Effect of Helicobacter pylori infection on chronic periodontitis by the change of microecology and inflammation.

Helicobacter pylori (H. pylori), a pathogen inducing peptic disease, is recently found to be binding to the progress of periodontitis. Most previous studies are case-controlled, and they investigate the risk of H. pylori infection in disease the development of while few studies evaluate the correlation between H. pylori and periodontal pathogens. Therefore, we investigated the correlation between H. pylori infection with periodontal parameters, periodontal pathogens and inflammation. The results indicated that patients with H. pylori showed significantly higher probing depth and attachment loss than those without (p < 0.05). Among 28 subgingival plaque samples from 14 patients, the frequencies of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Treponema denticola were significantly higher with H. pylori infection than those without H. pylori infection (p < 0.05). However, the frequency of Aggregatibacter actinomycetemcomitans was lower (p < 0.05). Furthermore, after human acute monocytic leukemia cell line (THP-1) was stimulated with cagA-positive standard strains (cagA+ H. pylori 26695), the expression of periodontitis-related molecules Wnt5a, interleukin 8 (IL-8), interleukin 6 (IL-6) and interferon gamma (IFN-γ) significantly increased (p < 0.05). Conversely, the expression of tumor necrosis factor alpha (TNF-α) was almost stable. Meanwhile, cagA+ H. pylori promoted significantly higher expression of IL-8 and Wnt5a than isogenic cagA mutants strains (cagA- H. pylori 26695) did. Taken together, our data suggested that H. pylori might promote the growth of some periodontal pathogens and aggravate the progress of chronic periodontitis.

Determination of NLRP3 (rs4612666) and IL-1B (rs1143634) genetic polymorphisms in periodontally diseased and healthy subjects.

OBJECTIVE: The focus of the current study was to identify if a possible association between NLRP3 (rs4612666) and IL-1B (rs1143634) single-nucleotide polymorphisms (SNPs) may be implicated in the etiopathogenesis of chronic periodontitis (CP) in a Colombian population. DESIGN: One hundred and twenty-four CP subjects and 81 periodontally healthy controls (HC) were recruited. Periodontal status was assessed by criteria based on probing depth, clinical attachment level, extent, and severity of periodontal breakdown. Human genomic DNA was obtained from saliva samples of the study subjects. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to identify the NLRP3 (rs4612666) and IL-1B (rs1143634) SNPs. The association of polymorphisms with CP was assessed individually and adjusted for confounding using a multivariate binary logistic regression model. RESULTS: Bivariate analysis showed a weak association between CT genotype of NLRP3 (rs4612666) SNP and CP, however after logistic regression analysis, neither NLRP3 (rs4612666) nor IL-1B (rs1143634) polymorphisms were strongly/independently associated with disease status. Even so, an interaction effect was significantly detected not only among CT/CC genotypes of NLRP3 gene regarding to the age stratum ≥ 48 years, but also between CC genotype of the same gene and smoking habit. CONCLUSION: Although the present results do not support that IL-1B (rs1143634) SNP could be identified as a risk predictor for CP in the present population, the synergistic interaction of the CT/CC genotypes of NLRP3 (rs4612666) SNP with ageing and/or smoking habit potentially might play a significant role in the pathogenic pathways of periodontal disease.

Insulin Response Genes in Different Stages of Periodontal Disease.

Bacterial infections are known to alter glucose metabolism within tissues via mechanisms of inflammation. We conducted this study to examine whether insulin response genes are differentially expressed in gingival tissues, comparing samples from experimental gingivitis and periodontitis subjects to those from healthy individuals. Total RNA was extracted from gingival biopsies from 26 participants: 8 periodontally healthy, 9 experimental gingivitis, and 9 periodontitis subjects. Gene expression patterns were evaluated with a polymerase chain reaction array panel to examine 84 candidate genes involved with glucose metabolism, insulin resistance, and obesity. Array data were evaluated with a t test adjusted by the false discover rate (P < 0.05), and ingenuity pathway analysis was performed for statistical testing of pathways. Although tissue samples were not sufficient to enable protein quantification, we confirmed the upregulation of the key gene using lipopolysaccharide-stimulated primary gingival epithelial cells by Western blot. The mRNA expression patterns of genes that are associated with insulin response and glucose metabolism are markedly different in experimental gingivitis subjects compared with healthy controls. Thirty-two genes are upregulated significantly by at least 2-fold, adjusted for false discover rate (P < 0.05). Periodontitis subjects show similar but attenuated changes in gene expression patterns, and no genes meet the significance criteria. Ingenuity pathway analysis demonstrates significant activation of the carbohydrate metabolism network in experimental gingivitis but not in periodontitis. G6PD protein increases in response to lipopolysaccharide stimulation in primary gingival epithelial cells, which is in the same direction as upregulated mRNA in tissues. Acute gingival inflammation may be associated with tissue metabolism changes, but these changes are not evident in chronic periodontitis. This study suggests that acute gingival inflammation may induce localized changes that modify tissue insulin/glucose metabolism.

