Browsing by Author "Moodley, Desigar"

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    Bio-Active Nano-Diamond Designer Materials and Dentures: From Design to Application
    (Dentistry, 2015) Perchyonok, V. Tamara; Souza, John; Zhang, Shengmiao; Moodley, Desigar; Grobler, Sias
    Objective: The present study aims to design functional biomaterials and evaluate performance of nano-diamond: chitosan based bio-active containing PMMA (polymethyl methacrylate) materials towards application in treatment and prevention of denture stomatitis and associated conditions in denture wearers. Methods: The bio-active nano-diamond modified PMMA were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan gelling agent. The release behaviors at physiological pH and also under acidic conditions and stability of the antioxidant-chitosan-nano-diamond were also evaluated. Mechanical performance such as tensile strength and compressive strength were measured as well bio-adhesive studies were investigated in order to assess the suitability of these designer materials. Results: The bio-active nano-diamond modified PMMA materials showed a high adhesive force and they only swelled slightly in the aqueous medium. Bioactive release suggested prolonged release of the therapeutic agent from the hydrogels. The hydrogels also had significant free radical defense capability. Conclusion: In this study we demonstrated that the newly prepared bio-active modified PMMA resins are suitable novel bio-active materials capable of comparable performance with the conventional PMMA materials with additional benefit of therapeutic bioactive release as well as potential antimicrobial properties to be demonstrated in vitro. Our findings might be thus a step forward towards the development of alternative non antibiotic based strategies targeting bacterial infections.
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    The colour stability of various glass ionomer cements
    (University of the Western Cape, 2019) Karjiker, Farzana; Moodley, Desigar; Khan, Saadika
    Introduction: Together with bonding to both enamel and dentine, an ideal restorative material would display physical properties similar to that of natural tooth tissue and would not be prone to degradation as a result of the oral environment. This includes changes in colour. Glass ionomer technology has undergone many changes to its original chemistry since it was developed in the early 1970’s. In 1988 resin-modified glass ionomers were introduced and in 2008, nano-ionomers were introduced. As a result of the progression in material sciences and the use of more sophisticated techniques and methods in restorative dentistry, it is possible to accomplish much improved aesthetics and functional durability of a restoration, both anteriorly and posteriorly. However, for as long as aesthetic restorations have been available, and in spite of advances in material structure and performance, one of the greatest challenges facing clinicians still remains that aesthetic restorations have to be replaced relatively frequently as staining and discolouration is a common problem. Aim of the study: The aim of this study was to determine the stainability of four resin-modified glass ionomers and one glass ionomer cement when exposed to a staining broth. Objectives: To record any change in colour before and after exposing the sample with the staining broth using a spectrophotometer, to compare the stainability, to examine the depth of staining using a light microscope and to observe the particle size of the powder and the surface texture using Scanning Electron Microscopy of the four resin- modified glass ionomer cements and one glass ionomer cement. Materials and Methods: Four resin-modified glass ionomers (one nano-ionomer) and one glass ionomer (zinc-reinforced ionomer) were selected. All were shade A2, except for Vitremer™ which was not available in A2. 15 discs of each material were prepared. The discs were 15 mm in diameter and 2 mm in thickness. All the materials were handled and cured according to the manufacturers’ instructions. After curing, only one side of each disc was polished using Sof-Lex™ discs (3M ESPE, USA). The unpolished side of each disc was designated as a matrix finish. The specimens were all immersed in distilled water at 37 °C for one week. They were then immersed in a staining broth for a period of one week and readings were taken after a period of 2 hours, 4 hours, 8 hours, 24 hours and one week. Colour was read on each side of each disc at the indicated intervals with a spectrophotometer. The colour difference was calculated using the CIELAB colour co-ordinates. Sample discs were then sectioned to determine the depth of staining. An additional sample disc of each material was made for observation with the SEM and was therefore not stained. Also, an unmixed sample of each material was prepared for examination with the SEM. Results: In general, for all materials there was an increase in staining when assessed with the colour difference between the baseline colour and the 7 day reading. Ketac™ N100, showed the highest total colour change of 43.84 for the unpolished surface followed by Riva™ which showed the total colour change of 28.55 for the unpolished surface. This was similar to Fuji II LC® which had a total colour change of 28.16 for the unpolished surface. For Vitremer™, the total colour change increased to 18.07 for the unpolished surface. For the unpolished surfaces, ChemFil™ Rock showed the least colour difference from baseline to 7 days (ΔE*ab = 10.45), followed by Vitremer™ (ΔE*ab = 18.07). Both Fuji II LC® and Riva™ Light Cure showed similar colour change from baseline to 7 days for unpolished surfaces (ΔE*ab of 28.16 and 28.55 respectively). Ketac™ N100 showed the highest staining after 7 days in the staining broth with a colour difference of 43.84. For the polished surfaces, the colour change for Fuji II LC® was 25.72 which was similar to Riva™ Light Cure which was 22.44 and Ketac™ N100 which showed a colour change of 22.79 on the polished surface. ChemFil™ Rock showed the least colour change of 17.69 for the polished surface followed by Vitremer™ which showed a colour change of 23.63 for the polished surface. Thus, for both the unpolished and polished surfaces there was a similar staining pattern. Conclusion: In this study it was demonstrated that all products evaluated in this study showed some degree of staining when exposed to a staining broth when evaluated using the ΔE*ab CIELAB colour evaluation. Ketac™ N100 showed the highest colour change compared to the other materials, but the reason for this was not explored. Both Vitremer™ and ChemFil™ Rock showed similar patterns of staining.
