The interleukin-1 genotype as a severity factor in adult periodontal disease

Microbiological composition associated with interleukin-1 gene polymorphism in subjects undergoing supportive periodontal therapy

BACKGROUND

Interleukin-1 gene polymorphism (IL-1 gene) has been associated with periodontitis. The present study examined the subgingival microbiota by IL-1 gene status in subjects undergoing supportive periodontal therapy (SPT).

METHODS

A total of 151 subjects with known IL-1 gene status (IL-1A +4845/IL-1B -3954) (IL-1 gene) were included in this study. Clinical data and subgingival plaque samples (40 taxa) were collected. These taxa were determined by the checkerboard DNA-DNA hybridization method.

RESULTS

Gender, smoking habits (n-par tests), age, and clinical periodontal conditions did not differ by IL-1 gene status. IL-1 gene-negative subjects had a higher total bacterial load (mean difference, 480.4 x 10(5); 95% confidence interval [CI], 77 to 884 x 10(5); P <0.02). The levels of Actinobacillus actinomycetemcomitans (mean difference, 30.7 x 10(5); 95% CI, 2.2 to 59.5 x 10(5); P <0.05), Eubacterium nodatum (mean difference, 4.2 x 10(5); 95% CI, 0.6 to 7.8 x 10(5); P <0.02), Porphyromonas gingivalis (mean difference, 17.9 x 10(5); 95% CI, 1.2 to 34.5 x 10(5); P <0.05), and Streptococcus anginosus (mean difference, 4.0 x 10(5); 95% CI, 0.2 to 7.2 x 10(5); P <0.05) were higher in IL-1 gene-negative subjects, an observation specifically found at sites with probing depths <5.0 mm.

CONCLUSIONS

Bleeding on probing did not differ by IL gene status, reflecting clinical SPT efficacy. IL-1 gene-negative subjects had higher levels of periodontal pathogens. This may suggest that among subjects undergoing SPT, a lower bacterial load is required in IL-1 gene-positive subjects to develop the same level of periodontitis as in IL-1 gene-negative subjects.

Risk factors for endosseous dental implant failure

Failures of endosseous dental implants are rare and tend to cluster in patients with common profiles or risk factors. Clinical trials indicate that factors related to implant devices, anatomy, occlusion,systemic health or exposures, microbial biofilm, host immuno-inflammatory responses, and genetics may increase the risk for im-plant complications or loss. In general, factors associated with the patient appear more critical in determining risk for implant failure than those associated with the implant itself. Several risk factors can be modified. For example, the patient can modify smoking and the clinician can modify implant selection, site preparation,and loading strategy. In identifying these factors and making appropriate interventions, clinicians can enhance success rates while improving oral function, esthetics, and patient well-being.

Association of Matrix Metalloproteinase-9 Promoter Gene Polymorphism With Chronic Periodontitis

BACKGROUND

Matrix metalloproteinases (MMPs) are related to tissue destruction and remodeling events in periodontal diseases. A single nucleotide polymorphism in the promoter region of human MMP-9 gene is associated with the risk of some inflammatory diseases. Therefore, the aim of this study was to investigate the association between MMP-9 promoter polymorphism and severe generalized chronic periodontitis in a Turkish population.

METHODS

Samples of venous blood and DNA were obtained from 70 severe generalized chronic periodontitis patients and 70 healthy subjects. The alleles of the C/T polymorphism at position -1562 in the promoter region of the MMP-9 gene were distinguished by cutting with the SphI restriction enzyme. Genotype and allele frequencies were calculated, and data were analyzed by the chi2 test.

RESULTS

There was a significant difference in MMP-9 genotypes between chronic periodontitis patients and healthy controls. The odds ratios for the CT genotype and the combination of CT and TT genotypes were 0.4 (95% confidence interval, 0.17 to 0.93; P=0.02) and 0.37 (95% confidence interval, 016 to 0.85; P=0.01) relative to the subjects with the CC genotype, respectively.

CONCLUSION

MMP-9 promoter gene polymorphism seems to be associated with severe generalized chronic periodontitis.

Assessment of single nucleotide polymorphism at IL-1A+4845 and IL-1B+3954 as genetic susceptibility test for chronic periodontitis in Maharashtrian ethnicity

BACKGROUND

The inflammatory response that is directed in large part by proinflammatory cytokine interleukin (IL)-1 is genetically determined, with some people having a more vigorous response than others to the same stimulus. The reason for this is speculated that the dysregulated production of IL-1 in some individuals overrides the feedback mechanisms that normally master the dose of inflammation to a level sufficient to fight microbial invasion without long-lasting damage to the tissues involved. The aims of the present study were to determine the distribution of IL-1 gene polymorphism (IL-1A+4845 and IL-1B+3954) and their association with periodontal disease severity and to determine the significance of detecting the composite genotype (IL-1A allele2+IL-1B allele2) versus detecting either of them alone.

METHODS

A total of 120 subjects were included and divided into four groups of 30 subjects each, namely, healthy, mild, moderate, and severe periodontitis groups. After a complete clinical examination, DNA was isolated from 0.5 ml blood. Specific primers were used to detect the presence of IL-1 gene polymorphism with the help of polymerase chain reaction (PCR) and subsequent allele detection with restriction fragment length polymorphism (RFLP) and separation by gel electrophoresis.

RESULTS

The distribution of the allele1 homozygous genotype was 3% in the severe periodontitis group, and the distribution for the allele2 genotype was 30%. A higly significant difference (Wilcoxon signed-rank test; P<0.001) was seen between subjects positive and negative for the composite genotype.

CONCLUSIONS

Results of the present study reinforced the association of the IL-1 genotype as a risk factor for severe chronic periodontitis. Positivity for the composite genotype was found to be significantly associated with severe chronic periodontitis (odds ratio [OR]=12.42).

IL-1 gene polymorphism and periodontal status of HIV Brazilians on highly active antiretroviral therapy

A genotype in the IL-1 gene cluster is associated with an increased risk of periodontitis. We investigated whether polymorphisms in the IL-1A +4845 and IL-1B +3954 loci affect the periodontal status of HIV-infected Brazilians on HAART. HIV-positive and HIV-negative subjects with periodontitis were genotyped for IL-1 by polymerase chain reaction and restriction enzyme digestion. Only 11.4% of patients were genotype positive. No associations between genotype positivity and HIV infection or periodontal status were found in this population.

The gene expression profile in refractory periodontitis patients

BACKGROUND

There are no specific bacterial profiles or diagnostic tests capable of identifying refractory periodontitis patients before a treatment regimen is initiated. Therefore, in this high-risk cohort of patients who do not respond appropriately, host factors that might be partly under genetic control may play a crucial role in their susceptibility. Specifically, we tested the hypothesis that patients with refractory periodontitis have multiple upregulated and/or downregulated genes that might be important in influencing clinical risk.

METHODS

Oral subepithelial connective tissues were harvested aseptically from seven refractory periodontitis and seven periodontally well-maintained patients. An RNA isolation kit was used to isolate total RNA from tissue samples that had been stabilized in the RNA stabilizing reagent. The isolated total RNA was then subjected to gene expression profiling using the microarray to measure gene expression levels. The retrieved data were analyzed with a computer program for the differential analysis of gene expression microarray experiments. In addition, real-time polymerase chain reaction (PCR) analysis was performed on selected samples to confirm the microarray data's gene expression patterns.

RESULTS

A total of 68 upregulated and six downregulated genes were identified that were differentially expressed at least two-fold out of 22,283 genes we analyzed. The selected model provided a 93% intrinsic validation along with a 93% extrinsic validation. To validate the microarray data, five upregulated genes (lactotransferrin [LTF], matrix metalloproteinase-1 [MMP-1], MMP-3, interferon induced-15 [IFI-15], and Homo sapiens hypothetical protein MGC5566) and two downregulated genes (keratin 2A [KRT2A] and desmocollin-1 [DSC-1]) were randomly selected for further analysis by real-time PCR. The relative RNA expression level of these genes measured by real-time PCR was similar to those measured by microarrays.

CONCLUSION

The combined use of microarray technology with the computer program for the differential analysis of gene expression microarray experiments provided a set of candidate genes that may serve as novel therapeutic intervention points and improved diagnostic and screening procedures for high-risk individuals.

Fcgamma receptor polymorphisms and periodontal status: a prospective follow-up study

AIMS

The aims of this study were to assess: (i) the distribution of Fcgamma receptor polymorphisms among patients with chronic periodontitis ("cases") and control subjects with no/minimal loss of periodontal tissue support in a Caucasian population; (ii) whether these polymorphisms can serve as severity markers for periodontitis; and (iii) whether they have any bearing on the response to periodontal therapy.

