Towards Bioactive Containing Restorative Materials: From Design to Testing In vitro Approach

In any repair of a tooth with permanent restorative materials, the interface is always a sensitive region. The appearance of adhesive materials was a great step forward in dealing with the problems of this region and improving the overall performance of the restorations. However, contemporary adhesive materials do have a major disadvantage, namely that their durability is limited, a limitation which often arises due to their inadequate marginal adaptation. Restorative materials in the new era aim to be “bio-active” and longlasting. As part of our continuous interest in developing the novel bioactive containing restorative materials, we evaluated the effect of the additional bio-actives (such as chitosan, β-carotene, guar gum resin and the combination of the materials) to the commercially available flowable restorative materials such as Premise on the volumetric shrinkage, flexural strength, compressive strength, the surface hardness of the “bio-active” containing composite. Materials and Methods: The bioactive modified restorative materials were prepared by dispersion of the corresponding component with the addition of commercially available flowable restorative material. The surface morphology (SEM) of the freshly prepared restorative materials as well as reactive surface of the material after 24 hours and 3 months storage in artificial saliva has been performed. The physicochemical properties such volumetric shrinkage, Vickers Hardness and flexural strength of the bio-active restorative materials have been measured and are reported. The effect of the bioactive additionto the commercially available flowable restorative materials such as Premise on the shear bond strength of dentin has been evaluated. Results: The SEM images were obtained to characterize the microstructure of the freeze-dried modified restorative material as well as evaluated the durability of the bioactive restorative materials after 24 hours and 3 month exposure to artificial saliva.All bioactive containing flowable restorative materials gave significantly (P< 0.05; non-parametric ANOVA test) higher shear bond values (P< 0.05) than dentin treated or not treated with phosphoric acid.Volumetric changesdue to polymerization in modified composites have been explored using an electronic mercury dilatometer. The average Received: June 04, 2015; Accepted: July 15, 2015; Published: August 04, 2015 *Corresponding author: V. Tamara Perchyonok,VTPCHEM PTY LTD, Glenhuntly, Melbourne, 3163, Australia, E-Mail:[email protected] volumetric change reached a plato at about 20 seconds for the samples tested and the total volumetric changes were reached at 25 seconds. The average for the control Premise samples had a total volumetric change of 2.74%. Guar/Premise had the largest volumetric change from all the modified Premise samples (2.41%). The Chitosan/Premise (1.07%) had the least volumetric change, followed by β−Carotene/ Chitosan/Premise (1.63%) andβ Carotene/Premise (1.75%). The volumetric change starts at different time intervals for all the materials. The Turkey-Kramer multiple comparison test on the rate of shrinkage slopes has confirmed the statements (p<0.05).TheVickers Hardnessof the bio-active composites such as β-carotene/chitosan/ Premise (37.4VH), Guar Gum/Premise (36.2VH), β-carotene/ Premise (36VH), Chitosan/Premise (5.2 VH) versus Premise control (37.6VH) were measured and relevant clinical applications have been elaborated. All modified bio-active flowable composites, which an exception of chitosan and β-carotene containing materials have shown comparable compressive and flexural strength to the commercially available Premise material which makes the newly modified bioactive composites ideal candidates for further evaluation and development is bio-functional restorative materials. Conclusion: The materials were tested using effective in-vitro development of “dual function restorative materials”. We quantified the effects of functional designer biomaterials on the dentin bond strength of composite, measure volumetric changes due to polymerization in dental resins as well as Vickers hardness and % of water uptake by the modified composites. Within the limitations of the study design chitosan based hydrogels are suitable materials for functional restorative applications in vitro. Cytotoxicity data is currently being evaluated in our laboratory.The clinical significance is that the decrease in volumetric change will have a positive effect on the stress formation on the tooth/adhesive/restoration interface.The additional therapeutic benefits of addition of the bioactive materials such as chitosan, beta-carotene, guar gum resin as well as combination are described.