Development of experimental gingivitis in the juvenile and adult beagle dog

Abstract. In a previous paper a lower tendency to develop gingivitis was reported among preschool children compared to adults. The aim of the present study was to clarify if the same age-dependent difference exists in dogs.
Six beagle dogs from the same litter were used. two periods of discontinued oral hygiene were studied, one period when the dogs were 3 months old and the other at 12 months. Prior to and between the experimental periods the animals were subjected to meticulous toothcleaning. During the experimental periods the Gingival and Plaque Index scores as well as the amounts of gingival exudate and crevicular leukocytes were determined on days 0, 4, 7, 14, 21 and 28.
During the juvenile period the development of dental plaque was lower compared with the adult period. The frequency of gingival units with high Gingival Index scores was lower at every registration interval during the juvenile period. The amounts of gingival exudate and crevicular leukocytes increased to high values during the adult stage but only small increments were found in the juvenile stage. An intraindividual comparison of the increase in the amount of gingival exudate from day 0 to day 28 in areas with the same amount of dental plaque accumulation showed a lower increase in gingival exudate during the juvenile stage in all dogs.     

Electron microscopic study of junctional and oral gingival epithelia in the juvenile and adult beagle dog

A previous study demonstrated structural differences in the junctional epithelium between juvenile and adult dogs. In juveniles the junctional epithelium showed some resemblances to the oral gingival epithelium, and a cuticular structure at the dento-gingival junction was of particular interest. The oral gingival epithelium is considered to be less permeable than the junctional epithelium. As cytoplasmic filaments are held to be the main component in the process of keratinization, and to have a stabilizing influence on the cells and tissues, the present investigation was designed to study the relative amounts of cytoplasmic filaments in the junctional and the oral epithelia of beagle dogs during juvenile and adult stages. In addition, the ultrastructure of the dento-gingival junction was characterized. Six beagle dogs were used. The material consisted of gingival biopsies sampled when the dogs were 3 and 12 months old, respectively. On these occasions the gingiva was in excellent health. The biopsies were prepared for electron microscopic analysis and three randomly selected fields were recorded photographically from each of the following epithelial strata: basal and granular cell layers of the oral epithelium and basal and superficial cell layers of the junctional epithelium. Morphometric analysis was performed in order to estimate the density of cytoplasmic filaments of the cells in these epithelial strata. The amount of cytoplasmic filaments was considerably lower in the cells of the junctional epithelium than in those of the oral epithelium. In the oral epithelium the amount increased from basal towards superficial cells, whereas no such increase was seen in the junctional epithelium. The pattern was the same in the juvenile and the adult stage. At the dento-gingival junction all dogs had a thick, laminated layer of dental cuticle material in the juvenile stage. In the adult stage a similar structure was seen only infrequently, and it never attained the thickness observed in the juvenile stage.     

Putative periodontal and teeth in pathogens on titanium implants and teeth in experimental gingivitis and periodontitis in beagle dogs

The microflora around titanium implants and teeth in 4 beagle dogs was analyzed in order to follow the longitudinal development from healthy conditions to experimental gingivitis and periodontitis. A 2-month plaque control program was performed to establish healthy conditions on titanium implants and control teeth (baseline, day 0). Subgingival bacterial samples and radiographs were obtained. The plaque control was ceased and all measurements were repeated on day 21 (gingivitis). A new period of plaque control was initiated to re-establish healthy conditions (day 49). A cotton ligature was placed subgingivally around the implants and the control teeth to induce tissue breakdown. The ligatures were removed on day 91. The study was completed with registrations on day 121 (periodontitis). No significant microbiological difference was found between titanium implants and teeth in healthy conditions and in gingivitis and periodontitis. The mean total viable count increased 10 times on implants as well as on teeth. Streptococci were dominating at baseline: 40.2% on implants and 60.6% on teeth and decreased in gingivitis to 11.7% and 5.4%. When periodontitis had developed, the proportion of streptococci was < 1%. At baseline few Porphyromonas gingivalis and Prevotella intermedia were detected. They increased at gingivitis to 37.4% and 21.0%; when periodontitis developed, they comprised about 25.0%. Microbial colonization and establishment on titanium implants with healthy gingiva, experimental gingivitis and periodontitis follow the same pattern as on teeth.     

