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Objective: This current study was designed to compare and correlate between smear layer eradication and reduction in microhardness by natural 0.2%chitosan nanoparticles and novel chemical irrigants with surfactant at the apical root third. Materials and method: One hundred and twenty straight single-rooted extracted lower premolars were decoronated and working length obtained with #10 K-file. Pro-taper rotary files were used till apical size F3. The canals were simultaneously flushed with assigned irrigant containing surfactant [(ChX-Ultra, NaOCl-Extra, Pro-EDTA, 0.2%chitosan nanoparticles, Biopure MTAD]. The samples were randomly divided into two equal groups (n = 60). InGroup S (n = 60), the residual smear layer was examined by scanning electron microscope and in Group M(n = 60) microhardness was determined by Vickers Microhardness Tester. Further both groups were divided into six equal groups (n = 10 each) according to assigned irrigating solutions.For smear layer removal; Kruskal-Wallis tests followed by pair wise comparison using Mann Whitney U test was done. For change in microhardness ANOVA and post hoc Tukey tests was done. Results: Maximum smear layer removal was recorded in Biopure MTAD (1.8 ± 0.63), followed by pro-EDTA (2.2 0 ± 0.63) then 0.2%chitosan (2.6 ± 0.51), then NaOCL Extra (3.5 ± 0.53)and least in CHX-Ultra (4.4 ± 0.52) and saline (5.0 ± 0.00). Pro-EDTA group (12.8 ± 2.47) revealed significant highest reduction in microhardness followed by Biopure MTAD (8.01 ± 3.06), 0.2%chitosan nanoparticles (5.48 ± 2.87), NaOCl-Extra (5.44 ± 1.62) and least recorded in CHX-Ultra (4.94 ± 1.43) and saline (3.04 ± 0.63). Conclusion: The elimination of the smear layer is always accompanied by a reduction in microhardness. Moreover, irrigant with surfactant and chelators enhanced smear layer removal, with best perceived in Biopure MTAD.
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OBJECTIVES: The present study aimed to assess antioxidant activity of herbal antioxidants namely 6% cranberry extract, 10% green tea, 50% aloe vera and 10% sodium ascorbate and their effect on reversal of bond strength in bleached enamel. MATERIALS AND METHOD: From one hundred and twenty extracted maxillary central incisors enamel blocks of 5 â× â5 âmm were prepared and arbitrarily divided into six experimental groups (n â= â20): Group A: no bleaching, Group B: only bleaching protocol, Group C - bleaching â+ â6% cranberry extract solution, Group D - bleaching +10% Green Tea extract, Group E - bleaching â+ â50% aloe vera extract, Group F - bleaching â+ â10% Sodium Ascorbate. After bleaching antioxidants were applied for 10 âmin and were subjected to bonding procedures. The specimens were sectioned into 120 small strips of size (1 â× â1 â× â8 âmm). Sixty sticks were analyzed to micro tensile bond strength using Universal testing machine and fractured segment were observed for failure modes (Adhesive, Cohesive and Mixed) under stereomicroscope. Remaining 60 sticks were observed for interface gap between tooth and composite resin under SEM. The %AA (antioxidant activity) was assessed with spectrophotometric analysis. RESULTS: Data was statistically analyzed using ANOVA and Post Hoc Tukey's test. Group A (91.68 â± â2.24 Mpa) showed higher mean micro tensile bond strength versus group D (82.14 â± â1.45 Mpa), followed by group E (75.26 â± â1.92Mpa), group F (63.89 â± â1.95Mpa), group C (57.58 â± â1.96 Mpa) and least in group B (31.5 â± â1.27 Mpa). The %failure mode inferred maximum adhesive mode of failure (86.25%). CONCLUSION: All the four antioxidants were able to reverse the compromised bond strength comparatively after bleaching maximum being green tea followed by aloe vera, sodium ascorbate, and minimum in cranberry. CLINICALLY SIGNIFICANCE-: Easily available, biocompatible, cost effectual, and potent herbal antioxidants could be used considerably for immediate esthetic cases where time is a restricting factor.
