Subgingival microbial diversity and respiratory decline: A cross-sectional study.

AIM: To investigate whether there is an association between subgingival microbial diversity and reduced respiratory function. MATERIALS AND METHODS: A group of dentate 58-72-year-old men in Northern Ireland had a comprehensive periodontal examination including subgingival plaque sampling. DNA was extracted from plaque samples and the V1-V3 regions of the 16S rRNA gene were analysed by high-throughput sequencing and a microbial diversity index (MDI) was derived. Spirometry measurements were made using a wedge bellows spirometer. The primary outcome variable of interest was the percentage of predicted forced expiratory volume in 1 s (% predicted FEV1 ). Analysis included multiple linear regression with adjustment for various confounders. RESULTS: Five-hundred and seven men were included in the analysis. The mean age was 63.6 years (SD = 3.1). Of these, 304 (60.0%) men had no or mild periodontitis, 105 (20.7%) had moderate periodontitis and 98 (19.3%) had severe periodontitis. Multiple linear regression analysis showed that a one unit increase in MDI was associated with a 0.71% loss (95% confidence interval: 0.06%-1.35%; p = .03) in % predicted FEV1 after adjustment for all confounders. CONCLUSIONS: In this group of dentate men from Northern Ireland, subgingival microbial diversity was associated with reduced respiratory function.

Differential regulation of NPY and SP receptor expression in STRO-1+ve PDLSCs by inflammatory cytokines.

OBJECTIVES: The aims of this study were to investigate neuropeptide receptor expression regulation on STRO-1 +ve periodontal ligament stem cells (PDLSCs) in response to inflammatory cytokines and to investigate a potential osteogenic effect of neuropeptides. BACKGROUND: Nerve fibres innervating the periodontal tissues in humans contain several neuropeptides including neuropeptide Y and substance P. The role of neuropeptide receptors on PDLSCs, including their response to the local inflammatory environment of periodontitis, is currently unknown. METHODS: A homogenous population of STRO-1 +ve PDLSCs was prepared by immunomagnetic separation of cells obtained by the tissue out-growth method from healthy premolar teeth from a single donor. Regulation of gene expression of the neuropeptide Y Y1 receptor and substance P receptor tachykinin receptor 1 was investigated. A potential osteogenic effect of neuropeptide Y and substance P was also investigated by measuring alkaline phosphatase (ALP) activity, Alizarin red staining and quantifying osteogenic gene expression. RESULTS: Treatment of STRO-1 +ve PDLSCs with tumour necrosis factor-alpha or interleukin 1-beta up-regulated the expression of the neuropeptide Y's Y1 receptor, but down-regulated substance P's receptor. Significantly increased ALP activity was observed in STRO-1 +ve PDLSCs treated with neuropeptide Y but not substance P. Further studies showed that neuropeptide Y had a modest osteogenic effect on cells at both a functional level and a gene level. CONCLUSIONS: Expression of the neuropeptide Y Y1 receptor gene on STRO-1 +ve PDLSCs was sensitive to local inflammatory cytokines. Treatment of cells with neuropeptide Y was found to produce a modest enhanced osteogenic effect.

Fusobacterium nucleatum and oral cancer: a critical review.

There is a growing level of interest in the potential role inflammation has on the initiation and progression of malignancy. Notable examples include Helicobacter pylori-mediated inflammation in gastric cancer and more recently Fusobacterium nucleatum-mediated inflammation in colorectal cancer. Fusobacterium nucleatum is a Gram-negative anaerobic bacterium that was first isolated from the oral cavity and identified as a periodontal pathogen. Biofilms on oral squamous cell carcinomas are enriched with anaerobic periodontal pathogens, including F. nucleatum, which has prompted hypotheses that this bacterium could contribute to oral cancer development. Recent studies have demonstrated that F. nucleatum can promote cancer by several mechanisms; activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation and immune evasion. This review provides an update on the association between F. nucleatum and oral carcinogenesis, and provides insights into the possible mechanisms underlying it.

Systemic inflammation and the relationship between periodontitis, edentulism, and all-cause mortality: A 17-year prospective cohort study.