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.

Evaluation of lipid peroxidation and oxidative DNA damage in patients with periodontitis and hyperlipidemia.

BACKGROUND: The purpose of this study is to determine the serum levels of malondialdehyde (MDA), as a lipid peroxidation marker, and 8-hydroxydeoxyguanosine (8-OHdG), as an oxidative DNA damage marker, in patients with chronic periodontitis (CP) and hyperlipidemia. METHODS: A total of 74 individuals were divided into four age- and sex-matched groups: 18 patients with hyperlipidemia and CP (HLp), 18 periodontally healthy patients with hyperlipidemia (HLh), 19 systemically healthy individuals with CP (Cp), and 19 systemically and periodontally healthy controls (Ch). Clinical periodontal parameters were measured, and serum lipids, MDA, and 8-OHdG levels were assessed in blood samples. RESULTS: 8-OHdG, MDA, probing depth, clinical attachment level, and percentage of sites bleeding on probing (BOP) were significantly higher in the HLp group than the Cp group. In the hyperlipidemic group, BOP was significantly correlated with total cholesterol, the ratio of total cholesterol to high-density lipoprotein cholesterol, and 8-OHdG levels. A significant correlation between 8-OHdG and MDA was also observed in the hyperlipidemia group. CONCLUSIONS: In this study, serum MDA and 8-OHdG were found to be highest in the HLp group. The increased levels of MDA and 8-OHdG in HLp patients may be a result of a harmful oxidative status in association with hyperlipidemia and periodontitis.

Can periodontal infection induce genotoxic effects?

OBJECTIVE: This study aimed to evaluate the occurrence of chromosomal abnormalities, through micronuclei, and apoptosis by the sum of karyorrhexis, pyknosis and condensed chromatin in individuals with chronic periodontitis, gingivitis associated with biofilm and no periodontal disease. MATERIALS AND METHODS: This study included 72 individuals divided into three groups: gingivitis (n = 21), periodontitis (n = 24) and control (n = 27). Information on sociodemographic characteristics, health and lifestyle was obtained. Full mouth clinical examination was performed to define the periodontal condition. Exfoliated cells from gingival mucosa were collected for computation of micronuclei and nuclear changes indicative of apoptosis. The differences in the occurrence of endpoints (micronucleus, karyorrhexis, pyknosis and condensed chromatin) were evaluated using the conditional test to compare proportions in a rare events situation. RESULTS: There was no statistically significant difference in the occurrence of micronucleus (p > 0.1) between gingivitis, periodontitis and control groups. The occurrence of apoptosis was significantly higher among individuals with periodontitis compared to individuals with gingivitis (p < 0.05) and controls (p < 0.025). CONCLUSIONS: The findings showed that the inflammatory process generated by gingivitis and periodontitis is not related to a higher occurrence of chromosomal damage. However, the higher occurrence of apoptosis in individuals with periodontitis points to genotoxic effects induced by periodontal infection.

Molecular differences between chronic and aggressive periodontitis.

