[Efficacy of subgingival scaling of the molars with conventional scalers in vitro].

PURPOSE: To evaluate the efficacy of traditional manual scaling and piezoelectric and magnetostrictive ultrasonic scaling in regard to periodontal pocket depth and power setting. METHODS: Thirty extracted human molars were assigned to receive manual scaling or ultrasonic scaling (both on the full or half power setting) with probing depth of 5 and 7 mm for 2 min. The remained oil materials on the roots were calculated as supplementary data. The data were compared using SAS6.12 software package. RESULTS: The procedures of ultrasonic scaling resulted in reductions of the values than manual scaling in all groups. The data of the magnetostrictive group were significantly smaller than the piezoelectric group in 5 mm pocket depth (P<0.01) on full power setting, while the opposite in 7 mm pocket depth. There was no significant difference between piezoelectric and magnetostrictive scaling in both 5 mm (P=0.217) and 7 mm (P=0.574) pocket depth on half power setting. The data increased significantly from 5 to 7 mm pocket depth (P<0.01), but no significant influence on different power settings. CONCLUSIONS: The study indicates that ultrasonic scaling instruments are more effective than a hand curette and the scaling efficacy decreased in deeper periodontal pocket.The results reveal no significant difference between magnetostrictive and piezoelectric ultrasonic instruments whether on half or full power settings.

[Comparison of subgingival debridement efficacy of air polishing and manual scaling].

PURPOSE: To assess the efficacy of subgingival air polishing and traditional manual scaling in 3-6 mm pockets. METHODS: Patients with chronic periodontitis who were in the maintenance phase were randomly assigned to receive subgingival air polishing (experimental group) and manual scaling (control group) in 4 teeth with probing depths of 3 to 6 mm. Clinical variables including plaque index (PI), probing depth (PD), probing on bleeding (BOP) and gingival recession (GR) were recorded at baseline, 7 and 30 days post-treatment. "Pocket closure" [PD ≤ 4 mm and BOP⁻] was also calculated as supplementary data. The data of the 2 groups were compared using paired t test with SAS 8.2 software package. RESULTS: Thirty-one patients were enrolled and PI was 0.8 during the study. Both treatment procedures resulted in significant reductions of PD at day 7 (P<0.0001). BOP% had significant reduction in the experimental group at day 7 (P=0.0390), but there was no significant difference compared to baseline at day 30. Meanwhile, BOP% in the control group demonstrated downward trends during the study, and significant improvement at day 30. The percentages of sites of "pocket closure" significantly increased in both groups (P=0.0329 and P=0.0035, respectively). CONCLUSIONS: The study indicates that subgingival air polishing and traditional manual scaling are both effective for improving clinical variables during supportive periodontal therapy (SPT) in teeth with probing depths of 3 to 6 mm. But the results reveal no significant difference between the 2 modalities.

[The effect of vascular endothelial cells on the migration of periodontal ligament cells and gingival fibroblasts].

PURPOSE: To investigate the effect of human vascular endothelial cells (HUVEC) on the migration of human periodontal ligament cells (HPDLC) and human gingival fibroblasts (HGF) through a model mimicking periodontal wound healing or regeneration. METHODS: HUVEC, HPDLC and HGF were co-cultured using a Transwell system, while HPDLC or HGF was cultured independently as control. Chemotaxis assay was performed using cell culture inserts (0.8µm pore size) to assess the effect of HUVEC on HPDLC and HGF vertical migration at 24h. A scratch wound assay was performed to assess the effect of HUVEC on HPDLC and HGF horizontal migration at 0 h, 8 h, 16 h and 24 h. A round glass sheet assay was performed to assess the effect of HUVEC on HPDLC and HGF wound healing ability at 1d, 4d and 7d. The data was processed with SPSS 13.0 software package. RESULTS: At the round glass sheet assay, while HUVEC was present, the integrated option density (IOD) of HPDLCs and HGFs were significantly higher than each of the single culture (P<0.01). Results of chemotaxis assay and scratch wound assay showed that the cell number of HPDLCs and HGFs were significantly higher than each of the single culture while HUVEC was present (P<0.01), and the number of PHDLCs was significantly higher than HGFs on chemotaxis assay (P<0.01) but the result of scratch wound assay was on the contrary (P<0.01). CONCLUSIONS: The presence of HUVEC can promote migration of periodontal cells, and the effect is more prominent on HPDLC than on HGF in vertical migration and wound healing, while horizontal migration is more prominent on HGFs as contrast.

[The reliability of the salivary occult blood to test gingival inflammation].