METHODS

The study sample consisted of 132 cases and 73 controls of comparable age and gender. Full-mouth periodontal status was assessed. Subgingival plaque (PL) samples and blood samples were obtained and analysed with respect to 19 bacterial species and homologous serum immunoglobulin G titres. Polymorphisms in the Fcgamma receptor IIa (131R/H) and IIIb (NA1/NA2) were assessed by polymerase chain reaction. Patients underwent periodontal therapy and were followed up at 4 and 30 months.

RESULTS

Neither polymorphism showed a skewed distribution among cases and controls. At baseline, periodontitis patients with Fcgamma RIIa-H/H131 genotype had more PL and deeper pockets than patients in other genotype groups (p < 0.05). Both bacterial levels and antibody titres were unrelated to genotype. The longitudinal analysis failed to detect an association between genotype and response to periodontal therapy.

CONCLUSIONS

The present data failed to demonstrate a clinically relevant relationship between the Fcgamma receptor IIa (131R/H) or IIIb (NA1/NA2) polymorphism and periodontal status.

IL-1RN gene polymorphism is associated with peri-implantitis

OBJECTIVES

Interleukin (IL)-1alpha, IL-1beta and their natural specific inhibitor IL-1 receptor antagonist (IL-1ra) play a key role in the regulation of the inflammatory response in periodontal tissues. Polymorphisms in the IL-1 gene cluster have been associated with severe adult periodontitis. We aimed to investigate the IL-1 gene cluster polymorphisms in patients with peri-implantitis.

MATERIAL AND METHODS

The study included 120 North Caucasian individuals. A total of 71 patients (mean age 68 years, 76% smokers) demonstrating peri-implantitis at one or more implants as evidenced by bleeding and/or pus on probing and bone loss amounting to >3 threads on Brånemark implants and 49 controls (mean age 66 years, 45% smokers) with clinical healthy mucosa and no bone loss around the implants were recruited for the study. The titanium implants, ad modum Brånemark, had been in function for at least 2 years. Mouthwash samples were collected and used for genotyping of the bi-allelic polymorphisms IL-1A(-889), IL-1B(+3953), IL-1B(-511) and a variable number of tandem repeat IL-1RN gene polymorphisms using PCR technique.

RESULTS

Significant differences were found in the carriage rate of allele 2 in the IL-1RN gene between peri-implantitis patients and controls (56.5% vs. 33.3%, respectively; odds ratios (OR) 2.6; 95% confidence interval (CI) 1.2-5.6; P=0.015). Logistic regression analysis taking smoking, gender and age into account confirmed the association between the IL-1RN allele 2 carriers and peri-implantitis (OR 3; 95% CI 1.2-7.6; P=0.02).

CONCLUSIONS

Our results provide evidence that IL-1RN gene polymorphism is associated with peri-implantitis and may represent a risk factor for this disease.

Periodontitis and plasma C-reactive protein during pregnancy

BACKGROUND

Periodontitis has been associated with increased risk of adverse pregnancy outcomes and elevated C-reactive protein (CRP) concentrations in non-pregnant adults. We examined the relationship between periodontitis and CRP among women who provided dental radiographs and had blood collected during early pregnancy, excluding smokers and diabetic patients.

METHODS

From Project Viva, an ongoing cohort study, we measured plasma CRP in 35 subjects with periodontitis (i.e., at least one site with > or =3 mm of alveolar bone loss) and a random sample of 66 periodontally healthy subjects matched on age and race/ethnicity. We performed linear regression analysis with log-transformed CRP levels as the outcome.

RESULTS

The mean (+/- SE) CRP level was 65% higher (95% confidence interval: -2%, 180%; P = 0.06) in women with periodontitis (2.46 +/- 0.52 mg/l) than in controls (1.49 +/- 0.22 mg/l), adjusting for factors related to CRP levels, including age, race/ethnicity, pre-pregnancy body mass index, alcohol intake, education, income, and gestational age at blood collection.

CONCLUSIONS

These findings suggest that periodontitis may increase CRP levels in pregnancy. CRP could potentially mediate the association of periodontitis with adverse pregnancy outcomes.

The association between periodontal disease and joint destruction in rheumatoid arthritis extends the link between the HLA-DR shared epitope and severity of bone destruction

OBJECTIVE

To evaluate a possible association between wrist and periodontal destruction in rheumatoid arthritis, and between periodontal destruction, dry mouth, and labial salivary gland biopsy and the contribution of genetic factors (the shared epitope (SE) and IL1B (+3954) or TNFA (-238 or -308) gene polymorphisms).