The 2 major forms of periodontitis, chronic (CP) and aggressive (AgP), do not display sufficiently distinct histopathological characteristics or microbiological/immunological features. We used molecular profiling to explore biological differences between CP and AgP and subsequently carried out supervised classification using machine-learning algorithms including an internal validation. We used whole-genome gene expression profiles from 310 'healthy' or 'diseased' gingival tissue biopsies from 120 systemically healthy non-smokers, 65 with CP and 55 with AgP, each contributing with ≥ 2 'diseased' gingival papillae (n = 241; with bleeding-on-probing, probing depth ≥ 4 mm, and clinical attachment loss ≥ 3 mm), and, when available, a 'healthy' papilla (n = 69; no bleeding-on-probing, probing depth ≤ 4 mm, and clinical attachment loss ≤ 4 mm). Our analyses revealed limited differences between the gingival tissue transcriptional profiles of AgP and CP, with genes related to immune responses, apoptosis, and signal transduction overexpressed in AgP, and genes related to epithelial integrity and metabolism overexpressed in CP. Different classifying algorithms discriminated CP from AgP with an area under the curve ranging from 0.63 to 0.99. The small differences in gene expression and the highly variable classifier performance suggest limited dissimilarities between established AgP and CP lesions. Future analyses may facilitate the development of a novel, 'intrinsic' classification of periodontitis based on molecular profiling.

Genome-wide association study of chronic periodontitis in a general German population.

AIM: To identify loci associated with chronic periodontitis through a genome-wide association study (GWAS). MATERIALS AND METHODS: A GWAS was performed in 4032 individuals of two independent cross-sectional studies of West Pomerania (SHIP n = 3365 and SHIP-TREND n = 667) with different periodontal case definitions. Samples were genotyped with the Affymetrix Genome-Wide Human SNP Array 6.0 or the Illumina Human Omni 2.5 array. Imputation of the HapMap as well as the 1000 Genome-based autosomal and X-chromosomal genotypes and short insertions and deletions (INDELs) was performed in both cohorts. Finally, more than 17 million SNPs and short INDELs were analysed. RESULTS: No genome-wide significant associations were found for any periodontitis case definition, regardless of whether individuals aged >60 years where excluded or not. Despite no single SNP association reached genome-wide significance, the proportion of variance explained by additive effects of all common SNPs was around 23% for mean proximal attachment loss. Excluding subjects aged >60 years increased the explained variance to 34%. CONCLUSIONS: No single SNPs were found to be genome-wide significantly associated with chronic periodontitis in this study.

Beta-defensin-2 genomic copy number variation and chronic periodontitis.

Chronic periodontitis (ChP) is a multifactorial disease influenced by microbial and host genetic variability; however, the role of beta-defensin-2 genomic (DEFB4) copy number (CN) variation (V) in ChP remains unknown. The association of the occurrence and severity of ChP and DEFB4 CNV was analyzed. Our study included 227 unrelated Caucasians, that is, 136 ChP patients (combined ChP) and 91 control individuals. The combined ChP group was subdivided into the severe ChP and slight-to-moderate ChP subgroups. To determine DEFB4 CNV, we isolated genomic DNA samples and analyzed them by relative quantitation using the comparative CT method. The serum beta-defensin-2 (hBD-2) level was determined via ELISA. The distribution pattern and mean DEFB4 CN did not differ significantly in combined ChP cases vs. the controls; however, the mean DEFB4 CN in the severe ChP group differed significantly from those for the control and slight-to-moderate ChP groups. Low DEFB4 CN increased the risk of severe ChP by about 3-fold. DEFB4 CN was inversely associated with average attachment loss. Mean serum hBD-2 levels were highest in the controls, followed by the slight-to-moderate ChP group and the severe ChP group. The results suggested an association between decreased DEFB4 CN and serum hBD-2 levels and periodontitis severity.

HLA-DRB and HLA-DQA/HLA-DQB allele and haplotype frequencies in Iranian patients with aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Genetic backgrounds play a key role in susceptibility to and protection against a spectrum of periodontal diseases. Like other infectious diseases, the human leukocyte antigen (HLA) have been found to be associated with periodontitis. This study aimed to investigate differences in allele and haplotype frequencies of HLA class II antigens in a sample of Iranian patients with aggressive periodontitis compared with a healthy control group. MATERIAL AND METHODS: Fifty unrelated patients with aggressive periodontitis and 130 healthy volunteers were enrolled in this study. HLA genotyping for HLA-DRB, HLA-DQA1 and HLA-DQB1 was performed using the PCR with sequence-specific primers. Allele and haplotype frequencies were compared across groups. RESULTS: The frequencies of HLA-DQA1*03:01, HLA-DQB1*03:02 and HLA-DQB1*03:05 alleles, as well as that of the HLA-DRB1*04:01 allele, were significantly higher in patients with aggressive periodontitis compared with control subjects (p = 0.01, p = 0.04, p = 0.05 and p = 0.04, respectively). In contrast, the frequency of the HLA-DQB1*0603 allele was significantly lower in patients with aggressive periodontitis compared with control subjects (p = 0.006; odds ratio = 0.20). With regard to haplotype association, a significantly higher frequency of two haplotypes - HLA-DRB1*04:01/HLA-DQA1*03:01/HLA-DQB1*03:02 and HLA-DRB1*16:01/HLA-DQA1*01:03/HLA-DQB1*05:01 - was observed in patients with aggressive periodontitis compared with healthy controls (p = 0.01, odds ratio = 2.56 and p = 0.05, odds ratio = 5.38, respectively). CONCLUSION: These results provide additional evidence that class II HLA polymorphisms, particularly in the DQ locus, are associated with protection against and susceptibility to aggressive periodontitis.