The effect of metronidazole on the development of plaque and gingivitis in the beagle dog

The present investigation was performed in order to assess if the administration of metronidazole changed the composition of developing plaque in dogs, which at the start of the study were free from signs of gingivitis. Five beagle dogs were used. Throughout the observation period the animals were fed a diet which favored plaque accumulation. A baseline examination involved assessments of plaque, gingivitis and gingival exudate. Gingival biopsies were sampled and the tissue examined by a point counting procedure. The composition of the subgingival bacterial flora was assessed by dark-field microscopy. The bacteria were characterized into the following types: coccoid cells, straight rods, filaments, fusiforms, motile and curved rods and spirochetes. Following the baseline examination the teeth of the right jaws were allowed to accumulate plaque. A careful tooth cleaning program was maintained in the left jaw quadrants. Plaque and gingivitis assessments were repeated and biopsies sampled in the right jaws after 7, 14 and 28 days of no tooth cleaning. On experimental day 28 the second part of the study was initiated. A baseline examination was performed in the left jaws, after which the tooth cleaning program also in this part of the dentition was terminated. During the subsequent 28-day period each animal was given a dosage of 20 mg metronidazole/kilogram bodyweight/day. Clinical examinations and biopsies were repeated after 7, 14 and 28 days. The results demonstrated that metronidazole administered via the systemic route during a 28-day period can effectively decrease plaque and gingivitis development in dogs. The bacterial flora from subgingival sites of healthy gingiva was dominated by coccoid cells and straight rods. During the phase of developing gingivitis the percentage of coccoid cells and rods tended to decrease, while motile rods and spirochetes increased. During the 28 days of metronidazole treatment the subgingival plaque flora maintained its "healthy" composition, i.e. a gradual influx of motile rods and spirochetes was prevented.     

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.     

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.     

Experimental gingivitis and frequency of tooth brushing in the beagle dog model

The aim of this experiment was to study clinical parameters when 3 different frequencies of tooth brushing were applied to sites of experimental gingivitis in beagle dogs. 12 beagle dogs, at the start of the experiment 2 years of age, were used. After a thorough cleaning, the maxillary left and right first, second and third premolars were brushed daily for a period of 8 weeks. Subsequently, for 4 weeks, all brushing was omitted in order to establish an experimental gingivitis. After this pre-experimental period, the dogs were distributed into 3 groups of 4 dogs each: one group was brushed 7 times a week, a second was brushed 3 times a week and the third group was brushed only once a week. Brushing was carried out for 24 weeks, only on the right sides of the upper jaws, the left upper jaws serving as controls. At regular intervals, plaque index, gingival index and probing depths were assessed. A brushing effect was calculated for each dog, to include information on all within-dog and between-dog variations. The present study demonstrated that only by brushing every day can clinically healthy gingivae be obtained in the beagle dog model with experimental gingivitis at baseline. The state of gingival health at baseline may be used to determined the frequency of brushing necessary to create or maintain healthy gingivae.     

Effect of selective antimicrobial therapy on plaque and gingivitis in the dog

Abstract. The present investigation was performed to assess the effect of selective antibiotic therapy on developing plaque and gingivitis in dogs, which at the start of the study had normal gingiva. Fifteen beagle dogs were used. Throughout the entire observation period the animals were fed a diet which favored plaque accumulation. A baseline examination involved assessments of plaque, gingivitis and gingival exudate. The subgingival bacterial flora was assessed by dark-field microscopy. Subsequently the teeth of the right jaws were allowed to accumulate plaque. A careful tooth-cleaning program was maintained in the left jaws. Plaque and gingivitis assessments were repeated and subgingival plaque sampled in the right jaws after 14 and 28 days. On experimental day 28 the second part of the study was initiated. The dogs were randomly distributed into three groups of five animals each. A new baseline examination was performed in the left jaws, after which all tooth cleanings were terminated. During the subsequent 28 days each group of dogs was treated with one of three antimicrobial compounds (vancomycin, metronidazole or clindamycin). Examinations were repeated after 14 and 28 days.
The results demonstrated that systemic administration of antimicrobial substances can reduce the rate of plaque formation, change the composition of the developing subgingival microbiota and prevent (or retard) the onset of gingivitis. A comparison of the ability of the three compounds to prevent the formation of a "gingivitis-inducing" plaque revealed that metronidazole and clindamycin were markedly more effective than vancomycin. In fact, in dogs receiving metronidazole and clindamycin treatment, the initiation of gingivitis was almost entirely prevented during the 28 days of treatment.     

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。     

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.     

局限性青少年海绵状牙龈增生的系统综述

目的 系统性分析局限性青少年海绵状牙龈增生(localized juvenile spongiotic gingivitis hyperplasia,LJSGH)的患病情况和治疗方法.方法 通过万方数据库、中国知网、PubMed、迈特思创和泉方学术等数据库检索2007年1月至2021年5月LSJGH相关文献,经筛选后对...     

