| Fixed appliances are sophisticated devices, which can precisely position the teeth. They are the appliances of choice for most orthodontic treatment because the results are far more predictable and of a higher standard achieved than by other means. However, fixed appliances are relatively complex to use and may bring some negative effect to oral hygiene and an increased prevalence of food impaction around brackets and underneath bands may occur, that may lead to dental plaque accumulation. Plaque retention in the orthodontic patient has significant influence on oral physical, chemical, and biologic characteristics, which contribute to the potential formation of white spot lesions and the development of dental caries or periodontal disease. A method of solving all those complications accompanying with orthodontic treatment may build upon the development of oral material study. Recent developments in science and technology have focused attention on mechanical behavior of materials on the scale of nanometers. Nano-technology and science has provided the means to manipulate materials on an atom-by-atom basis, and established procedures for material characterization on small size scales. Thesedevelopments have an almost immediate impact on technology, and serious researchefforts have begun in order to exploit them in various applications including in thefield of bio-medicine. A particularly challenging aspect of oral material research isits highly efficiency of antimicrobial effect. Shu et al. have developed the nano-TioB2Bceramic-coated orthodontic brackets and have done some primary study on themechanical and biological properties of the nano-TiOB2B ceramic film on brackets.This study was aimed to assess bacterial plaque accumulation adjacent to nano-TiOB2B ceramic brackets and to assess bacterial plaque clearance of nano-TiOB2B ceramicbrackets developed by us compared with general SWA brackets manufactured by thexinya factory, hang zhou. Our study involves two parts:â‘ To access bacterialplaque clearance of two SWA brackets, that are nano-TiOB2B ceramic bracketsdeveloped by us and general brackets manufactured by the xinya factory, hang zhou.â‘¡To assess bacterial plaque accumulation adjacent to nano-TiOB2B ceramic bracketsby a scanning electron microscopy study.Results:1,PLI-O increased after brackets placement in both the nano- TiOB2B ceramicorthodontic brackets group and the normal stainless steel orthodontic bracketsgroup. From 1PstP to 4PthP week, with time going, PLI-O increased in both bracketsgroups. However, bacterial plaque clearance of nano- TiOB2B ceramic orthodonticbrackets was better than the normal stainless steel orthodontic brackets.2,Difference of PLI-O between two experimental brackets groups primarilyexisted in the brackets surface region and the region around brackets.Especially, difference of PLI-O in the brackets surface region was significant statically.3,Excess composite around the bracket base is the critical site for plaqueaccumulation due to its rough surface and the presence of a distinct gap atcomposite-enamel interface; Plaque deposition on the enamel surface in thecervical region is also prominent for difficulty in oral hygiene.4,At 3PthP weeks after brackets bonding, the dental plaque on the compositesurface had a more mature composition compared with the dental plaque onthe cervical enamel surface.Conclusions:1,PLI-O increased after brackets placement in both two orthodontic bracketsgroups and regions that around and gingival to the bracket base are criticalsites for plaque accumulation.2,Nano-TiOB2 Bceramic orthodontic brackets show better bacterial plaqueclearance compared with the normal stainless steel orthodontic brackets .3,Both excess composite around the bracket base and the distinct gap atcomposite-enamel interface contribute to dental plaque accumulation. And themature plaque was present on the composite at 3 week after bonding ,whereasplaque on the gingival enamel surface was still at an early stage ofdevelopment.
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