Experimental Gingivitis Research Articles

Daily Probiotic Ayran Intake Reduces Gingival Inflammation: An Experimental Gingivitis Study.

This study investigates the effects of daily consumption of a probiotic ayran drink on gingival inflammation and the development of experimental gingivitis. This randomised, double-blind, placebo-controlled trial involved 54 volunteer students. The participants were randomly assigned to two groups: the control group received regular ayran for 42 days, while the test group received probiotic enriched ayran (including Lactobacillus acidophilus and Bifidobacterium bifidum) for 42 days twice a day. After 42 days, mechanical plaque control was stopped for 5 days. The plaque index (PI), gingival index (GI), probing bleeding (BOP), and probing depth (PPD) were measured at baseline, day 42, and day 47. At the same time, gingival crevicular fluid was taken for matrix metalloproteinase-8 examination. The mean scores of BOP, GI, PI, and MMP-8 levels increases in both groups following the 5-day experimental gingivitis period compared to baseline and day 42. Patients using probiotic ayran had significantly less PI, GI, BOP scores and MPP-8 values (p = 0.002; p 0.001; p 0.001; p = 0.001; p = 0.001, respectively) at day 47 compared to the control group. No statistically significant differences in probing pocket depth (PPD) were observed at any time point. The present study suggests that daily consumption of a probiotic ayran drink containing Lactobacillus acidophilus and Bifidobacterium bifidum statistically significantly lowers clinical and immunological markers of gingival inflammation.

Multi-way modelling of oral microbial dynamics and host-microbiome interactions during induced gingivitis

Gingivitis—the inflammation of the gums—is a reversible stage of periodontal disease. It is caused by dental plaque formation due to poor oral hygiene. However, gingivitis susceptibility involves a complex set of interactions between the oral microbiome, oral metabolome and the host. In this study, we investigated the dynamics of the oral microbiome and its interactions with the salivary metabolome during experimental gingivitis in a cohort of 41 systemically healthy participants. We use Parallel Factor Analysis (PARAFAC), which is a multi-way generalization of Principal Component Analysis (PCA) that can model the variability in the response due to subjects, variables and time. Using the modelled responses, we identified microbial subcommunities with similar dynamics that connect to the magnitude of the gingivitis response. By performing high level integration of the predicted metabolic functions of the microbiome and salivary metabolome, we identified pathways of interest that describe the changing proportions of Gram-positive and Gram-negative microbiota, variation in anaerobic bacteria, biofilm formation and virulence.

Supra- and Subgingival Microbiome in Gingivitis and Impact of Biofilm Control: A Comprehensive Review.

This comprehensive review aimed (1) to characterize the sub- and supragingival microbiome in patients with biofilm-induced gingivitis (including experimental gingivitis), (2) to assess its stability and evolution over time, and (3) to assess the impact of biofilm control measures on this stability. An electronic search of the MEDLINE®/PubMed® database until December 2023 was conducted. NCBI Taxonomy, eHOMD 16S rRNA Reference Sequence, and Tree Version 15.23 databases were used to standardize taxonomic nomenclature. Out of 89 papers initially retrieved, 14 studies were finally included: 11 using experimental gingivitis as a model and three randomized clinical trials evaluating the impact of biofilm control measures. Among them, five characterized the subgingival microbiome, nine the supragingival microbiome, and one both the sub- and supragingival microbiome. In addition, five studies evaluated the effect of toothpaste, and four studies evaluated the effect of mouth rinses. The diversity and structure of the microbiome differed significantly between patients with periodontal health and those with biofilm-induced gingivitis (including experimental gingivitis). Those differences were not reversed through conventional oral hygiene measures. Specific antiseptic agents, especially if delivered as mouth rinses, may have an impact on the supra- and subgingival microbiome in gingivitis.

Inflammation and tissue remodeling mediator expression during gingivitis: A comparison between experimental, naturally occurring gingivitis, and periodontal health.