Sulfadiazines reduce gingivitis and plaque formation in beagle dogs

The effect of zinc sulfadiazine (ZnSD) and silver sulfadiazine (AgSD) on reducing plaque formation and gingivitis was studied in 12 beagle dogs over a 14-week period. 12 beagle dogs were scaled, root planed and pumiced to bring them to a similar level of gingival health, prior to placing them on a diet of Purina Dog Chow softened with canned gravy and molasses to promote the build-up of plaque and the initiation of gingivitis. At the end of 8 weeks, the dogs were determined to have substantial bacterial plaque accumulation and apparent gingivitis. Thereafter, 4 dogs were treated 2 x daily with topical applications of 3% zinc sulfadiazine; 4 dogs were treated with 2% silver sulfadiazine while 4 dogs were treated with placebo gel serving as control over a 14-week treatment period. By week 2, the zinc and silver sulfadiazine dogs showed a significant decrease in gingival index which was maintained throughout the study. Additionally, by week 2, the % of sites with bleeding was also seen to decrease significantly in the experimental groups. The plaque index remained consistent in all 3 groups until week 6 when the 2 experimental groups indicated significant decrease in plaque accumulation as compared to controls. Probing depths were also seen to decrease significantly in the experimental groups after 10 weeks of therapy. The mean stain index was similar in all 3 groups of dogs throughout the study. Data indicate that both zinc and silver sulfadiazine inhibit plaque formation and reduce existing gingivitis in beagle dogs.     

Inhibition of experimental gingivitis in beagle dogs with topical salivary histatins

Abstract Histatins, histidine-rich proteins found within parotid and submandibular secretions, are a novel class of endogenous peptides with antimicrobial properties. This masked, randomized, placebo-controlled preclinical investigation examined the effect of 3 topical histatins on the development of plaque and gingivitis in beagle dogs. 16, female, 1-year-old beagles were brought to optimal gingival health by mechanical scaling and polishing followed by rigorous daily tooth brushing. At the conclusion of this pretreatment period, dogs were randomly divided into 4 groups for the application of test formulations, and were placed on a plaque-promoting diet, Test agents included 3 synthetic salivary histatins (histatin 5, P-113 and P-113D) which were incorporated in hydroxypropyl methylcellulose gel at a concentration of 0.125%, and a placebo, or negative control, which was the gel vehicle alone. Throughout the 10-week treatment period, test formulations (2.0 ml) were applied 2xdaily to all premolar teeth using a Monojet syringe. Plaque formation and gingival inflammation were assessed using the plaque (PI) and gingival (GI) indices on days 0, 7, 14, 21, 28, 42, 56 and 70. Furthermore, bleeding to probing was recorded as a percent of sites (%BOP) and according to the modified sulcus bleeding index (mSBI). Comparisons among groups and between group pairs (active versus placebo) were made with Kruskal-Wallis tests with the average of data over the interval, days 14–42, being the primary focus of the analysis. From baseline to day 7, all groups expressed similar indices. Thereafter, overall significant differences among the groups were noted at day 42 for PI, at days 21, 28, 42 and 70 for GI, and at days 14 and 28 for %BOP (p<0.05). In particular, beagles treated with P-113 demonstrated significantly lower PI scores at day 42 (p<0.05), significantly lower GI scores from days 21 through 42 (<0.05), and significantly lower %BOP scores at days 14 and 28 (p<0.05) compared to beagles treated with placebo. Beagles treated with P-113D exhibited significantly lower GI at day 42 compared to the placebo (p<0.05). For the primary analysis conducted over the midtreatment interval (days 14–42), significant differences were detected for all parameters except mSBI (p<0.05). Accordingly, significantly lower PI scores were found for P-113, lower GI scores for P-113 and P-113D, and lower %BOP for P-113 and P-113D compared to placebo (p<0.05). These data indicate that in the beagle model, salivary histatins, P-113 and P-113D, topically applied, can significantly reduce clinical signs of plaque formation and gingival inflammation.     

Development of gingivitis in pre-school children and young adults

Earlier studies suggest that children and adults differ in the propensity to develop gingivitis when oral hygiene is abandoned. To confirm the existence of such a difference, a comparative study of pre-school children and young adults was made with objective registration methods. The author performed all registrations. After a period of intensive oral hygiene, all cleaning of teeth was discontinued for 21 days. The amount of bacterial plaque, the amount of gingival exudate and crevicular leukocytes and the bleeding tendency were registered on days 0, 7, 14 and 21. During the experiment the amount of bacterial plaque increased continously in both groups. The amount of gingival exudate and the tendency to gingival bleeding increased to high values in the adults, while only a small rise was seen in the children. The amount of crevicular leukocytes increased in both groups, but the increment was greater in the adults. A comparison concerning differences in gingival exudate and bleeding tendency between pre-school children and adults was undertaken for gingival units that showed a similar plaque development. Under these statistically acceptable prerequisites, it was shown that there is a real difference in the tendency to develop gingivitis between pre-school children and adults.     

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.     

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.     

