In vitro comparative evaluation of antioxidative effect of selenium alone and in combination with green tea and alpha-tocopherol on the shear bond strength of universal composite resin to enamel after in-office bleaching.

Background: Antioxidant application soon after bleaching process increases the shear bond strength (SBS) of composite resin to enamel. Aims: The aim of the study was to evaluate the antioxidant effects of selenium alone and in combination with alpha-tocopherol (αT) and green tea (GT) on SBS of composite resin to enamel following in-office bleaching with 38% hydrogen peroxide (HP). Methods: Sixty extracted human single -rooted premolar teeth were cleaned and embedded in acrylic resin blocks at the level of cementoenamel junction(CEJ) followed by bleaching with 38% hydrogen peroxide (HP) and arbitrarily divided into seven groups (n=10) for antioxidant application: Group I (negative control): intact teeth, Group II (positive control): only bleaching, Group III: 10% selenium (Se), Group IV: 10% alpha tocopherol (αT), Group V: 10% αT +10% Se, Group VI: 10% Green tea (GT), Group VII: 10%GT+10% Se. In all groups, self-etch adhesive was applied and composite restoration was done, and specimens were stored in distilled water for 24h followed by SBS evaluation. Statistical Analysis: One-way analysis of variance and post hoc Tukey's tests were used (P < 0.05). Results: The highest SBS was found in negative control Group I (intact teeth) and least in positive control Group II (bleached teeth), whereas in experimental groups, Group VII (GT + Se) showed highest followed by Groups V (αT + Se), III (Se), and VI (GT) and least in Group IV (αT). Conclusion: Combination of selenium with green tea and alpha tocopherol enhanced the SBS of composite resin following in-office bleaching.

Evaluation of push-out bond strength of different concentrations of chitosan nanoparticles incorporated composite resin and eighth-generation bonding agent for class II restoration: An in vitro study.

Aim: The aim of this study is to evaluate the push-out bonding strength of class II cavities of maxillary molars restored with different concentrations of chitosan nanoparticles (CSN) incorporated in universal composite resin and eighth-generation dentin bonding agent (DBA). Materials and Methods: Seventy extracted human maxillary first molar teeth were cleaned and mounted in acrylic mold up to 2 mm below cementoenamel junction and mesio-occlusal Class II cavities with standard measurements were prepared. CSN 2% and 0.25% powder were added to the DBA and composite resin. The samples then arbitrarily divided into three groups for restoration: Group 1: composite restoration without CSN (control group) (n = 10), Group 2: 2% CSN (n = 30), and Group 3: 0.25% CSN (n = 30). Groups 2 and 3 were further subdivided into three subgroups (n = 10 each) subgroup A. CSN incorporated in composite resin. B. CSN incorporated in DBA and C. CSN incorporated in composite and DBA. After restoration, push-out bond strength was evaluated in each sample using a universal testing machine, and data collected were statistically analyzed by one-way analysis of variance and Post hoc Tukey tests (P ≤ 0.05). Results: Subgroup 3A (0.25% CSN + composite) has shown an increase in bond strength among all experimental groups with no significant difference between group 1 (control group). Conclusion: CSN 0.25% incorporated in composite or DBA exhibits no harmful effect on the bond strength of class II restorations. Hence, it can be used to improve the antibacterial action and longevity of composite resin.

Biosynthesis, Characterization and Antibacterial Efficacy of Silver Nanoparticles Derived from Endophytic Fungi against P. gingivalis.

INTRODUCTION: Microbial resistance to existing antimicrobial agents in periodontal therapy is a growing problem. Therefore, there is a need for development of new antimicrobial agents. AIM: To biosynthesize and characterize Silver Nanoparticles (AgNPs) using endophytic fungi and to evaluate the antibacterial efficacy against P. gingivalis. MATERIALS AND METHODS: Cut leaf segments of Withania Somnifera (Ashwagandha) were used to isolate the fungi. Fresh cultures of fungi were inoculated in Erlenmeyer flask of 100 ml Malt Glucose Yeast Peptone (MGYP) broth and incubated at 29°C for 72 hours for the biomass to grow. Biomass was filtered and cell free fungal filtrate was used further. Biosynthesized AgNPs were characterized by visual observation, Ultraviolet-Visible (UV-Vis) spectrophotometer, Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction Analysis (SAED) and Fourier Transform Infrared Spectroscopy (FTIR). Antibacterial efficacy was evaluated by agar diffusion method measuring the zone of inhibition. The study groups included different concentrations of AgNPs: A (20 µl), B (40 µl), C (60 µl), D (80 µl) and E (100 µl) of AgNPs, F (0.2% CHX), G (2% CHX), H (Ampicillin) and I (sterile distilled water). The data collected for inhibition zones were statistically analysed using One-way Anova followed by Tukey post-hoc multiple comparison tests. RESULTS: The fungi were identified as Fusarium semitectum. Characterization studies showed the colour change from colourless to reddish brown; U-V spectrum showed peak 420 nm, TEM revealed the particles spherical in shape and 10-20 nm in size. FTIR analysis revealed the presence of functional groups. AgNPs 80 µl and 100 µl showed mean zone of inhibition 17.33 and 18 mm against P. gingivalis. CHX (0.2%) 17.85 and CHX (2%) 19.97 mm, Ampicillin 20.5 mm and no zone for sterile distilled water. CONCLUSION: Biosynthesized AgNPs showed efficient antibacterial efficacy against P. gingivalis hence, creates a new horizon in periodontal therapy.

Evaluation of antibacterial efficacy of biosynthesized silver nanoparticles derived from fungi against endo-perio pathogens Porphyromonas gingivalis, Bacillus pumilus, and Enterococcus faecalis.

BACKGROUND: Even after rapid progress in contemporary dental practice, we encounter the failures due to endodontic, periodontal, or combined lesions. Complex anatomy of tooth and resistant microbes demands the development of new treatment strategies. AIM: The aim of this study is to biosynthesize silver nanoparticles (AgNPs) using fungi and determine the antibacterial efficacy against Porphyromonas gingivalis, Bacillus pumilus, and Enterococcus faecalis. MATERIALS AND METHODS: Fungi isolated from healthy leaves of Withania somnifera were used to biosynthesize AgNPs. The biosynthesized AgNPs were characterized by different methods, and antibacterial efficacy was evaluated by agar well diffusion method measuring the zone of inhibition. Test microorganisms were divided as Group 1: B. pumilus 27142 (American Type Culture Collection [ATCC]), Group 2: E. faecalis 29212 (ATCC), and Group 3: P. gingivalis 33277 (ATCC). Agents used for antibacterial efficacy were grouped as: AgNPs: A (20 µl), B (40 µl), C (60 µl), D (80 µl), E (100 µl), F (0.2% chlorhexidine [CHX]), G (2% CHX), H (Ampicillin), and I (sterile distilled water). RESULTS: Characterization studies showed the color change from colorless to reddish brown color; ultraviolet spectrum showed peak at 420 nm, transmission electron microscope revealed the particles spherical in shape and 10-20 nm size. Fourier transform infrared spectroscopy analysis revealed the presence of functional groups. Data collected for antibacterial efficacy were analyzed using one-way ANOVA and post hoc Tukey's multiple shows no significant difference among three groups (P < 0.0001). AgNPs were as effective as CHX and positive control ampicillin. No zones were seen for I (distilled water). CONCLUSION: Biosynthesized AgNPs showed efficient antibacterial efficacy. Therefore, it creates a new horizon in the management of endodontic, periodontal, and combined lesions.

Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis.

AIM: To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. METHODOLOGY: One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. RESULTS: Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. CONCLUSION: Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration.