Table_5_Microbiota in Gingival Crevicular Fluid Before and After Mechanical Debridement With Antimicrobial Photodynamic Therapy in Peri-Implantitis.xlsx

ObjectivesThis study aims to compare the microbiota of gingival crevicular fluid (GCF) before and after mechanical debridement (MD) with antimicrobial photodynamic therapy (aPDT) and determine the core efficient microbiota in peri-implantitis after treatment.
MethodsWe recruited 9 patients (14 implants) treated with MD+aPDT for peri-implantitis at our center from February 1, 2018, to February 1, 2019. GCF was collected using filter paper strip before and after the treatment. The bacterial 16S rRNA was amplified and sequenced using an Illumina MiSeq platform to characterize the GCF. Bioinformatics and statistical analyses were performed using QIIME2 and R.
ResultsA total of 4,110,861 high-quality sequences were obtained from GCF samples. Based on the reference database, 1,120 amplicon sequence variants (ASVs) were finally harvested. Principal coordinates analysis indicated significant differences in the bacterial community structure between the 180 days after-treatment group and pre-treatment group. Difference analysis and least discriminant analysis showed that the differences were mainly reflected in non-dominant bacteria between these two groups. The non-dominant genera with significantly different distribution between the 180 days after-treatment group and the pre-treatment group included Lactobacillus, Pedobacter, Bulleidia, Centipeda, Desulfovibrio, Ochrobactrum, Staphylococcus, Microbacterium, Brevundimonas, Desulfobulbus, and Parvimonas. Moreover, a total of 29 predictive functional categories at KEGG level 2 were identified. The significant difference pathways at KEGG level 2 between after-treatment and pre-treatment were concentrated in infectious disease-related pathways.
ConclusionsPatients with peri-implantitis have significant changes in the low-abundance bacteria of the GCF before and after MD+aPDT. MD+aPDT may change the composition of GCF microbiota by increasing the abundance of cluster 1 (beneficial) and decreasing that of cluster 4 (harmful), which may decrease metabolic response to infection and thus improve peri-implantitis.

**研究目的** 本研究旨在对比机械清创术（mechanical debridement, MD）联合抗菌光动力疗法（antimicrobial photodynamic therapy, aPDT）治疗前后龈沟液（gingival crevicular fluid, GCF）的微生物群构成，并明确种植体周围炎（peri-implantitis）治疗后核心功能菌群。**研究方法** 本研究于2018年2月1日至2019年2月1日期间，纳入本中心收治的9例（共14颗种植体）因种植体周围炎接受MD+aPDT治疗的患者。分别于治疗前后采用滤纸条采集龈沟液样本。通过Illumina MiSeq测序平台对细菌16S核糖体RNA进行扩增与测序，以解析龈沟液的微生物群落特征。本研究采用QIIME2与R语言进行生物信息学及统计学分析。**研究结果** 本研究从龈沟液样本中共获得4,110,861条优质序列。基于参考数据库，最终得到1,120个扩增子序列变异体（amplicon sequence variants, ASVs）。主坐标分析结果显示，治疗后180天组与治疗前组的细菌群落结构存在显著差异。差异分析与最小判别分析表明，两组间的差异主要体现在非优势菌群落层面。治疗后180天组与治疗前组分布存在显著差异的非优势菌属包括乳酸杆菌属（Lactobacillus）、Pedobacter属、布勒氏菌属（Bulleidia）、千头菊属（Centipeda）、脱硫弧菌属（Desulfovibrio）、苍白杆菌属（Ochrobactrum）、葡萄球菌属（Staphylococcus）、微杆菌属（Microbacterium）、短波单胞菌属（Brevundimonas）、脱硫碱菌属（Desulfobulbus）以及Parvimonas属。此外，本研究共鉴定出29个KEGG二级水平的预测功能类别。治疗后组与治疗前组在KEGG二级通路中存在显著差异的通路主要集中于感染性疾病相关通路。**研究结论** 种植体周围炎患者在接受MD+aPDT治疗前后，其龈沟液中的低丰度细菌群落会发生显著改变。MD+aPDT可能通过增加有益簇1的丰度、降低有害簇4的丰度来改变龈沟液微生物群的构成，进而降低机体对感染的代谢应答反应，最终改善种植体周围炎症状。