Influence of cigarette smoking on vascular reaction during experimental gingivitis

The influence of cigarette smoking on the vascular reaction during plaque induced gingivitis was studied in humans for 28 days. Sixteen healthy dental students, 8 smokers and 8 non-smokers, aged 19-42 yr, volunteered for the experiment. A numerical method was used for the evaluation of the vascular reaction. With the aid of stereophotographs changes in the number of gingival vessels were followed during the experiment. It was found that the number of vessels identified increased over time during the experiment in both smokers and non-smokers. However, in spite of the fact that the plaque accumulation rate was equal, the vascular reaction was less pronounced in smokers. At the end of the experiment after 28 days the intensity of the vascular reaction in smokers was only 50% of that observed in non-smokers. The difference was statistically significant at the P-level of 0.05. One week after termination of the experiment and reinstitution of oral hygiene the number of gingival vessels equaled the pre-experimental values in both groups. The results indicate that the vascular reaction associated with plaque induced gingivitis is suppressed in smokers.     

Influence of cigarette smoking on vascular reaction during experimental gingivitis

Abstract — The influence of cigarette smoking on the vascular reaction during plaque induced gingivitis was studied in humans for 28 days. Sixteen healthy dental students, 8 smokers and 8 non-smokers, aged 19–42 yr, volunteered for the experiment. A numerical method was used for the evaluation of the vascular reaction. With the aid of stereophotographs changes in the number of gingival vessels were followed during the experiment. It was found that the number of vessels identified increased over time during the experiment in both smokers and non-smokers. However, in spite of the fact that the plaque accumulation rate was equal, the vascular reaction was less pronounced in smokers. At the end of the experiment after 28 days the intensity of the vascular reaction in smokers was only 50% of that observed in non-smokers. The difference was statistically significant at the P -level of 0.05. One week after termination of the experiment and reinstitution of oral hygiene the number of gingival vessels equaled the pre-experimental values in both groups. The results indicate that the vascular reaction associated with plaque induced gingivitis is suppressed in smokers.     

Influence of experimental neutropenia in dogs with chronic gingivitis

The influence of a four day period of experimental neutropenia on the clinical state and the structural constituents of chronically inflamed gingiva has been studied in four beagle dogs. Neutropenia was induced by heterologous anti-neutrophil serum. The effects on the gingiva were evaluated by Gingival Index (GI) and Gingival Exudate measurements and by morphometric analysis of various tissue components in sections from biopsies of buccal gingiva sampled on days 2, 3, and 4. Control biopsies were obtained before induction of neutropenia. The GI did not markedly change during the observation period. The amount of Gingival Exudate, however, significantly decreased following the induction of neutropenia and remained low throughout the experiment. Neutrophilic granulocytes disappeared in the gingival tissues, while, apart from a relative increase in plasma cells, no other tissue components seemed to change. No bacterial invasion of the junctional epithelium or of the gingival connective tissue could be observed. Thus during a four day period the bacterial defense mechanisms at the dentogingival junction seem to be able to prevent penetration of microorganisms into the gingival tissues despite the absence of neutrophilic granulocytes.     

The influence of experimental gingivitis on plaque formation

The rate of plaque growth was assessed using daily Plaque Index measurements over a 7-day period in eleven dental students with an initial mean Gingival Indes of 1.21 (+/- 0.05). The mean Gingival Index was then reduced to 0.27 (+/- 0.04) and the rate of plaque growth assessed in the same way. Bacterial smears were taken from the teeth at intervals during both experimental periods and percentage counts of various morphological types of bacteria made. The rate of plaque growth was found to be significantly greater when the Gingival Index was high compared with when the Gingival Index was low (P less than 0.001). There was also an earlier development of a complex bacterial flora when the Gingival Index was high. The hypothesis is presented that gingival exudate has no inhibitory action on the formation of dental plaque, but contains substances which enhance bacterial aggregation and the colonization of the tooth surfaces by these aggregates.     

Chemotactic activity in experimental gingivitis

abstract — Forty-eight dental students were screened regarding the rate of plaque formation. The four most rapid (RPF-group) and the four slowest (SPF-group) plaque formers were selected and compared as to: (1) the development of gingivitis during a 14-day period without oral hygiene, (2) the chemotactic activity elaborated by (a) gingival crevicular material (GCM) sampled 24 h after withdrawal of oral hygiene measures and (b) 4- and 8-day-old plaques, and (3) permeability-inducing factors in 4- and 8-day-old plaques. The Gingival Index, Plaque Index and flow of gingival fluid were used for assessing plaque formation and gingivitis development. The chemotactic activity was estimated with the use of Boyden's in vitro model, and subcutaneously implanted wound chambers were used for demonstrating change in vascular permeability. It was found that: (1) individuals vary considerably with regard to the rate of formation of dental plaque, (2) gingivitis developed faster in the RPF group than in the SPF group, (3) GCM sampled already 24 h after cessation of oral hygiene yielded higher chemotactic activity in the RPF group than in the SPF group, and (4) the RPF and SPF groups did not differ from one another regarding chemotactic activity or permeability-inducing activity of equal amounts (wet weight) of plaque.     

