Cellular aspects of and effects on the gingiva in children with Down''s syndrome during experimental gingivitis

In a previous experimental gingivitis study, it was shown that in children with Down's syndrome (DS), gingival inflammation started earlier, was more extensive and developed faster, than in normal healthy control children. In both groups, the start of the process was accompanied by an acute inflammatory response and an increase of the infiltrated connective tissue area (ICT). The purpose of the present study was to investigate how these facts were reflected at a cytological level. The study was carried out in 8 DS and 8 matched control children. Their ages ranged from 5-10 years. A "normal" healthy gingiva was attained after strict oral hygiene procedures. During a period of 21 days in which oral hygiene was abolished, gingival biopsies were taken on days 0, 7, 14, and 21. In both groups, junctional epithelium (JE) and ICT contained low numbers of polymorphonuclear leucocytes (PMNs). The start of the inflammation (day 7 for the DS and day 14 for the control children) was marked by a significant positive correlation between the numbers of PMNs in the JE and the ICT, and a significant increase of the numbers of PMNs in ICT. In ICT, a concomitant decrease in collagen fibre density was observed. In the control group, the decrease correlated with the numbers of PMNs in ICT, which suggests that this collagen breakdown is caused by PMN products. After the initial decrease, the collagen fibre density remained fairly constant in this group throughout the study. In the DS group, there was a tendency to a further decrease in the ICT3 area, correlated with the numbers of PMNs in ICT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Experimental gingivitis around deciduous teeth in children with Down's syndrome

Abstract. Epidemiological studies have shown that there is a high prevalence and rapid progression of periodontal disease in children with Down's Syndrome (DS). In this respect, DS children exhibit a markedly different response compared with healthy children. In order to understand the reasons for this difference, a controlled study was set up to determine the extent and the quality of the differences in the early periodontal tissue response towards dental plaque in the deciduous dentition of DS children and matched control children. In a preliminary investigation, the gingival health was estimated by determining the bleeding tendency. 9 healthy children were selected from a group of 14 and matched with 9 DS children with respect to plaque development, sulcus depth and age. The DS children had a higher bleeding tendency than the matched controls. In the DS children, moreover, a correlation was found between bleeding tendency and age. No such correlation was found in the controls. After a period of intensive oral hygiene, all cleaning of teeth was discontinued for 21 days. The amount of plaque according to the plaque index, the gingival health according to the gingival index, and the amount of crevicular leucocytes and gingival exudate were assessed at days 0, 7, 14 and 21. During the experimental phase of the study, the amount of plaque increased at a similar rate in both groups. In the DS children, the development of gingival inflammation started earlier and was more extensive. It increased after day 14, whereas in the control children, the gingival inflammation seemed to stabilize at this time. The results of the present experimental study thus confirm earlier results from epidemiological studies. The amount of gingival exudate was very low in both groups, but in the DS group it increased after day 14. In contrast to the DS children, the amount of crevicular leukocytes increased significantly in the control children from day 0 to day 21, the highest score being found on day 14. On day 7, a significantly larger amount of crevicular leucocytes was found in the DS children than in the controls. The findings of this study suggest that DS children have a different leucocyte response together with a more extensive gingival inflammation than normal children.     

Observations on the initial stages of healing following human experimental gingivitis A clinical and morphometric study

The aim of the present study was to investigate stereologically the histologic alterations occurring during gingival healing after experimental gingivitis and to compare clinical parameters with histological findings. 8 dental students volunteered for the investigation. After a prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching zero. They then abolished all oral hygiene procedures for a period of 21 days. After this experimental gingivitis phase, they again performed optimal oral hygiene for 8 days to restore gingival health. At days 0, 1, 2, 4 and 8 after experimental gingivitis, the plaque index (PlI), the gingival index (GI) and the gingival exudate flow rate (GEFR) were assessed and their buccal gingiva was biopsied. Point counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils, lymphocytes, plasma cells and macrophages were estimated by counting the number of profiles of these cells in a specific connective tissue area adjacent to the apical end of the junctional epithelium. A rapid drop in the PlI was noted with increasing time after oral hygiene, followed by a slower decrease in the GI and GEFR scores. The histological picture during the entire experiment was that of an initial gingival lesion. At day 0, no chronic inflammation of the gingiva characterized by a predominance of plasma cells was observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

A long junctional epithelium - A locus minoris resistentiae in plaque infection?

