牙周菌斑控制对孕妇妊娠期龈炎龈沟液CRP的影响

目的：探讨牙周基础治疗中菌斑控制对孕妇妊娠期龈炎龈沟液中C反应蛋白（CRP）影响。方法：选择在深圳市龙岗区妇幼保健院妇保科建档的单胎,无系统性疾病,患妊娠期龈炎的孕妇65例,随机分为实验组（牙周菌斑控制＋牙周洁治组）33例、对照组（单纯牙周洁治组）32例。收集患者初始时及治疗后龈沟液（GCF）,用ELISA法测定其中CRP含量,记录治疗前后牙周健康指数（PLI、SBI、PD）。比较各组龈沟液CRP表达与牙周健康状况。结果：妊娠期龈炎患者初始龈沟液CRP水平均高于各组牙周基础治疗后龈沟液CRP表达,差异有统计学意义（P＜0．01）;牙周菌斑控制＋牙周洁治组患者治疗后龈沟液CRP水平低于单纯牙周洁治组,与牙周健康指数呈正相关,差异有统计学意义（P＜0．05）。结论：实施菌斑控制的牙周基础治疗能更有效降低孕妇妊娠期龈炎龈沟液CRP水平,改善牙周健康状况。     

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.     

Serum IgG reactivity to subgingival bacteria in initial periodontitis, gingivitis and healthy subjects

BACKGROUND/AIMS: Established periodontal diseases may be associated with antibody responses to periodontal pathogens, but it is not known at which stage of disease this antibody response is initiated. This study aimed to characterize the host systemic response in initial periodontitis, gingivitis, and periodontal health, to evaluate whether elevated serum antibodies to subgingival species could be detected in initial periodontitis. METHOD: Human systemic immune response were evaluated to 40 subgingival bacterial species in 16 healthy, 21 gingivitis, 11 initial periodontitis and 5 progressing recession adults. Subjects had minimal periodontal attachment level (AL) loss at baseline. Disease categories were determined after 12 months monitoring at three-month intervals. Increased AL loss > or = 1.5 mm (disease activity) at interproximal sites defined initial periodontitis, recession was characterized by AL loss at buccal sites. Serum IgG antibodies were evaluated semi-quantitatively by immunoblot from blood taken at baseline, active and final visits. RESULTS: No antibody was detected from 55% of reactions. When detected, levels were below those reported for advanced periodontitis subjects. There were no major differences in serum antibody levels between healthy, gingivitis and initial periodontitis subjects, despite differences in the subgingival microbiota. Serum antibodies for more species were detected in recession subjects, compared with the other study subjects. No changes in antibody levels were detected between baseline, active, and final visits. No systematic association between species colonization and presence of systemic antibody was observed. CONCLUSIONS: This study did not detect differential elevation of mean serum antibody levels in initial periodontitis subjects, suggesting that serum antibody levels are not sensitive risk markers for initial periodontitis.     

Reversibility of experimental peri-implant mucositis compared with experimental gingivitis in humans

Objective: To monitor clinical, microbiological and host‐derived alterations occurring around teeth and titanium implants during the development of experimental gingivitis/mucositis and their respective healing sequence in humans. Material and methods: Fifteen subjects with healthy or treated periodontal conditions and restored with dental implants underwent an experimental 3‐week period of undisturbed plaque accumulation in the mandible. Subsequently, a 3‐week period with optimal plaque control was instituted. At Days 0, 7, 14, 21, 28, 35 and 42, the presence/absence of plaque deposits around teeth and implants was assessed, (plaque index [PlI]) and the gingival/mucosal conditions were evaluated (gingival index[GI]). Subgingival/submucosal plaque samples and gingival/mucosal crevicular fluid (CF) samples were collected from two pre‐determined sites around each experimental unit. CF samples were analyzed for matrix‐metalloproteinase‐8 (MMP‐8) and interleukin‐1beta (IL‐1β). Microbial samples were analyzed using DNA–DNA hybridization for 40 species. Results: During 3 weeks of plaque accumulation, the median PlI and GI increased significantly at implants and teeth. Implant sites yielded a greater increase in the median GI compared with tooth sites. Over the 6‐week experimental period, the CF levels of MMP‐8 were statistically significantly higher at implants compared with teeth (P<0.05). The CF IL‐1β levels did not differ statistically significantly between teeth and implants (P>0.05). No differences in the total DNA counts between implant and tooth sites were found at any time points. No differences in the detection frequency were found for putative periodontal pathogens between implant and tooth sites. Conclusion: Peri‐implant soft tissues developed a stronger inflammatory response to experimental plaque accumulation when compared with that of their gingival counterparts. Experimental gingivitis and peri‐implant mucositis were reversible at the biomarker level. Clinically, however, 3 weeks of resumed plaque control did not yield pre‐experimental levels of gingival and peri‐implant mucosal health indicating that longer healing periods are needed. To cite this article:
Salvi GE, Aglietta M, Eick S, Sculean A, Lang NP & Ramseier CA. Reversibility of experimental peri‐implant mucositis compared with experimental gingivitis in humans.
Clin. Oral Impl. Res. 23 , 2012; 182–190.
doi: 10.1111/j.1600‐0501.2011.02220.x     

