Kishore Ginjupalli

Evaluation of the properties of a tissue conditioner containing origanum oil as an antifungal additive

STATEMENT OF PROBLEM Adherence and colonization of Candida albicans on tissue conditioners is common and results in irritation of the denture-bearing mucosa. PURPOSE The purpose of this study was to investigate the antifungal activity and properties of a tissue conditioner by incorporating origanum oil. MATERIAL AND METHODS Origanum oil at varying concentrations was incorporated into a poly(methyl methacrylate) based tissue conditioner (Visco-gel), and its antifungal activity against Candida albicans was evaluated at 1 day and 1 week by using the agar punch well method. The adherence of Candida albicans, surface roughness, tensile strength, and bond strength of the tissue conditioner with an optimized origanum oil concentration were evaluated. The data were subjected to 2-way ANOVA (α=.05). RESULTS Sixty vol% origanum oil in tissue conditioner (Visco-gel) showed a mean inhibitory zone of 21.00 ± 1.58 mm at 1 day and 13.44 ± 0.88 mm at 1 week. The control group showed 90 ± 6.80 yeast cells/mm(2) at 1 day and 165 ± 7.63 yeast cells/mm(2) at 1 week, whereas the group with origanum oil showed 16 ± 1.15 yeast cells/mm(2) at 1 day and 32 ± 4.00 yeast cells/mm(2) at 1 week. Surface roughness was less with the incorporation of origanum oil. Tensile strength at 1 day was 0.91 ± 0.52 N for the control group, whereas the group with origanum oil showed 0.16 ± 0.05 N. At 1 day, the bond strength of 3.97 ± 0.75 MPa was observed with control specimens, whereas tissue conditioner with origanum oil showed a bond strength of 3.73 ± 0.65 MPa. CONCLUSIONS Within the limitations of this in vitro study, origanum oil can be used as an additive to tissue conditioner to reduce the adherence of Candida albicans without significantly affecting its bond strength to heat-polymerized acrylic resin.

Evaluation of properties of irreversible hydrocolloid impression materials mixed with disinfectant liquids.

Background: Addition of disinfectant to irreversible hydrocolloid impression materials can eliminate the disinfection step to avoid dimensional changes associated with it. The aim of the present study was to evaluate the effect of various disinfectant mixing liquids on the properties of commercially available irreversible hydrocolloid impression materials. Materials and Methods: Four commercially available irreversible hydrocolloid impression materials (Zelgan, Vignette, Tropicalgin, and Algitex) were mixed with disinfectant liquid containing chlorhexidine (0.1 and 0.2%) and sodium hypochlorite (0.1 and 0.5%). After mixing with disinfectant liquids, materials were evaluated for pH changes during gelation, gelation time, flow, gel strength, permanent deformation and detail reproduction. Results: Significant changes in gelation time were observed in irreversible hydrocolloid impression materials upon mixing with disinfectant liquids. In general, chlorhexidine increased the gelation time, whereas sodium hypochlorite reduced it. However, no significant changes in the flow were observed both with chlorhexidine and sodium hypochlorite. Gel strength was found to decrease when mixed with chlorhexidine, whereas an increase in gel strength was observed upon mixing with sodium hypochlorite. Permanent deformation of the most irreversible hydrocolloid impression materials was below the specification limit even after mixing with disinfectant liquids. Sodium hypochlorite significantly reduced the surface detail reproduction, whereas no change in detail reproduction was observed with chlorhexidine. Conclusion: Chlorhexidine solution can be used to mix irreversible hydrocolloid impression materials in regular dental practice as it did not significantly alter the properties. This may ensure effective disinfection of impressions.

High-Performance Thin-Layer Chromatographic Determination of Etoricoxib in the Bulk Drug and in Pharmaceutical Dosage Form

A sensitive, accurate, precise, and stability-indicating high-performance thin-layer chromatographic method has been established and validated for analysis of etoricoxib in both bulk drug and formulations. Chromatography is performed on aluminum-backed silica gel 60F254 plates with toluene-1,4-dioxane-methanol 8.5:1.0:0.5 (v/v) as mobile phase. This system furnished compact bands for etoricoxib (RF 0.24). Rofecoxib (RF 0.38) was used as internal standard. Densitometric analysis of etoricoxib was performed in absorbance mode at 235 nm. Linear regression data for the calibration plots showed there was a good linear relationship between response and amount of etoricoxib in the range 100-1500 ng per spot; the correlation coefficient was 0.9922 ± 0.001. The mean values of the slope and intercept of the plot were 280.14 ± 0.26 and 320.01 ± 0.22, respectively. The method was validated for precision, accuracy, robustness, and recovery. The limits of detection and quantitation were 30 and 100 ng per spot, respectively. The drug undergoes degradation when subjected to neutral, acidic, or basic hydrolysis, oxidation, or dry heat treatment, but the degradation products were well separated from the drug (different RF values). Because the method could effectively separate the drug from its degradation products it can be regarded as stability-indicating.

