Library

Notes: Background, aim: The present study describes (i) the natural distribution of the three putative periodontopathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in an Australian population and (ii) the relationship between these organisms, pocket depths and supragingival plaque scores.Methods: Subgingival plaque was collected from the shallowest and deepest probing site in each sextant of the dentition. In total, 6030 subgingival plaque samples were collected from 504 subjects. An ELISA utilising pathogen-specific monoclonal antibodies was used to quantitate bacterial numbers.Results:: A. actinomycetemcomitans was the most frequently detected organism (22.8% of subjects) followed by P. gingivalis and P. intermedia (14.7% and 9.5% of subjects respectively). The majority of infected subjects (83%) were colonised by a single species of organism. A. actinomycetemcomitans presence was over-represented in the youngest age group but under-represented in the older age groups. Conversely, P. gingivalis and P. intermedia presence was under-represented in the youngest age group but over-represented in the older age groups. Differing trends in the distribution of these bacteria were observed between subjects depending upon the site of the infection or whether a single or mixed infection was present; however, these differences did not reach significance. Bacterial presence was strongly associated with pocket depth for both A. actinomycetemcomitans and P. gingivalis. For A. actinomycetemcomitans, the odds of a site containing this bacterium decrease with deeper pockets. In contrast, for P. gingivalis the odds of a site being positive are almost six times greater for pockets 〉3 mm than for pockets 〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:03036979:JCPE281212:les" location="les.gif"/〉3 mm. These odds increase further to 15.3 for pockets deeper than 5 mm. The odds of a site being P. intermedia positive were marginally greater (1.16) for pockets deeper than 3 mm.Conclusions: This cross-sectional study in a volunteer Australian population, demonstrated recognised periodontal pathogens occur as part of the flora of the subgingival plaque. Prospective longitudinal studies are needed to examine the positive relationship between pocket depth and pathogen presence with periodontal disease initiation and/or progression.

Notes: Abstract After gingival health had been achieved in four subjects they were instructed to cease all oral hygiene measures. At 0, 8 and 21 days Plaque and Gingival Indices were recorded and gingival biopsies were removed from the buccal aspect of a first molar. Frozen sections of the gingival oral epithelium were stained for ATPase and 5′-nucleotidase to determine the number of Langerhans cells in a defined cross-sectional area. It was found that, as plaque accumulated, there was a statistically significant increase in the number of Langerhans cells in oral epithelium, particularly in the stratum spinosum. These results indicate that dental plaque can elicit a response in Langerhans cells located in the oral epithelium of the gingiva.

Notes: Abstract The spontaneous proliferative response (SPR) of peripheral blood lymphocytes, as a measure of the autologous mixed lymphocyte reaction (AMLR), has been found to be depressed in adults with chronic inflammatory periodontal disease (CIPD). The aim of the present study was to test the hypothesis that initial treatment of CIPD in adults restores the SPR to normal levels. 10 periodontal disease subjects (mean probing attachment loss of 4.2 mm and a mean bleeding index of 0.65) and 10 age- and sex-matched healthy control subjects were studied. The SPR for each patient was evaluated on days 3, 5, 7, 9 and 11 in culture, before and after initial treatment for CIPD. The peak SPR, which occurred at day 5, was depressed in the untreated periodontal disease subjects compared to the healthy control subjects (p〈0.01). In addition, the kinetics of the SPR were found to be significantly different in 4 of the 10 parameters compared with the untreated periodontal disease patients and the healthy control subjects. After treatment, there was a significant reduction in probing attachment loss and bleeding indexes (p〈0.001). In addition, the magnitude of the peak SPR was not significantly different from that of the healthy control subjects. Nevertheless, a difference in 1 of the 10 kinetic parameters persisted, which suggested that complete resotration of the SPR to normal had not occurred so soon after treatment. Although individual variations occurred, no significant differences in magnitude or kinetics of the SPR were found when the 2 healthy samples were compared, whereas the treated periodontal disease samples were significantly different from the untreated periodontal disease samples in both kinetics and magnitude at day 5 (p〈0.001) and day 7 (p〈0.05). These results support previous findings that the SPR is depressed in patients with untreated CIPD and that it returns to normal following initial treatment and reduction in antigenic load.

