Objective: To investigate periodontal status of patients with pre-diabetes and evaluate the prevalence of periodontal pathogens in oral cavity. Methods: All the subjects were under regular care in urban area of Beijing, including 88 subjects with normal blood glucose (normal blood glucose group), 27 pre-diabetic patients (pre-diabetic group), 58 well-controlled diabetic patients (glucose well controlled group) and 72 poor-controlled diabetic patients (glucose poor controlled group). Whole unstimulated saliva samples were collected before periodontal examination. Periodontal parameters, including plaque index (PLI), probing depth (PD), bleeding index (BI), bleeding on probing (BOP) and clinical attachment loss (CAL), were examined at mesial-buccal and distal-lingual sites of each tooth. Number of missing teeth was recorded. DNA was extracted from the salivary deposition, Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), Campylobacter rectus (Cr), and Prevotella nigrescens (Pn) were detected by using PCR method based on 16SrRNA. Periodontal status and prevalence and quantity of the pathogens under various blood glucose states were compared. Results: The PD scores of four groups had no statistical differences. The CAL [(2.29±1.35) mm] and the number of missing teeth[2.0 (7.0)] in pre-diabetic group were significantly lower than that in glucose poor controlled group [(3.07±1.45) mm, P=0.04 and 5.0 (10.0), P=0.04, respectively]. The number of missing teeth in pre-diabetic group [2.0 (7.0)] was significantly lower than that in glucose well controlled group [5.0 (9.0), P=0.02]. The percent of bleeding on probing [BOP(+)%] in pre-diabetic group [(63.89±20.03)%] was significantly higher than that in normal blood glucose group [(54.51±22.29)%, P=0.04] and glucose well controlled group [(53.12±21.77)%, P=0.03]. The prevalence of Pg in pre-diabetic group (81.5%) was significantly higher than that in glucose poor controlled group (54.2%, P=0.02). The prevalence of Tf in pre-diabetic group (96.3%) was significantly higher than that in glucose poor controlled group (76.4%, P=0.01). Meanwhile the quantity of Pg [1.58 (4.75)] and Tf [5.46 (7.77)] in pre-diabetic group were significantly higher than that in glucose poor controlled group [0.60 (1.87), P=0.01 and 1.63 (3.06), P<0.01, respectively]. The quantity of Pn [0.85 (1.68)] in pre-diabetic group was significantly higher than that in normal blood glucose group [0 (1.02), P=0.04]. Conclusions Pre-diabetic patients showed severe periodontal infection and BOP(+)% than other three groups and had high risk-level of periodontitis.

Objective: To research the variation of subgingival microorganisms after 65 μm glycine powder air-polishing (GPAP) in patients with periodontitis during periodontal maintenance phase and make comparison with conventional method. Methods: From Department of Periodontology, Peking University School and Hospital of Stomatology, twenty-one patients at the age of 35-72 (8 males and 13 females) who were systematically healthy were recruited in this study. According to splitting-mouth design, one side of a mouth was randomly assigned to the experiment group (21 patients, 248 teeth, 1 488 sites) with 65 μm GPAP therapy while the opposite side served as the control group (21 patients, 249 teeth, 1 494 sites) with ultrasonic scaling plus polishing paste therapy. The clinical periodontal parameters including probing depth (PD), bleeding index (BI), bleeding on probing (BOP) and plaque index (PLI) were recorded. Using sterile currette, the subgingival plaque samples were collected at the mesio-buccal site of the first or second molars at baseline, 2, 4, 8 and 12 weeks after therapy, respectively. After Congo red staining, the microorganisms were classified into cocci, bacilli and spirochetes and counted respectively. Results: All clinical periodontal parameters have no difference between two groups at baseline and after treatment 12 weeks. In the experiment group and the control group, PD ([2.33±0.90] and [2.37±1.18] mm), BI (0.96±0.70 and 0.98±0.78) and PLI (0.00[1.00] and 0.00[1.00]) of two groups after treatment 12 weeks were better than those at baseline (PD: [2.48±1.17] and [2.46±0.99] mm; BI: 1.07±0.72 and 1.08±0.75; PLI: 0.00 [1.00] and 0.00 [1.00]) (P<0.05). But BOP(+)% was observably reduced only in the control group after treatment 12 weeks ([17.25±2.21]% vs [25.23±2.83]%) (P<0.05). The percentages of cocci, bacilli and spirochetes were stable and there were not significant differences between the two groups (P>0.05). Conclusions After 65 μm GPAP therapy, the differences of proportion of subgingival microorganisms are not significant, while the control group has the same trend. The spirochetes remained at a low level, but they rebounded fasterly in the test group than that in the control group. The results indicate that 65 μm glycine powder air-polishing has the similar clinical effects compared with ultrasonic scaling plus polishing paste. However, the clinical indications should be limited to the patients with shallow pockets and without obvious dental calculus.