Subgingival Host-Microbial Interactions in Hyperglycemic Individuals.

Type 2 diabetes mellitus (T2DM) is an established risk factor for periodontitis, yet its contribution to creating host-bacterial disequilibrium in the subgingival crevice is poorly understood. The present investigation aimed to quantify the impact of hyperglycemia on host-bacterial interactions in established periodontitis and to map shifts in these dynamics following mechanical nonsurgical therapy. Seventeen T2DM and 17 non-T2DM subjects with generalized severe chronic periodontitis were recruited along with 20 periodontally healthy individuals. Subjects with periodontitis were treated with scaling and root planing (SRP). Samples of subgingival biofilm and gingival crevicular fluid were collected at baseline and at 1-, 3-, and 6 mo postoperatively. Correlations were generated between 13.7 million 16S ribosomal DNA sequences and 8 immune mediators. Intermicrobial and host-microbial interactions were modeled using differential network analysis. Periodontal health was characterized by a sparse interbacterial and highly connected cytokine-bacterial network, while both normoglycemics and T2DM subjects with periodontitis demonstrated robust congeneric and intergeneric hubs but significantly fewer cytokine-bacterial connections. Following SRP, the cytokine-bacterial edges demonstrated a 2-fold increase 1 mo postoperatively and a 10-fold increase at 6 mo in normoglycemics. In hyperglycemics, there was a doubling at 1 mo but no further changes thereafter. These shifts accompanied an increasingly sparse interbacterial network. In normoglycemics, the nodes anchored by interleukin (IL)-4, IL-6, and IL-10 demonstrated greatest rewiring, while in hyperglycemics, IL-1ß, IL-6, INF-γ, and IL-17 exhibited progressive rewiring. Thus, the present investigation points to a breakdown in host-bacterial mutualism in periodontitis, with interbacterial interactions rather than host-bacterial interactions primarily determining community assembly. Hyperglycemia further exacerbates this uncoupled mutualism. Our data also demonstrate that while nonsurgical therapy might not consistently alter microbial abundances or lower proinflammatory molecules, it "reboots" the interaction between the immunoinflammatory system and the newly colonizing microbiome, restoring a role for the immune system in determining bacterial colonization. However, this outcome is lower and delayed in hyperglycemics.

Periodontal status of individuals with Down syndrome: sociodemographic, behavioural and family perception influence.

BACKGROUND: The aim of the present study was to assess the periodontal condition of individuals with Down syndrome and the association with sociodemographic and behavioural characteristics and family perception of oral health. METHODS: This cross-sectional observational study was performed at a referral centre for dental assistance to disabled persons in Araçatuba, Brazil. Parents of the individuals were interviewed, and the visible plaque index, bleeding on probing, probing pocket depth and clinical attachment level were recorded by one periodontist in six sites per tooth of all teeth. The individual was the unit of analysis. The significance level was set at 5%. RESULTS: Sixty-four subjects (23.8 ± 8.3 years old) were included. Eighteen (28.1%) were diagnosed with gingivitis and 46 (71.9%) with periodontitis. In the multiple logistic regression final model, age and self-reported oral hygiene practices were associated with the occurrence of periodontitis. The chance of having periodontitis was 4.7 times higher among individuals older than 20 years and approximately 4 times higher in patients whose oral hygiene was performed by themselves and their parents, compared with those who performed oral hygiene alone. Sex, follow-up time in the centre, education, degree of participants' dependence, flossing and family history of periodontal disease were not associated with the occurrence of periodontitis. Higher levels of plaque and bleeding were observed for participants with parents reporting bad gingival health (76.2% and 46.9%) and deficient oral hygiene (79.5% and 47.3%). The perception of parents regarding gingival bleeding was correlated with higher bleeding detected clinically (P = 0.01; 50.1%). CONCLUSIONS: The prevalence of periodontitis in individuals with Down syndrome is high and increases with age, even in the face of the parents' perception about their children's oral condition.

The impact of different torques for the insertion of immediately loaded implants on the peri-implant levels of angiogenesis- and bone-related markers.