Notes: Objectives: The present study describes the natural history of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia over a 5-year period and the effect of a triclosan/copolymer dentifrice on these organisms in a normal adult population.Material and Methods: Subgingival plaque samples were collected from 504 adult volunteers. Probing pocket depths (PPD) and relative attachment levels were measured using an automated probe. Participants were matched for disease status (CPI), plaque index, age and gender, and allocated to receive either a triclosan/copolymer or placebo dentifrice. Re-examination and subgingival plaque sampling was repeated after 1, 2, 3, 4 and 5 years. P. gingivalis, A. actinomycetemcomitans and P. intermedia were detected and quantitated using an enzyme linked immunosorbent assay. Logistic regression and generalised linear modelling were used to analyse the data.Results: This 5-year longitudinal study showed considerable volatility in acquisition and loss (below the level of detection) of all three organisms in this population. Relatively few subjects had these organisms on multiple occasions. While P. gingivalis was related to loss of attachment and to PPD ≥3.5 mm, there was no relationship between A. actinomycetemcomitans or P. intermedia and disease progression over the 5 years of the study. Smokers with P. gingivalis had more PPD ≥3.5 mm than smokers without this organism. There was no significant effect of the triclosan dentifrice on P. gingivalis or A. actinomycetemcomitans. Subjects using triclosan were more likely to have P. intermedia than those not using the dentifrice; however this did not translate into these subjects having higher levels of P. intermedia and its presence was uniform showing no signs of increasing over the course of the study.Conclusion: The present 5-year longitudinal study has shown the transient nature of colonisation with P. gingivalis, A. actinomycetemcomitans and P. intermedia in a normal adult population. The use of a triclosan-containing dentifrice did not lead to an overgrowth of these organisms. The clinical effect of the dentifrice would appear to be independent of its antimicrobial properties.

Notes: Abstract Contamination of periodontally involved cementum by bacterial substances such as lipopolysaccharide (LPS) is considered a major reason for root planing. The purpose of the present study was to investigate the presence and location of lipid and polysaccharide within involved cementum as compared with uninvolved cementum. Frozen sections were prepared from the decalcified roots of 36 periodontally diseased and two control teeth. Serial sections were stained for either lipid (Oil-Red-O) or polysaccharide (Alcian Blue - PAS) and also with haematoxylin & eosin (H & E) or Huberstone's gram stain. Specimens of involved and uninvolved cementum were then examined under the light microscope for assessment of differences. Involved cementum from 12 of the periodontally diseased teeth exhibited strongly PAS-positive stained processes penetrating 3-7 μm into the surface of cementum from overlying plaque. Such processes were not observed in uninvolved cementum, suggesting a possible bacterial origin. Lipid granules were noted in only one involved specimen where they were situated up to 10μm beneath the cemental surface. Similar granules were observed within plaque deposits but never in uninvolved cementum, again suggesting a possible bacterial origin. H & E and gram-stained specimens revealed the presence of microbial deposits in surface defects and within defects at the cemento-dentinal junction (CDJ), as well as penetration of micro-organisms into cementum in the absence of any surface defects. The results indicate that although lipid and polysaccharide of possible bacterial origin may be present within the 10μm surface zone of involved cementum, the finding of microbial deposits down to the level of the CDJ suggests that all periodontally involved cementum should be removed during root planing, in order to achieve a root surface free of bacterial contamination.

Notes: Abstract The antimicrobial effects of subgingival chlorhexidine (CH) irrigations on the pathogenic flora in advanced periodontal lesions were assessed. Changes in the patterns of colonization within the subgingival sites were monitored by differential dark-field microscopy, in 16 patients, over a period of 10 weeks. In addition, changes in the clinical parameters of the diseased sites were also monitored.Initial base-line evaluations were made for both the clinical and microbiological parameters. 4 sites of moderate to advanced periodontal disease were selected in each patient. These were randomly irrigated with a single dose of either 0.2% CH gel, 0.2% CH solution, or physiological saline, while 1 site was left as a control. The patients were seen weekly, until the 5th week, then at the 7th and 10th weeks. At each appointment, a microbiological sample was taken from the subgingival region of each site, together with an assessment of the clinical indices. Results indicated that a single irrigation of an 0.2% solution of CH or 0.2% CH gel had a marked effect in decreasing the % of spirochaetes and, to some extent, motile bacteria. There was a concomitant shift in colonization to cocci, fusiform and filamentous organisms in pockets that were irrigated; this coincided with a reduction in the % of bleeding sites. Various patterns of colonization were observed which have been described and may assist in differential dark field (DDF) monitoring of lesions. Bleeding on blunt probing was found to be correlated with a flora dominated by spirochaetes. No other correlations were found over the 10-week period between the other parameters.The therapeutic effect of a single application of CH gel and solution did not exceed 10 weeks and a peak response was recognised at 2 to 4 weeks. It was concluded that treatment regimes involving CH irrigation could be undertaken on a monthly basis. No differences in efficacy could be found between the use of CH gel and solution.