The aim of this study is to evaluate the immune regulation and tissue remodeling responses during experimental gingivitis (EG) and naturally occurring gingivitis (NG) to provide a comprehensive analysis of host responses. Gingival crevicular fluid (GCF) was obtained from 2 human studies conducted in university settings. The EG study enrolling 26 volunteers provided controls for the baseline (Day 0) from healthy disease-free participants, while Day 21 (the end of EG induction of the same group) was used to represent EG. Twenty-six NG participants age-matched with those of the EG group were recruited. GCF samples were analyzed for 39 mediators of inflammatory/immune responses and tissue remodeling using commercially available bead-based multiplex immunoassays. The differences in GI and mediator expression among groups were determined at a 95% confidence level (p ≤ 0.05) by a 2-way analysis of variance (ANOVA) with a post-hoc Tukey's test. Our findings showed that EG had a greater gingival index than NG and was healthy (p<0.01 of all comparisons). Furthermore, EG showed significantly higher levels of MPO (p<0.001), CCL3 (p<0.05), and IL-1B (p<0.001) than NG. In contrast, NG had increased levels of MIF (p<0.05), Fractalkine (p<0.001), angiogenin (p<0.05), C3a (p<0.001), BMP-2 (p<0.001), OPN (p<0.05), RANKL (p<0.001), and MMP-13 (p<0.001) than EG. Consistent with the findings from chronic (NG) versus acute (EG) inflammatory lesions, these data reveal that NG displays greater immune regulation, angiogenesis, and bone remodeling compared to EG.

Effects of a stabilized stannous fluoride dentifrice on clinical, immunomodulatory, and microbial outcomes in a human experimental gingivitis model.

Stannous fluoride dentifrice is well established for its beneficial clinical effects. In this study, we evaluated the effects of stannous fluoride on inflammation and oral microbiome. In this randomized, parallel-arm, double-blind, controlled clinical trial, we compared clinical resolution of experimental gingivitis by evaluating bleeding on probing, gingival index, and plaque index between stannous fluoride stabilized with zinc phosphate (test) and sodium fluoride (control) dentifrices. Further, these groups were compared for oral neutrophil counts, systemic priming of neutrophils, gingival crevicular fluid (GCF) expression of inflammatory markers, and the oral microbiome. We found significant reduction in bleeding on probing in the test group compared to the control group in experimental gingivitis when participants used the test dentifrice prior to induction of experimental gingivitis. The test group also showed significant reductions in GCF levels of inflammatory markers (matrix metalloproteinase 8 [MMP8], receptor activator of nuclear factor kappa-Β ligand [RANKL]), oral polymorphonuclear neutrophil (PMN) counts, and systemic neutrophil priming (CD11b expression) during experimental gingivitis. Further, significant reductions in the gram-negative genera Porphyromonas, Tannerella, and Treponema were noted in the test group. The stannous fluoride stabilized with zinc phosphate dentifrice formulation demonstrated clinical reduction in gingival inflammation and a beneficial effect on microbiome and immune markers. This intervention should be explored as a preventive aid in the progression of plaque-induced gingivitis to periodontitis.

Genetic Control of GCF Exudation: Innate Immunity Genes and Periodontitis Susceptibility.

Chronic periodontitis is a bacterial infection associated with dentally adherent biofilm (plaque) accumulation and age-related comorbidities. The disease begins as an inflammatory exudate from gingival margins, gingival crevicular fluid (GCF) in response to biofilm lysine. After a week of experimental gingivitis (no oral hygiene), biofilm lysine concentration was linearly related to biofilm accumulation (plaque index) but to GCF as an arch-shaped double curve which separated 9 strong from 6 weak GCF responders (hosts). Host DNA was examined for single nucleotide polymorphisms (SNPs) of alleles reported in 7 periodontitis-associated genes. Across all 15 hosts, an adenine SNP (A) at IL1B-511 (rs16944), was significant for strong GCF (Fisher's exact test, p < 0.05), and a thymidine SNP (T) at IL1B+3954 (rs1143634) for weak GCF provided 2 hosts possessing IL6-1363(T), rs2069827, were included. The phenotype of IL1B+3954(T) was converted from weak to strong in one host, and of the non-T allele from strong to weak in the other (specific epistasis, Fisher's exact test, p < 0.01). Together with homozygous alternate or reference SNPs at IL10-1082 or CD14-260 in 4 hosts, all hosts were identified as strong or weak GCF responders. The GCF response is therefore a strong or weak genetic trait that indicates strong or weak innate immunity in EG and controllable or uncontrollable periodontal disease, dental implant survival and late-life comorbidities.