The aim of this split-mouth, randomized, double-blind, controlled clinical trial was to evaluate the influence of different insertion torque values for dental implants on bone- and angiogenesis-related marker profiles. Eighteen edentulous patients received dental implants and fixed complete-arch mandibular prostheses. The implants (n=36) were assigned randomly to two groups: reduced torque (n=18), with insertion torque <30Ncm; and conventional torque (n=18), with insertion torque ≥30Ncm. Levels of vascular endothelial growth factor (VEGF), placental growth factor, bone morphogenetic protein 9 (BMP-9), periostin, osteoprotegerin (OPG), and tartrate-resistant acid phosphatase (TRAP) in the peri-implant fluid were quantified at 7, 14, 30, and 120days after implant placement. Inter-group comparisons showed that VEGF and OPG levels were higher in the low-level torque group than in the conventional torque group on days 7 and 30, respectively (P<0.05). BMP-9 and periostin levels were higher in the conventional group than in the low-level torque group on day 120, and TRAP was up-regulated around implants inserted with conventional torque when compared to those inserted with lower-level torque at all time points evaluated (P<0.05). In conclusion, the use of different levels of torque for implantation of immediately loaded implants significantly influenced the levels of bone- and angiogenesis-related markers during early peri-implant repair.

Transgenerational effects of a hypercaloric diet.

The effects of a maternal hypercaloric diet (HD) during puberty and early adulthood on neuroimmune aspects in offspring were investigated. In female rats of the F0 generation and male rats of the F1 generation, bodyweight (BW) gain, retroperitoneal fat (RPF) weight, the number of hypodermic adipocytes (HAs) and expression of glial fibrillary acidic protein (GFAP) were measured in hypothalamic astrocytes. On Postnatal Day 50, the F1 pups were challenged with lipopolysaccharide (LPS, 100µgkg-1, s.c.) or an equal volume of saline (S), and behaviour in the open field test was evaluated, as were plasma neuropeptide and cytokine concentrations. The maternal HD caused the female F0 rats to become overweight. The F1 offspring of dams fed the HD and challenged with saline (HDS group) exhibited increases in BW gain, RPF weight and in the number of large HAs and a decrease in GFAP immunoreactivity. F1 offspring of dams fed the HD and challenged with LPS (HDLPS group) exhibited decreases in BW gain, RPF weight and GFAP immunoreactivity, but no differences were observed in the number of larger and small HAs. Plasma tumour necrosis factor-α concentrations were high in the HDS and HDLPS groups. Thus, the maternal HD during puberty and early adulthood caused the F1 generation to become overweight despite the fact that they received a normocaloric diet. These results indicate a transgenerational effect of the HD that may occur, in part, through permanent changes in immune system programming. The attenuation of neuroinflammation biomarkers after LPS administration may have resulted in a decrease in the number of adipocytes, which, in turn, reduced cytokine, adipokine and chemokine levels, which are able to recruit inflammatory cells in adipose tissue.

Systemic treatment with resveratrol and/or curcumin reduces the progression of experimental periodontitis in rats.