Notes: Abstract A retrospective study was carried out to determine the frequency of early periodontal bone loss in 15 year olds as seen in bite-wing radiographs. A total of 468 radiographs of 15 year olds was examined, 246 from 1970–74 and 222 from 1978–80. The alveolar bone crest on the mesial and distal of the first permanent molar teeth was examined for radiographic evidence of early chronic periodontitis. The condition of the adjacent proximal tooth surfaces was also recorded. No significant difference was found between the two groups; 39% of the 1978–80 and 43% of the 1970–74 group showed radiographic evidence of early chronic periodontitis (p〈0.05). Males and females showed a similar frequency of periodontal disease levels. The mesial interproximal space of the first molars had significantly higher frequencies of radiographic evidence of chronic periodontitis than the distal interproximal spaces in the two groups examined. Fewer proximal restorations with overhangs were noted in the 1978–80 group, however more proximal subgingival calculus was found in this group than the 1970–74 group.

Notes: Objectives: The aim of the present study was to determine the effect of unsupervised, long-term use of a 0.3% triclosan/2% copolymer dentifrice on the progression of periodontal disease in a general adult population.Methods: Five hundred and four volunteers were enrolled in a double-blind, controlled clinical trial. Participants were matched for disease status, plaque index, age and gender. At the baseline examination, probing pocket depths and relative attachment levels were recorded and participants were assigned to either the test or control group. Re-examinations took place after 6, 12, 24, 36, 48 and 60 months. Subgingival plaque samples were collected at each examination and assayed for Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia. A generalised linear model was used to analyse the data, with a number of covariates thought to influence the responses included as the possible confounding effects.Results: The triclosan/copolymer dentifrice had a significant effect in subjects with interproximal probing depths ≥3.5 mm, where it significantly reduced the number of sites with probing depths ≥3.5 mm at the following examination, when compared with the control group (p〈0.001). Furthermore, this effect increased with increasing numbers of affected sites. There was no effect of the triclosan/copolymer dentifrice in individuals without probing depths ≥3.5 mm at the previous examination. Other factors significantly affecting probing pocket depths (PPD) included increasing age, smoking and presence of P. gingivalis. PPD ≥3.5 mm were positively associated with loss of attachment some 2 years later.Conclusion: This study showed that in a normal adult population, unsupervised use of a triclosan/copolymer dentifrice is effective in slowing the progression of periodontal disease.

Notes: Abstract Stages in the pathogenesis of gingival recession were observed in rats in which pocketing had been induced by replacement of natural incisors with dental implants. Suitable conditions were thus created on the palatal aspect of the implant sockets for recession to occur.The recession process was examined at intervals by taking transverse serial sections. In the epithelial and connective tissues deep to the receding margin, morphological changes were seen which apparently lead to cleft formation and recession. These appeared to be associated with mononuclear cell infiltration of the connective tissue. The study suggests that gingival recession involves a localized inflammatory process which causes breakdown of connective tissue and leads to proliferation of the epithelium into the site of connective tissue destruction. Proliferation of the epithelial cells into the connective tissue brings about a subsidence of the epithelial surface, which is manifest clinically as recession.

Notes: Abstract Citric acid conditioning of dentine has been proposed as an efficacious treatment for promoting re-attachment after periodontal surgery. This study investigated the pulpal reactions to periodontal surgery combined with citric acid (pH 1) demineralization of exposed dentine for 3 min. 9 cats were used as the experimental animals, with each cat providing 1 negative and 1 positive control and 2 experimental canine teeth. Evaluation was over 3 observation periods, with 3 cats in each period being sacrificed at 4, 21 and 83 days.Positive control teeth, which underwent periodontal surgery combining the removal of approximately 3 mm2 of labial bone and vigorous root planning of the exposed root surfaces, displayed mild to moderate pulpal reactions during the short- and intermediate-term periods and only mild to no reactions in the long-term period. The addition of citric acid demineralization, however, resulted in 5 experimental teeth (28%) becoming abscessed or totally necrotic in the intermediate- and long-term periods. At 21 days, the frequency of adverse pulpal responses to surgery and citric acid conditioning was significantly (p〈0.05) greater than to surgery alone. Although 4 experimental teeth were relatively uninflamed at the long-term period of observation, all showed irritational dentine formation. Penetration of exposed dentinal tubules by plaque bacteria was observed only in the citric acid treated teeth.