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BACKGROUND: During the biomechanical preparation of the root canal by rotary file systems, stress is generated within the canal, which leads to dentinal microcrack formation. Such defects are evaluated only under the microscope. AIM: The present study aimed to evaluate dentinal microcrack formation after instrumentation with ProTaper Next (M-wire), Revo S (conventional NiTi), and WaveOne Gold (Gold-wire) file systems under the stereomicroscope. MATERIALS AND METHODS: Forty single-rooted teeth free from any defect were selected and divided into four groups (Control, PTN, RS, and WOG). Experimental groups were instrumented with file system used in the study, and the control group were left unprepared. Samples were further decoronated and sectioned at 3 mm, 6 mm, and 9 mm from the apex perpendicular to the long axis and examined under a stereomicroscope at ×25 for different types of microcracks (no fracture, complete fracture, partial fracture, and other fracture). STATISTICAL ANALYSIS USED: Data analysis was done by the Chi-square test using the SPSS version 17.0 software. A two-sided (α = 2) P < 0.05 (P < 0.05) was considered statistically significant. RESULTS: The null hypothesis was rejected. There was a statistically significant difference between the groups. All file systems created microcracks in the root dentin. WOG group showed an incidence of 66.7% for no fracture, PTN group had 40% for other fracture, and RS group had 60% for complete fracture. CONCLUSION: Single file system WOG with gold wire technology proves to be the best choice for canal preparation among the tested groups in terms of least dentinal crack formation.
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This study was carried out to compare the different techniques of placement of polyethylene fibre (Ribbond) on reinforcement of endodontically treated teeth with MOD cavities in vitro. Forty extracted human premolars were randomly assigned to four groups (n = 10). Teeth in Groups I-IV received root canal treatment and a MOD cavity preparation, with gingival cavosurface margin 1.5 mm in coronal to cementoenamel junction. Group I served as no fibre group, Group II as occlusal fibre group, Group III as base fibre group and Group IV as dual-fibre group (occlusal and base both). Subsequent to restoring with composite resin and thermocycling, a vertical compressive force was applied at a cross-head speed of 0.5 mm min(-1) using universal testing machine until fracture. Data were analysed using one-way analysis of variance and Tukey's post hoc tests. Fracture resistance was significantly highest in dual-fibre group (P < 0.001) as compared with other groups. The highest favourable fracture rate was observed in the base fibre group (70%). This study concluded that the use of polyethylene fibre inserted over or under the restoration significantly increased the fracture strength of the root canal-treated teeth and maximum fracture resistance was observed when cavity was restored using dual-fibre technique.
Assuntos
Resinas Compostas , Materiais Dentários , Restauração Dentária Permanente , Análise do Estresse Dentário , Humanos , Teste de Materiais , Dente Molar , Estresse Mecânico , Fraturas dos Dentes , Dente não VitalRESUMO
OBJECTIVE: To evaluate the antimicrobial activity of different concentrations of Matricaria chamomilla and Chlorhexidine gel against Candida albicans and Enterococcus faecalis. MATERIALS AND METHODS: The agar diffusion test was used to evaluate the antimicrobial activity of 15%, 25% Matricaria chamomilla in aq. base and 2% chlorhexidine gel against C. albicans (ATCC 24433) and E. faecalis (ATCC 24212) strains. Vancomycin was used as the positive control for E. faecalis and fluconazole for C. albicans . The agar plates were incubated at 37°C for 48 h after which the zone of inhibition were measured separately for each material. Data thus obtained were statistically analyzed using the Wilcoxon rank-order test. RESULTS: 2% chlorhexidine showed maximum inhibitory zone for C. albicans (33.26 mm) and E. faecalis (24.54 mm). 25% Matricaria showed zones of 24.16 mm and 20.62 mm for C. albicans and E. faecalis, respectively. 15% Matricaria did not show any antimicrobial activity (0 mm). CONCLUSION: The results of the current in vitro study suggest that 25% Matricaria can be used as an antimicrobial agent, but it is less effective than 2% chlorhexidine gluconate gel against C. albicans and E. faecalis. Matricaria at a lesser concentration of 15% aq. base is ineffective against both the microorganisms.