An in vivo comparative evaluation to determine the accuracy of working length between radiographic and electronic apex locators.

Background: An in vivo comparative evaluation to determine the accuracy of working length between radiographic and electronic apex locators. Aim: The study was aimed at evaluating the accuracy of electronic apex locator, to determine the working length of root canal, and to compare it with the radiographic method of working length determination. Materials and Methods: A total of 20 teeth selected for the study had to go for extraction because of periodontal or orthodontic reasons. Access cavity was prepared and the clinical estimated working length (CEWL) was determined with 10-25 no. K-file. A radiograph was then taken for determining the radiographic estimated working length (REWL). For electronic measurement of root canal, a 10 no. K-file was advanced toward the apex until it reached a 0.5 mm short of apex as shown by the apex locator. After fixing the file with a light cured composite, the tooth was extracted, the tooth surface was then longitudinally grounded using straight fissure diamond bur until the root canal and the tip of the file were visible. The distance of file from the minor constriction was measured with help of stereomicroscope. Statistical analysis : The chi-square test was used for statistical analysis for this study. Results: The chi-square test where χ2 = 21.034 with P = 0.000 indicated that a significant difference exists among the groups. The electronic method showed highest number of cases with the working length at the minor constrictor. Conclusion: The electronic method for determining the working length of root canal was found to be more accurate than the radiographic method.

Effect of occlusal restoration on stresses around class V restoration interface: A finite-element study.

Background: Causes of failures in class V restorations have always been controversial until now, since the biomechanical aspects of these restorations have been understood. Aims and Objective: This study was aimed to verify the hypothesis that eccentric forces are the cause of cuspal flexure, which lead to excessive stresses at the periphery of a class V restoration, further it identifies the amount of the stress and the flexure increase in the presence of an occlusal restoration using different restorative materials to restore (both cervical and occlusal) along with their comparison with respect to amount of stresses around the cervical restorations. Materials and Methods : The study was done by modeling a mandibular first premolar which was sectioned bucco-lingually, in the NISA, EMRC II finite element software. A 100N eccentric load was applied on the tooth structure and stresses were observed at the peripheries of the class V restoration when it was restored with composite and with glass ionomer cement. The stresses were further analyzed in the presence of occlusal restorations with different materials and configurations. Results: It was seen that the stresses at the gingival wall interface in case of class V glass ionomer cement was more than that for composite. In the presence of an occlusal amalgam restoration, the cuspal flexure was more than that of occlusal composite and the stresses at the class V peripheries were also statistically significant. Conclusion: It was suggested that lower modulus composites can flex with the tooth structure decreasing the bond failure and that the stresses are much lesser when there is absence of an occlusal restoration. Occlusal composite restorations reinforce the tooth structure and reduce the cuspal flexure as compared to silver amalgam.

Effect of cavity varnish and intermediate restorative material on coronal microleakage in endodontically treated tooth.

Aim: Evaluation of microleakage in endodontically treated teeth that have been coronally sealed with eugenol and noneugenol containing zinc oxide cement, with and without the use of cavity varnish. Materials and Methods: The crowns of single rooted teeth were removed at the cementoenamel junction (CEJ) and the root canals were prepared and obturated with gutta-percha points and zinc oxide eugenol (ZOE) sealer using lateral condensation technique. The samples were randomly divided into four groups-group 1, coronal seal was obtained with ZOE cement; in group 2, three coats of cavity varnish followed with coronal seal of ZOE cement; in group 3, Litark a (noneugenol cement) was placed in the prepared cavity as in group 1; and in group 4, cavity varnish and Litark were placed instead of ZOE as in group 2. The specimens were immersed in 2% methylene blue dye and examined under traveling microscope for evidence of dye penetration of the material. Statistical Analysis: In this study, Kruskal-Wallis test, Mann-Whitney U, and Wilcoxon W tests were used. Results: Kruskal-Wallis test with P=0.000 indicated that a significant difference exists between the four groups. Mann-Whitney U test and Wilcoxon W test showed a significant difference at 0.05 levels as follows: group 1 with group 3 and 4, group 2 with group 3 and 4, and group 3 with group 4. There was no significant difference at 0.05 levels between group 1 and group 2. Conclusion: Group 4 showed significant less amount of dye penetration as compared with other groups.

An in vitro study of antibacterial effect of calcium hydroxide and chlorhexidine on Enterococcus faecalis.

Aim: To evaluate and compare the antibacterial effects of chlorhexidine and calcium hydroxide on Enterococcus faecalis. Materials and Methods: Root canal treatment involves a number of steps. In spite of all the steps done thoroughly, root canal treatment might fail due to the remnant microbes. Of all such bacteria, E. faecalis is found in failed root canals. The study tests the antibacterial activity of various intracanal medicaments. Agar diffusion test was used to evaluate the antibacterial effects of the following antibacterial agents: i. hexidine:0.2% chlorhexidine gluconate; ii. periogard:0.12% chlorhexidine gluconate; iii. calcium hydroxide powder plus sterile water; iv. metapaste plus sterile water; v. calcium hydroxide plus hexidine; vi. calcium hydroxide plus periogard; vii. metapaste plus hexidine; viii. metapaste plus periogard. The size of zones of inhibition was measured. Results: The average size of zones of inhibition after 72 hours were hexidine: 5 mm; periogard: 4.25 mm; calcium hydroxide plus sterile water: 0.5 mm; metapaste plus sterile water: 0.5 mm; calcium hydroxide plus hexidine: 4.7 mm; calcium hydroxide plus periogard: 4 mm; metapaste plus hexidine: 4.65 mm; metapaste plus periogard: 4 mm. Results were subjected to statistical analysis using one way analysis of variance and Tukey tests. Conclusion: Chlorhexidine and its preparations are more potent antibacterial agents againstE. faecalis in comparison to calcium hydroxide.