Association of CD28 and CTLA-4 gene polymorphisms with aggressive periodontitis in Brazilians.

OBJECTIVE: Susceptibility to and severity of periodontal disease is influenced by gene polymorphisms related to the immune response. Co-stimulatory molecules, such as CD28 and CTLA-4, are critical in the development of such responses. Our hypothesis is that polymorphisms in genes that code for these molecules may be associated with periodontitis. The aim of the study was to investigate the association between +17 (T/C) CD28 and +49 (A/G) CTLA-4 gene polymorphisms and periodontitis in Brazilians. MATERIALS AND METHODS: Genomic DNA was obtained from oral swabs of 424 individuals categorized into three groups (control group, aggressive, and chronic periodontitis) considering clinical parameters such as probing depth and clinical attachment loss. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There was an association between the T(-) genotype of the CD28 polymorphism and aggressive periodontitis (P = 0.04). Moreover, the A(+) genotype for CTLA-4 was associated with greater clinical attachment loss in non-smokers with aggressive periodontitis (P = 0.006, OR = 16.25, CI = 2.25-117.11). CONCLUSIONS: These findings show that T(-) in CD28 + 17 (T/C) and the A(+) in CTLA-4 +49 (A/G) genotypes are associated with susceptibility to aggressive periodontal disease. Thus, our study highlights these polymorphisms as potential genetic susceptibility markers of periodontitis in Brazilians.

MMP3 and TIMP1 variants contribute to chronic periodontitis and may be implicated in disease progression.

AIM: Matrix metalloproteinases (MMPs) play a key role in the tissue destruction characteristic of chronic periodontitis. The purpose of this study was to investigate the association of MMP and TIMP polymorphisms with chronic periodontitis in two populations. MATERIAL AND METHODS: A total of 34 polymorphisms spanning 12 MMP and 2 TIMP genes were genotyped in 401 individuals from Brazil (99 cases with chronic periodontitis and 302 controls), and 274 individuals from the US (70 cases and 204 controls). Individuals were considered cases if presenting at least three teeth exhibiting sites of clinical attachment loss ≥ 5 mm in two different quadrants. Controls were characterized by absence of clinical attachment loss and no sites with probing depth >3 mm. MMP3 and TIMP1 mRNA expression was evaluated in healthy and diseased periodontal tissues. RESULTS: TIMP1 showed association with chronic periodontitis in the Brazilian population (for rs5906435, p = 0.0004), whereas MMP3 showed association in the US population (for rs679620, p = 0.0003; and rs650108, p = 0.002) and in the Brazilian population (for rs639752, p = 0.005). MMP3 and TIMP1 mRNA expression was significantly higher in diseased tissues when compared to control tissues. CONCLUSIONS: Our results further support a role for variations in MMP3 in chronic periodontitis and report a novel association with TIMP1. These genes may be considered additional candidate genes for chronic periodontitis.

Aggregatibacter actinomycetemcomitans serotypes, the JP2 clone and cytolethal distending toxin genes in a Thai population.