AIM: The aim was to investigate the role of systemic inflammation in the relationship between periodontitis, edentulism, and all-cause mortality in a group of men in Northern Ireland aged 58-72 years. MATERIALS AND METHODS: A representative sample of 1558 men had a detailed dental examination between 2001 and 2003. The primary end point was death from any cause. Cox's proportional hazards model was used to assess the longitudinal relationship between periodontitis, edentulism, and all-cause mortality. Accelerated failure time modelling was performed to investigate the mediating role of systemic inflammation. RESULTS: Mean age of the men at baseline was 64.3 (standard deviation 2.9) years. During a median follow-up of 17 years, 500 (32.1%) men died. After adjustment for confounding variables, compared to men with no/mild periodontitis, edentulous men had a hazard ratio for all-cause mortality of 1.52 (95% confidence interval [CI] 1.16-1.99) p < .01 and for those with severe periodontitis, it was 1.34 (95% CI 1.06-1.70) p = .01. Systemic inflammation accounted only for a minor mediating pathway effect of 10%. CONCLUSIONS: There was evidence in this group of men that those who were edentulous or had severe periodontitis had a significantly increased risk of all-cause mortality. Systemic inflammation was not a major explanatory mediator of this association.

Periodontal status and chronic obstructive pulmonary disease (COPD) exacerbations: a systematic review.

BACKGROUND: A growing body of evidence suggests a role for oral bacteria in lung infections. This systematic review aimed to analyse the association between poor periodontal status and the frequency of chronic obstructive pulmonary disease (COPD) exacerbations. METHODS: PubMed, Embase, Web of Science, CINAHL and Medline were searched for studies published until May 2020, with no language restriction. Studies reporting periodontal condition, or periodontal treatment outcomes, with data on the frequency of exacerbations of COPD, were identified. The primary outcome was the frequency of exacerbations and secondary outcomes included quality of life (QoL) and hospitalisation. Quality and risk of bias assessment were carried out using the Newcastle Ottawa Scale for observational studies, Robins-1 tool for non-randomised intervention studies and Cochrane risk of bias assessment (RoB-2) tool for randomised clinical trials. Studies were assessed for eligibility and quality by two assessors independently. RESULTS: Searches identified 532 records and 8 met the inclusion criteria. Included studies were three clinical trials, one prospective cohort study, one case-control, and three cross-sectional studies. A narrative synthesis was performed. The data from intervention studies showed reduction in the frequency of exacerbations following periodontal treatment. Data from observational studies suggest association of worse plaque scores and fewer teeth with exacerbation, but not pocket depth or clinical attachment loss. Better periodontal health was also associated with reduced frequency of COPD exacerbations, hospitalisations and improved quality of life in COPD patients. Due to the high heterogeneity no meta-analysis was performed. The quality of some of the included studies was low and there was evidence of a high risk of bias. CONCLUSION: The data supports possible association between poor periodontal health, the frequency of exacerbations, hospitalisation and quality of life in COPD patients. The evidence is of moderate to low certainty and is limited by high risk of bias suggesting the need for well-designed and adequately powered randomised controlled trials, to inform future research and clinical practice. The PROSPERO registration number CRD42020180328.

Periodontitis and risk of prevalent and incident coronary heart disease events.

OBJECTIVE: To investigate periodontitis as a risk factor for prevalent and incident coronary heart disease (CHD) in a group of middle-aged men from Northern Ireland. METHODS: A representative sample of 1400 dentate men had a comprehensive periodontal examination between 2001 and 2003. Prevalent and incident CHD events were validated by independent cardiologists. Logistic regression was used to assess the cross-sectional relationship between periodontitis and prevalent CHD and Cox's proportional hazards analysis to assess the longitudinal relationship between periodontitis and incident CHD. RESULTS: The mean age of the men at baseline was 63.7 (SD 3.0) years. Of the 1400 men examined, 126 (9%) had prevalent CHD. After adjusting for confounding variables, men with highest mean CAL (Q4) had an odds ratio of 2.15 (95% CI 1.15-4.02), p = 0.02 for prevalent CHD in comparison to men with the lowest CAL (Q1). During a median follow-up of 12.7 years, 137 (10.8%) of the 1274 men free of CHD at baseline had an incident CHD event. After adjusting for confounding variables, the hazard ratio for incident CHD in men in Q4 versus Q1 CAL categories was 1.36 (95% CI 0.81-2.29), p = 0.24. CONCLUSIONS: In this group of dentate men, periodontitis was associated with prevalent CHD. However, there was no association with incident CHD.