The effect of a dexibuprofen mouth rinse on experimental gingivitis in humans

Objectives: The pharmacodynamic properties of ibuprofen are related nearly exclusively to the S(+)enantiomer (dexibuprofen). This study investigated the effect of a 1.5% dexibuprofen mouth rinse in an experimentally induced gingivitis. Materials and Methods: The trial was a randomized, double‐blinded, placebo‐controlled, two‐period and two‐sequence parallel group cross‐over study in 24 healthy volunteers aged 21–30 years (16 males, eight females). Customized guards were worn during tooth brushing to prevent any plaque removal from the experimental area (first and second pre‐molars and molars in one upper quadrant). After 22 days of plaque accumulation, the mouth rinses (1.5% dexibuprofen and placebo) were administered under supervision three times daily (rinsing for 1 min. with 15 ml) for 8 days. The wash‐out time between the two study periods was 14 days. Parameters evaluated at days 0, 7, 14, 22, and 30 were the Löe & Silness gingival index (GI) and the Quigley & Hein plaque index (QHI). Data were tested for treatment, period, and carry‐over effects (parametric cross‐over analysis). Results: There was no statistically significant difference (p=0.240) in GI between placebo and dexibuprofen. However, the decrease in QHI was significantly greater (p=0.019) with dexibuprofen as compared with the placebo. Conclusion: In the present study, a 1.5% dexibuprofen mouth rinse had no effect on gingivitis whereas an anti‐plaque effect was demonstrated.     

The effect of a systemically-administered non-steroidal anti-inflammatory drug (flurbiprofen) on experimental gingivitis in humans

Non-steroidal anti-inflammatory drugs reduce the acute inflammatory reaction and alveolar bone loss of experimental periodontitis in dogs by mechanism thought to be associated with the inhibition of prostaglandin synthesis. 25 healthy volunteers abstained from tooth cleaning for 21 days. Experimental gingivitis developed in all subjects. On day 21, the subjects were divided into 3 treatment groups: oral flurbiprofen (100 mg/day)/toothbrushing (A), placebo+toothbrushing (B) and oral flurbiprofen (100 mg/day) only (C). Treatment continued for 6 days. Plaque indices (PI), gingival indices (GI) and probing pocket depths (PPD) were recorded at 6 points on each of 6 maxillary teeth on days 1. 22, 23, 24 and 27. Crevicular fluid flow (CFF) was quantified with a Periotron on days 1, 22 and 27 in groups A and B, and on days 1 and 27 in group C. There were no changes in PPD throughout the study. A reduction of GI occurred between days 22 and 27 for all treatment groups. CFF was also reduced between days 22 and 27 in groups A and B. The differences between the 3 treatments were very small. It is concluded that systemic flurbiprofen (100 mg/day) can reduce the signs of an experimental gingivitis over 6 days. This effect may be seen when the drug is used alone and as an adjunct to toothbrushing.     

