In Vitro Comparative Evaluation of Effectiveness of Sodium Hypochlorite with Conventional Irrigation Method versus EndoVac and Ultrasonic Irrigation in the Elimination of Enterococcus faecalis from Root Canals.

AIM: The aim of this study was to compare the decrease in bacterial population in the root canals with 2.5% sodium hypochlorite (NaOCl) and three irrigation systems: Conventional Needle Irrigation, Passive Ultrasonic Irrigation, and EndoVac Apical Negative Pressure Irrigation system. MATERIALS AND METHODS: Access open was carried out in 48 extracted single-rooted maxillary and mandibular human premolar teeth. The canals were instrumented 1 mm short of apical foramen up to No. 50 size file; irrigated and apical foramen was sealed with cyanoacrylate. The teeth were mounted in plaster and autoclaved for 20 min at 121°C. The plaster blocks containing the teeth were inoculated with Enterococcus faecalis and incubated at 37°C for 24 h. The specimens divided randomly into four groups (n = 12) depending on the type of irrigation system used: Group 1: Conventional Irrigation Needle, Group 2: Ultrasonic system, Group 3: EndoVac Negative Pressure Irrigation system used with 2.5% NaOCl, and Group 4: Control group, normal saline irrigation. The normal saline is used as control. The samples were collected using 45 size sterile paper points and quantitative bacterial assessment was carried out by seeding each dilution on plates containing brain heart infusion broth. Then, incubated at 37°C for 7 days and colony-forming units were counted. Data obtained were statistically analyzed. RESULTS: Statistically, EndoVac irrigation systems were more effective in reducing the number of bacteria than the other irrigation systems. CONCLUSION: EndoVac irrigation system was more effective in reducing bacterial numbers in infected root canals than the other two irrigation systems.

Comparative evaluation of the depth of cure and surface roughness of bulk-fill composites: An in vitro study.

BACKGROUND: Composites are in great demand due to the esthetic needs of the patients, which explains a wide variation in the types of available composites. However, the mechanical strength of the materials is questionable. Therefore, the mechanical properties of the newly available bulk-fill composites have been tested. OBJECTIVES: The main objective of the study was to compare the depth of cure (DOC) and surface roughness of 3 different bulk-fill composites: X-tra fil® (XTF), Tetric EvoCeram® Bulk Fill (TEC) and Beautifil® Bulk Restorative (BBR). MATERIAL AND METHODS: Fifty-seven (n = 19 in each group) samples were made using brass molds. All samples were subjected to Vickers hardness testing and profilometry. The one-way analysis of variance (ANOVA) test was used for the data analysis, followed by Tukey's post hoc test. RESULTS: The differences in the mean surface microhardness values of the materials were statistically significant (p < 0.001), with XTF showing the highest value. The TEC composite showed a higher surface roughness as compared to BBR and XTF. CONCLUSIONS: The results of the present study indicate that variations in the filler size and amount significantly influence the DOC and surface roughness of dental composites. Among the tested composites, the multi-hybrid composite exhibited superior DOC (XTF), whereas the nanohybrid composite exhibited superior surface finish (TEC).

Evaluation of Hybrid Layer and Bonding Interface after Water Storage with and without the Usage of 2% Chlorhexidine: A Scanning Electron Microscope Study.

AIM: Restorative dentists employ different bonding systems between the resin and the dentin and other dentinal tissues to achieve the goal of micromechanical retention. Studies have shown that the bond between composite and dentin degrades over time because of the action of matrix metalloproteinases (MMPs) on collagen fibrils left unprotected by acid etching. The MMPs may be partially responsible for hybrid layer degradation. Since chlorhexidine (CHX) inhibits MMPs, we hypothesized that CHX would decelerate the loss of resin-dentin bonds. Hence, this in vitro study is intended to evaluate the effects of 2% CHX on hybrid layer and bonding interface. MATERIALS AND METHODS: Totally, 40 freshly extracted molars were randomly divided into four experimental groups. In all 40 specimens, class II cavities were prepared to a depth of 1 mm below the dentinoenamel junction with no axial wall, but the elimination of the proximal enamel ridge. The teeth were then randomly divided into four experimental groups, i.e., All Bond 2 without 2% CHX (group I), All Bond 2 with 2% CHX (group II), One Coat 7.0 without 2% CHX (group III), and One Coat 7.0 with 2% CHX (group IV). All the specimens were derooted and sectioned mesiodistally into two halves and placed under water at 37°C for 3 months and observed under scanning electron microscope for the hybrid layer and resin tag formation. RESULTS: Groups I and II showed statistically significant difference when the presence/absence of resin tags was compared. When groups III and IV were compared for the presence/absence of hybrid layer and resin tags, the results were statistically significant. CONCLUSION: Between all the four experimental groups, irrespective of the bonding systems used, we concluded that groups with 2% CHX usage showed promising results with presence/ absence of hybrid layer and resin tags formation. CLINICAL SIGNIFICANCE: Studies suggest that the bond between composite and dentin degrades over time because of the action of MMPs on collagen fibrils left unprotected by acid etching. Measures should be taken to prevent this from happening and thus allow bond between composite and dentin last longer.