth were resected with diamond disk. The tooth were divided into four groups with two subgroups for each group containing 10 tooth (N = 10) as: Group IA (Negative Control and IB (Positive Control); Group IIA and IIB: Prepared with round carbide bur and round diamond bur respectively, filled with GIC; Group IIIA and IIIB: Prepared with round carbide bur and round diamond bur respectively, filled with MTA; Group IVA and IVB: Prepared with round carbide bur and round diamond bur, filled with Biodentine. After applying two coats of nail varnish leaving apical 3 mm (except for negative control group) all teeth were immersed in 2% methylene blue for 3 days and again in 65% nitric acid for next 3 days for extraction of dye. The obtained solution was then transferred to eppendorf tube and centrifuged in microcentrifuges at 14,000 revolution per minutes (RPM) for 5 min. Optical density or absorbance of the supernatant solution was measured with UV spectrophotometer at 550 nm. RESULTS: The absorbance of the supernatant solution after dye extraction is decreasing in the order of positive control> GIC > MTA > Biodentine> negative control group. The significant difference was observed between GIC and MTA (p = 0.0001) and GIC and Biodentine (p = 0.0001) with two different burs but statistically non-significant difference was observed between MTA and Biodentine with Carbide bur (p = 0.127) and Diamond bur (p = 0.496) respectively. CONCLUSIONS: Within the limitations of the present study, it can be concluded that Biodentine and MTA showed less microleakage as compared to GIC. There is no significant difference between mean microleakage of MTA and Biodentine. However, the mean OD of the Biodentine was least of all evaluated materials. Preparation of the root-end using round carbide bur as well as round diamond burs showed comparable microleakage for all three filling materials.

To comparatively evaluate the antimicrobial efficacy of chlorhexidine, nisin and linezolid as an intracanal medicament on Enterococcus faecalis: An in vitro study.

AIM: The present study evaluated the antimicrobial efficacy of Chlorhexidine, Nisin and Linezolid and a control group (Normal saline ) against Enterococcus faecalis (EF). METHODS: Human single rooted premolars with type I canal anatomy were instrumented with ProTaper using NaOCl as an irrigant. Supension of EF was inoculated into each root specimen and incubated. The medicaments were syringed into each root and incubated. After 24 hours, 8 samples per group (among the 4 groups) were retrieved. A hole was drilled on each root, and the dentinal shavings obtained were allowed to fall in brain-heart infusion (BHI) broth. Dilutions from the broth were plated and spread over blood agar. Colony-forming units (CFU) of EF was counted. The procedure was repeated after 72 hrs and 1 week. RESULTS: In group Nisin, the mean CFU was 10.6250 at 24 hrs, 6.6250 at 72 hrs and 6.2500 after 1 week respectively (statistically significant). In group Chlorhexidine, mean CFU was found to be the lowest of 10.5000 at 24 hrs, with further gradual increase to 13.7500 at 72 hrs and further increase to 15.8750 by 1 week. Similarly, in group linezolid , the mean CFU was found to decrease from 49.0000 at 24 hrs to 29.8750 at 72 hrs and then increase to 34.8750 in 1 week.

Evaluation and comparision of the shear bond strength of rebonded orthodontic brackets with air abrasion, flaming, and grinding techniques: an in vitro study.

AIM: To evaluate and compare in vitro the shear bond strength of rebonded orthodontic brackets among the three most frequently used rebonding methods--sandblasting, direct flaming, and grinding with a green stone bur. The surface characteristics of new and rebonded bracket bases were also compared using scanning electron microscopy (SEM). METHODS: The sample used in the present study comprised 60 extracted human premolars bonded with brackets. The sample was divided into three groups (each n = 20; sandblasting, direct flaming, and grinding with a green stone bur). SEM was used to compare the surface characteristics of the new and rebonded bracket bases for all three groups. RESULTS: The Z test for the direct flaming and grinding groups revealed statistically significant bond strength (P < .05). The ANOVA test for all three groups showed P < .05, which is statistically significant. SEM for the sandblasting method showed well-defined retentive areas. CONCLUSION: When rebonding brackets, sandblasting the bracket base yields the highest bond strength.