Chronic periodontitis and reduced respiratory function.

OBJECTIVE: To investigate whether there was an association between chronic periodontitis (CP) and reduced respiratory function. METHODS: A group of dentate 58- to 72-year-old men in Northern Ireland had a comprehensive periodontal examination. Parallel to the periodontal examination, participants completed questionnaires gathering information on their medical history, social circumstances, demographic background and tobacco use. A physical examination assessed anthropometric measures. Fasting blood samples were obtained and analysed for high-sensitivity C-reactive protein (hs-CRP). Spirometry measures were performed using a wedge bellows spirometer (Vitalograph S Model). The primary outcome variable of interest was the percentage predicted forced expiratory volume in one-second (% predicted FEV1 ). Analysis included multiple linear regression with adjustment for various confounders and a regression-based mediation analysis. RESULTS: A total of 1,380 men were included in the analysis. The mean age was 63.7 years (SD 3.0). Multiple linear regression analysis showed that a doubling in mean clinical attachment loss (CAL) equated to a -3.33% (95% CI: -4.80, -1.86), p < 0.001 change in % predicted FEV1 after adjustment for all other potential confounding variables. Systemic inflammation, as measured by hs-CRP, only accounted for a minor mediating pathway effect (9%). CONCLUSIONS: In this homogenous group of dentate men, CP was significantly associated with a reduced respiratory function.

Increased Population Risk of AIP-Related Acromegaly and Gigantism in Ireland.

The aryl hydrocarbon receptor interacting protein (AIP) founder mutation R304* (or p.R304* ; NM_003977.3:c.910C>T, p.Arg304Ter) identified in Northern Ireland (NI) predisposes to acromegaly/gigantism; its population health impact remains unexplored. We measured R304* carrier frequency in 936 Mid Ulster, 1,000 Greater Belfast (both in NI) and 2,094 Republic of Ireland (ROI) volunteers and in 116 NI or ROI acromegaly/gigantism patients. Carrier frequencies were 0.0064 in Mid Ulster (95%CI = 0.0027-0.013; P = 0.0005 vs. ROI), 0.001 in Greater Belfast (0.00011-0.0047) and zero in ROI (0-0.0014). R304* prevalence was elevated in acromegaly/gigantism patients in NI (11/87, 12.6%, P < 0.05), but not in ROI (2/29, 6.8%) versus non-Irish patients (0-2.41%). Haploblock conservation supported a common ancestor for all the 18 identified Irish pedigrees (81 carriers, 30 affected). Time to most recent common ancestor (tMRCA) was 2550 (1,275-5,000) years. tMRCA-based simulations predicted 432 (90-5,175) current carriers, including 86 affected (18-1,035) for 20% penetrance. In conclusion, R304* is frequent in Mid Ulster, resulting in numerous acromegaly/gigantism cases. tMRCA is consistent with historical/folklore accounts of Irish giants. Forward simulations predict many undetected carriers; geographically targeted population screening improves asymptomatic carrier identification, complementing clinical testing of patients/relatives. We generated disease awareness locally, necessary for early diagnosis and improved outcomes of AIP-related disease.

Periodontitis and incident type 2 diabetes: a prospective cohort study.