Abstract The present experiment was undertaken to examine whether a gingival unit with a long junctional epithelium provides a. less efficient seal against plaque infection than a unit with a junctional epithelium of normal length. Periodontal tissue breakdown was produced around 8 teeth (test teeth) in each of 4 monkeys by placing elastic ligatures around the neck of the teeth. When the periodontal pockets at the approximal tooth surfaces were 4–5 mm deep and angular bony defects had been produced, the ligatures were removed. The periodontal tissues of the test teeth were subjected to flap surgery. The exposed root surfaces were scaled and planed but no osseous surgery was carried out. Following surgery, plaque control comprising all teeth of the dentition was instituted and maintained for 4 months. Healing following this type of surgical treatment involved the establishment of a long junctional epithelium. During the final 6 months of experimentation, oral hygiene measures were abandoned and plaque was allowed to accumulate. In each animal, 4 test teeth and 3 normal control teeth were selected to study gingival inflammation resulting from undisturbed plaque accumulation. In order to enhance subgingival plaque formation, in each animal cotton floss ligatures were placed in the entrance of the gingival sulci of the remaining 4 test teeth and in 3 controls. The animals were sacrificed 10 months after surgery. The jaws were removed and histological sections of the teeth including surrounding periodontal tissues were produced. The histological analysis revealed that the inflammatory lesion in the gingival connective tissue (the ICT area) resulting from plaque infection did not extend deeper into the periodontal tissues in sites with a long junctional epithelium than in gingival units of normal height. The results were interpreted to indicate that the barrier function of a long junctional epithelium against plaque infection is not inferior to that provided by a dentogingival epithelium of normal length.     

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)     

Ultrastructure of developing subgingival plaque in beagle dogs

The aim of this study was to describe the ultrastructure of developing subgingival plaque. In 6 beagle dogs, healthy gingiva prevailed after a pre-experimental period of intensive plaque control. At the start of the experiment, all oral hygiene measures were withdrawn. Biopsies comprising buccal gingiva and adjacent dental tissues were obtained from premolars and molars on days 0, 4, 7, 21, and 28 and processed for electron microscopy. Sections of day 0 exhibited a junctional epithelium in close contact with the tooth and absence of subgingival aggregations of bacteria on the tooth surface. For each of the subsequent periods studied, some sections did not exhibit subgingival plaque. In the remaining sections with subgingival plaque, almost all bacteria appeared in aggregates attached to the tooth surface. The number of bacteria at the orifice of the gingival sulcus increased with time. Further apically, the micro-organisms formed either a continuous layer of even thickness or, more frequently, discrete microcolonies along the tooth surface. The bacteria comprised practically entirely Gram-negative cocci, rods or spirochetes. The latter were present either mixed with the other types in the discrete microcolonies or constituted the bulk of the continuous layer of plaque. In the apical part of the subgingival plaque, a shift from Gram-negative cocci and rod during the early stages of gingival inflammation, to a predominance of spirochetes in later stages was noted. The study shows that in dogs, starting from a plaque- and gingivitis-free baseline, a predominantly Gram-negative subgingival flora may form within a few days after withdrawal of all oral hygiene measures and that a shift in the bacterial composition of the subgingival plaque takes place during a 4-week period of no oral hygiene.     