Preparation and characterization of biodegradable scaffolds of poly(lactide-co-glycolide) 50:50 and hydroxyapatite for dental applications

In the present study, biodegradable scaffolds of poly(lactide-co-glycolide) PLGA 50:50 with acidic microclimate controlling additives were prepared and characterized for their degradation behavior, physical, and mechanical properties. Results indicate that scaffolds with acidic microclimate controlling additives undergo degradation without large variation in pH of the surrounding medium. Results also indicated that microclimate controlling additives did not significantly alter the physical and mechanical properties of the scaffolds. From the results, it can be concluded that PLGA 50:50 scaffolds with acidic microclimate controlling additives can be used as root replicas after the tooth extraction.

Profilometric study to compare the effectiveness of various finishing and polishing techniques on different restorative glass ionomer cements

Objective: The aim of the present study was to evaluate the effect of various finishing and polishing techniques on the surface roughness of different types of glass ionomer (GI) restorative cements. Materials and Methods: Surface roughness of conventional, resin modified and nano-ionomer cements was evaluated after different polishing regimens. Totally 20 specimens of 12 mm thick and 10 mm diameter were prepared using Teflon mold. Prepared specimens were subjected to polishing (n = 5) by Sof-Lex discs, diamond finishing points and 30-fluted carbide burs. Control specimens did not receive any polishing treatment, but mylar trip was used as matrix. Average surface roughness (Ra) in micrometers was measured using Surtronic 3 + profilometer. Results were analyzed using Kruskal-Wallis and Mann-Whitney test. Results: Control specimens (mylar strip) showed least Ra values followed by Sof-Lex disc, carbide finishing burs and diamond finishing points with all types of glass ionomer cements used in the study. Among the GIs tested, Nano-ionomer showed least Ra followed by resin-modified GI and conventional GI. Conclusion: Mylar strip produced the smoothest surface on all the GIs tested. Nano-Ionomer showed the best polish ability with least Ra values. Clinical Relevance to Interdisciplinary Dentistry Glass ionomer cements (GIC) is one of the most commonly used direct restorative material used in non-stress bearing areas especially to restore cervical lesion at tooth gingival interface Polished GIC surface reduces plaque accumulation and thus decreases the incidence of gingival inflammation and thereby prevents periodontal problems Finishing and polishing of the GIC enhances the longevity and color stability of the restoration.

Effect of novel chelating agents on the push-out bond strength of calcium silicate cements to the simulated root-end cavities

To compare the effects of different chelating agents on the push‐out bond strength of calcium silicate‐based cements to the simulated root‐end cavities. Root‐end cavities were prepared on the roots of fifty extracted maxillary anterior teeth. The specimens were then randomly divided into 5 groups (n = 10) based on the final irrigation regimen: Group 1: 17% EDTA, Group 2: 7% maleic acid, Group 3: QMix, Group 4: 2.25% peracetic acid (PAA), Group 5: 0.9% saline. Then, the samples from each group were subdivided into two groups (n = 5) based on the apical filling material. In group 1, root‐end cavities of all samples were filled with Biodentine and in group 2, with MTA. Each sample was horizontally sectioned to produce two discs of ∼1 mm thick per specimen. The maximum load required for the dislodgement of 100 retrofillings was recorded. The specimens were examined under scanning electron microscope after debonding to assess the type of bond failure. Data were statistically analyzed using Kruskal Wallis and Mann Whitney U tests. Irrigation with saline resulted in higher bond strength compared to the other irrigants in the retrograde cavities obturated with MTA or Biodentine (p < .05). In MTA group, there was no significant difference between the test irrigants (p > .05). EDTA and PAA groups showed higher dislodgement resistance values than the other test irrigants, when Biodentine was used as a filling. The type of irrigation solution influences the bond strength of the root‐end fillings.

Does the size matter? Evaluation of effect of incorporation of silver nanoparticles of varying particle size on the antimicrobial activity and properties of irreversible hydrocolloid impression material

OBJECTIVES The main objective of the present in vitro study is to evaluate the antimicrobial activity and properties of irreversible hydrocolloid impression material incorporated with silver nanoparticles of varying size at different concentrations. METHODS Silver nanoparticles of 80-100, 50-80, 30-50 and 10-20nm size were added to irreversible hydrocolloid impression material at 0.5, 1.0, 2.0 and 5.0wt%. Antimicrobial activity of the silver nanoparticle incorporated irreversible hydrocolloid was measured using disk diffusion method. The gel strength, flow, gelation time and permanent deformation were measured according to American Dental Association specification #18. Data were analyzed using analysis of variation at a confidence interval of 95% (α=0.05). RESULTS Silver nanoparticles of 80-100nm size have imparted superior antimicrobial activity to the irreversible hydrocolloid in a dose-dependent manner whereas finer nanoparticle size did not exhibit any antimicrobial activity. The addition of silver nanoparticles did not alter the properties of irreversible hydrocolloid at 0.5 and 1.0wt% whereas at higher concentrations significant differences in flow, gelation time and strength were observed. SIGNIFICANCE The results of the present study indicate that silver nanoparticles of size range 80-100nm are superior in imparting antimicrobial activity to irreversible hydrocolloid compared to finer particle size range.