Stereological observations on long-term experimental gingivitis in man

The purpose of the present investigation was to study stereologically the histopathologic changes in the gingiva during 6 months of abolished oral hygiene and to study the development of chronic gingivitis in man. After a thorough prophylaxis procedure, 5 dental students performed optimal oral hygiene under supervision for a period of 3 weeks. At the end of this pre-experimental phase, they were asked to abolish all oral hygiene procedures for 4 (2 individuals) to 6 months (3 individuals). At day 21, and after 2, 3, 4, 5 and 6 months, the gingival exudate flow rate and the gingival index were assessed, and buccal gingival biopsies taken. Semi-thin histologic sections were stained with basic fuchsine and methylene blue. By point counting at 2 different levels of magnification, the volume densities of epithelium, infiltrated (ICT) and non-infiltrated connective tissue, and collagen were estimated. The %s of fibroblasts, PMN's lymphocytes, plasma cells and macrophages were estimated in a predetermined standardized area close to the apical termination of the junctional epithelium. With increasing time, the volume densities of the ICT rose concomitantly with a decrease in the volume densities of the collagen. In spite of great interindividual variations, a slow shift in the proportions of some cell populations was consistently observed. While the fraction of PMN's, lymphocytes and macrophages remained stable, a decrease of fibro-blasts (57 to 39%) and an increase of plasma cells (0.2 to 10%) was observed. This study has, therefore, demonstrated that, in 6 months of plaque accumulation, a chronic gingivitis with a predominance of PMN's and lymphocytes develops.(ABSTRACT TRUNCATED AT 250 WORDS)     

The reversal of localized experimental gingivitis

Twenty dental students randomly divided into four groups of five participated in this trial. Three weeks of supervised oral hygiene preceded the study in order to ensure a optimum state of gingival health. The gingival condition was assessed by means of the Gingival Index and measurements of gingival exudate. Plaque accumulation was assessed by means of the Plaque Index. Using plaque-guards, two 21-day periods were alllowed for the induction of localized experimental gingivitis around a lateral incisor and adjacent canine in each jaw. The contralateral areas served as controls. Habitual oral hygiene procedures were maintained in all other areas of the mouth throughout the experimental periods. Following 21 days of localized plaque accumulation in the mandibular experimental areas, mechanical toothcleaning procedures were introduced at intervals of once a day (Group A), once every second day (Group B), once every third day (Group C) and once every fourth day (Group D). Groups A and B regained gingival health in 10 days. The experiment was then repeated in the maxillary experimental areas. Group A, rinsing once daily with chlorhexidine solution regained gingival health in 4 days. The results obtained in the localized experimental gingivitis model were similar to those reported when totally withdrawing oral hygiene.     

Oral odors in early experimental gingivitis

Volatile chemicals were isolated from mouth air and from incubated whole saliva of 5-matched pairs of male subjects who participated in a 30-day experimental gingivitis protocol. Endogenous oral chemicals were monitored by GC/MS and GC/FPD during the test period. Malodorous sulfur compounds of mouth air were found to increase quantitatively in subjects with gingivitis as compared to control subjects. Salivary volatile production increased with deterioration in gingival health and, conversely, decreased with maintenance of optimal periodontal condition.     

Effect of experimental neutropenia on initial gingivitis in dogs

Abstract – The role of neutrophilic granulocytes in the loss of gingival collagen has been studied by inducing experimental neutropenia during initial gingivitis in beagle dogs. Neutropenia was induced for 4 d in three animals with normal gingiva by repeated injections of rabbit anti-neutrophil serum. During neutropenia microbial plaque was allowed to form on the teeth. Samples of junctional (crevicular) leukocytes and gingival fluid were taken on days 0 and 4. Block biopsies of buccal gingiva were obtained on day 4. Stained semi- and ultrathin sections were used for histometric and serologic tissue analysis. Gingival fluid flow increased from day 0 to day 4 in all dogs while junctional leukocytes increased in one dog only. Subgingival plaque had formed in most biopsies, and in the junctional epithelium very few neutrophilic granulocytes were present. In the coronal connective tissue subjacent to the junctional epithelium lymphoid cells, structurally abnormal neutrophilic granulocytes and monocytes/macrophages were diffusely scattered. The gingival collagen appeared mainly displaced by the inflammatory cells rather than dissolved. The data suggest that neutrophilic granulocytes may contribute to the loss of gingival collagen during initial gingivitis in dogs. The neutrophils also seem to be of importance for the limitation of subgingival plaque growth along the tooth surface.     

