[Effect of periodontal surgery on the subgingival periodontal microbiota in artificial class III furcation defects: an experimental study in monkeys].

OBJECTIVE: This study was to longitudinally evaluate the change of prevalence of five periodontal putative pathogens in the subgingival plaque of artificial class III furcation defects at the three time-points, including before the establishment of furcation defects, before and 6 months after periodontal surgery. METHODS: Eighteen chronic infected class III FI defects were created at the mandibular first molars, second molars and second premolars of three adult male Macaca fascicularis. The samples of subgingival plaque were obtained from the subgingival area of furcation defects in buccal and lingual sites before the establishment of furcation defects, before and 6 months after periodontal surgery. 36 samples were obtained at one time-points. Five periodontal putative pathogens, including Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema dinticola (Td), Actinobacillus actinomycetemcomitans (Aa) and Fusobacterium nucleatum (Fn), were detected with 16SrRNA based PCR. RESULTS: 1. The prevalence of Pg, Tf, Td and Fn was gradually increased, from 58.3% to 69.4% to 88.9%, 47,2% to 69.4% to 83.3%, 13.9% to 36.1% to 61.1% (P<0.01), and 69.4% to 91.7% to 91.7% (P<0.05), respectively during the experimental period. The prevalence of Fn was higher than Pg, Tf and Td. The prevalence of Aa was the lowest and no obvious difference among the three samplings(from 25.9% to 13.9% to 33.3%)was detected. 2. The prevalence of more than 3 species simultaneously detected was increased from 38.9% to 61.1% to 83.3% (P <0.01). The red complex (Pg + Tf + Td) was detected from 8.3% to 27.8% to 44.4% (P<0.01) at the different time point. 3. The combined detection frequency of red complex in the inflammatory sites (87.5%), which were histologically defined as inflammatory cells infiltrated in furcation area 6 months post-surgery, and the same sites pre-surgery (62.5%) was more than that in pre-creation of furcation defects (P<0.01). But there were no significant differences compared to that in non inflammatory area (60.0%, 40.0%), respectively. CONCLUSION: The prevalence of periodontal pathogenic bacteria correlated with the severity of local inflammation. The increase of coexistent rate of red complex at the second and third sampling times suggests that the red complex play important role in the pathogenesis of periodontitis. Fn may be a resident bacteria in the subgingival plaque, play a bridge role on the biofilm formation and maturation. Aa may not be a major causative bacteria in the clinical periodontitis.

[Clinical and radiographic evaluation of class III furcation defects in the treatment using autogenous periodontal ligament cells with or without enamel matrix derivatives].

OBJECTIVE: To evaluate whether the use of periodontal ligament cells(PDLC) with or without enamel matrix derivatives(EMD) influences periodontal tissue repair in class III furcation defects. METHODS: Three adult male Macaca fascicularis monkeys were used. Class III furcation defects were created at the mandibular second pre-molars, first molars and second molars. The autogenous PDLC were cultured in vitro with Bio Oss Collagen. Six furcation defects in the 3 monkeys were divided as follows, Group A (one second molar): PDLC/Bio Oss Collagen+EMD; Group B (another second molar): Bio Oss Collagen+EMD; Group C (one first molar): PDLC/ BiojOss Collagen; Group D(another first molar): Bio Oss Collagen; Group E (one second pre-molar): EMD; Group F (another second pre-molar): the empty control. All sites (including buccal and lingual side) were covered with collagen membranes. The monkeys were euthanized at the end of 6 months. The periodontal depth (PD) and clinical attachment level (AL) at the buccal and lingual furcation defects were examined before and 6 months after the implantation. X-rays were also obtained at the same time points. RESULTS: PD and AL were decreased in most sites, the reductions in groups E and F (the second pre- molars) were the most significant, and then in turn were in groups A, C, B and D. The repaired alveolar bones were almost full of furcation area in the second pre-molars, and the relatively clear lamina dura was also found. The alveolar bones in the other sizes only had a little repair, and the obviously low density area still remained in the coronal of the defects. CONCLUSION: The results of this study indicate that class III furcation defects can not be predictably resolved even with the combination of autogenous PDLC and EMD, although they may increase the repair of periodontal tissue in the area of class III furcation defects separately. The sizes of furcation defects and the coverage of gingival flap would influence the outcome of the treatment of class III furcation defects.

[Correlation analysis between plasma levels of 25-hydroxy vitamin D3 and osteocalcin in patients with aggressive periodontitis].

OBJECTIVE: To explore the relationship between plasmatic 25-hydroxy vitamin D3 (25OHD3) level and plasmatic osteocalcin level in patients with aggressive periodontitis (AgP). METHODS: Thirty four AgP patients and 29 healthy controls were included in this study. 25OHD3 and osteocalcin levels in plasma were measured using commercially available radioimmunoassay kits. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured using a standard hospital analytical technique. RESULTS: Plasmatic 25OHD3 level was significantly higher in AgP patients than that in healthy controls (8.65 microg/L vs 3.10 microg/L; P<0.01). Osteocalcin level was also significantly higher in AgP patients than that in healthy subjects (1.0 microg/L vs 0.8 microg/L; P=0.028). AST level was significantly lower in AgP patients than that in healthy controls(20.0 U/L vs 23.0 U/L). No correlations between the plasmatic levels of 25OHD3 and osteocalcin were detected in AgP patients or in healthy controls (r=0.271, P=0.12; r=-0.356, P=0.58). CONCLUSION: Plasmatic 25OHD3 and osteocalcin concentrations were not correlated but might be influenced by AgP.