BACKGROUND AND OBJECTIVE: Periodontitis is a chronic inflammatory disease of periodontal tissues that leads to the destruction of bone and other connective tissues. Resveratrol and curcumin are plant-derived substances with biological properties that may have immunomodulatory properties. This study investigated the effect of continuous administration of resveratrol and curcumin and the association of resveratrol and curcumin on the progression of experimental periodontitis in rats. MATERIAL AND METHODS: Forty Wistar rats were assigned randomly to the following groups: group 1, experimental periodontitis + placebo (PL) (n = 10); group 2, experimental periodontitis + resveratrol (RSV) (n = 10); group 3, experimental periodontitis + curcumin (C) (n = 10); and group 4, experimental periodontitis + resveratrol + curcumin (COMBI) (n = 10). Periodontitis was induced in rats by tying a silk suture, as a ligature, around one of the first molars. Daily administration of the placebo solution, 10 mg/kg of resveratrol, 100 mg/kg of curcumin or 10 mg/kg of resveratrol plus 100 mg/kg of curcumin was carried out from day 0 to day 30. At the end of the relevant experimental periods, rats were killed and the specimens obtained were processed for morphometric analysis of bone loss. Gingival tissues surrounding the first molar were collected for quantification of interleukin (IL)-1ß, IL-4, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) using a Luminex/MAGPIX assay. RESULTS: Intergroup comparisons of the morphometric outcomes revealed higher bone-loss values in the PL group (p < 0.05) when compared with RSV, C and COMBI groups. There was no difference in bone-loss values among RSV, C and COMBI groups (p > 0.05). The immunoenzymatic assay of the gingival tissue showed a lower concentration of IL-1ß in the COMBI group in comparison with the PL group (p < 0.05). Higher values of IL-4 were demonstrated in groups RSV, C and COMBI in comparison with the PL group (p < 0.05). Only RSV caused a reduction in the levels of IFN-γ (p < 0.05). There was no difference in the concentration of TNF-α amongst the four groups (p > 0.05). CONCLUSION: Resveratrol and curcumin are capable of reducing alveolar bone loss in an animal model of periodontitis. This occurred when these agents were added singly or in combination with one another, but there did not appear to be either synergistic or additive effects.

Impact of smoking on experimental gingivitis. A clinical, microbiological and immunological prospective study.

OBJECTIVE: The present study assessed the effect of smoking on clinical, microbiological and immunological parameters in an experimental gingivitis model. MATERIAL AND METHODS: Twenty-four healthy dental students were divided into two groups: smokers (n = 10); and nonsmokers (n = 14). Stents were used to prevent biofilm removal during brushing. Visible plaque index (VPI) and gingival bleeding index (GBI) were determined 5- on day -7 (running phase), baseline, 21 d (experimental gingivitis) and 28 d (resolution phase). Supragingival biofilm and gingival crevicular fluid were collected and assayed by checkerboard DNA-DNA hybridization and a multiplex analysis, respectively. Intragroup comparison was performed by Friedman and Dunn's multiple comparison tests, whereas the Mann-Whitney U-test was applied for intergroup analyses. RESULTS: Cessation of oral hygiene resulted in a significant increase in VPI, GBI and gingival crevicular fluid volume in both groups, which returned to baseline levels 7 d after oral hygiene was resumed. Smokers presented lower GBI than did nonsmokers (p < 0.05) at day 21. Smokers had higher total bacterial counts and higher proportions of red- and orange complex bacteria, as well as lower proportions of Actinomyces spp., and of purple- and yellow-complex bacteria (p < 0.05). Furthermore, the levels of key immune-regulatory cytokines, including interleukin (IL)-8, IL-17 and interferon-γ, were higher in smokers than in nonsmokers (p < 0.05). CONCLUSION: Smokers and nonsmokers developed gingival inflammation after supragingival biofilm accumulation, but smokers had less bleeding, higher proportions of periodontal pathogens and distinct host-response patterns during the course of experimental gingivitis.

DNA methylation levels of SOCS1 and LINE-1 in oral epithelial cells from aggressive periodontitis patients.

OBJECTIVE: DNA methylation has been shown to be critical in the regulation of inflammatory genes. Infections are able to trigger susceptibility to disease and it can be considered as potential epimutagenic factors in reshaping the epigenome. Therefore, what would be the DNA methylation status in cells present in an infected and inflamed oral environment? The aim was to verify the DNA methylation pattern in oral epithelium cells from aggressive periodontitis (AgP) patients in a specific gene involved in the inflammation control, as suppressor of cytokine signalling (SOCS)1 and in a broader way through long interspersed nuclear element (LINE)-1. DESIGN: Genomic DNA from oral cells of 30 generalized AgP patients and 30 healthy patients were purified and modified by sodium bisulfite. DNA methylation patterns were analyzed using combined bisulfite restriction analysis (COBRA) for SOCS1 and LINE-1. RESULTS: An overall scenario of demethylation was seen for both groups, whereas the healthy group presented a higher percentage of demethylation (p<0.001), also presenting the majority of total demethylated samples (83.3% versus 70.8% in the AgP group). Total LINE-1 methylation or at each specific loci presented significant differences amongst groups. CONCLUSION: Epithelial cells, present in an infected and inflamed oral environment, show different DNA methylation status from those present in a healthy oral environment, regarding the SOCS1 and LINE-1. In addition, the investigation allows detecting alterations in the DNA in a non-limited manner, since the results observed might reflect a generalized condition of the oral epithelial cells, besides reflecting the condition of the gingival epithelium cells.