PURPOSE: To evaluate the reliability of salivary occult blood test(SOBT) for gingival inflammation. METHODS: Forty-five pre- and post-stimulation saliva samples were tested for occult blood, with bleeding on probing (BOP) as an indicator of gingival inflammation. Subjects with BOP%<15% were defined as control group. The examinations were repeated 3 months after periodontal initial therapy. The relationship between the results of SOBT and gingival inflammation was analyzed. SAS6.12 software package was used for statistical analysis. RESULTS: The SOBT of pre-stimulation was higher in gingivitis group than in control group (P<0.05). BOP% and SOBT of post-therapy was significantly decreased (P<0.01), with 90% of pre- and 63% of post-stimulation SOBT turning negative. The sensitivity and specificity of pre- stimulation SOBT in screening gingivitis were 32.35% and 100%. The sensitivity and specificity of the post-stimulation SOBT were 88.24% and 81.82%. CONCLUSIONS: SOBT is correlated with gingival inflammation, which may be used as an objective parameter to evaluate gingival inflammation and the efficacy of periodontal therapy at individual level. It may offer a simple screening method for gingival inflammation applied in periodontal epidemiologic studies in large population.

[The effect of vascular endothelial cells on the proliferation of periodontal ligament cells and gingival fibroblasts].

PURPOSE: To investigate the effect of vascular endothelial cells on the proliferation of periodontal ligament cells and gingival fibroblasts through a model mimicking the periodontal wound healing and regeneration. METHODS: Human vascular endothelial cells, periodontal ligament cells and gingival fibroblasts were co-cultured using a Transwell system. The number of each type of cells at 2, 4, 6, 8 and 10 days after co-culture were counted using a cell counter machine, while periodontal ligament cells and gingival fibroblasts single culture were used as control. The results were statistically processed with SPSS 13.0 software package. RESULTS: When vascular endothelial cell was present, the proliferation of periodontal ligament cells and gingival fibroblasts were faster than each single culture, the difference between them was significant (P<0.01). The proliferation of periodontal ligament cells was faster than gingival fibroblast as they were co-cultured with vascular endothelial cells(which happened at day 6), although the results were contrary when they were single cultured, the difference between them was significant (P<0.01). CONCLUSIONS: The presence of vascular endothelial cells can promote the proliferation of periodontal cells, and the effect is more prominent on human periodontal ligament cells than on gingival fibroblasts.

[Expression of IL-6 in cyclosporin A-induced gingival overgrowth].

PURPOSE: To estimate the role of IL-6 in cyclosporin A(CsA)-induced gingival overgrowth(GO) and collect the evidence of pathomechanism for CsA-induced GO. METHODS: Gingival fibroblasts and epithelial cells were treated with CsA of three different concentrations (600ng/mL, 800ng/mL, and 1000ng/mL) with different time (48h, 72h). After cell stretched preparation, the secretion of IL-6 was analyzed by ELISA while expression of IL-6 was analyzed by immunohistochemistry (ABC). SAS 6.0 software package was used for statistical analysis. RESULTS: The growth speed of gingival epithelial cells in the group treated with CsA was significantly faster than the control group (P<0.05). The IL-6 expression of gingival epithelial cells and fibroblasts had no significance difference, but changed depending on the concentration and treated time with CsA. During the first 24h, there was no significant difference between the experimental and control groups of gingival fibroblasts, while after stimulation of 1000ng/mL CsA for 24h or longer, the secretion of IL-6 in gingival fibroblasts was significantly higher than the control group (P<0.05). CONCLUSIONS: IL-6 is not the main cytokine of gingival epithelial cells, IL-6 in CsA-induced GO probably secreted by the gingival fibroblasts; the effect of CsA on the secretion of IL-6 in the gingival epithelial cells and gingival fibroblasts is associated with the time and concentrations of CsA.

[Expression of TGF-ß1 and PCNA in cyclosporin A-induced gingival overgrowth].

PURPOSE: To investigate the expression of transforming growth factor-ß1(TGF-ß1) and proliferating cell nuclear of antigen (PCNA) in cyclosporin A(CsA)-induced gingival overgrowth (GO) tissues. METHODS: After extraction of half of the maxillary molars, 20 male Sprague-Dawley rats were randomized into a CsA-injection group (10mg·kg⁻·d⁻¹) or a normal saline control group. Ten rats per group were sacrificed at the fourth week after injection. The gingival width was measured under a stereo-microscope. After full demineralization of the mandible, gingival specimens were taken. The linear measurements and the immunohistochemistry analysis of TGF-ß1 and PCNA were made using the software of Image Pro-plus 6.0. The data was analyzed with SAS6.12 software package. RESULTS: The percentage of cells positive staining for TGF-ß1 and PCNA was significantly higher in the CsA rats than in the control rats (P<0.05), but there was no significant difference between the edentulous and denti-gingiva in the same group(P>0.05). CONCLUSIONS: The upregulation of TGF-ß1 may have no direct relations with gingival inflammation in CsA-induced gingival overgrowth.In addition, TGF-ß1 may be one of the key cytokines for CsA-induced gingival overgrowth. Increased epithelial proliferative activity may be the main cause of epithelial hyperplasia.