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    Nanoparticles as advanced treatment modalities to disinfect the root canal system
    (University of the Western Cape, 2019) Ibrahim, Amir I.O.; Moodley, Desigar
    Persistent root canal pathogens are one of the main causes of endodontic treatment failure. These pathogens are usually isolated in areas within the root canals that are inaccessible to mechanical instrumentation, chemical irrigants and medicaments resulting in incomplete sterilization of the root canal system. Furthermore, the development of resistant microbial species renders it difficult to disinfect the root canal system using commonly available root canal irrigants and intra-canal medicaments. Intra-canal medicaments are antimicrobial agents that are placed inside the root canal system in order to eliminate the remaining microorganisms that persist after mechanical instrumentation and irrigation. However, their antimicrobial efficacy is effective only against some of the root canal pathogens. Furthermore, the presence of tissue inhibitory factors such as dentine powder and serum albumine within the root canal system inhibits their antimicrobial activity. The use of nanoparticles as antimicrobial agents has recently attracted considerable attention especially in the medical field as a result of their unique antibacterial properties. These properties include their ability to use multiple mechanisms to eradicate microbial cells and their low potentiality to produce microbial resistance. Polymeric nanoparticles such as chitosan nanoparticles (Ch-Np) gained significant interest as a result of their biocompatible and antimicrobial properties. In medicine, several vehicles were designed to carry these antibacterial nanoparticles. Zeolites (Ze) are microporous crystalline hydrated sodium aluminosilicate material that is utilized in the chemical sciences as a carrier for various nanoparticles.
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    Temporomandibular Joint Dysfunctions and Bio-Materials: Design, Free Radical Defense and Mechanism In Vitro
    (EC Dental Science, 2015) Perchyonok, V Tamara; Souza, Tatiana; Moodley, Desigar; Basson, Nickolas; Zhang, Shengmiao; Grobler, Sias
    The aim of this investigation is to evaluate the suitability and flexibility of the bio-active containing designer materials to act as an “in vitro” probe to gain insights into molecular origin of TMJ. The hydroxyapatite/chitosan containing hydrogels represent a reliable biocompatible scaffold and allowed to evaluate the defense “build in” free radical defense mechanism of the functionalized bio-scaffolds on the molecular level, compare the effectiveness of the designer materials with the earlier reported capabilities of N-acetyl cysteine and apply the newly developed materials for the evaluation of new therapeutic treatment modalities in the TMJ therapy in vitro. Materials and Methods: The hydrogels were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan: hydroxyapatite as a molecular scaffold. The surface morphology (SEM), release behaviors (physiological pH and also in acidic conditions), stability of the antioxidant-chitosan were also evaluated. Structural investigations of the reactive surface of the hydrogel are reported. Bio-adhesive studies and mechanical properties of newly prepared materials were conducted to assess the suitability of these designer materials. Ability of the materials to release the phenolic components as potential therapeutic agents was assessed. Results: The sustained release of total phenolic component as a potential therapeutic agent confirms the added benefit of synergistic action of a functional therapeutic delivery when comparing the newly designed chitosan/HA-based hydrogel molecular scaffold. The hydrogel formulations have a uniform distribution of drug content. The bio-adhesive capacity, tensile strength, compressive strength as well as modulus of elasticity of the hydroxyapatite containing materials in the “in vitro” systems was tested and quantified. Conclusion: The added benefits of the chitosan hydroxyapatite treated hydrogels involved positive influence on the phenolic component release, sustainable bio-adhesion, tensile strength, compressive strength as well as modulus of elasticity of the hydroxyapatite containing materials in the “in vitro” systems was tested and demonstrated in vitro “build in” free radical defense mechanism.
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    Towards Bio-active Restorative Materials with Copaiba Oil and Oblepicha Oil: In vitro
    (J Dent Oral Disord Ther, 2015) Perchyonok, V. Tamara; Moodley, Desigar; Grobler, Sias; Souza, Tatiana; Augusto de Souza, Joane; Zhang, Shengmiao
    We developed and evaluated chitosan - fucoidan bio-composites with additional bioactive components of oblepicha oil and copaiba oil for bioactive restorative material as intra-dental and wound healing applications such as bioadhesion to soft and hard tissue in vitro, dentin bond strength and free radical defense mechanism for the compounds in the oral environment.