Reduction of the formation of dental plaque and gingivitis in humans by crude mutanase

abstract — The effect of a Trichoderma harzianum enzyme preparation containing mutanase (α-1,3 glucan glucanohydrolase) on plaque accumulation and composition and on occurrence of gingivitis was assessed in 20 persons in a double-blind cross-over investigation. The enzyme preparation was administered in chewing gum. Two test periods of 1 week were preceded by scaling and cleansing of the teeth, oral hygiene instruction, and controlled hygiene for at least 3 weeks. Oral hygiene measures were discontinued during the test periods, while the persons chewed six pieces of chewing gum per day, one half using enzyme-containing gum, and the other half using placebo gum. The test periods were identical, only enzyme gum was used instead of placebo, or vice versa . Evaluations of plaque and gingivitis showed that less plaque had accumulated and less gingivitis developed during the enzyme than during the placebo period, but bacteriologic studies of interproximal plaque did not reveal differences that could explain the clinical findings. Treatment with the enzyme preparation caused some local side effects, but no primary skin irritation, delayed hypersensitivity, nor anti-enzyme IgE was detected in any of the persons.     

Variability of gingival bleeding in experimental gingivitis trials

Gingival bleeding is a difficult parameter to assess in experimental trials. The Confirmed Bleeding Day was recently developed as a measurement for this purpose. It was observed that considerable variations existed between the measurements made in a pilot study and an experimental trial, and these variations were subjected to a statistical analysis. The reasons for the variations are discussed, and recommendations made for the design of experimental trials involving gingival bleeding.     

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.     

Clinical and microbial evaluation of a histatin-containing mouthrinse in humans with experimental gingivitis

OBJECTIVE: P-113, a 12 amino acid histatin-based peptide, was evaluated in a mouthrinse formulation for safety, prevention of the development of experimental gingivitis, and for its effects on periodontal flora. METHOD: 159 periodontally healthy subjects abstained from oral hygiene procedures and self-administered either 0.005%, 0.01%, 0.05% P-113 or placebo mouthrinse formulations twice daily over a four week treatment period. During this time, the safety, anti-plaque, and anti-gingivitis effects of P-113 were evaluated. RESULTS: There was a significant reduction in plaque (p=0.046) and a reduction in gingivitis (p=0.086) for subjects using 0.01% P-113 mouthrinse. Significantly more subjects in the 0.01% and 0.05% treatment groups showed a small increase in plaque index of <0.25 as compared to the placebo group (p<0.05). Similar trends were noted for changes in the % of sites with bleeding on probing in the 0.01% P-113 group. There were no treatment-related adverse events, and there were no adverse shifts in supragingival microflora during the study. CONCLUSION: These data suggest that P-113 mouthrinse is safe and reduces plaque, gingivitis and gingival bleeding in the human experimental gingivitis model.     

Effect of mechanical plaque control on development of subgingival plaque and initial gingivitis in neutropenic dogs

abstract — Histologic, histometric and morphometric investigations were performed on the gingival tissues of three neutropenic dogs. Over a period of 4 d the animals had been subjected to daily toothcleaning on the left side of both jaws, whereas plaque accumulation and subsequent gingivitis occurred on the uncleaned teeth of the right side of both jaws. Observations and data revealed that subgingival plaque had formed in both sides and extended further apically (max. 0.6 mm) on the cleaned than on the uncleaned sides. In the responding gingival tissues, leukocytes of the junctional epithelium were more numerous and blood vessels of the marginal connective tissue occupied a greater volume on the cleaned sides when compared with the uncleaned sides. It is concluded that neutrophilic granulocytes normally help to prevent bacterial invasion into the dentogingival region, and that, in the presence of subgingival plaque, toothcleaning may aggravate the inflammatory response of the gingiva.     