Influence of Nutrition and Physical Activity on Local and Systemic Inflammatory Signs in Experimentally Induced Gingivitis.

Although numerous studies have been published investigating the relationship between various dietary components and inflammatory periodontal disease, it has not yet been possible to clearly distinguish between periodontally healthy and unhealthy diets. This clinical study aimed to assess the association of specific food ingredients and physical activity on local and systemic inflammatory signs in experimentally induced gingivitis. Thirty-nine non-smoking periodontally healthy volunteers (mean age 23.2 ± 3.8 years) refrained from oral hygiene in the right maxilla for 21 days to induce an experimental gingivitis. Clinical examination (baseline and day 21) included plaque index, bleeding on probing (BOP), gingival crevicular fluid volume and high sensitive C-reactive protein levels (blood sample). Accompanying the intervention, volunteers documented with validated questionnaires their physical activity converted into metabolic equivalent (MET) and their nutrition converted into the dietary inflammatory index (DII). Significantly lower BOP (p = 0.039) was found for subjects with a more anti-inflammatory DII than for those with a more pro-inflammatory DII; higher MET values were correlated with lower BOP at day 21 (correlation coefficient -0.36). The results show an influence of nutrition and physical activity on periodontal inflammation signs. The DII may be a suitable parameter to verify the relationship between nutrition and inflammatory periodontal diseases.

The natural history of periodontal disease: The Java study-Origin, implementation, and results 35 years on.

This review describes the origin and results of the prospective longitudinal study to test potential prognostic indicators for periodontal breakdown in a population deprived of regular dental care. Experimental gingivitis studies in individuals highly susceptible or highly resistant to periodontitis showed that bleeding on probing developed quite differently: 50% versus 18% bleeding, respectively, after 18 days of no oral hygiene. This formed, together with other clinical and microbiological parameters, the basis for the 15-year prospective study in the Java tea worker population to test potential prognostic indicators for periodontal breakdown. Evaluation showed that during the 15-year observation period of this population aged 15-25 years at baseline, the number of teeth decreased and the periodontal condition deteriorated. Gingival recession showed no increase during the first 7 years of observation, whereas a sixfold increase had occurred thereafter. Attachment loss doubled during the first 7 years, but almost tripled thereafter. Risk markers for disease onset/progression during the first 7 years of observation were age, the number of sites with subgingival calculus, and the subgingival presence of Aggregatibacter actinomycetemcomitans. Over the full period of 15 years the number of sites with a pocket depth of at least 5 mm and the number of sites with recession were identified as risk markers and male gender as a risk determinant. The prevalence of severe periodontitis amounted to 20% in 2002. Analysis showed that, already at baseline and throughout the study period, the periodontal condition in these individuals was more severe compared with the other participants. In conclusion, characteristics of susceptibility to periodontitis are already apparent in young adulthood.

The anti-plaque effect of high concentration sodium bicarbonate dentifrice on plaque formation and gingival inflammation, irrespective to individual polishing technique and plaque quality

AimTo assess the anti-plaque effect of a high concentration sodium bicarbonate dentifrice on plaque formation, and gingivitis, as compared to a control toothpaste, irrespective of individual brushing technique and plaque quality.MethodsThe experimental gingivitis model, with a split-mouth design was used to assess the anti-plaque effect of a high concentration sodium bicarbonate dentifrice on plaque formation. By producing individual fitted trays, the toothpaste was applied in the test quadrant and a control dentifrice in the contralateral. The participants used the individual fitted trays for 1 min every morning and evening, for 21 days. In this period, the participants was only allowed to brush the teeth in the opposite jaw, as usual. Twenty healthy individuals successfully completed the study.ResultsAt 21 days, there was no statistically significant difference between test quadrant and control quadrant with regard to plaque indices, gingival index and number of bleeding sites.ConclusionThis study demonstrated that the high concentration sodium bicarbonate dentifrice used did not produce statistically significant anti-plaque effect compared to the control dentifrice, in terms of Plaque- and Gingival Indices, number of bleeding sites or by Quigely and Hein, the Turesky modification Plaque Index, irrespective of brushing technique and individual plaque quality.Trial registrationRegional Committee for Medical Research and Ethics, South-East Norway in 2021 (REK.2021/370116).Clinical Trial Registration: NCT05441371 (First registered 09/06/2022, First posted 01/07/2022) (http://www.clinicaltrials.gov). (Retrospectively registered).