[Evaluation of the remaining periodontal ligament from attachment level].

PURPOSE: To estimate the total periodontal ligament areas and the remaining periodontal ligament areas from different attachment level of each tooth type, and to determine the relationship between the attachment loss and the prognosis of periodontal diseases. METHODS: Four hundred and twenty extracted teeth (30 of each tooth type of one side of both arches,except for the third molar) were collected.The root surface of each tooth was coated with polyvinyl alcohol to produce a membrane after cleaning. The membrane was peeled off after guidelines were drawn on to simulate various attachment levels. The root surface area of each simulated attachment level was measured using image analysis software Photoshop cs 9.0 and Scion Image 4.0.3. SAS 6.12 software package was used for statistical analysis. RESULTS: The correlation and significance of the linear function for each tooth type were significant(P<0.001);Based on the regression beeline, the mean total periodontal ligament area of the teeth was reduced to about 50% when the attachment loss was more than 5.37mm. CONCLUSIONS: The linear function provides an appropriate fit for estimation of the remaining area of periodontal ligament from the attachment level measurement.The remaining periodontal ligament of teeth whose attachment loss is more than 5.37mm could not supply half of the original support force. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality(Grant No.08DZ2271100).

[The effect of dental plaque in cyclosporin A-induced gingival overgrowth].

PURPOSE: To evaluate the role of dental plaque in cyclosporin A(CsA)-induced gingival overgrowth. METHODS: After extraction of half of the maxillary molars, twenty male Sprague-Dawley rats were assigned to a CsA-injection group (10mg/k x d) or a control group. Ten rats per group were sacrificed at week 4. The gingival width was measured under a stereomicroscope. Gingival specimens were taken, and the linear measurements were made with the help of software Image Pro-plus 6.0. The data was analyzed with SAS 6.12 software package. RESULTS: The gingival width of the CsA group was significantly greater than the control group in both macroscopic analysis and histomorphometrical analysis (P<0.05). CONCLUSIONS: Dental plaque seems not to be a essential but to be a co-factor for the CsA-induced gingival overgrowth.

[The effect of initial periodontal therapy on metabolic control in type 2 diabetes mellitus].

PURPOSE: To investigate the effect of periodontal initial therapy on metabolic control in type 2 diabetes mellitus patients with chronic periodontitis. METHODS: Thirty type 2 diabetic patients with chronic periodontitis were selected as experimental group, 30 patients with chronic periodontitis were selected as control group. Their gingival index(GI), probing depth(PD), clinical attachment level(CAL), fasting plasma glucose(FPG), glycated hemoglobin A1c(HbA1c), total cholesterol(TC) and triglyceride(TG) were evaluated using SAS 6.12 software package for multiple linear regression analysis before treatment(as base) and 1, 3 month(s) after periodontal initial therapy. RESULTS: In both two groups, a significant improvement of periodontal index was found after periodontal initial therapy (P<0.05). After therapy, TC, TG in diabetic patients showed no changes(P>0.05), and FPG, HbA1c in fairly-controlled diabetic patients were reduced significantly(P<0.05) whereas the well-controlled diabetic patients showed slight but insignificant decrease for these parameter(P>0.05). CONCLUSION: The result of periodontal initial therapy in the type 2 diabetic patients with chronic periodontitis is significant in short time. It can reduce the level of FPG and HbA1c. Supported by National Key Science and Technology Project from "Tenth Five Year Plan" (Grant No.2004BA720A26).

[Periodontal wound filling affected by aging in an in vitro model].

PURPOSE: Using human periodontal ligament cells (PDLC) and gingival fibroblasts (GF) , that were cultured in vitro for a long period of time to simulate the aging cells, we evaluated the influence of aging on periodontal healing in an in vitro wound model. METHODS: Human PDLC and GF were cultured in vitro over to 12 passages as aging cells for experiment, the same type of cells that were cultured under 5 passages as younger for control. The in vitro wound models were mechanically created in subconfluent cultures of this 4 types of cells, by removing a 7 mm wide band of the cell layer respectively. Wounded cultures were then incubated for 2, 6, 9 days in the same media. Slides were fixed, stained with crystal violet and cell filling area within the wound boundaries were quantified by computer-assisted histomorphometry. Statistical analysis was performed by SAS6.12 software package to determine the differences between the time points and groups. RESULTS: The ability of filling wound of aging PDLC and GF decreased, there was significant difference (P<0.05) at day 6, 9 between the experimental and control groups. There was difference between GF and PDLC in filling wound in vitro over 9 days of healing period in both groups, but only the experimental group showed significant difference (P<0.05) at 9th day after wound creating. CONCLUSION: The ability of filling wound of aging PDLC and GF were weaker then that of the younger. Within the limits of the present study, data analysis suggests that aging may impair the healing characterization of PDLC and GF.

