Expression of receptors for basic fibroblast growth factor on human periodontal ligament cells

Basic fibroblast growth factor (FGF-2; bFGF) is a major mitogen for connective tissue cells, and participates in the healing process. It has already been reported that FGF-2 could be applicable to enhance periodontal regeneration. In the present study, we examined FGF receptor (FGFR) expression on human periodontal ligament (PDL) cells. The binding of [¹²⁵I]-labeled FGF-2 to human PDL cells was studied by radioreceptor assay. The binding of [¹²⁵I]-FGF-2 to PDL cells reached a plateau after 2.5 h incubation at 4°C and was inhibited by the addition of unlabeled FGF-2 and acidic FGF (FGF-1; aFGF), but not insulin-like growth factor-I, platelet-derived growth factor and transforming growth factor-β₁. Scatchard analysis revealed the presence of approximately 1.0 × 10⁵ FGF-2 binding sites per cell with an apparent Kd of 1.2 × 10-¹⁰ M. Interestingly, the binding of [¹²⁵I]-FGF-2 on PDL cells reached its maximum at d 6 of the culture and then gradually decreased. Scatchard analysis also demonstrated that the number of FGFRs on a PDL cell was altered during the course of the culture, while the affinity between FGF-2 and its receptor was not. The responsiveness of PDL cells to FGF-2, which was monitored by the inhibitory effect on alkaline phosphatase activity, was reduced in proportion to the decrease in the number of FGFRs on the PDL cells. The present study suggests that PDL cells alter the responsiveness to FGF-2 during the course of the culture by changing the density of its receptor, and that the density of FGFR expression might be a marker of the cytodiflerentiation of PDL cells into mineralized tissue forming cells.     

Macaca nemestrina: a non-human primate model for studies of periodontal disease

The non-human primate Macaca nemestrina was evaluated for use as a potential model in periodontal research by study of 16 animals. Using one incisor, premolar, and molar per quadrant, we measured supragingival plaque, severity of gingival inflammation, and pocket depth, and analyzed the subgingival flora. Serum IgG titers and avidities to antigens of Porphyromonas gingivalis (Pg) and Actinobacillus actinomycetemcomitans (Aa) were also assessed. Ten animals were between 13 and 24 years old, and six were between 4 and 5 years old. While mean gingival inflammation scores were significantly higher for older than for for younger animals (2.2 vs 1.8, p < 0.05), mean plaque index scores and mean probing depths did not differ significantly. The animals harbored a subgingival microflora considered to be pathogenic for humans including Aa, Pg, Bacteroides forsythus, Prevotella intermedia I and II, Campylobacter recta and Fusobacterium nucleatum . Aa, however, was found only in the younger animals. All of the animals had serum IgG antibodies reactive with antigens of Pg and Aa, and titers for Pg but not for Aa were significantly higher in the older relative to the younger animals (t test p < 0.02). In contrast, antibody avidity did not significantly differ between the two groups. A combined clinical assessment index based on maximum probing depth, gingival index score, and tooth loss was used to assess the overall disease severity. Titers were positively associated with disease severity (Spearman's rank correlation 0.57, p=0.02). We conclude that M. nemestrina harbors a subgingival microflora considered to be pathogenic for humans, manifest serum IgG antibodies to antigens of Pg and Aa, and exhibits clinical features of periodontitis comparable to those seen in humans. This species appears, therefore, to be a useful model for investigating periodontal microbial-host interactions, including the immune response.     

两种生长因子对人牙周膜成纤维细胞在钛金属表面附着和生长的影响

目的：研究两种生长因子对牙周膜成纤维细胞在然金属表面附着和生长的影响。方法：将纯钛、钛75试件入在12孔培养板内，取生长良好的第五代人牙周膜成纤维细胞（PDLF）接种在试件表面，分别在接种后4h、12h、24h、72h进行贴壁细胞地数。结果：接种后4h、12h、24h、72h、bFGF组纯钛、钛75表面细胞附着数与空白对照组的差异均有显著性（P＜0．05），rhBMP－2组纯钛、然75表面细胞附着数在初期（24h）与空白对组无显著性差异（P＞0．05）。72h时与空白对照组差异有显著性（P＜0．05），表明bFGF促进细胞附着和生长作用显著，而rhBMP－2促进细胞生长作用较促附着作用明显。结果：PDLF在钛金属表面的附着和生长可被生长因子所增强，但不同的生长因子对细胞附着和生长的生物学效应不尽相同。     

The effect of three different periodontal pre-treatment procedures on the success of telescopic removable partial dentures

