ABSTRACT
Aim: Evaluate the effect of different chromatic filters of the dental operating microscope on the volumetric shrinkage, surface micro-hardness, and depth of cure of bulk-fill composite. Methods: Bulk fill composite specimens of 4 mm depth, 4 mm width, and 4 mm length were prepared. Five groups were designed based on a light source under which composite samples were condensed. Group 1: dental chair light without filter, Group 2: microscopic light without filter, Group 3: microscopic light with a yellow filter, Group 4: microscopic light with a green filter, Group 5: dental chair light with a red filter. After condensation, the samples were subjected to curing using Bluephase NM curing light. The parameters like volumetric shrinkage, surface hardness, and depth of cure were measured for all the samples. The results were subjected to statistical analysis using one-way ANOVA, followed by post-hoc Tukey tests. Results: Group-2 showed the highest mean volumetric shrinkage (14.514%), surface micro-hardness (58.065 kg/m2), depth of cure (0.831%), whereas group-5 showed the least volumetric shrinkage (7.386%), surface micro-hardness (46.536 kg/m2), and depth of cure (0.789%). Working time was 40 seconds for group-2, whereas the remaining groups were allowed to complete 1-minute condensation. A statistically significant difference was shown between groups 1 and 5 (p=0.050), 2 and 5 (p=0.007) for volumetric shrinkage. Regarding surface micro-hardness, a statistically significant difference was observed between all the groups (p=0.001) except group-3, group-4 (p=0.100). There was no statistically significant difference between all the groups except group 2 and 5 for depth of cure (p=0.016). Conclusion: Microscope light without filter showed the highest surface hardness and depth of cure. However, the highest volumetric shrinkage and lesser working time were also observed, which are undesirable. Use of filters during composite manipulation showed less detrimental effects on depth of cure, volumetric shrinkage and working time. Overall, composite condensed under filters showed acceptable properties.
ABSTRACT
Aim: The aim of the study is to determine the effect of autoclaving on the cyclic fatigue resistance (CFR) in respect to three different rotary nickel-titanium (NiTi) systems. Methods: Three rotary NiTi files with different manufacturing process were selected and arranged into three groups. Group 1: Neolix Neoniti files (n = 15), Group 2: Edge Files (n = 15), Group 3: NeoendoFlex files (n = 15). Each group was then subdivided into three subgroups containing 5 samples each based on the number of cycles of autoclaving (0, 1, 5 cycles). The instruments were subjected to autoclave without usage. The files of size 25, taper 6%, and 25 mm length were taken. After the autoclaving cycles, the files were rotated in cyclic fatigue testing device with simulated canal curvature of 60° until file separation. Time taken for the instrument separation (in minutes) was multiplied by the number of rotations per minute to attain the mean number of cycles to failure for every file. The obtained results were subjected to statistical analysis using two-way ANOVA and Newman-Keuls multiple post hoc procedures. Results: Neolix Neoniti files exhibited the maximum CFR (98.80) than EdgeFiles (80.47) and Neoendo Flex files (41.80) (P = 0.0001). Reduction in CFR was observed with increase in the number of cycles of autoclaving (i.e., 0, 1, 5 cycles). Conclusion: Autoclaving has a negative influence on the CFR of the rotary NiTi files used. Neolix Neoniti files exhibited greater CFR than EdgeFiles and Neoendo Flex files.
ABSTRACT
AIM: The study was aimed to evaluate the effect of 5.25% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA) Solutions on Surface Topography of ESX, TruShape, and ProTaper Gold nickel-titanium (NiTi) Rotary Instruments using Atomic Force Microscope (AFM). MATERIALS AND METHODOLOGY: A total of 27 each of three commercially available brands of endodontic NiTi instruments were analyzed, which were divided into three groups as follows: Group I: ESX (Brasseler, USA) Group II: Tru shape (Dentsply Tulsa, USA) Group III: Pro Taper Gold (Dentsply Tulsa, USA). These files were further divided into three subgroups containing nine files each, no immersion, immersion in 5.25% NaOCl for 5 min, and immersion in 17% EDTA for 5 min. Surface areas along 3 mm sections at the tip of the files (perfect squares of 10 µm × 10 µm) were analyzed using AFM operating in contact mode under ambient conditions. STATISTICAL ANALYSIS: Data were analyzed using two-way ANOVA and pairwise comparison of three main groups with respect to Ra and RMS by Tukey's multiple posthoc procedures. RESULTS: Three-dimensional AFM images of the surface of all the rotary NiTi instruments, including new and those immersed in 5.25% NaOCl and 17% EDTA solutions, revealed topographic irregularities at the nanometric scale. Ra and RMS values of instruments treated with 5.25% NaOCl and 17% EDTA solutions were statistically higher than that of the new ones (P < 0.05). CONCLUSION: Using AFM for analysis indicated that short-term contact between 5.25% NaOCl and 17% EDTA solutions and NiTi instruments caused alterations in the topography of instruments.