Gingival condition in areas of minimal and appreciable width of keratinized gingival

Sixteen dental, dental hygiene, and dental assisting students and dental faculty members who had contralateral or unilateral areas of minimal (less than or equal to 1.0 mm) and appreciable (greater than or equal to 2.0 mm) widths of keratinized gingiva on mid-buccal plaque-free surfaces of mandibular bicuspids were examined. Gingival exudate amounts and clinical inflammation based on color change and/or swelling and bleeding on probing were evaluated. The results showed that gingiva with "appreciable" width as well as gingiva with "minimal" width of keratinized tissue exhibited only minute amounts of gingival exudate. Also, there were generally no clinical signs of inflammation for both types of tissue. From the groups of 16, six subjects were selected who had contralateral pairs of minimal and appreciable keratinized gingiva. They were instructed to cease oral hygiene in the lower bicuspid area for 25 days. At day 0, 4, 7, 11, 14, 18, 21, and 25, plaque, gingival exudate, and clinical gingival inflammation were evaluated. Results revealed increases in plaque, gingival exudate scores and clinical gingival inflammation over the 25-day period with no apparent difference between the areas with minimal and appreciable width of keratinized gingiva.     

Non-surgical treatment of pseudo-recession in children and adolescents

A case of a 7 year-old girl with gingival pseudo-recession at a mandibular permanent central incisor was successfully treated with a non-surgical approach. Patient compliance (oral hygiene), the location of the junctional epithelium in relation to the cemento-enamel junction (pseudo or true recession), the width of the buccal alveolar bone of the affected tooth, the potential for an increase in the width of the attached gingiva and tooth alignment should be taken into account when considering the type of treatment (surgical or not) of uneven buccal gingival margins in children and adolescents.     

Comparison between histological and clinical parameters during human experimental gingivitis

The purpose of this investigation was to study stereologically the histopathologic alterations occurring during a human experimental gingivitis, and to establish a relationship between clinical parameters and histologic findings. Eight dental students volunteered for the study. After a prophylaxis they performed optimal oral hygiene for 3-4 weeks to reach mean plaque and gingival indices approaching zero. They then abandoned all oral hygiene procedures for a period of 21 days. At d 0, 4, 7, 14 and 21, Plaque Index (PII), Gingival Index (GI) and Gingival Exudate Flow Rate (GEFR) were assessed, and a buccal biopsy of their gingiva was taken. Point counting procedures were performed at 2 different levels of magnification to estimate the volume densities of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The percentages of polymorphonuclear neutrophilic granulocytes, lymphocytes, plasma cells, macrophages and fibroblasts were estimated by counting the number of profiles of these cells in the connective tissue area close to the apical end of the junctional epithelium. The histological picture during the entire experiment was one of an early lesion (Page & Schroeder 1976). The clinically healthy gingiva did not correspond to a histologically healthy gingiva containing only a few inflammatory cells, probably because the 3-4 wk of perfect oral hygiene were not sufficient to generate histological health. Furthermore, no chronic inflammation of the gingiva, as characterized by a predominance of plasma cells, was observed after 3 wk without oral hygiene. Thus, more than 3 wk of no oral hygiene are necessary to obtain an established gingival lesion. With increasing gingivitis scores between GI = 0 and GI = 2 there was a significant increase in the percentages of lymphocytes and a significant decrease in the percentages of fibroblasts. With increasing GEFR similar trends in percentages were observed for lymphocytes and fibroblasts. It was concluded that GI scores and GEFR reflect histologic changes in tissue and, hence, are valid indicators of gingivitis development.     