OBJECTIVES: The aim of this study was to investigate periodontitis as a risk factor for incident type 2 diabetes mellitus (T2DM) in a group of men aged 58-72 years. METHODS: One thousand three hundred and thirty-one dentate, diabetes-free men in Northern Ireland underwent a detailed periodontal examination during 2001-2003. Follow-up was by bi-annual questionnaire and for those reporting diabetes their general medical practitioner was contacted to validate diabetes type, treatment and diagnosis date. Cox's proportional hazard models were used to estimate the effect of periodontitis on incident diabetes. Multivariable analysis included adjustment for various known confounders. RESULTS: The mean age of the men was 63.7 (SD 3.0) years. There were 80 cases (6.0%) of incident T2DM. Follow-up was for a median period of 7.8 years (IQR 6.7-8.3). After adjusting for confounding variables, the hazard ratio (HR) for incident T2DM in men with moderate/severe periodontitis versus those with no/mild periodontitis was 1.69 (95% CI 1.06-2.69), p = 0.03. CONCLUSION: There was evidence in this homogenous group of dentate men, that those with moderate to severe periodontitis had a significantly increased risk of incident T2DM.

TNF-α-induced p38MAPK activation regulates TRPA1 and TRPV4 activity in odontoblast-like cells.

The transient receptor potential (TRP) channels are unique cellular sensors that are widely expressed in many neuronal and nonneuronal cells. Among the TRP family members, TRPA1 and TRPV4 are emerging as candidate mechanosensitive channels that play a pivotal role in inflammatory pain and mechanical hyperalgesia. Odontoblasts are nonneuronal cells that possess many of the features of mechanosensitive cells and mediate important defense and sensory functions. However, the effect of inflammation on the activity of the odontoblast's mechanosensitive channels remains unknown. By using immunohistochemistry and calcium microfluorimetry, we showed that odontoblast-like cells express TRPA1 and TRPV4 and that these channels were activated by hypotonicity-induced membrane stretch. Short treatment of odontoblast-like cells with tumor necrosis factor (TNF)-α enhanced TRPA1 and TRPV4 responses to their chemical agonists and membrane stretch. This enhanced channel activity was accompanied by phospho-p38 mitogen-activated protein kinase (MAPK) expression. Treatment of cells with the p38 inhibitor SB202190 reduced TNF-α effects, suggesting modulation of channel activity via p38 MAPK. In addition, TNF-α treatment also resulted in an up-regulation of TRPA1 expression but down-regulation of TRPV4. Unlike TRPV4, enhanced TRPA1 expression was also evident in dental pulp of carious compared with noncarious teeth. SB202190 treatment significantly reduced TNF-α-induced TRPA1 expression, suggesting a role for p38 MAPK signaling in modulating both the transcriptional and non-transcriptional regulation of TRP channels in odontoblasts.

Gingival Inflammation and Aggressive Periodontitis in a Child with a Specific Antibody Deficiency.

Exuberant gingival inflammation accompanied by periodontitis is a rare finding in a very young child and may indicate a defect in the host response. Affected children should be referred to appropriate specialists to establish a definitive diagnosis. A 5-year-old girl presented with persistent gingival inflammation and periodontal destruction. Immunological investigations identified specific polysaccharide antibody deficiency which, when treated, resulted in a significant improvement in the gingival condition. This case illustrates the need for integrated management by a wide range of dental and medical specialists. Antibody deficiency is rare but, if not identified and treated effectively, can be associated with chronic ill health and decreased life expectancy. CPD/Clinical Relevance: This article describes a rare case of gingival inflammation accompanied by periodontitis in a very young child secondary to an underlying host antibody deficiency and details the investigation, management and clinical outcomes.

Replication of the association of GLT6D1 with aggressive periodontitis in a Sudanese population.

BACKGROUND: Susceptibility to aggressive periodontitis (AgP) is influenced by genetic as well as environmental factors. Studies linking gene variants to AgP have been mainly centred in developed countries with limited data from Africa. AIM: To investigate whether previously reported candidate gene associations with AgP could be replicated in a population from Sudan. METHODS: The investigation was a case-control design. Cases with AgP (n = 132) and controls (n = 136) were identified from patients attending the Periodontal Department in Khartoum Dental Hospital. Genotyping was performed using the Sequenom MassARRAY iPLEX platform. Analysis focused on gene variants with a minor allele frequency (MAF) > 25% in the Sudanese subjects that had previously been reported to be associated with AgP. RESULTS: One candidate gene rs1537415 (GLT6D1) was significantly associated with AgP, OR = 1.50 (95% CI 1.04-2.17), p = 0.0295 (increasing to p = 0.09 after correction for multiple testing). The association strengthened to OR = 1.56 (95% CI 1.15-2.16), p = 0.0042 when the controls were supplemented with data from the Hap map for the Yoruba in Ibadan (n = 147) and remained significant (p = 0.013) after correction for multiple testing. CONCLUSION: The study independently replicated the finding that rs1537415, a variant in glycosyl transferase gene GLT6D1, is associated with AgP and provided the first report of genetic associations with AgP in a Sudanese population.