Release of bone markers in immediately loaded and nonloaded dental implants: a randomized clinical trial.

The aim of this study was to compare the release of bone markers during osseointegration of immediately loaded and nonloaded implants. Forty patients who were indicated for rehabilitation with dental implants randomly received either implant and prosthesis placement within 72 hours (group IM) or implant insertion and no prosthesis placement (group NL). Peri-implant crevicular fluid was collected immediately after implant insertion and 7, 15, 30, 60, 90, and 120 days after surgery and levels of osteoprotegerin, transforming growth factors, osteocalcin, osteopontin, and parathyroid hormone were evaluated using Luminex assay. Bleeding index and peri-implantar sulcus depth were also evaluated. The data were compared using statistical tests (α = 5%). No statistical difference was found regarding demographic and clinical parameters (p > .05). Transforming growth factors, osteoprotegerin, osteopontin, and parathyroid hormone presented an earlier release peak in group IM than in NL group (p < .05). Osteocalcin achieved higher levels in group IM versus group NL between 7 and 30 days of evaluation (p < .05). It may be concluded that earlier loading positively modulates bone mediators release around immediately loaded implants when compared with nonloaded dental implants.

Subgingival biodiversity in subjects with uncontrolled type-2 diabetes and chronic periodontitis.

BACKGROUND AND OBJECTIVE: There is a bidirectional relationship between periodontal disease and type-2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end-products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type-2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. MATERIAL AND METHODS: Twelve subjects with uncontrolled type-2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. RESULTS: Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). CONCLUSION: Subjects with uncontrolled type-2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.

Levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, inflammatory cytokines and species-specific immunoglobulin G in generalized aggressive and chronic periodontitis.

BACKGROUND AND OBJECTIVE: Aggressive periodontitis pathogenesis still is not completely understood in the literature regarding the relationship between microbial and inflammatory aspects. So this study aimed to compare microbial and inflammatory patterns in the gingival crevicular fluid of generalized aggressive and chronic periodontitis patients. MATERIAL AND METHODS: Forty aggressive and 28 chronic periodontitis patients were selected. Biofilm and gingival crevicular fluid were collected from a deep pocket (periodontal probing depth >7 mm) and a moderate pocket (periodontal probing depth = 5 mm) of each patient, and microbiological and immunoenzymatic assays were performed. Real-time PCR was used to determine quantities of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Enzyme-linked immunosorbent assay (ELISA) was employed to determine gingival crevicular fluid levels of interleukin-1beta, interferon-gamma, prostaglandin E(2) and interleukin-10. In addition, immunoglobulin G (IgG) levels against A. actinomycetemcomitans and P. gingivalis lipopolysaccharide were also determined by ELISA. Analysis of variance/Tukey test, Mann-Whitney U-test and the Pearson correlation test were used to determine differences and correlations between variables analysed (alpha = 5%). RESULTS: Patients suffering from generalized aggressive periodontitis had their mouth colonized by higher amounts of A. actinomycetemcomitans and P. gingivalis than chronic periodontitis patients. Conversely, the gingival crevicular fluid levels of IgG against both pathogens were statistically inferior in aggressive periodontitis patients (p < 0.05). With regard to gingival crevicular fluid levels of cytokines, aggressive periodontitis patients presented reduced levels of interleukin-10 (p < 0.05). CONCLUSION: In comparison to chronic periodontitis, generalized aggressive periodontitis patients have an imbalance in the host response, with reduced levels of interleukin-10 and IgG, and increased periodontal pathogens.