Location of proliferating gingival cells following toothbrushing stimulation

OBJECTIVES: Mechanical stimulation by toothbrushing promotes healing of gingivitis through accelerating cell proliferation. Junctional epithelium proliferates at periodontal pocket formation. A question is arisen whether toothbrushing contributes to the repair of gingival inflammation or deterioration of pocket formation. The location of proliferating cells in gingiva stimulated mechanically by toothbrushing was investigated. MATERIALS AND METHODS: A total of 24 teeth of dogs underwent daily plaque removal with a curette (plaque removal) or both plaque removal and toothbrushing (toothbrushing). Proliferative activity of gingival cells in six individual zones was evaluated by assaying expression of proliferating cell nuclear antigen (PCNA). RESULTS: Toothbrushing increased densities of PCNA-positive basal cells in the junctional epithelium, connective tissues adjacent to the junctional epithelium, the alveolar bone of the oral epithelial side and the oral epithelium. However, the densities of PCNA-positive cells at the apical portion of the junctional epithelium, connective tissues adjacent to the cementum and the alveolar bone of the periodontal ligament side did not increase following toothbrushing. CONCLUSIONS: Toothbrushing promotes proliferation of gingival cells other than fibroblasts in periodontium and basal cells in the apical portion of the junctional epithelium. The repair of periodontal tissues might be promoted by toothbrushing within the limit of the direct mechanical stimulation.     

实验性龈炎的临床观察和龈沟液量的分析

目的　观察实验性龈炎发展过程中的临床表现及龈沟液 (GCF)量的变化 ,探讨GCF量与牙龈炎症发生和发展的关系。方法　选取 11名受试者 ,在其停止口腔卫生措施后 2 1d内 (第 0、7、14、2 1天 )和恢复口腔卫生措施 1周后 (第 2 8天 )记录临床指标的变化 ,并且测量GCF量 (每人测18颗牙 )。结果　在实验性龈炎发展过程中 ,各项临床指标 (菌斑指数、出血指数、牙龈指数、探诊深度 )和GCF量在基线时数值较低 ,停止刷牙后随着菌斑量的不断增多而逐渐上升 ,恢复刷牙后又下降到接近基线水平。GCF量与各项临床指标均为显著正相关。结论　临床指标和GCF量在基线、停止刷牙和恢复刷牙 1周后随菌斑量的改变而存在显著差异 ,反映了牙龈炎症的形成和发展过程     

Experimental gingivitis in young dogs

abstract — The aim of the present study was to analyze and express in quantitative terms some of the structural alterations which develop in an initially normal gingiva during a phase of continuous plaque accumulation. Four beagle dogs were used. The animals had from birth been twice daily subjected to meticulous mechanical tooth cleaning. When the dogs were 10 months of age their gingiva were in excellent health as evaluated by Gingival Index and Gingival Exudate measurements. Gingival tissues were harvested from the premolar and molar regions in the right jaws. The tooth cleanings were then terminated and plaque allowed to accumulate. Clinical examinations were performed and gingival biopsies sampled after 4, 7, 14, 21 and 28 d. The composition of the gingival biopsies was analyzed in a sampling microscope. After 4 d of plaque accumulation significant amounts of gingival exudate could be sampled. The exudation then gradually increased during the following weeks. Biopsies representing day zero did not contain any inflammatory cell infiltrates. However, after 4 d of the experiment leukocytes were found in the collagen-poor connective tissue immediately beneath the junctional epithelium. The size of the infiltrated connective tissue (ICT) gradually increased during the experiment. The volumetric density of collagen in the noninfiltrated connective tissue (NCT) was always much higher than in ICT. In ICT, however, this density parameter remained rather constant throughout the study. On days 4 and 7 neutrophilic granulocytes constituted 60–70% of the leukocyte population. On day 28, however, the infiltrate comprised mainly mononuclear leukocytes, especially plasma cells, neutrophils at that time occupying only a small fraction of the infiltrate.     

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.     

Histologic characteristics of experimental gingivitis in the juvenile and adult beagle dog

Abstract An earlier study (Matsson & Attström 1979) revealed an unexplained difference between juvenile and adult dogs in the propensity to develop clinical signs of gingivitis. The aims of the present investigation were to depict the structural composition of clinically normal gingiva and to analyze the histologic changes in the gingiva during plaque development in juvenile and adult dogs. Six beagle dogs were used. Two periods of discontinued oral hygiene were studied, the first at 3 and the second at 12 months of age. Biopsies were sampled on days 0, 4, 7, 14, 21 and 28 of each period. Sections from the biopsies were analyzed at two levels of magnification. Compared to adult dog gingiva, juvenile gingiva seemed to display: 1) a thicker keratinized layer of the oral epithelium, 2) a junctional epithelium that structurally resembles the oral epithelium, 3) a cuticular structure at the surface of the junctional epithelium, 4) a limited mononuclear inflammatory cell response during experimental gingivitis, and 5) a delayed establishment of an infiltrated connective tissue portion during experimental gingivitis. In addition, during experimental gingivitis, subgingival plaque formed along the tooth surfaces to a lesser extent in the juvenile stage compared to adult dogs.     