The association between subgingival periodontal pathogens and systemic inflammation.

AIM: To investigate associations between periodontal disease pathogens and levels of systemic inflammation measured by C-reactive protein (CRP). METHODS: A representative sample of dentate 60-70-year-old men in Northern Ireland had a comprehensive periodontal examination. Men taking statins were excluded. Subgingival plaque samples were analysed by quantitative real time PCR to identify the presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia. High-sensitivity CRP (mg/l) was measured from fasting blood samples. Multiple linear regression analysis was performed using log-transformed CRP concentration as the dependent variable, with the presence of each periodontal pathogen as predictor variables, with adjustment for various potential confounders. RESULTS: A total of 518 men (mean age 63.6 SD 3.0 years) were included in the analysis. Multiple regression analysis showed that body mass index (p < 0.001), current smoking (p < 0.01), the detectable presence of P. gingivalis (p < 0.01) and hypertension (p = 0.01), were independently associated with an increased CRP. The detectable presence of P. gingivalis was associated with a 20% (95% confidence interval 4-35%) increase in CRP (mg/l) after adjustment for all other predictor variables. CONCLUSION: In these 60-70-year-old dentate men, the presence of P. gingivalis in subgingival plaque was significantly associated with a raised level of C-reactive protein.

Periodontal systemic associations: review of the evidence.

AIM: To critically appraise recent research into associations between periodontal disease and systemic diseases and conditions specifically respiratory disease, chronic kidney disease, rheumatoid arthritis, cognitive impairment, obesity, metabolic syndrome and cancer. METHODS: A MEDLINE literature search of papers published between 2002 and April 2012 was conducted. Studies that included periodontitis as an exposure were identified. Cross-sectional epidemiological investigations on large samples, prospective studies and systematic reviews formed the basis of the narrative review. A threshold set for the identification of periodontitis was used to identify those studies that contributed to the conclusions of the review. RESULTS: Many of the investigations were cross-sectional secondary analyses of existing data sets in particular the NHANES studies. There were a small number of systematic reviews and prospective studies. There was substantial variability in the definitions of exposure to periodontitis. A small number of studies met the threshold set for periodontitis and supported associations; however, in some of the chronic diseases there were no such studies. There was strong evidence from randomized controlled trials that interventions, which improve oral hygiene have positive effects on the prevention of nosocomial pneumonias. CONCLUSIONS: There was substantial heterogeneity in the definitions used to identify periodontitis and very few studies met a stringent threshold for periodontitis. Published evidence supports modest associations between periodontitis and some, although not all, of the diseases and conditions reviewed. There is a need to reach a consensus on what constitutes periodontitis for future studies of putative associations with systemic diseases.

The association of denture wearing with reduced lung function and increased airflow limitation in 58-72 year old men.