[Effect of enamel matrix protein on periodontal cells in an in vitro wound healing model].

PURPOSE: The aim of this study was to evaluate the influence of enamel matrix protein (EMP) on wound filling of periodontal ligament cells (PDLC) and gingival fibroblasts (GF), using an in vitro model of wound healing. METHODS: In vitro wound models were mechanically created in subconfluent cultures of human GF and PDLC, by removing a 7mm wide band of the cell layer respectively. Wounded cultures were then incubated for a time periods up to 2,6,9 days in a media containing 10% fetal bovine serum (FBS), stimulated with EMP (100microg/ml) simultaneously, negative controls were those cultured only with media containing 10% FBS. Slides were fixed, stained with crystal violet and cell filling area within the wound boundaries was quantified by computer assisted histomorphometry. Statistical analysis was performed by SAS6.12 software package to determine the differences between the time points and groups. RESULTS: in the control group, there was difference between GF and PDLC in filling wound in vitro over 9 days of healing period. The difference was significant (P<0.05) at the 9th day after wound creating, with GF filling the wound faster than PDLC. In contrast, under the stimulation of EMP (100microg/ml), there was no significant difference (P>0.05) between the filling rate of two types of periodontal cells at the 6th, 9th day after wound creating. CONCLUSION: GF has a significantly greater ability to fill a wound than PDLC. However, EMP appears to exert an influence on cells that is compatible with improved wound healing, especially in that of PDLC.

[A study on the state of periodontal health of 400 professional adults by random sampling in Shanghai].

PURPOSE: To investigate and analyze the state of periodontal health of 400 adults at their post and risk factors in Shanghai. METHODS: 400 subjects (249 male, 151 female), aged from 25 to 59, were requested to fill a questionnaire. The probing depth (PD), clinical attachment level (CAL), tooth mobility (TM) and bleeding on probing(BOP) on 6 sites of each indicated tooth were measured and recorded. SAS 6.12 software package was used for statistical analysis. RESULTS: OHI-S of Shanghai adults at their post was 2.16 +/- 0.99 and GI = 1.2227, indicating moderate gingivitis. The difference of periodontal disease among the adults at varied occupations in Shanghai municipality was significant. Periodontal destruction of the clerk group was the lightest The difference of periodontal disease among the adults at varied age groups in Shanghai municipality was also significant. Periodontal destruction of the elder group was heavier than of the lower age group. 146 subjects suffered from initial to moderate periodontitis. 140 subjects suffered from advanced periodontitis. 79, 317 and 4 subjects had received college education, high school education and postgraduate school education respectively. There was no relationship between the severity of periodontitis and educational level. 330 out of 400 (82.5%) subjects had never been treated, 70 out of 400 (12.5%) had scaling,and only 3.25% of subjects had received regular periodontal treatment. CONCLUSION: It is very important to develop an education program on oral health for people in Shanghai. Supported by National "Tenth Five-Year" Key Project (Grant No.2004BA720A26), Research Fund of the Science and Technology Committee of Shanghai Municipality (Grant No.0352nm126) and Shanghai Leading Academic Discipline Project(Grant No.94-III-008).

[Histological evaluation of domestic poly-DL-lactic acid membranes for periodontal guided tissue regeneration].

OBJECTIVE: To evaluate the possibility of domestic poly-DL-lactic acid membranes as barriers during periodontal guided tissue regeneration. METHODS: Two-wall intrabony defects were made by artificially removing buccal and distal alveolar bone from the distal roots of the second, third and fourth mandibular premolars as well as the first mandibular molars of dogs. These experiment defects received four membranes (PDLLA, ePTFE, COL, Vicryl ) respectively for GTR, the control treated without membrane. Animals were sacrificed for histological evaluation and histometric analysis 2,4,8 weeks after surgery. RESULTS: Domestic poly-DL-lactic acid membranes for periodontal guided tissue regeneration only induce a non-specific inflammation, which began its bioresorption at 4 weeks after surgery. Just like the other GTR materials including Vicryl mesh,domestic poly-DL-lactic acid membrane acts as barrier preventing the apical downgrowth of gingival epithelium and prompting periodontal tissue regeneration. As compared with the control, PDLLA exhibited its more effects 4 weeks after surgery, there is statistically difference between them. CONCLUSION: Domestic poly-DL-lactic acid membranes exhibit excellent biocompatibility, as a guided tissue regenerative materials, it may have beneficial effects in the treatment of 2-wall periodontal intrabony defects.