The usage of orally gavage and topically applied omega -3 in the treatment of experimental gingivitis in rats.

Abstract&#x0D; Aim of the study: This study aimed to evaluate effects of omega 3 polyunsaturated fatty acids on ligation induced gingivitis in rats through the immunological analysis for rat’s gingival tissue level of tumor necrotic factor-α( TNF-α) .&#x0D; Materials and methods: The gingivitis was induced for rats by ligation around lower central incisors. Fifty animals with the induced gingivitis were divided into: five animals were sacrificed at the first day after removal of ligature, and fifteen animals as positive control group. Fifteen animals were used as 1st treatment group with orally gavage omega 3 polyunsaturated fatty acid and fifteen animals as 2nd treatment groups with topically applied omega3 a Five animals were used as negative control groups (-ve) group.&#x0D; Animals were sacrificed and tissue sections were evaluated for Tumor necrotic factor –α (TNF-α) levels, this biomarker were measured by ELISA method for four times, first after ligation removal (day zero), three days, one week and two weeks for immunological analysis.&#x0D; Results: The result showed that level of TNF-α were significantly lower in systemic treatment groups in comparison with positive control groups in all duration of study, and there were significant difference between topical treatment groups on the 3rd and 7th days and no significant differences on the 14th day after removal of ligature in comparison with (+ve) ,also there was no significant&#x0D; difference between these two treatment groups in all duration of study. T-test used for statistical analyses, with p&lt;0.05 regarded as significant and p&gt; 0.001 as high significant.&#x0D; Conclusion: orally gavage and topical application of omega-3 FAs is effective treatment for reduction of inflammation in gingivitis, resulting in lower level of TNF-α.

Changes in the activity of phosphatases, calcium and phosphorus in rats with the different courses of gingivitis under correction by anti-inflammatory gel

The aim of the study was to evaluate changes in the activity of acid and alkaline phosphatases, calcium and phosphorus levels in rats with different courses of experimental gingivitis upon treatment with anti-inflammatory gel with Neovitin and peptide complexes. The experiment was conducted on 100 white nonlinear male rats aged 5-6 months divided into 10 groups: 1 control and 9 – with different courseі of gingivitis. The activity of alkaline and acid phosphatase (ALP, ACP), the levels of calcium (Ca) and phosphorus (P) in rat blood serum and gingiva supernatant were determined. It was found that upon gingivitis, the activity of ALP in blood serum decreased and in gingiva supernatant increased in all groups of animals compared to the control group. The activity of ACP in the serum decreased in hypoergic and hyperergic animal groups and increased in normergia, and in gingiva supernatant increased in all groups: by 2 times in normoergic and hypoergic animals and by 1.4 times in hyperergic. The treatment with anti-inflammatory gel normalized the activity of ALP in both serum and supernatant and decreased the ACP activity in the serum of animals in hypo- and hyperergic groups. The content of serum Ca increased in all groups, and in the supernatant of the gingiva even exceeded the control value. The content of phosphorus in the supernatant of periodontal tissues decreased. The development of the inflammatory process in the periodontium of rats with gingivitis was accompanied by changes in the activity of ACP, ALP, the content of Ca and P in the blood serum and gingival supernatant. The treatment with gel containing neovitin and peptide complexes had a more pronounced therapeutic effect in rats with unchanged reactivity of the organism. Keywords: acid phosphatase, alkaline phosphatase, anti-inflammatory gel, calcium and phosphorus levels, gingivitis

Impact of Gingivitis on Circulating Neutrophil Reactivity and Gingival Crevicular Fluid Inflammatory Proteins.