Professional prophylaxis and its effect on the periodontium of full-banded orthodontic patients

The effect of professional prophylaxis on the periodontium was studied in 14 adolescent orthodontic patients while under active treatment using a split-mouth experimental design. A full-banded appliance was used on all of the patients. The following variables were examined: plaque registration, gingival index, gingival migration, and width of the attached gingiva. Professional rubber-cup prophylaxis was performed on the test side of all patients together with reinforced oral hygiene instruction on a monthly basis. Measurements for the plaque registration, gingival index, gingival migration, and the width of the attached gingiva were recorded at the initial visit (baseline records), the 6-month evaluation, and the 10-month evaluation. Monthly registrations were completed for the plaque deposits and gingival inflammation at each of the 11 visits. All measurements were taken at the midfacial surface of the selected teeth. Four conclusions can be drawn from the findings of this study: the presence of an orthodontic appliance did not result in an increase of plaque accumulation or gingival inflammation for the full-banded orthodontic patient; monthly oral hygiene instruction was effective in significantly reducing the amount of visible plaque and gingival inflammation; monthly rubber-cup prophylaxis had a significant effect in reducing the gingival enlargement routinely associated with a fixed orthodontic appliance; and the width of attached gingiva showed no significant change throughout the course of the study.     

Gingival inflammation at deciduous and permanent teeth An intra-individual comparison

Previous studies showed that the tendency to develop gingivitis differed between pre-school children with deciduous dentition and adults. A similar difference was noted between juvenile dogs with deciduous teeth and adult dogs with permanent teeth. The juvenile dogs showed morphologic characteristics which might interfere with the permeability of the junctional epithelium, thus protecting the underlying tissues from bacterial irritation. An indirect way to test whether structural differences of clinical importance exist in humans between the gingiva at deciduous and that at permanent teeth is to study the gingival reaction to a controlled amount of plaque in children with mixed dentition. The present paper reports an intra-individual comparison of the gingival reaction at deciduous teeth with that at permanent teeth. 30 children, 7-9 years of age, took part in the study. The amount of plaque was assessed in terms of the plaque index and the degree of gingival inflammation by applying the gingival index. The mean distribution of gingival index scores did not differ significantly between deciduous and permanent teeth, but a higher % of plaque index score 2 + 3 was found in permanent teeth. In the comparison based on areas of similar plaque irritation, a tendency toward a higher degree of gingivitis was found at the deciduous teeth. The results indicate that structural differences, if any, between the gingiva at deciduous teeth and that at permanent teeth have no impact of clinical significance on the gingivitis reaction.     

Histopathology of initial gingivitis in humans

Abstract The present study concerns the inflammatory alterations in the gingival margin during initial gingivitis in 11–13 year old human subjects. At day 0 of the experiment, all participants had clean teeth and healthy gingiva. All active oral hygiene measures were excluded for 4 days. From upper and lower premolars, which were extracted for orthodontic reasons, contralateral gingival biopsies, including the tooth and the adjacent gingiva, were obtained on days 0 and 4. The presence of inflammatory cells in the junctional epithelium and the adjacent connective tissue was determined quantitatively in semi-thin sections. The collagen content of the gingival margin was also determined. From day 0 to day 4 there was only a slight increase in the number of neutrophilic granulocytes in the junctional epithelium and adjacent connective tissue, while a more pronounced increase was found in the number of mononuclear leukocytes. A loss of collagen was noticed in 4 of the subjects, while 2 did not show any changes in collagen content. The inflammatory reaction seen in the present study differs somewhat from that observed in adult humans and adult dogs. The results correspond more to the reaction seen in juvenile dogs.     