In this prospective study, 120 teeth consisting of maxillary and mandibular canines and premolars were divided into three groups each containing 40 teeth. The teeth were assigned randomly in quadrants to three different periodontal treatment protocols. The first group was treated with professional prophylaxis only. The second group received additional deep scaling. With the third group, additional surgical periodontal flap surgery and scaling was performed. Both papillary bleeding index (PBI) and probing depth (PD) were evaluated before, during and after treatment. During the subsequent prosthetic treatment phase all teeth were then used as telescope abutments supporting a removable prosthesis. The documentation of the attachment level (AL) was then used as a clinical parameter. One year after the incorporation of telescopic removable partial dentures (RPDs), PD, PBI and AL were again evaluated. The resulting periodontal parameters were compared between the different groups using the general linear model (GLM) repeated measures and the Kruskal-Wallis test for non-parametric variables. Differences within the three treatment groups were determined using the t-test, e.g. the Wilcoxon test for dependent variables (P < 0.05). A significant decrease in inflammatory indices (PBI) was found for all types of periodontal treatment (P < 0.03 for all groups). Additionally, the reduction in PD was significant for all of the three groups (P < 0.001 for all groups). The greatest reduction in PD was observed in the group in which a surgical approach was used. Evaluation of the attachment level after the incorporation of the telescopic RPDs showed that tooth position did not influence the periodontal prognosis and that the use of telescopic RPDs exerted no ascertainable negative influence on the periodontium of the abutment teeth.     

人牙周膜细胞体外三维立体培养模型的建立

目的：建立人牙周膜细胞（PDLC）体外三维立体培养模型，初步探讨两种支架材料应用于牙周组织工程的可行性，为进一步研究牙周组织生理病理及牙周组织工程奠定实验基础。方法：组织块法培养人PDLC，传代扩增后，接种于珊瑚和珊瑚转化羟基磷灰石（CHA）两种三维支架上，体外继续培养3d，进行细胞计数和扫描电镜观察。结果：细胞在两种支架材料上均能形成良好贴附并增殖，扫描电镜可见两种支架材料均具有良好的多孔网状结构，细胞在支架材料上生长旺盛，伸展充分。结论：可通过将人PDLC接种到珊瑚或CHA上建立体外三维立体培养模型，珊瑚和CHA均有望成为牙周组织工程的支架材料。     

Plasma antibody levels in periodontitis patients and controls

BACKGROUND: A major aspect of the adaptive host response in periodontitis is the production of antibodies. Several risk and susceptibility factors for periodontitis, including smoking, age and composition of the subgingival microflora, have also been suggested to influence antibody production. AIM: The present study was conducted to investigate plasma levels of immunoglobulin (Ig) G, A and M antibodies in periodontitis patients of Caucasian European heritage in relation to disease severity, smoking, diagnosis and prevalence of periodontopathogens. METHODS: In this study, 29 patients with severe periodontitis, 51 with moderate periodontitis and 55 controls without periodontal destruction were enrolled. From the total of 80 patients, 18 were diagnosed with aggressive periodontitis and 62 with chronic periodontitis. Total IgG, IgA and IgM as well as IgG isotypes were analyzed in plasma samples. RESULTS: Levels of total IgG, IgA and IgM were not different between patients and controls; however, in periodontitis, higher levels of IgG1 and IgG2 were observed. Smoking appeared to be significantly and inversely related to antibody levels in periodontitis, in particular for total IgG and IgG2. The absence of an elevated total IgG and IgG2 in smoking patients was irrespective of severity, prevalence of periodontal pathogens and diagnosis. The elevation of total IgG and IgG1 and IgG2 in non-smoker periodontitis patients was observed in patients with moderate periodontitis and even greater in patients with severe periodontitis, but was independent whether patients were infected with Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis and independent of diagnosis. Clinically, it was observed that patients who smoked had more periodontal bone loss; the current findings on antibody levels may be one of several mechanisms related to more extensive periodontal breakdown in smoker patients. CONCLUSION: The current study shows that non-smoker periodontitis patients have higher levels of total IgG and IgG2 than smoker periodontitis patients.     

Associations of serum concentrations of IgG,IgA, IgM and interleukin-1beta with early-onset periodontitis classification and race