Effect of comonomer of methacrylic acid on flexural strength and adhesion of Staphylococcus aureus to heat polymerized poly (methyl methacrylate) resin: An in vitro study

Aims and Objective: The purpose of the present study was to evaluate and compare flexural strength and Staphylococcus aureus adhesion of heat-activated poly (methyl methacrylate [MMA]) resin modified with a comonomer of methacrylic acid (MAA) and MMA monomer. Materials and Methods: Comonomer preparation was done with the addition of varying concentration of MAA (0, 15, 20, and 25 wt %) to the MMA of conventional heat-activated denture base resin to prepare the specimens. Prepared specimens were stored in distilled water at 37°C for 1 day and 1 week before the evaluation of flexural strength and microbial adhesion. Flexural strength was measured using a universal testing machine at a crosshead speed for 2 mm/min (n = 10). Microbial adhesion (colony-forming unit [CFU]) was evaluated against S. aureus using a quadrant streaking method (n = 5). Data were subjected to one-way ANOVA, and the significant differences among the results were subjected to Tukeys HSD test. P < 0.05 was considered statistically significant. Results: Addition of MAA to the MMA monomer was found to significantly reduce the adhesion of S. aureus for all the groups. Reduction of CFU of S. aureus was found be more significant for Group 3 as compared to control, both at 1-day (P < 0.001) and 1-week (P < 0.002) storage in distilled water. However, no statistically significant changes in the flexural strength were observed with the addition of MAA at 1-day (P = 0.52) and 1-week (P = 0.88) time interval. Conclusion: Addition of MAA to conventional denture base resin reduced the microbial adhesion without significantly affecting the flexural strength.

A Novel Long-acting Biodegradable Depot Formulation of Anastrozole for Breast Cancer Therapy

The purpose of the present study was to fabricate PLGA 50:50 and PLA microspheres for controlled delivery of anastrozole. The microspheres were prepared by oil-in-water (o/w) emulsion/solvent evaporation technique and evaluated for particle size and encapsulation. The optimised formulations were studied for solid state characterization, in vitro release and pharmacokinetic studies. The maximum encapsulation efficiency for PLGA 50:50 and PLA microspheres with 40:1 polymer - drug ratio was observed to be 78.4±2.5 and 87.7±2.6%. The solid state characterization confirmed dispersion of drug at the molecular level in the polymeric matrix. Microspheres were spherical in shape with a very smooth surface texture. Drug release was found to be in a sustained fashion, releasing constantly up to 720h (30days) for PLGA and 60days for PLA microspheres. The pharmacokinetic study data revealed that the intramuscular administration of PLA microspheres showed improved pharmacokinetic profile as compared to PLGA microspheres, and therefore this formulation can be considered as the best optimised formulation with sustained exposure of the drug in vivo compared to other microspheres. From experimental results, PLA microspheres demonstrate the feasibility of employing biodegradable depot polymeric microspheres of anastrozole for long-term treatment of breast cancer.

Effect of various dentin disinfection protocols on the bond strength of resin modified glass ionomer restorative material

Background Disinfection of dentin surface prior to any restorative therapy is important for the longevity of the treatment rendered. However, these dentin disinfection methods should itself not interfere with the adhesion of the restorative material. Therefore the aim of this study was to determine the effect of various dentin disinfection protocols on the shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC). Material and Methods The occlusal surface of 40 extracted premolars were trimmed to obtain a flat dentinal surface and was randomly divided into four groups. CTRL was the control group; NaOCl was 1% sodium hypochlorite disinfection group; CHX was 2% chlorhexidine disinfection group; and PAD was the photo-activated disinfection group. Then a predetermined dimension of RMGIC was bonded to the pre-treated dentin surfaces. Following this, each sample was tested for SBS using universal testing machine at a crosshead speed of 0.5mm/min. Results Among the test groups, CHX showed the least reduction in SBS and NaOCl the highest reduction in SBS as compared to the control group. PAD on the other hand showed significantly lower SBS than CTRL and CHX groups, but the values were higher than the NaOCl group. Conclusions Thus, it could be concluded from the present study that use of chlorhexidine based dentin disinfection does interfere with the adhesion of RMGIC. However, photo-activated disinfection should be done with caution. Moreover, sodium hypochlorite based disinfectants should be avoided prior to the use of RMGIC. Key words:Chlorhexidine, Dentin disinfection, Photo-activated disinfection, Resin modified glass ionomer cement, Shear bond strength, Sodium hypochlorite.