Effects of folate mouthwash on experimental gingivitis in man

Although the experimental gingivitis model has been used extensively since 1965, some doubts exist concerning the nature of the tissue response in this model. Accordingly, the present study was designed to determine whether or not experimental gingivitis responded to 0.1% folate mouthwash (MW) in a similar manner to that already reported for established gingivitis. 20 male dental students took part in a double blind cross-over study which involved two 3-week experimental periods with random allocation to folate or placebo MW. The experimental site was the lower anterior area and 24 points of gingival examination were made at baseline and weeks 1, 2 and 3. Inflammation was assessed by presence or absence of colour change, and bleeding being slight, profuse or absent when gingivae were stroked with a blunt probe. A plaque sample was evaluated using dark field microscopy, and dry weight of accumulated plaque was measured at the end of each experimental period. Folate MW did not appear to have any statistically significant effects on accumulated plaque, or clinical signs of experimental gingivitis in this study. The different response of experimental gingivitis to folate MW, compared with the response of established gingivitis already reported, further suggests that experimental gingivitis may not represent an authentic replica of the cellular and immunological responses occurring in established gingivitis.     

Microcirculatory dynamics in experimental human gingivitis

Abstract The purpose of this study was to determine the changes that occur in the gingival microcirculation during the development of experimental gingivitis in humans. There have been no studies published to date combining videomicroscopy and laser Doppler flowmetry to study vascular dynamics in experimental gingivitis. Alterations occurring in the microcirculation of the marginal gingiva in 10 (18–30-year-old), healthy male humans when they suspended oral hygiene procedures in a proscribed area for 12–16 days were monitored. A partial mouth, experimental gingivitis model was employed. Gingival health was evaluated before and after the experimental period by assessing gingival and plaque indices and gingival crevicular fluid volume. Gingival vascular monitoring included measurement of red blood cell velocity in individual gingival microvessels via video-microscopy and measurement of regional gingival blood flow using laser doppler flowmetry. The number of vessels visible in a given microscopic field in a given subject and the number of vessels exhibiting flow were also determined from the videotapes. Systemic cardiovascular and respiratory parameters were monitored to ensure that gingival vascular changes were not secondary to systemic changes. Gingivitis developed in all subjects; significant increases (Student t-test, P < 0.05) were seen in plaque index, gingival index, bleeding on probing and crevicular fluid volume. No change in superficial capillary blood velocity and a significant decrease in gingival regional blood flow were seen with gingivitis. A significant increase in the number of vessels visible in microscopic fields and a decrease in the % of vessels exhibiting flow were observed. Gingival microcirculation exhibited a dramatic, dynamic change in response to the development and progression of gingivitis.     

Influence of alcohol in mouthwashes containing triclosan and zinc: an experimental gingivitis study

OBJECTIVES: An experimental gingivitis model was used to analyse the influence of alcohol in mouthwashes containing 0.15% triclosan and zinc chloride on the formation of supragingival plaque, the development of gingivitis and the appearance of adverse events. MATERIAL AND METHODS: Using a double-blind crossover design, 30 subjects underwent two consecutive experimental phases with two 0.15% triclosan and zinc chloride mouthwashes, differentiated mainly by their excipient (hydroalcoholic or aqueous). In each phase, the subjects discontinued all oral hygiene measures and were treated solely with the randomly assigned experimental mouthwash for 21 days. Each experimental phase was preceded by a 14-day washout period in which, after receiving a complete oral prophylaxis, the subjects were instructed to perform thorough oral hygiene procedures. Gingivitis and plaque levels were assessed at the start and end of both the experimental phases. RESULTS: The evolution of the gingivitis and plaque indices showed no statistically significant differences between both treatments. The mean gingival index increased from 0.30 to 0.38 with the non-alcoholic mouthwash and from 0.32 to 0.42 with the hydroalcoholic mouthwash. The respective changes in plaque index were from 0.88 to 1.93 and from 0.94 to 1.92. The hydroalcoholic mouthwash produced a larger number of fresh symptoms (p=0.033), oral itching being the most reported. CONCLUSIONS: Alcohol does not influence the effectiveness of a 0.15% triclosan and zinc chloride mouthwash against gingivitis development and supragingival plaque formation. The absence of alcohol significantly decreases the incidence of adverse events produced by the mouthwash.     