Microbiota of health, gingivitis, and initial periodontitis

Abstract. This study compared the subgingival microbiota in periodontal health, gingivitis and initial periodontitis using predominant culture and a DNA probe, checkerboard hybridization method. 56 healthy adult subjects with minimal periodontal attachment loss were clinically monitored at 3-month intervals for 12 months. More sites demonstrated small increments of attachment loss than attachment gain over the monitoring period. Sites, from 17 subjects, showing ≥1.5 mm periodontal attachment loss during monitoring were sampled as active lesions for microbial analysis. Twelve subjects demonstrated interproximal lesions, and 5 subjects had attachment loss at buccal sites (recession). Cultural studies identified Bacteroides forsythus, Campylobacter rectus, and Selenomonas noxia as the predominant species associated with active interproximal lesions (9 subjects), whereas Actinomyces naeslundii, and Streptococcus oralis, were the dominant species colonizing buccal active sites. A. naesludii, Campylobacter gracilis, and B. forsythus (at lower levels than active sites) were the dominant species cultured from gingivitis (10 subjects). Health-associated species (10 subjects) included Streptococcus oralis, A. naeslundii, and Actinomyces gerencseriae. DNA probe data identified higher mean levels of B. forsythus and C. rectus with active (7 subjects) compared to inactive periodontitis sites. Porphyromonas gingivalls and Actinobacillus actinomycetemcomitans were detected infrequently. Cluster analysis of the cultural microbiota grouped 8/9 active interproximal lesions in one subcluster characterized by a mostly gram-negative microbiota, including B. forsythus and C. rectus. The data suggest that B. forsythus C. rectus and S. noxia were major species characterizing sites converting from periodontal health to disease. The differences in location and microbiota of interproximal and buccal active sites suggested that different mechanisms may be involved in increased attachment loss.     

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.     

Subgingival temperature and microbiota in initial periodontitis

Abstract. The association between subgingival temperature, other clinical characteristics, and the subgingival microbiota was examined in adult subjects with initial periodontitis and differing levels of gingival inflammation, 43 subjects were measured at 6 sites per tooth for pocket depth, attachment level, presence of plaque, gingival redness, bleeding on probing and subgingival temperature at 3-month intervals for 1 year. Subgingival plaque was sampled from 15 initial active periodontitis sites (10 subjects), 121 gingivitis, sites (20 subjects) and 202 healthy sites (13 subjects), and included the 5 hottest and 5 coldest sites in each subject. Plaque samples were analyzed for 13 subgingival species using whole-genomic DNA probes. The major influences on the subgingival microbiota were the clinical status of sites, pocket depth, and the presence of supragingival plaque. No significant association between species and site temperature was observed. Initial active sites were associated with Bacteroides forsythus and Campylobacter rectus. and had a higher mean subgingival temperature and deeper mean pocket depth than inactive sites, A weak association between pocket depth and site temperature was noted. The major influence on subgingival temperature of sites was the anterior to posterior anatomical temperature gradient in the mandible and maxilla.     

Microbiota of gingivitis in man

ABSTRACT – A Study on the predominant cultivable microorganisms inhabiting gingival crevices affected with a chronic gingivitis was carried out using the roll tube culture technique. Samples were obtained from nine individuals 25–42 years of age. Gram-positive rods made up 26.1% of the isolates and included mainly Actinomyces naeslundii, Actinomyces israelii , and Actinomyces viscosus. Streptococcus mitis and Streptococcus sanguis together made up 26.8% of the cultivable organisms. Feptostreptococcus averaged 3.0% of the organisms recovered. Gram-negative anaerobic rods constituted 25.0% of the total isolates with Fusobacterium nucleatum, Bacteroides melaninogenicus ss. intermedius, Bacteroides ochraceus , other Bacteroides species, Selenomonas sputigena , and Campylobacter sputorum as the most predominant isolates. Haemophilus parainfiuenzae averaged about 14% and Veillonella species 4.3% of the cultivable microflora. The data presented indicate that the subgingival microflora of a chronic gingivitis differs from those of healthy periodontium and advanced adult and juvenile periodontitis. This might suggest that different infectious processes may be operative in various clinical entities of periodontal disease.     

Safety and clinical effects of topical histatin gels in humans with experimental gingivitis

