The effect of intrasulcular brushing on sulcular epithelial permeability

PAF levels in saliva are regulated by inflammatory cells

Platelet activating factor (PAF), a powerful inflammatory phospholipid mediator, has been detected in normal human saliva and found to be increased in periodontitis. The cellular source of PAF in saliva is controversial although several data suggest an origin related to the presence of inflammatory cells. PAF levels in biological fluids are regulated by PAF-producing cells and by the PAF-degrading acetylhydrolase. Although in normal human saliva acetylhydrolase activity is very low, no information is available on the levels of this enzyme in inflammatory conditions of the mouth. The aim of our study was to assess the contribution of inflammatory cells to the levels of PAF in saliva in normal subjects and in patients with periodontitis. PAF was measured by radioimmunoassay (RIA) in mixed uncentrifuged saliva and in cell-free saliva from healthy subjects, before and after tooth brushing, and in patients with periodontitis. In healthy subjects PAF levels were significantly higher in whole saliva than in centifuged saliva (1.51 +/- 0.22 vs. 0.92 +/- 0.04 ng/ml, p < 0.0039). A significant increase in the amount of PAF was detected in whole saliva, but not in centifuged saliva, 2 h after tooth brushing. In patients with periodontitis PAF levels were not different from those of healthy individuals when using centrifuged saliva but were significantly higher when using whole, uncentrifuged saliva. Exogenous radiolabelled PAF was degraded much more rapidly by the saliva of periodontitis patients than by that of normal subjects. In conclusion, our study shows that inflammatory cells regulate the levels of PAF in saliva contributing to its production and degradation. The differential degradation of PAF in normal and inflammatory saliva highlights the absolute need of a series of methodological precautions when performing studies on salivary PAF.

The effects of megadoses of ascorbic acid on PMN chemotaxis and experimental gingivitis

A double-blind study was undertaken to determine the effects of megadose ascorbic acid supplementation on plasma ascorbate levels, polymorphonuclear neutrophil (PMN) chemotaxis and clinical and biochemical determinations of inflammatory progression in individuals with a mean daily ascorbate intake level of approximately twice the recommended daily allowances. Results indicate that although the group receiving ascorbate supplementation demonstrated a significant increase in plasma levels of the vitamin as compared to a placebo group, no significant differences with respect to PMN chemotaxis or responses to experimental gingivitis were found between the groups.

The influence of gingival stimulation on recovery from human experimental gingivitis

The present study concerns an investigation carried out to determine the effects of gingival stimulation on the resolution of a human experimental gingivitis. 10 young male dental students participated in the experiment. Following the baseline examination (day 0), the participants were instructed to abstain from all oral hygiene procedures during a 21-day period. Heavy plaque accumulation and gingivitis developed during the 21-day induction period. On the evening of the 21st day, active oral hygiene measures were reinstitued, for an 8-day period, using 2 different methods. For the left side of the maxillary arch, a hygiene procedure including gingival stimulation was prescribed. On the other hand, for the right side, a hygiene method without gingival stimulation was instituted. On both sides of the upper arch, the gingival condition was assessed by means of the gingival index, and soft deposits were assessed by the plaque index (selected teeth: 13, 14, 15, 23, 24, 25). Measurements were performed on days 0, 21, 22, 23, 24, 25, 26, 27, 28, 29. On day 29, ideal oral hygiene conditions and gingival health were re-established on both sides. However, a statistical analysis of the data collected during the recovery period revealed that gingival index scores were temporarily, but significantly, higher on the side where mechanical stimulation was performed, although plaque deposits there decreased more rapidly. Thus the present work supports the idea that gingival stimulation does not in any way improve recovery from experimental gingivitis.

Dextran penetration through nonkeratinized and keratinized epithelia in monkeys

The purpose of this study was to determine if polysaccharide dextrans would pass through intact-nonkeratinized and induced-keratinized sulcular epithelia in monkeys. Dextran penetration through normally keratinized oral gingival epithelium also was evaluated in the same gingival specimens. Each of three Rhesus monkeys received a thorough prophylaxis 1 week prior to the experiment. During this week, the monkeys also received daily IV injections of Achromycin. After the antibiotic treatment, the teeth were polished and cleaned with a rubber cup using prophylactic paste for 2 consecutive months, as follows: (1) the right maxillary and mandibular teeth received daily prophylaxes on weekdays and (2) the left maxillary and mandibular teeth received one prophylaxis weekly. These frequencies of plaque removal on one-half of the mouth maintained clinically healthy gingiva and produced keratinization of the sulcular epithelium. At the end of the 2-month prophylaxes, a 5% solution of dextrans derived from Leuconostoc mesenteroides was applied topically to the gingiva once daily for 3 consecutive weeks. During this time, the monkeys continued having dental prophylaxes following the previous time schedule. The study showed that induced-keratinized sulcular epithelium as well as normally keratinized oral gingival epithelium resisted penetration of dextrans, whereas intact-nonkeratinized sulcular epithelium apparently lacked a surface layer resistant to penetration.