BACKGROUND: The significance of serum concentrations of various antibodies and cytokines in the pathogenesis of early-onset periodontitis (EOP) is not well understood. Recent reports suggest differences between young blacks and whites in certain humoral responses, regardless of periodontal status. This study was undertaken to compare the serum concentrations of IgG, IgA, IgM, and IL-1beta in EOP subjects with that of healthy controls, and to study the effect of race on these levels. MATERIAL AND METHODS: This case-control study included 228 individuals, 19-25 years old who were selected from a larger population examined in the National Survey of Oral Health of United States Children in 1986/1987. The subjects were classified by their EOP status and they included 166 subjects with EOP and 62 healthy controls. Blood samples were used to assess the serum concentrations of IgG, IgM, IgA, IgG subclass, and IL-1beta. RESULTS: The serum concentrations of IgG, IgG subclasses, IgA, and IgM in blacks were not significantly different in the generalized, localized and incidental EOP groups as compared to the healthy controls. The serum IL-1beta concentration was slightly and uniformly lower in the EOP groups than in the control group, although not statistically significant. Blacks had significantly higher serum concentrations of total IgG, and of IgG1, IgG2 and IgG3 than whites and Hispanics. Hispanics had significantly higher serum concentrations of IgM and IgG4 than whites and blacks. Hispanics also had a significantly higher serum concentration of IL-1beta than blacks. CONCLUSIONS: Total antibody response in blacks is not associated with EOP classification. Race has a significant effect on serum antibody concentrations irrespective of disease classification, with blacks having significantly higher serum concentrations of IgG1, IgG2 and IgG3 than whites and Hispanics.     

The use of DNA probes to examine the distribution of subgingival species in subjects with different levels of periodontal destruction

The present investigation examined the distribution of 14 subgingival species at a total of 2299 sites in 90 subjects with different levels of periodontal destruction. Subgingival plaque samples taken from the mesial aspect of each tooth were anaerobically dispersed, diluted and plated on non selective media. After anaerobic incubation, colonies were lifted to nylon filters and specific species detected using digoxygenin-labeled whole chromosomal DNA probes. The mean total viable count for all sites in all subjects was 8.3 x 10(6). The probes accounted for an average of 27.8% of the total viable count. The % of subjects in which each species was detected was as follows; V. parvula, 98; B. intermedius I, 98; S. sanguis II, 96; B. intermedius II, 95; C. ochracea, 94; B. gingivalis, 91; S. sanguis I, 85; W. recta, 83; F. nucleatum ss. vincentii, 82; S. intermedius, 80; B. forsythus, 76; P. micros, 74; A. actinomycetemcomitans serotype a, 62 and A. actinomycetemcomitans serotype b, 52. The % of sites colonized by each of the 14 test species varied considerably within different subjects. The median number of sites colonized by different species ranged from 3.6% for A. actinomycetemcomitans serotype b to 43.5% for V. parvula. In half the subjects, the mean % of the total viable counts for each of the test species was less than 4%. When subjects were divided on the basis of % of sites at baseline with greater than 3 mm attachment loss, the 14 probes accounted for 29.9% of the microbiota in the localized disease group and 25% in the widespread disease group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tooth mobility and resolution of experimental periodontitis

Abstract The aim of the present experiment was to study alterations in the mobility of teeth that occurred during resolution of experimentally induced periodontitis lesions in the dog. 5, 1-year-old, beagle dogs were used in the study. The left and right 4th, 3rd, and 2nd mandibular premolars (₄P₄, ₃P₃, ₂P₂) served as experimental teeth. Periodontal tissue breakdown was initiated by placing plaque-collecting cotton-floss ligatures around the neck of the experimental teeth. The ligatures were replaced to the level of the receding gingival margin 1 × every month. On Day 120, the ligatures were removed and debridement was performed. A groove, parallel to the long axis of the mesial root, was prepared in the mesio-buccal surface of the crowns of ₂P and P₂. Guided by the groove and with a probing force of 0.5 N, a probe was inserted into the buccal gingival pocket of the mesial root and was attached to the buccal surface. Biopsies including both the mesial and distal root of ₂P and P₂ and the surrounding hard and soft tissues were harvested. The biopsy procedure was repeated in a similar manner 15 days (i.e. Day 135) and 3 months (i.e. Day 225) after ligature removal in the 4th (₄P₄) and 3rd (₃P₃) premolar regions. After fixation, decalcification and sectioning, the biopsy material was exposed to histometric and morphometric measurements. Assessment of the mobility of the experimental teeth was performed on Days 120, 135 and 225 using the Periotest system. The amount of remaining bone at the experimental teeth was evaluated in radiographs obtained in a standardized manner. The findings of the present experiment disclosed that in dogs allowed to form plaque, the placement of cotton-floss ligatures at the neck of mandibular premolars initiated a process that resulted in (i) the formation of an inflammatory lesion which extended deep into the supracrestal connective tissue; (ii) extensive loss of alveolar bone; (iii) markedly increased tooth mobility. It was also observed that, within a 4-month period the removal of the ligature and, as a consequence, a substantial portion of the subgingival microbiota, reduced the size and the apical extension of the inflammatory lesion in the supracrestal connective tissue. The alterations in the soft supracrestal tissue were accompanied by a marked decrease in the mobility of the experimental teeth and a reduced probing pocket depth. It was suggested that the reduced penetration of the probe was the result of the change in the size and position of the infiltrate as well as of a reduced mobility of the experimental teeth.