Influence of trauma from occlusion on progression of experimental periodontitis in the beagle dog

Abstract The experiments were performed in six beagle dogs fed a soft diet which allowed dental plaque formation. During a pre-experimental period of 7 weeks, periodontitis was induced by (1) surgically creating a bony pocket and (2) adapting a copper band to the exposed tooth surface. Two dogs were sacrificed at the end of this period and tissue sections were prepared for histological examination. In the remaining four dogs, trauma from occlusion was produced on the left mandibular fourth premolar by the installation of a cap splint and a bar device. The contralateral premolar served as a control. At the start of, and at regular intervals during, an experimental period of 180 days, tooth mobility, gingival inflammation and plaque accumulation were assessed. After sacrifice, radiographs were taken of test and control tooth regions and histological sections analysed regarding the width of the marginal periodontal ligament space and the degree of apical downgrowth of the gingival pocket epithelium. Only the test teeth showed a gradually increasing horizontal mobility, but gingival inflammation and Plaque Index scores were similar on test and control sides. Radiographs revealed (1) horizontal bone loss in both test and control areas, and (2) angular bone destruction only in test areas. Histological sections showed that the degree of apical proliferation of the pocket epithelium was more pronounced in test than in control regions.     

Experimental gingivitis in relation to susceptibility to periodontal disease

The aim of the present study was to investigate the rate of development of experimentally-induced gingival inflammation in relation to the susceptibility to periodontal disease. By selection according to age, a younger (25-39 years) and an older (45-54 years) age group, with a comparable reduced but healthy periodontium, was selected. This equal amount of periodontal breakdown may suggest that the younger age group represented individuals with a relatively higher degree of susceptibility to periodontal disease. At the start of the experiment, each patient was instructed to abstain from oral hygiene procedures in 1 quadrant of the mouth for a period of 18 days. Results showed that all subjects developed signs of gingival inflammation. Regarding the development of redness and swelling, no differences could be assessed between the 2 age groups. However, analysis of the bleeding scores revealed that bleeding on probing developed more rapidly in the younger age group. It was concluded that those patients who have suffered from a more rapid form of periodontal disease also develop inflammation, in terms of bleeding on probing, more rapidly.     

The effect of locally released oxygen on the development of plaque and gingivitis in man

Abstract An experimental gingivitis study was designed to test the effect of a 5-min twice daily oxygen application on the development of plaque and onset of gingivitis A method for the local application of medical grade oxygen to the upper anterior teeth was developed, with the lower anterior teeth used as controls. Fourteen periodontally healthy dental students of average age 21.9 years participated in the study. There was no significant effect of oxygen on plaque formation, crevicular fluid flow, or the number of gingival bleeding sites. Experimental and control gingival segments exhibited bleeding on probing at an average of 6.6 days after cessation of mechanical plaque control, much earlier than reported in other experimental gingivitis studies.     

Development of plaque and gingivitis following antibiotic therapy in dogs

Abstract Changes in the subgingival microbiota were studied during a 4-week period of plaque accumulation in beagles which initially had clean teeth and healthy gingiva. The effect of Clindamycin, Metronidazole and Vancomycin on the microbiota and associated gingivitis was also determined. Fifteen 1-year-old beagle dogs were used. During two subsequent periods of plaque accumulation, one without (control) and one with (test) antibiotic therapy, the animals were allowed to accumulate plaque. Plaque and gingivitis development was assessed by clinical measurements. Plaque samples were harvested from the gingival sulcus region and the percentage distribution of different bacteria was determined following aerobic and anaerobic incubation in selected media. Following microbial sampling, biopsies of the gingiva and surrounding soft and hard tissues were removed and the size of the inflammatory cell infiltrate assessed. The results demonstrated that beagle dogs with a normal gingiva harbored a microbiota within the gingival sulcus region dominated by gram-positive and gram-negative rods. After 4 weeks of undisturbed plaque accumulation, the number of sulcus bacteria had increased 100-fold. This increase was the result of a proliferation of gram-negative anaerobic rods. Concomitant with this change of the microflora, an inflammatory reaction developed in the gingiva. When the dogs during a similar 4-week period were given Metronidazole, no increase of the subgingival microbiota occurred. The inflammatory response of the gingiva was minute. Treatment with Clindamycin and Vancomycin did not entirely prevent the proliferation of the subgingival bacteria. The number of microorganisms harbored after 4 weeks of Clindamycin and Vancomycin treatment was, however, only 50% of that of the control period. Even if the number of colony forming units was similar at the end of Vancomycin and Clindamycin treatment the quality of the two subgingival microbiotas was different. Vancomycin treatment resulted in a plaque dominated by gram-negative bacteria while Clindamycin allowed gram-positive bacteria to increase in number. Gingival inflammation resulting in the Vancomycin group was more pronounced than the gingivitis response in the Clindamycin group.