Gingivitis is an extremely common oral inflammatory condition and can be induced in humans using an acute 21-day experimental gingivitis model. Neutrophils are known to be highly prevalent in the gingival crevice during gingival inflammation; however, the effect of gingivitis and the associated biofilm on peripheral blood neutrophils (PBN) is not well characterised. Thus, the aim of this study was to examine the impact of inflammation induced by experimental gingivitis and its resolution upon the function of PBN. Fifteen systemically healthy volunteers undertook a split-mouth 21-day experimental gingivitis study followed by a resolution phase of 14 days. PBN function, including reactive oxygen species (ROS) production, neutrophil extracellular trap (NET) release, directional chemotactic accuracy and expression of host mediators in gingival crevicular fluid (GCF), were measured at baseline (day 0), on day 21 and on day 35. NET formation and ROS production were significantly elevated at day 21. Chemotactic speed was also elevated in response to bacterial peptide fMLP at day 21. At day 35, ROS production in response to an Fcgamma stimulant, opsonised Staphylococcus aureus, remained elevated. The data presented suggest a lasting biological impact of the experimental gingivitis on PBN function even after clinical symptoms have abated.

Effect of a new mouthwash based on Tea polyphenols and chlorogenic acid on dental caries and gingivitis

ObjectiveTo observe the preventive effect of new mouthwash on experimental dental caries and gingivitis in SD rats. Materials and Methods1. The animal model of dental caries was established and evaluated according to the classical Keyes scoring method.2.After the animal model of gingivitis was established, aspartate aminotransferase (AST) levels were measured and superoxide dismutase inhibition (SOD) and peroxidase activity (CAT) were evaluated. Results1.Caries group: the Keyes scoring results showed that the number of surface caries and the E and DS grade caries in the experimental group was significantly lower than that in the control group (P<0.05). 2.Gingivitis group:After treatment, significantly decreased salivary AST values were observed in the experimental group compared to the negative control group (P< 0.05). Both the experimental and positive control groups showed greater inhibition of SOD and CAT activity compared to the negative control group (P<0.05). ConclusionThe new mouthwash has a preventive and therapeutic effect on experimental caries and gingivitis in SD rats.

The Evaluation of the Effects of Two Probiotic Strains on the Oral Ecosystem: A Randomized Clinical Trial.

IntroductionIn the current study, we evaluated the effectiveness of two well-defined probiotic strains, Lactobacillus paracasei LPc-G110 (CCTCC M 2013691) and Lactobacillus plantarum GOS42 (DSM 32131), during an experimental gingivitis challenge. The primary objective was to evaluate clinically the effectiveness of lozenges containing one of the two oral probiotic strains, compared with placebo lozenges, on the gingival bleeding (bleeding on marginal probing; BOMP change) after a two-week experimental gingivitis period. The secondary objectives were to assess the effects of the test products on gingival health (Modified Gingival Index; MGI), dental plaque accumulation and fluorescence, and the dynamics of immunological and microbiological aspects after the wash-in phase, followed by a two-week period refraining from oral hygiene and a two-week wash-out phase.MethodsThis single-center challenge intervention study was a triple-blind randomized placebo-controlled clinical trial with three parallel groups. The full study population consisted of 117 healthy 18–55 years old human volunteers. Subjects were instructed to use one lozenge, 3 times daily after each meal, containing either L. plantarum, L. paracasei, or lozenges without probiotics (placebo group). After a 2-week wash-in period, the subjects were requested to refrain from any form of oral hygiene for 2 weeks.ResultsThere were no differences in the primary outcome (BOMP change) among the groups. However, gingival health (MGI) in individuals from the groups exposed to the test products recovered better from experimental gingivitis than the individuals in the placebo group (p = 0.021, one-way ANOVA). The two test products inhibited pro-inflammatory cytokine IL-1ß production, measured in saliva, during the experimental gingivitis period. Both test strains significantly reduced bacterial DNA in tongue samples and L. paracasei strain showed stronger microbiome-modulating potential than the L. plantarum strain.ConclusionsThe two tested lozenges with the L. paracasei or L. plantarum strains did show potential for beneficial effects for the oral health of the host during experimental gingivitis to the oral ecosystem.