AIM: To examine the genetic diversity of Aggregatibacter actinomycetemcomitans in Thai adults. MATERIALS AND METHODS: Subgingival plaque samples from 453 subjects were analysed for A. actinomycetemcomitans serotypes, the presence of the high leukotoxin-producing JP2 clone and cytolethal distending toxin genes (cdtABC) using the polymerase chain reaction technique. In subjects who were positive for cdtABC, restriction fragment length polymorphism analysis was used to identify a single nucleotide polymorphism (SNP) in the cdtB gene at amino acid position 281. The extent and severity of periodontal disease were compared between subjects harbouring different A. actinomycetemcomitans genotypes. RESULTS: Eighty six subjects (19%) were positive for A. actinomycetemcomitans. The JP2 clone was not detected. Serotype c was the most prevalent (57%), followed by serotypes a (33%) and b (7%). Among A. actinomycetemcomitans-positive subjects, 27% were positive for cdtABC. All cdtABC-positive subjects possessed the SNP in the cdtB, which is involved with increased toxin activity. The presence of A. actinomycetemcomitans, but not a specific genotype, was significantly related to increased probing depth and periodontal attachment loss. CONCLUSIONS: Our results confirm the previous findings that genotype distribution of A. actinomycetemcomitans varies between ethnic groups. However, no clear relationship between a specific genotype and periodontal conditions was observed.

Association analysis between the -2518MCP-1(A/G) polymorphism and generalized aggressive periodontitis in a Chinese population.

BACKGROUND AND OBJECTIVE: It has been suggested that aggressive periodontitis has a genetic basis. Monocyte chemoattractant protein 1 (MCP-1) plays a critical role in the recruitment of monocytes and the development of periodontitis. The -2518MCP-1(A/G) polymorphism has been implicated as a risk or susceptibility factor for a variety of autoimmune conditions and inflammatory diseases. The intent of this investigation was to study whether the -2518MCP-1(A/G) polymorphism is associated with generalized aggressive periodontitis in the Chinese population. MATERIAL AND METHODS: One hundred and twenty-four patients with generalized aggressive periodontitis and 94 healthy subjects were included in this case-control study. Genomic DNA was isolated from a peripheral blood sample obtained from each subject. Gene polymorphisms of -2518MCP-1(A/G) were analyzed by a standard polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. A logistic regression analysis was performed to test the association between the -2518MCP-1(A/G) genotype (alleles) and generalized aggressive periodontitis with adjustment of the major covariates (gender, age and smoking status). RESULTS: There was no significant association of the -2518MCP-1(A/G) polymorphism with generalized aggressive periodontitis in the unstratified subjects. However, when patients were stratified by gender, the frequency of the G(+) genotype was significantly lower in female patients with generalized aggressive periodontitis compared with female controls (p = 0.036, adjusted odds ratio = 0.3, 95% CI: 0.1-0.9). In female patients with generalized aggressive periodontitis, the probing pocket depth was larger in subjects with the AA genotype than in subjects with the G(+) genotype (5.07 mm vs. 4.30 mm; Z = -2.470, p = 0.014). CONCLUSION: The polymorphisms of -2518MCP-1 may play an important role in determining generalized aggressive periodontitis susceptibility in this cohort of Chinese women.

Periodontal disease in adults with untreated congenital growth hormone deficiency: a case-control study.

AIM: The aim of this study was to investigate the possible associations between isolated growth hormone deficiency (IGHD) and periodontal attachment loss (PAL) in adults affected by congenital IGHD. MATERIALS AND METHODS: Forty-five previously identified IGHD subjects were eligible for this study. The final study sample comprised 32 cases (gender:20M/12F; age:44.8 ± 17.5) matched for age, gender, diabetes, smoking status and income to 32 controls (non-IGHD subjects). Participants were submitted to a full-mouth clinical examination of six sites per tooth and were interviewed using a structured, written questionnaire. Periodontitis was defined as proximal PAL≥5 mm affecting ≥30% of teeth. RESULTS: No significant differences were observed in the percentage of sites with visible plaque between IGHD and non-IGHD subjects (59.4% versus 46.9%, p=0.32). IGHD subjects had significant less supragingival calculus (31.3% versus 59.4%, p=0.02) and more bleeding on probing (71.9% versus 18.8%, p<0.01) than controls. PAL≥5 mm was significantly more prevalent (100% versus 71.9%, p<0.01) and affected more teeth (30.5% versus 6.7%, p<0.01) in cases than in controls. After adjusting for supragingival calculus, IGHD cases had a higher likelihood of having periodontitis than controls (OR=17.4-17.8, 95% CI=2.3-134.9, p=0.004-0.005). CONCLUSION: Congenital IGHD subjects have a greater chance of having PAL.

