SURFACE MODIFICATION OF ORTHODONTIC MINI-IMPLANTS WITH H2O2 GEL FOR ITS ANTIADHERENT AND ANTIBACTERIAL PROPERITES IN THE PRESENCE OF STREPTOCOCCUS MUTANS

Abstract

Widespread applications have made the use of mini-implants common throughout orthodontic treatment. The mini-implant provides an osseous anchor that is easily inserted, minimally invasive, and easily removed. The failure rate of mini-implants is estimated around 15%; this is high when juxtaposed with an endosseous implant. The majority of failures occur early; this results from a weakened bone-implant interface usually accompanied by soft tissue inflammation. This inflammation is exacerbated by poor oral hygiene and in areas of non-keratinized tissue, which provides an inadequate soft tissue barrier to bacterial challenges. Streptococcus mutans is involved in initial biofilm formation and has been implicated in endosseous peri-implantitis in the absence of periodontal disease. S. mutans is acidogenic, and has been shown to negatively affect the topography of titanium surfaces. Mini-implants are mainly comprised of titanium alloys due to their biocompatibility and mechanical strength. Literature suggests that enhancing the native TiO2 on titanium surfaces in the presence of UV light improves osseointegration, increases antibacterial effects, and increases soft tissue adhesion. The goal of this study was to enhance the TiO2 surface of mini-implants and evaluate the resultant anti-adherent, antibacterial, and topographical changes in the presence of S. mutans. Orthodontic mini-implants compromised of Ti6I4V, (Wrought Titanium-6 Aluminum 4 Vanadium ELI), were modified according to the parameters set by Unosson et al, 2015. These samples were then exposed to Streptococcus mutans and incubated at 37° C. Initial contact of viable bacteria was evaluated after 4 hours using resazurin dye that was measured on a fluorescence plate reader. Bacterial growth was evaluated at 4, 8, and 24 hours using a spectrometer to assess turbidity. Four samples were also plated to evaluate growth. SEM images were taken prior to and after treatment to assess topographical changes. ANOVA and pair-wise post-hoc tests were used to analyze the data. The amount of viable bacteria on modified mini-implant surfaces after 4 hours was significantly decreased when compared to controls (p< 0.004). Growth of S. Mutans on the modified surface after 24 hours was significantly less when assessed by spectroscopy (p<0.00083). Preliminary results show that modifying the surface of orthodontic mini-implants with H2O2 gel increases antibacterial properties against Streptococcus mutans, despite the lack of UV radiation.