BACKGROUND: Our research group has recently reported that exogenously applied histatins can inhibit plaque accumulation and gingival inflammation in a preclinical canine model (Paquette et al. 1997). OBJECTIVES: The aims of the present double-blinded, randomized, controlled clinical trial were to evaluate the safety and toxicity of three histatin (P-113) concentrations in gel formulations, and to assess potential clinical benefit on the development of gingivitis (partial mouth design). MATERIAL AND METHODS: One hundred and six healthy subjects were recruited and brought to optimal gingival health (GI < 0.5) prior to treatment initiation. At baseline, eligible subjects were randomized for one of the following treatments: (1) placebo; (2) 0.0625% P-113; (3) 0.125% P-113; and (4) 0.375% P-113. Patients self-applied gels twice daily for 29 days to the maxillary right quadrant with the use of customized stents. In addition, patients deferred all oral hygiene procedures within this quadrant for the duration of the treatment period. Safety was assessed in terms of physical and oral examinations, clinical laboratory testing and recording of adverse events. Clinical indices were measured weekly and included gingival index (GI), plaque index (PI) and %BOP. RESULTS: All study formulations were well tolerated by patients, and no differences in adverse event occurrences were noted among treatment groups, including taste alteration or staining. For the intent-to-treat population, significantly smaller %BOP changes were noted in subjects treated with 0.0625, 0.125 and 0.375% P-113 gels (17.4, 18.18 and 17.9%, respectively) versus placebo (28.0%) (p < 0.05) at day 29. When groups were compared in terms of per cent responders (change in %BOP < 15 or < 20%), P-113 treatment groups exhibited a higher frequency of response, especially for the 0.0625 and 0.125% P-113 formulations (p < 0.05). Although no statistically significant intergroup differences were noted for changes in GI or PI among all subjects (intent-to-treat population), significantly smaller changes in PI at day 22 were observed among compliant individuals (defined as subjects using > 60% of the target gel mass) administering P-113 gels as compared with compliant placebo subjects (p < 0.05). CONCLUSIONS: These data indicate safety and tolerance of P-113 gels for topical oral use in human subjects. These data also suggest that P-113 gels administered twice daily may reduce experimental gingivitis as measured with bleeding on probing in humans.     

Comparison of experimental gingivitis with persistent gingivitis: differences in clinical parameters and cytokine concentrations

BACKGROUND AND OBJECTIVE: Experimental gingivitis has been studied extensively as a well-controlled laboratory model of gingivitis. It is unclear, however, how experimental gingivitis compares with persistent plaque and gingivitis in more naturalistic settings. The present study compares both conditions in a randomized controlled design. MATERIAL AND METHODS: Twenty-six students suffering from plaque and gingivitis were randomly assigned to either a persistent gingivitis or an experimental gingivitis condition. Subjects with persistent gingivitis continued their habitual (i.e. insufficient) oral hygiene behaviour, resulting in persistence of plaque and gingivitis. Experimental gingivitis consisted of initial prophylaxis and subsequent total neglect of oral hygiene. Crevicular interleukin-1beta and interleukin-8 and clinical data were assessed weekly. RESULTS: After 4 wk, subjects with experimental gingivitis showed significantly more plaque accumulation (p = 0.005), higher interleukin-1beta (p = 0.037), and lower interleukin-8 (p = 0.043) concentrations than subjects with persistent gingivitis. Whereas in experimental gingivitis we observed considerable fluctuations in clinical and immunological parameters over the 4-wk period, persistent gingivitis was characterized by little fluctuation, indicating that we were monitoring an inflammatory steady state. CONCLUSION: The data indicate that conditions observed after 4 wk of experimental gingivitis are not comparable with persistent gingival inflammation in a naturalistic setting. Results are discussed with respect to current studies, indicating that chronic inflammation may reflect a stage of down-regulated pro-inflammatory response.     

Gingival health and gingivitis development during puberty

The purpose of this investigation was to follow the development of the gingival conditions during puberty and to correlate oral clinical parameters with chronological age as well as with parameters used for the determination of the pubertal development. In 22 boys and 20 girls pubertal and skeletal development, as well as plaque index (PlI) and gingival index (GI) were monitored at 1-year intervals between the ages of 11 and 15 years. During this time, the papillary bleeding index (PBI) was assessed 10 times in all interdental spaces of the dentition. The bleeding tendency, represented by whole mouth mean PBI values, as well as the % of bleeding interdental sites, was found to increase significantly with the start of the pubertal phase. It reached a peak value after 1-5 years in 35% of the children. A significant trend of decrease was noted after the age of 14 years in boys and girls. In boys, mean PBI and the % of interdental sites with bleeding were correlated with testes growth, in girls with the Tanner index for secondary sex characteristics (breast development). PlI and GI, which were only recorded annually, did not show a significant trend of increase or decrease.     

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.