Analysis of plasma calprotectin and polymorphisms of S100A8 in patients with aggressive periodontitis.

BACKGROUND AND OBJECTIVE: Calprotectin is an important proinflammatory mediator in various inflammatory diseases and is composed of two subunits (S100A8 and S100A9). However, the level of calprotectin in plasma of patients with aggressive periodontitis and its relationship with gene polymorphisms of S100A8 are unclear. MATERIAL AND METHODS: The plasma concentrations of calprotectin were measured, using an enzyme immunoassay, in 139 patients with aggressive periodontitis and in 88 periodontally healthy control subjects. These patients were genotyped for the rs3795391 and rs3806232 polymorphisms of S100A8. RESULTS: The plasma concentration of calprotectin in patients with aggressive periodontitis was significantly higher than in controls (2.17 mg/L vs. 1.72 mg/L, respectively, p = 0.001). The percentage of the AA genotype of S100A8 rs3795391 was significantly higher in patients than in controls (82% vs. 69.3%, respectively, p = 0.027), while the frequency of the allele G was decreased among patients compared with controls (9.6% vs. 16.1%, respectively, p = 0.036), which was especially apparent in men (rs3795391 genotype, p = 0.005; rs3795391 allele, p = 0.015). The mean probing depth in patients carrying the AA genotype was significantly higher than that of patients carrying the GA + GG genotype of two polymorphisms of S100A8 (rs3795391, p = 0.035; rs3806232, p = 0.040), whereas the levels of calprotectin between different genotypes were not significantly different (rs3795391, p = 0.11; rs3806232, p = 0.15). CONCLUSION: These findings indicate that aggressive periodontitis is associated with elevated levels of plasma calprotectin and that gene polymorphisms of S100A8 may influence the susceptibility and severity of aggressive periodontitis.

FcγRIIB polymorphisms, periodontitis and preterm birth in Japanese pregnant women.

BACKGROUND AND OBJECTIVE: Recently, numerous studies have investigated the association of preterm birth with periodontitis. FcγRIIb is a human low-affinity receptor for immunoglobulin G (IgG). We have previously demonstrated single nucleotide polymorphisms (SNPs) of FcγRIIb to be associated with periodontitis and the serum-specific IgG level against periodontopathic bacteria. In this study, we investigated whether FcγRIIB gene polymorphisms were associated with periodontitis and/or pregnancy outcome. MATERIAL AND METHODS: We assessed the periodontal conditions of 122 Japanese pregnant women within 5 d of delivery, and polymorphisms in FcγRIIB and in other Fcγ receptors were detected from the genomic DNA. Using clinical and genomic data, we analyzed the relationship between periodontitis, preterm birth and Fcγ receptor polymorphisms. RESULTS: A significant difference was observed in the distribution of FcγRIIB-nt645+25A/G (rs2125685) between preterm and term birth groups, with a higher prevalence of nt645+25AA in the preterm birth group (p = 0.032). Additionally, the FcγRIIB-nt645+25GG carrier showed significantly higher results for the prevalence of periodontitis (p = 0.048), mean pocket depth (p = 0.021), mean clinical attachment level (p = 0.010), percentage of sites with pocket depth ≥ 4 mm (p = 0.005) and percentage of sites with clinical attachment level ≥ 3 mm (p = 0.007) than the AA carrier. An association between preterm birth and periodontitis was not observed in this study. CONCLUSION: These findings suggest that FcγRIIB-nt645+25AA carriers are more likely to experience preterm birth than FcγRIIB-nt645+25AG and GG carriers. Also, women with FcγRIIB-nt645+25G exhibited a greater tendency to have periodontitis than those with nt645+25A.

Inter-generational continuity in periodontal health: findings from the Dunedin family history study.

