| Background:Peri-implantitis is the most common cause of implant failure.Current treatment couldn't effectively control peri-implantitis for long time.Atibiotics are liable to cause bacterial resistance,digestive system flora disturbance or other complications.Our team have confirmed that the D-valine could disperse biofilms through regulation of polysaccharide metabolism,Damino acid oxidase activation and bacterial cell walls synthesis.In addition,we preparated the D-valine sustained-release hydrogel and verified it's long-term sustained-release effect in vitro.Whereas there is none research of the D-valine hydrogel's effects in vivo.Objective:In this study,the effects of D-valine sustained-release hydrogel on biofilms disassembly and the treatment of peri-implantitis were investigated via constructing a canine peri-implantitis model.Methods:A total of 10 male beagles were used in this study.Implants were immediatly placed at the second,third and fourth premolars at both sites of mandible.After 3-months healing,the peri-implantitis model was induced by silk ligature.The soft tissue was evaluated by probing depth,bleeding on probing rate,plaque index and gingival index.The implant marginal bone level was evaluated by X-ray apical radiography.The morphology and activity of implant surface biofilms were observed by scanning electron microscope and laser confocal microscope.Comprehensive evaluating the construction of canine peri-implantitis model based on the above-mentioned indexes.After the successful inducement of peri-implantitis,the D-valine sustainedrelease hydrogel group,the negative control group,the minocycline hydrochloride gel group and the chlorhexidine gel group received different medications respectively,while the blank control group remained none treatment.The soft tissue was evaluated by probing depth,bleeding on probing rate,plaque index and gingival index and implant marginal bone level during 4-weeks treatment.The morphology and activity of implant surface biofilms of each group were observed by scanning electron microscope and laser confocal microscope.The disassembly of the biofilms was evaluated by crystal violet biofilm staining.Results:1.Establishment of canine peri-implantitis model: Peri-implantitis clinical parameters: Probing depth was 4.41±1.13mm;Bleeding on probing rate was 92.07%;Plaque index was 2.95±0.22;Gingival index was 2.77±0.57;Implant marginal bone level was reduced by 2.58±0.70 mm,which was considered to be the the severe peri-implantitis model.Implant surface biofilm observation: The massy biofilms with high-caliber bacterial activity were observed on the implant surface.These phenomenon showed that the canine periimplantitis were established successfully.2.The treatment of peri-implantitis and biofilms disassembly effects of Dvaline sustained-release hydrogel :After 4-weeks treatment,the D-valine sustained-release hydrogels revealed the effects of dispersing biofilms through the observation of biofilm morphology and activity.The peri-implantitis was significantly cured in the D-valine sustained-release hydrogel group.Except the probing depth,there was no significant difference bettwen D-valine sustained-release hydrogel group and minocycline hydrochloride gel group,the two groups showed significantly differences from chlorhexidine group,negative control group and control group in terms of probing depth,bleeding on probing rate,plaque index,gingival index.The evaluation of the implant marginal bone level showed that D-valine sustained-release hydrogel had the capability of osteogenesis.Conclusion:1.D-valine slow-release hydrogel have a significant effect on biofilms pyrolysis which could reduce the thickness and formation of the biofilms,while impairing the bacterial activity of biofilms.2.D-valine sustained-release hydrogel can improve the inflammatory conditions of soft tissue and hard tissue around implant,and promote the regeneration of reduced marginal bone,hence possess a therapeutic effect on peri-implantitis. |
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