Cell dynamics of experimental gingivitis in macaques

Counts were made of cells present within the inflammatory focus in gingival biopsies from adult macaque monkeys with gingivitis of varying chronicity and severity. Data (Set I) were derived from biopsies taken 3 to 85 days after withdrawal of oral hygiene: during this period the mean gingival index rose from 0.7 to 2.1 but corresponding trends in size and nature of cellular infiltrate were not apparent - the lesions containing 25–40 % macrophages, 20–30 % fibroblasts, 3–30% polymorphonuclear leucocytes, 10 % endothelial cells, 4–9 % lymphocytes and 5–11 % plasma cells. Infiltrates from molar teeth, however, tended to be smaller, to contain relatively more macrophages and fewer lymphocytes and plasma cells than tissue from anterior teeth. These data were compared with those derived from the same animals 5 months later (Set II) and from animals several years older with more severe disease (Set III). With more extensive and more long standing inflammation there were significant increases in plasma cell and polymorphonuclear leucocyte density, and decreases in fibroblasts and macrophages; lymphocyte and endothelial cell densities were relatively stable.
The findings are interpreted as a mixed immune inflammatory response in which delayed hypersensitivity mechanisms may initially play a part but in which, as disease progresses, the humoral arm of the immune response seems to he more extensively deployed.     

Sonic-powered toothbrushes and reversal of experimental gingivitis

OBJECTIVE: To compare two sonic toothbrushes in relation to the reversal of experimental gingivitis. MATERIALS AND METHODS: Subjects refrained from brushing mandibular teeth for 21 days. During a 4-week treatment phase, the right or left side of the mouth was brushed with either the Sonic Complete (SC) or Sonicare Elite (SE) toothbrush as randomly allocated. Plaque and gingivitis were assessed on day 0, after 21 days of no oral hygiene and after 1, 2 and 4 weeks of brushing twice daily. RESULTS: Thirty-four subjects provided evaluable data. The experimentally induced gingivitis (EIG) resulted in higher bleeding and plaque scores compared with day 0. The mean plaque scores at day 21 changed from 3.09 to 1.30 for the SC, and from 3.02 to 1.21 for the SE. At the end of the treatment period, there was no significant difference between the two brushes. The mean bleeding scores changed from 1.87 (day 21) to 0.97 for the SC, and from 1.83 to 0.92 for the SE. For the assessments at 1, 2 and 4 weeks post-EIG, both brushes showed a significant decrease in bleeding scores. There were no statistically significant differences between brushes.     

Cell dynamics of experimental gingivitis in macaques

The rate of cell devision in inflammatory Infiltrates from tissues showing gingivitis of varying severity and chronicity was studied by injecting tritiated thymidine directly into the gingvae prior to biopsy. Both the density and the proportion of labelled cells increased from initial low levels in clinically healthy tissue to a maximum 6–12 weeks after withdrawal of oral hygiene procedures, falling to intermediate levels in animals with established disease. These changes in total labelling indices appeared to be paralled by changes in the labelling of fibroblasts and: macrophages; the numbers of labelled lymphocytes, immunoblasts and endothelial cells rose more slowly reaching their maximum levels only in animals with established disease. These results support the concept of a macrophage response playing a large role in host defence during the initial stages of the disease process and being replaced by other, mainly humoral, defence mechanisms in the later stages of gingivitis.     

实验性龈炎的细菌成分变化的分析

目的:观察实验性龈炎发展过程中细菌成分的变化,分析细菌成分与临床指标间的关系。方法:选取11名受试者,在其停止口腔卫生措施后21d内(第0、2、4、7、14、21天)和恢复口腔卫生措施1周后(第28天)取龈下菌斑作刚果红涂片,分析细菌成分;同时记录临床指标的变化。结果:在实验性龈炎发展过程中,螺旋体的百分含量在基线时最低,随着停止刷牙的时间的延长而逐渐增加,并达到峰值,与基线存在显著性差异(P<0.05),恢复刷牙后迅速降低。其百分含量与各临床指标(菌斑指数、出血指数、牙龈指数)有显著性正相关(P<0.01),杆菌和球菌所占比例在试验过程中无明显变化(P>0.05)。结论:螺旋体的百分含量在基线、停止刷牙和恢复刷牙1周后存在显著差异,并与各临床指标有显著性正相关,其变化与牙龈炎症的形成和发展过程一致。