OBJECTIVE: To determine whether parental periodontal disease history is a risk factor for periodontal disease in adult offspring. METHODS: Proband periodontal examination [combined attachment loss (CAL) at age 32, and incidence of CAL from ages 26 to 32] and interview data were collected during the age-32 assessments in the Dunedin Study. Parental data were also collected. The sample was divided into two familial-risk groups for periodontal disease (high- and low-risk) based on parents' self-reported periodontal disease. RESULTS: Periodontal risk analysis involved 625 proband-parent(s) groups. After controlling for confounding factors, the high-familial-risk periodontal group was more likely to have 1+ sites with 4+mm CAL [relative risk (RR) 1.45; 95% confidence interval (CI) 1.11-1.88], 2+ sites with 4+mm CAL (RR 1.45; 95% CI 1.03-2.05), 1+ sites with 5+mm CAL (RR 1.60; 95% CI 1.02-2.50), and 1+ sites with 3+mm incident CAL (RR 1.64; 95% CI 1.01-2.66) than the low-familial-risk group. Predictive validity was enhanced when information was available from both parents. CONCLUSIONS: Parents with poor periodontal health tend to have offspring with poor periodontal health. Family/parental history of oral health is a valid representation of the shared genetic and environmental factors that contribute to an individual's periodontal status, and may help to predict patient prognosis and preventive treatment need.

Single nucleotide polymorphisms of pattern recognition receptors and chronic periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a multifactorial disease influenced partly by genetics. Activation of pattern recognition receptors (PRRs) can lead to the up-regulation of inflammatory pathways, resulting in periodontal tissue destruction. Hence, functional polymorphisms located in PRRs can explain differences in host susceptibility to periodontitis. This study investigated single nucleotide polymorphisms of PRRs including toll-like receptor (TLR)2 (G2408A), TLR4 (A896G), TLR9 (T1486C), TLR9 (T1237C) and CD14 (C260T) in patients with chronic periodontitis and in periodontally healthy subjects. METHODS: One-hundred and fourteen patients with chronic periodontitis and 77 periodontally healthy subjects were genotyped using TaqMan® allelic discrimination assays. Fisher's exact test and chi-square analyses were performed to compare genotype and allele frequencies. RESULTS: The frequency of subjects with the CC genotype of CD14 (C260T) (24.6% in the chronic periodontitis group vs. 13% in the periodontally healthy group) and those expressing the T allele of CD14 (C260T) (CT and TT) (75.4% in the chronic periodontitis group vs. 87% in the periodontally healthy group) was statistically different among groups (p = 0.04). Homozygocity for the C allele of the CD14 (C260T) polymorphism (CC) was associated with a two--fold increased susceptibility to periodontitis (p = 0.04; odds ratio, 2.49; 95% confidence interval, 1.06-6.26). Individuals with the CC genotype of TLR9 (T1486C) (14.9% in the chronic periodontitis group vs. 28.6% in the periodontally healthy group) and those expressing the T allele of TLR9 (T1486C) (CT and TT) (85.1% in the chronic periodontitis group vs. 71.4% in the periodontally healthy group) were also significantly differently distributed between groups without adjustment (p = 0.03). Further analysis of nonsmokers revealed a significant difference in the distribution of genotypes between groups for TLR9 (T1486C; p = 0.017) and CD14 (C260T; p = 0.03), polymorphisms again without adjustment. CONCLUSION: The CC genotype of CD14 (C260T) is related to susceptibility to chronic periodontitis in Caucasians. In addition, differences observed in the distribution of TLR9 (T1486C) genotypes between groups warrant further investigation.

Monozygotic twins are discordant for chronic periodontitis: clinical and bacteriological findings.

OBJECTIVES: The aim of this study was to assess, in monozygotic (MZ) and dizygotic (DZ) twin pairs in whom the proband of the twin pair was suffering from moderate to severe chronic periodontitis, the contribution of genetics, periodontal pathogens and lifestyle factors towards the clinical phenotype. MATERIAL AND METHODS: For this study, 18 adult twin pairs were selected on the basis of interproximal attachment loss (AL) >or=5 mm in >or=2 non-adjacent teeth in one twin member. The study included 10 MZ and eight DZ twin pairs, in whom the periodontal condition, presence of periodontal pathogens, educational level, smoking behaviour and body mass index (BMI) were evaluated. RESULTS: Both MZ and DZ twins were discordant regarding AL and alveolar bone loss. Discordance was greater in DZ compared with MZ twins. In MZ twins, the discordance could not be explained by education, smoking, BMI and periodontal pathogens. In DZ twins, 45.6% of the discordance could be explained by more pack-years of the probands. CONCLUSION: The results confirm a possible role of genetic factors in periodontitis. However, the magnitude of the genetic effects on disease severity may have been overestimated previously.