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AIM: The purpose of this study was to evaluate the clinical performance of Ketac Nano (Ketac™ N100), RMGIC (Fuji Filling™ LC), and Giomer (Beautifil® II) in noncarious cervical lesions (NCCLs). MATERIALS AND METHODS: One operator restored 120 NCCLs in 20 subjects, with at least two lesions restored with one of the restorative materials: RMGIC (control group), Giomer and Ketac Nano (experimental groups). Two observers evaluated retention, marginal discoloration, marginal adaptation, color match, surface roughness, and postoperative sensitivity using modified USPHS criteria at baseline, 6, and 12 months. STUDY DESIGN: Double-blinded randomized clinical trial (RCT). STATISTICAL ANALYSIS: Kruskal-Wallis test, Mann-Whitney U-test, Wilcoxon matched-pairs test. RESULTS: There was statistically significant difference observed between Giomer, Ketac Nano and RMGIC after 12 months (P < 0.05). There was a significant decrease in retention rates for Giomer (P = 0.0050), increased marginal discoloration and color mismatch for Ketac Nano (P = 0.0025, P = 0.0053), increased surface roughness and color mismatch with RMGIC (P = 0.0022, P = 0.0077) from baseline to 12 months. CONCLUSION: Within the limitations of this RCT of 12 months, Ketac Nano and RMGIC restorations were better retained in NCCLs while superior color match and surface finish were observed with Giomer restorations.
ABSTRACT
AIM: The purpose of this study was to evaluate the effectiveness of three desensitizing agents on dentinal tubule obliteration and their durability in use on the dentinal tubules. MATERIALS AND METHODS: Sixty specimens were obtained from 30 extracted sound human maxillary first premolars. Each tooth was mesiodistally sectioned to obtain 30 buccal and 30 lingual surfaces, and enamel was removed in order to simulate hypersensitive dentin. Specimens were divided into four groups with 15 specimens each. Group 1 samples were immersed in artificial saliva, Group 2 samples were coated with Vivasens, Group 3 samples were coated with VOCO Admira Protect, and Group 4 samples were coated with Neo Active Apatite suspension. These specimens were examined under scanning electron microscope (SEM) to find out the occluding ability of the respective products. The specimens were brushed to find out their durability for 1 week and 1 month and were examined under SEM. STATISTICAL ANALYSIS: The results were statistically analyzed by analysis of variance (ANOVA) and Tukey's test. RESULTS: Group 1 differed significantly from the Vivasens, Admira, and Neo Active Apatite groups at 5% level of significance (P < 0.05). The Vivasens group differed significantly from the Admira and Neo Active Apatite groups at 5% level of significance (P < 0.05). CONCLUSION: The Ormocer-based Admira Protect showed the best results.
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AIM: To evaluate the sealing ability of MICRO-MEGA Mineral Trioxide Aggregate, Endosequence, Biodentine as furcation repair materials using a dye extraction leakage method. MATERIALS AND METHODS: Forty mandibular molars were randomly divided according to the material used for perforation repair. Group I- (left unsealed) control, Group II-MICRO-MEGA Mineral Trioxide Aggregate, Group III - Endosequence, Group IV - Biodentine. All samples were subjected to orthograde and retrograde methylene blue dye challenge followed by dye extraction with 65% nitric acid. Samples were then analyzed using Ultra violet (UV) Visible Spectrophotometer. RESULTS: Biodentine showed highest dye absorbance, whereas Endosequence showed lowest dye absorbance when compared with other repair materials. CONCLUSION: Within the limitations of this study, it was observed that Endosequence showed better sealing ability when compared with other root repair materials.
