Dynamic Changes Of Subgingival Microflora In Human Periodontitis After Perioscopy Combined Nd:YAG Laser Aided Subgingival Scaling Therapy

Objective:Chronic periodontitis is a chronic infectious disease caused by periodontal pathogens.The initiating pathogenesis factor of periodontal disease is dental plaque. Completely removal of subgingival plaque and dental calculus is closely associated with the prognosis of periodontitis. Perioscopy can provide an indirect visible State to remove plaque more thoroughly. This experiment use 16s rDNA high-throughput sequencing detection to detecting microbial diversity of patients with chronic periodontitis, baseline and 1,3 months after scaling and root planning(SRP), observating subgingival bacterials’s colonization in periodontal tissue dynamically, to assess the microbiologic effects of Perioscopy combined Nd:YAG laser aided subgingival scaling therapy, Perioscopy aided subgingival scaling therapy and hand instruments.Methods:A total of 15 patients with moderately or severe chronic periodontitis were recruit and Randomly divided into 3 groups:group P were treated with Perioscopy aided subgingival scaling therapy, group PL were treated with Perioscopy combined Nd:YAG laser aided subgingival scaling therapy, group C were treated with traditional subgingival scaling. Each patient was selected 1-3 location as object of study which PD≥5mm, Collecting subgingival plaque samples baseline and 1,3 months after scaling and root planning. In addition, plaque samples from 5 periodontal health person were analyzed as healthy controls. Extract total DNA of these subgingival plaque samples, used high-throughput sequencing of the V3-V4 region of 16S rRNA genes, to characterize the composition of plaque during the SRP with these three methods.Results:1.Pyrosequencing yielded a final total of 7,812,022sequences after filtering, with a mean length of 420 bases, which were clustered into 1806 species-level Operational Taxonomic Units (OTUs) in total.2.The sequence numberof Porphyromonas、prevotella、Treponema、Fusobacterium after 1month all decreased compared with the levels before treatment.Group PL and group P decreased markely more than group C.The level between groupP and group PL showed non-significant difference. The level of four genes in 3 groups 3 months after treatment showed non-significant difference.3.Alpha diversity and 3 diversity decreased at 1 month, increased after 3months,with group PL significantly decreased. NMCS plots revealed significant shifts in the bacterial community structure of plaque as before and after subgingival scaling therapy, and community diversity decreased significantly 1 month after subgingival scaling therapy.Changes in the relative abundance of OTUs during the transition from before and after therapy resulted in the identification of new health-associated taxa.Conclusion:The three thearpys can also change the richness and diversity of subgigival microbial, and Perioscopy combined Nd:YAG laser aided subgingivalscaling therapy Shows a greater advantage, Both perioscopy aided subgingival scaling and traditional sudgingival can improve the inflammatory of periodontitis,while treatment with perioscopy can reach better outcomes.