OBJECTIVE: To investigate the association between denture wearing and airflow limitation in men in Northern Ireland enrolled in the Prospective Epidemiological Study of Myocardial Infarction (PRIME) study. METHODS: A case-control design was used to study partially dentate men. Cases were men aged 58-72 years who were confirmed as denture wearers. Controls were never denture wearers who were matched by age (± 1 month) and smoking habit to the cases. The men had a periodontal assessment and completed a questionnaire detailing their medical history, dental history and behaviours, social circumstances, demographic background and tobacco use. Physical examination and spirometry measurements of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were also undertaken. Spirometry data for edentulous men who wore complete dentures were compared with that recorded for the partially dentate men studied. RESULTS: There were 353 cases who were partially dentate and were confirmed denture wearers. They were matched for age and smoking habit to never denture wearer controls. The cases had an FEV1 that was on average 140 ml lower than the controls, p = 0.0013 and a 4% reduction in percent predicted FEV1, p = 0.0022. Application of the GOLD criteria indicated that 61 (17.3%) of the cases had moderate to severe airflow limitation compared with 33 (9.3%) of controls, p = 0.0051. Fully adjusted multivariable analysis showed that partially dentate men who were denture wearers were significantly more likely (p = 0.01) to have moderate to severe airflow reduction with an adjusted odds ratio (OR) of 2.37 (95% confidence intervals 1.23-4.55). In the 153 edentulous men studied moderate to severe airflow limitation was recorded in 44 (28.4%), which was significantly higher than in the partially dentate denture wearers (p = 0.017), and the men who had never worn a denture (p<0.0001). CONCLUSION: Denture wearing was associated with an increased risk of moderate to severe airflow limitation in the cohort of middle-aged Western European men studied.

All-cause mortality and periodontitis in 60-70-year-old men: a prospective cohort study.

OBJECTIVE: To investigate the association between periodontitis and mortality from all causes in a prospective study in a homogenous group of 60- to 70-year-old West European men. METHODOLOGY: A representative sample of 1400 dentate men, (mean age 63.8, SD 3.0 years), drawn from the population of Northern Ireland, had a comprehensive periodontal examination between 2001 and 2003. Men were divided into thirds on the basis of their mean periodontal attachment loss (PAL). The primary endpoint, death from any cause, was analysed using Kaplan-Meier survival plots and Cox's proportional hazards model. RESULTS: In total, 152 (10.9%) of the men died during a mean follow-up of 8.9 (SD 0.7) years; 37 (7.9%) men in the third with the lowest PAL (<1.8 mm) died compared with 73 (15.7%) in the third with the highest PAL (>2.6 mm). The unadjusted hazard ratio (HR) for death in the men with the highest level of PAL compared with those with the lowest PAL was 2.11 (95% CI 1.42-3.14), p < 0.0001. After adjustment for confounding variables (age, smoking, hypertension, BMI, diabetes, cholesterol, education, marital status and previous history of a cardiovascular event) the HR was 1.57 (1.04-2.36), p = 0.03. CONCLUSION: The European men in this prospective cohort study with the most severe loss of periodontal attachment were at an increased risk of death compared with those with the lowest loss of periodontal attachment.

Mapping biological to clinical phenotypes during the development (21 days) and resolution (21 days) of experimental gingivitis.

AIM: To characterize and map temporal changes in the biological and clinical phenotype during a 21-day experimental gingivitis study. MATERIALS AND METHODS: Experimental gingivitis was induced over 21 days in healthy human volunteers (n = 56), after which normal brushing was resumed (resolution phase). Gingival and plaque indices were assessed. Gingival crevicular fluid was collected from four paired test and contra-lateral control sites in each volunteer during induction (Days 0, 7, 14 and 21) and resolution (Days 28 and 42) of experimental gingivitis. Fluid volumes were measured and a single analyte was quantified from each site-specific, 30s sample. Data were evaluated by analysis of repeated measurements and paired sample tests. RESULTS: Clinical indices and gingival crevicular fluid volumes at test sites increased from Day 0, peaking at Day 21 (test/control differences all p < 0.0001) and decreased back to control levels by Day 28. Levels of four inflammatory markers showed similar patterns, with significant differences between test and control apparent at Day 7 (substance P, cathepsin G, interleukin-1ß, elastase: all p < 0.03) and peaking at Day 21 (all p < 0.002). Levels of α-1-antitrypsin showed no pattern. CONCLUSIONS: Levels of substance P, cathepsin G, interleukin-1ß and neutrophil elastase act as objective biomarkers of gingival inflammation induction and resolution that typically precede phenotypical changes.

Replication of the association of chromosomal region 9p21.3 with generalized aggressive periodontitis (gAgP) using an independent case-control cohort.