Myrrh And Chlorhexidine Mouthwashes Comparison For Plaque, Gingivitis And Inflammation Reduction: A 3-Arm Randomized Controlled Trial

This research was conducted to associate the effectivity of 1% myrrh mouthwash with 0.2% chlorhexidine mouthwash in terms of inhibition of the activity of plaque and gingivitis and decrease of pro-inflammatory cytokines. The clinical trial included 10 males and 9 females (myrrh group, n = 6; chlorhexidine group, n = 7; and saline group, n = 6). Participants initially refrained from daily routine oral health care practices for about two weeks to allow the growth of experimental gingivitis. After

A Comparative Study of Fluoride Containing Chlorhexidine and Non Chlorhexidine Mouthrinses in a Teenage Group

Background: Mouthwashes are important means used in chemical control of dental plaque. There is strong evidence suggestive of better effectiveness, when fluoride is added to chlorhexidine mouthwash.&#x0D; Objectives: The study was planned to assess the effect of a mouthrinse containing Chlorhexidine (CHX) and amine/stannous fluoride (AmF) on plaque accumulation, gingivitis and salivary fluoride levels in comparison with two mouthrinses containing either essential oils (EO) or cetylpyridinium chloride (CPC) with sodium fluoride (NaF) in a teenage group.&#x0D; Methodology: For this study 90 healthy teenage between 12 and 20 years were recruited for participation. The experimental gingivitis model consisted of a 2-weeks recruitment phase, followed by a 6-day rinsing period with one of the 4 mouthrinse formulations was used for the study. At the end of the pre-phase period and the rinsing period (Day-0/Day-6), gingival index (GI), plaque index (PI) and salivary fluoride levels were recorded. The statistical analyses were performed using Wilcoxon sign test and the dependent t test.&#x0D; Results: A reduction in plaque re-growth was seen for the CHX+AmF formulation rinse, although there were no significant differences among all groups (p&gt;0,001). During the experimental periods, the gingivitis indices increased significantly for all formulations (p&lt;0,001), except for the CHX+AmF formulation. The CHX+AmF formulation scored higher levels of salivary fluoride at the end of the rinsing period (p&gt;0,001).&#x0D; Conclusion: We would like to conclude that the adjunctive use of AmF containing CHX mouthrinses to mechanical oral hygiene should be recommended for teenage at risk groups.&#x0D; Keywords: CT KUB, Radiation safety, Minimise radiation

Cytokine profiles and the dynamic of gingivitis development in humans.

To investigate the relationship between cytokine profiles and "fast" and "slow" patterns of gingival inflammation development. Forty-two adults participated in an experimental gingivitis study, comprising a 2-week hygiene phase (clinical examination and professional cleaning); a 3-week induction phase (absence of oral hygiene); and a 2-week resolution phase (re-establishment of oral hygiene). Plaque and gingival inflammation scores were assessed. Interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and tumour necrosis factor-alpha (TNF-α) from gingival crevicular fluid were collected and measured by multiplex ELISA. Group-based-trajectory-modelling (GBTM) was used to model cytokine profiles over the induction phase. The effect of gingival inflammation on cytokine levels over time was estimated with mixed-effects modelling. GBTM analysis revealed two cytokine profiles, "non-organized response" (IL-4, IL-6, IL-8, IL-12, and IL-13) and "organized response" (IL-2, IL-10, and TNF-α). Among the "slow" responders, neither cytokine profile was associated with gingivitis. In contrast, a "fast" response was associated with a higher "non-organized response" factor (coef. 0.14) and a lower "organized response" factor (coef. -0.03). A "fast" gingivitis development was associated with a higher "non-organized response" and a lower "organized response", which may elucidate the role of individual variability in gingivitis susceptibility.

Increasing oral PMN during experimental gingivitis and its reversal by prophylaxis

This investigation evaluated clinical parameters and the levels of polymorphonuclear leukocytes [PMN] collected in an oral rinse amongst subjects who refrained from dental hygiene for a period of 12 days. MethodsStudy enrolled consenting adults and assigned to a non-prophy group [n = 16] and a separate prophy group [n = 27]. Both groups underwent clinical evaluations and sampling for PMN at baseline and on days 3,6,9 and 12 of study initiation. The prophy group underwent supragingival prophylaxis at the conclusion of the no-hygiene phase and recalled for a final clinical evaluation and PMN assessment 1 week later. ResultsProgressive increases in oral PMN were noted due to abstinence from oral hygiene (p < 0.05). Subjects registered PMN increases ranging from 20% recorded three days following abstinence of hygiene to the highest value of 298% at the 12-day evaluation (p < 0.05). One week after prophylaxis, average PMN scores were 22% lower than baseline (p < 0.05). Abstinence from dental hygiene led to progressive increases in clinical parameters for dental plaque, gingival inflammation and bleeding. Dental plaque, gingival index and gingival bleeding scores recorded increases of 59%, 64% and 126% respectively at the conclusion of the no-hygiene phase. Prophylaxis resulted in marked reductions in all clinical parameters. ConclusionsAbstinence from dental hygiene corresponded with increasing scores for dental plaque, gingival inflammation and bleeding in conjunction with increasing oral PMN. These effects were irrespective of age or gender and were reversed by supragingival prophylaxis.