Preparation of poly(L-lactic acid) nanofiber scaffolds with a rough surface by phase inversion using supercritical carbon dioxide.

Phase inversion using supercritical carbon dioxide (SC-CO2) has been widely used in the development of tissue engineering scaffolds, and particular attention has been given to obtaining desired morphology without additional post-treatments. However, the main challenge of this technique is the difficulty in generating a three-dimensional (3D) nanofiber structure with a rough surface in one step. Here, a poly(L-lactic acid) (PLLA) 3D nanofiber scaffold with a rough surface is obtained via phase inversion using SC-CO2 by carefully choosing fabrication conditions and porogens. It is found that this method can effectively modulate the structure morphology, promote the crystallization process of semicrystalline polymer, and induce the formation of rough structures on the surface of nanofibers. Meanwhile, the porogen of ammonium bicarbonate (AB) can produce a 3D structure with large pores, and porogen of menthol can improve the interconnectivity between the micropores of nanofibers. A significant increase in the fiber diameter is observed as the menthol content increases. Furthermore, the menthol may affect the mutual transition between the α' and α crystals of PLLA during the phase separation process. In addition, the results of protein adsorption, cell adhesion, and proliferation assays indicate that cells tend to have higher viability on the nanofiber scaffold. This process combines the characteristic properties of SC-CO2 and the solubility of menthol to tailor the morphology of polymeric scaffolds, which may have potential applications in tissue engineering.

[Computer aided design and computer aided manufacture of template for crown lengthening].

PURPOSE: To introduce a method applied in computer aided design and computer aided manufacture (CAD-CAM) of template for crown lengthening. METHODS: Point cloud data of dental stone model of the patient in the plan of crown lengthening surgery was obtained by laser scanning. The following processes were carried out, constructing 3-D curve of the gingiva, drawing template outline on the triangle mesh model, shelling it for 3-D model of template, and transferring the data to rapid prototyping equipment for manufacture. RESULTS: 3-D model of the template was preliminarily accomplished. The resin template was manufactured with rapid prototyping equipment. The fitness between resin template and plaster model was good. CONCLUSIONS: This method, as an integrated procedure including data acquisition, 3-D computer modeling and fabrication by rapid prototyping, is feasible to implement CAD-CAM of template for crown lengthening.

[17-ß estradiol promotes the expression of interleukin-6 in human periodontal ligament cells infected with Porphyromonas gingivalis].

OBJECTIVE: To investigate the effects of 17-ß estradiol (E(2)) and Porphyromonas gingivalis (Pg) W83 on the expression of interleukin (IL)-6 and IL-8 in human periodontal ligament cells (hPDLC). METHODS: Primary cultures of hPDLC were established and the cells of passage four were treated with 10(-10) mol/L E(2), 10(-7) mol/L E(2) or PgW83 individually or E(2) combined with PgW83. The expression levels of IL-6 and IL-8 protein at 12 h and 24 h were measured with enzyme-linked immunosorbent assay and the levels of mRNA at 24 h were detected with real-time reverse transcriptase polymerase chain reaction. RESULTS: The expression level of IL-6 reached (2482.88 ± 26.53) ng/L in hPDLC treated with Pg at multiplicity of infection (MOI) of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10:1 [(734.09 ± 87.90) ng/L, P = 0.000], the controls [(425.8 ± 77.25) ng/L, P = 0.000] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1157.50 ± 234.65) ng/L, P = 0.000]. The expression level of IL-8 reached (4965.81 ± 1072.55) ng/L in hPDLC treated with Pg at MOI of 100 for 24 h, which was significantly higher than that in hPDLC treated with Pg at MOI of 10 [(803.51 ± 162.08) ng/L, P = 0.007], the controls [(400.75 ± 2.27) ng/L, P = 0.005] and that in hPDLC treated with Pg at MOI of 100 for 12 h [(1431.12 ± 82.78) ng/L, P = 0.001]. E(2) did not show remarkable effect on the expressions of IL-6 and IL-8. E(2) combined with Pg (MOI = 100:1) significantly promoted the expression levels of IL-6 at 24 h while did not influence those of IL-8. The relative mRNA level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were 0.49 ± 0.15 (P = 0.021)and 0.53 ± 0.16 (P = 0.036) individually, which were significantly higher than that treated with Pg alone, 0.19 ± 0.06. The protein level of IL-6 in hPDLC treated with 10(-10) mol/L E(2) or 10(-7) mol/L E(2) combined with Pg were (5512.66 ± 1022.07) ng/L (P = 0.012) and (6988.78 ± 2279.13) ng/L (P = 0.000) individually, which were significantly higher than that treated with Pg alone, (3138.46 ± 183.72) ng/L. CONCLUSIONS: PgW83 significantly increased the expression levels of IL-6 and IL-8 in hPDLC in a dose-and time-dependent manner. Without the infection of periodontal pathogens, estrogen may exert no effect on the expression of IL-6 and IL-8 while it may promote the expression of IL-6 in hPDLC when combined with Pg, which may in turn promote the process of periodontal inflammation.