BACKGROUND: The human chromosomal region 9p21.3 has been shown to be strongly associated with Coronary Heart Disease (CHD) in several Genome-wide Association Studies (GWAS). Recently, this region has also been shown to be associated with Aggressive Periodontitis (AgP), strengthening the hypothesis that the established epidemiological association between periodontitis and CHD is caused by a shared genetic background, in addition to common environmental and behavioural risk factors. However, the size of the analyzed cohorts in this primary analysis was small compared to other association studies on complex diseases. Using our own AgP cohort, we attempted to confirm the described associations for the chromosomal region 9p21.3. METHODS: We analyzed our cohort consisting of patients suffering from the most severe form of AgP, generalized AgP (gAgP) (n = 130) and appropriate periodontally healthy control individuals (n = 339) by genotyping four tagging SNPs (rs2891168, rs1333042, rs1333048 and rs496892), located in the chromosomal region 9p21.3, that have been associated with AgP. RESULTS: The results confirmed significant associations between three of the four SNPs and gAgP. The combination of our results with those from the study which described this association for the first time in a meta-analysis of the four tagging SNPs produced clearly lower p-values compared with the results of each individual study. According to these results, the most plausible genetic model for the association of all four tested SNPs with gAgP seems to be the multiplicative one. CONCLUSION: We positively replicated the finding of an association between the chromosomal region 9p21.3 and gAgP. This result strengthens support for the hypothesis that shared susceptibility genes within this chromosomal locus might be involved in the pathogenesis of both CHD and gAgP.

Long-term outcomes for cross-arch stabilizing bridges in periodontal maintenance patients--a retrospective study.

BACKGROUND: Cross-arch bridges are used to stabilize teeth for patients with reduced periodontal support. Little is known about technical or biological complications, whether teeth and implants can be combined in this type of bridge and the long-term effects on tooth loss. MATERIALS AND METHODS: All patients treated in a specialist periodontal practice who received cross-arch stabilizing bridgework and were subsequently maintained for at least 7 years were included in the study. The patients were selected from all patients who underwent initial periodontal therapy after 1986 in a Norwegian periodontal practice. The bridges were assessed for biological and technical complications. Bridges retained by teeth or by a combination of teeth and implants were included in the study. RESULTS: Ninety-four rigid fixed bridges (77 teeth supported, 17 teeth and implant supported) in 80 patients (46 females, 34 males) were observed for an average of 10 years (range 7-22 years). In four patients, a bridge became loose and had to be re-cemented, and in one case the metal framework of a bridge fractured and the bridge had to be remade. In total, eight abutment teeth were lost from five patients but no implant abutments were lost. Overall, a higher rate of tooth loss was observed for patients provided with stabilizing bridges compared with control maintenance patients not treated with bridgework (p<0.0001); however, the rates in both groups were very low. CONCLUSION: Cross-arch stabilizing bridges constructed for periodontal patients as part of their periodontal maintenance therapy had few complications and were associated with low rates of abutment tooth loss. Combining teeth and implants did not affect the performance of these bridges.

Natural Antimicrobials in the Dental Pulp.

INTRODUCTION: Like many tissues, the dental pulp is equipped with innate and adaptive immune responses, designed to defend against infection and limit its spread. The pulp's innate immune response includes the synthesis and release of antimicrobial peptides by several dental pulp cell types. These naturally-occurring antimicrobial peptides have broad spectrum activity against bacteria, fungi and viruses. There is a resurgence of interest in the bioactivities of naturally-occurring antimicrobial peptides, largely driven by the need to develop alternatives to antibiotics. METHODS: This narrative review focused on the general properties of antimicrobial peptides, providing an overview of their sources and actions within the dental pulp. RESULTS: We summarized the relevance of antimicrobial peptides in defending the dental pulp, highlighting the potential for many of these antimicrobials to be modified or mimicked for prospective therapeutic use. CONCLUSION: Antimicrobial peptides and novel peptide-based therapeutics are particularly attractive as emerging treatments for polymicrobial infections, such as endodontic infections, because of their broad activity against a range of pathogens.