Impaired function of epithelial plakophilin-2 is associated with periodontal disease.

Plakophilin-2 (PKP2) is an intracellular desmosomal anchoring protein that has been implicated in a genome-wide association study, in which genetic variants of PKP2 are associated with Porphyromonas gingivalis (P.gingivalis) -dominant periodontal dysbiosis. In this study, we compared the ex vivo PKP2 expression in periodontitis gingival biopsies to periodontitis-free subjects and assessed the in vitro role of PKP2 in gingival epithelial barrier function and the mechanism by which P.gingivalis modulates PKP2 expression. Using reverse transcription quantitative real-time PCR (RT-qPCR), we determined PKP2mRNA expression levels in gingival biopsies collected from 11 periodontally healthy, 10 experimental gingivitis, and 10 chronic periodontitis subjects. PKP2 protein expression in gingival biopsies was detected by immunohistochemistry. We then challenged primary gingival epithelial cells with bacteria including P.gingivalis, Campylobacter rectus, and various Toll-like receptor agonists. Western blot and immunofluorescence staining were used to detect protein expression. Inhibitors blocking proteases pathways were tested for P.gingivalis-mediated PKP2 protein degradations. We also knocked down endogenous epithelial PKP2 using lentiviral short-hairpin RNA (shRNA) and evaluated cell proliferation, spreading, and barrier function. Periodontitis gingival biopsies had approximately twofold less PKP2 mRNA than did healthy controls (p<.05). PKP2 protein was predominantly expressed in gingival epithelium. In primary gingival epithelial cells, P.gingivalis challenge increased PKP2 mRNA levels, while protein expression decreased, which suggests that P.gingivalis has a protein degradation mechanism. Cysteine proteases inhibitors greatly attenuated P.gingivalis-mediated PKP2 protein degradation. Epithelial cells with deficient PKP2 exhibited inhibited cell proliferation and spreading and failed to form monolayers. Finally, P.gingivalis impaired gingival epithelial barrier function. PKP2 appears to be critical in maintaining gingival epithelial barrier function and is susceptible to degradation by cysteine proteases produced by P.gingivalis. Our findings have identified a mechanism by which P.gingivalis impairs epithelial barrier function by promoting PKP2 degradation.

Human variation in gingival inflammation.

Oral commensal bacteria actively participate with gingival tissue to maintain healthy neutrophil surveillance and normal tissue and bone turnover processes. Disruption of this homeostatic host-bacteria relationship occurs during experimental gingivitis studies where it has been clearly established that increases in the bacterial burden increase gingival inflammation. Here, we show that experimental gingivitis resulted in three unique clinical inflammatory phenotypes (high, low, and slow) and reveal that interleukin-1β, a reported major gingivitis-associated inflammatory mediator, was not associated with clinical gingival inflammation in the slow response group. In addition, significantly higher levels of Streptococcus spp. were also unique to this group. The low clinical response group was characterized by low concentrations of host mediators, despite similar bacterial accumulation and compositional characteristics as the high clinical response group. Neutrophil and bone activation modulators were down-regulated in all response groups, revealing novel tissue and bone protective responses during gingival inflammation. These alterations in chemokine and microbial composition responses during experimental gingivitis reveal a previously uncharacterized variation in the human host response to a disruption in gingival homeostasis. Understanding this human variation in gingival inflammation may facilitate the identification of periodontitis-susceptible individuals. Overall, this study underscores the variability in host responses in the human population arising from variations in host immune profiles (low responders) and microbial community maturation (slow responders) that may impact clinical outcomes in terms of destructive inflammation.