A clinical and histometric study of gingivitis associated with the human deciduous dentition

This study examined the relationship between clinical indices and the histologic parameters associated with the gingiva of the human deciduous dentition. The plaque index, gingival swelling and color, probing depth, bleeding on probing, contact with adjacent teeth and the degree of root resorption of 58 deciduous teeth were recorded. The teeth were extracted with their surrounding gingiva and prepared for histologic examination. The area of epithelium and connective tissue with and without inflammatory cells was measured as well as the epithelial length from the gingival margin including the junctional epithelium. When these measurements were grouped according to the values of the clinical indices, nonmobile teeth were found to have less epithelium than those with mobility and gingiva with a healthy color had a significantly smaller inflammatory cell infiltrate than red gingiva. Bleeding and increased probing depth were not associated with the other clinical signs of inflammation. The amount of plaque did not correlate with the measures of clinical inflammation. The inflammatory cell infiltrate was present irrespective of whether the gingiva was clinically normal or not and the inflammation did not correlate with the amount of plaque.     

Initial gingivitis induced by topical application of plaque extract

The present study was undertaken to examine if soluble substances in human dental plaque were able to induce structural alterations in the marginal gingiva characteristic of initial gingival inflammation.
Four-day old plaque was sampled from dental students; the plaque material was pooled, suspended in saline, homogenized, centrifuged and filtered. The supernatant, the plaque-extract, was then, during an eight hour period, topically applied to the gingival margin of the upper jaws of five Beagle dogs. In control regions saline was applied in an identical manner. One and a half hour before sacrifice the animals were given i.v. injections of colloidal carbon.
Biopsies of test and control regions were taken according to a technique described by Schroeder et al (1973). The biopsy specimens were embedded in Epon. Semithin sections (2-3 μm) were examined in the microscope regarding 1. amount of vascular units subjacent to the junctional epithelium containing carbon particles
2. number of polymorphonuclear and mononuclear leucocytes within the junctional epithelium.
The examinations revealed that the gingival units exposed to plaque extract in comparison to controls harboured larger numbers of carbon labelled vascular units and larger numbers of leukocytes within the junctional epithelium. The data also showed that the main reaction occurred in the marginal portion of the gingival tissue. The observations of this study indicate that soluble substances from human dental plaque when applied topically in the gingival sulcus may give rise to structural alterations similar to those developing in the gingival tissues in response to plaque accumulation.     

Histological and clinical parameters of human gingiva following 3 weeks of chemical (chlorhexidine) or mechanical plaque control

The aim of the present study was to compare stereologically the histopathologic variations following 3 weeks of chemical (chlorhexidine) or mechanical plaque control. 18 students and dental hygienists volunteered for this investigation. After prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching 0. Six of them then performed mechanical plaque control of 3 weeks (control), while the other 12 rinsed 3 times daily with a 0.12% chlorhexidine solution (test). At days 0 and 21, the plaque index (PlI), the gingival index (Gl) and the gingival exudate flow rate (GEFR) were assessed and biopsies were obtained from buccal sites. Point-counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils, lymphocytes, plasma cells, macrophages and mast cells were estimated by counting the number of nuclear profiles of these cells in a specific connective tissue area adjacent to the apical termination of the junctional epithelium. After 21 days, the PlIs of the test subjects were significantly higher than the PlIs of the controls, but their Gl were similar. At the end of the experimental period, the various volume fractions and %s of cell profiles remained stable with the exception of an increase in the %s of lymphocytes in the test group. This study has shown that, clinically as well as histologically, the daily use of chlorhexidine for a 3-week period is equally efficient as optimal mechanical tooth cleaning in maintaining a healthy gingiva in the buccal sites investigated.