As novel dental composites filler: Azol functional SiO₂
AbstractAs an alternative conventional dental composites, we developed them containing PGMA and functional nanoparticles to eliminate periodontal disease causing bacteria. Also, the silica(SiO2) nanoparticles enables the composite to prevent oral pathogen growth during orthodontic therapy. The epoxy functional SiO2 nanoparticles modified with triazole and aminotetrazol in order to obtain azol functional SiO2 molecules via ring opening of the epoxy ring. FT-IR, SEM, DSC, mechanical test, antibacterial test and TGA analysis were confirmed the functionalization of SiO2. Human are brush their teeth in order to prevent plaque and provide for good oral hygiene. However various oral bacteria still remain on the oral cavity. Therefore, these residual microorganisms may cause tooth diseases [1]. Treatment of tooth diseases, composites are significant materials which are becoming more durable with advances in the filler particles, monomer matrices, improved adhesive systems, and polymerization devices. Commercial dental restorative composite materials generally consist of three ingredients. The first ingredient is an organic phase with an initiator, diluents, pigments and stabilizers. The second ingredient consists of an inorganic phase such as colloidal silica, glass powder, or quartz. The third ingredient is an interfacing phase acting as a coupling agent between the organic monomer system and inorganic filler material [2]. Failure of dental composite to perform is often due to failure in layer interface. The wetting ability of the adhesive is essential to the formation of a quality bond. The difference in the free energies of the adhesive and solid surface dictates the manner of interaction. High energy surface is easily wetted, while low energy surface causes the adhesive to bead up on the surface. For optimal wetting solid surface energy should be maximized by surface treatments, which are usually able to expose charged groups or other high energy structures on the surface being treated [3]. Although the main reasons for failures of dental composite are usually going on mechanical fatigue, and development of caries lesions adjacent to restorations, the presence of residual microorganisms along the cavity margins or interfaces is inarguably a component playing a role on the development of secondary caries. As a result of this dental composite should provide restoratives materials with antibacterial potential [4]. Current studies are a special emphasis on antibacterial materials for dental applications to control the formation of biofilms within the oral cavity [5]. Bacterial biofilm can be decisive in the formation and progression of periimplantitis, so inhibiting or decreasing the bacterial colonization of the implant surface in order to reduce biofilm formation is important for the treatment of peri-implantitis. Functional SiO2 nanoparticles are highly effective for active molecules with different effects on cells and bacteria such as induction of cell proliferation, cell differentiation, or antibacterial properties. Azol units may also induce such biological effects by themselves [6]. Although widely employed approach is to incorporate quaternary ammonium based monomers into the resin formulas, the antimicrobial effects of the resulting resins were rather weak. Another option is to use antimicrobial inorganic fillers which are entrapped in the crosslinked polymers to provide antimicrobial functions [2]. Antibacterial activity of dental adhesives have been made either by the addition of soluble antimicrobial agents, or immobilisation of antibacterial components in the matrix. Nonetheless, the release of antibacterial agent could incline an unfavorable effect on mechanical properties, toxicity and short-term antibacterial effectiveness whilst, the immobilisation of antimicrobial agents frustrates or reduces colonisation of contacted bacteria without leaching out from the material, resulting in long-lasting antibacterial activity without unfavorable effects on mechanical properties and bonding characteristics. PGMA and MMA polymers containing quaternary ammonium groups exhibit bactericidal activity [7].