METHODS

147 patients with rheumatoid arthritis were enrolled. Periodontal damage was defined according to the Hugoson and Jordan criteria on panoramic dental x rays. Typing for the SE and cytokine polymorphisms was undertaken by enzyme linked oligosorbent assay. Odds ratios (OR), relative risk (RR), and chi2 values were calculated to quantify associations.

RESULTS

An association was observed between wrist and periodontal bone destruction (chi2=11.82; p<0.001): 63 patients had both wrist and periodontal destruction, 31 had wrist destruction alone, 20 had periodontal destruction alone, and 33 had no destruction at either site. An association was seen between a positive labial salivary gland biopsy and periodontal bone destruction (RR=2.73 (95% CI, 1.35 to 5.51), p<0.01, n=41) or wrist bone destruction (RR=4.52 (1.96 to 10.45), p<0.001, n=41). The SE was associated with wrist bone destruction (OR=2.5 (1.16 to 5.42), p<0.05) and periodontal bone destruction (OR=2.2 (1.04 to 4.84), p<0.05). No association was found between the selected cytokine polymorphisms and bone destruction.

CONCLUSIONS

A strong association was found between wrist and periodontal bone destruction. The destruction risk was further increased in patients with sicca syndrome. The SE appears to be a severity genetic marker for both wrist and periodontal bone destruction.

The role of titanium surface topography on J774A.1 macrophage inflammatory cytokines and nitric oxide production

A role for monocyte/macrophage modulation of wound healing at endosseous implants is proposed. The modification of the endosseous implant surface topography can alter cell adhesion and resultant cell behavior. The aim of this study was to define the effect of increased cpTitanium surface topography on adherent J744A.1 macrophage phenotype in culture. The J744A.1 cells were cultured on 20mm diameter cpTitanium disks prepared with smooth and grit-blasted/acid rough surface topographies for 24-72 h. Following culture in growth media with or without lipopolysaccharide (LPS), total RNA was isolated and real-time polymerase chain reaction (PCR) was used to measure the steady-state levels of the pro-inflammatory cytokines interleukin 1-beta (IL-1beta) and interleukin 6 (IL-6) and the anti-inflammatory cytokine interleukin-10 (IL-10). Additional evidence of pro-inflammatory signaling was sought by measurement of cellular nitric oxide (NO) production. In the absence of LPS, IL-1beta levels were increased on grit-blasted/acid rough surfaces during the first 48 h. In contrast, IL-6 levels were reduced on the grit-blasted/acid rough surfaces. When cultures were treated with LPS, high levels of IL-1beta and IL-6 expression were measured, irrespective of surface topography. The responses of J744A.1 cells to surface and superimposed LPS stimulation suggest only modest effects of the modeled endosseous implant surface on adherent cell pro-inflammatory cytokine expression and NO signaling.

Balance of inflammatory response in stable gingivitis and progressive periodontitis lesions

The balance between inflammatory mediators and their counter-regulatory molecules may be crucial for determining the outcome of immune pathology of periodontal diseases. Based on clinical and immunological findings, the immune response in stable gingivitis lesion is supposed to be in balance, whereas the response is skewed towards the predominance of proinflammatory reactivity in progressive periodontitis lesion. However, this hypothesis has not been verified. Therefore, the aim of this study was to compare the gene expression profile of inflammatory mediators including proinflammatory cytokines and other inflammatory molecules, and anti-inflammatory cytokines by using quantitative real-time polymerase chain reaction in gingivitis and periodontitis lesions showing distinct clinical entities. For inflammatory mediators, interleukin (IL)-1beta, interferon (IFN)-gamma and receptor activator of nuclear factor (NF)-kappaB ligand tended to be higher in periodontitis, whereas tumour necrosis factor (TNF)-alpha and IL-12 p40 showed no difference. Heat-shock protein 60 (HSP60) expression was up-regulated significantly in periodontitis. For anti-inflammatory cytokines, transforming growth factor (TGF)-beta1 expression tended to be higher in periodontitis compared with gingivitis, whereas no difference was observed for IL-10 and IL-4. These findings support further our previous finding that autoimmune response to HSP60 may exert in periodontitis lesion, and suggest that perhaps subtle differences in the balance of cytokines may result in different disease expression.

Influence of Combinations of Bacteria on the Levels of Prostaglandin E2, Interleukin-1β, and Granulocyte Elastase in Gingival Crevicular Fluid and on the Severity of Periodontal Disease

BACKGROUND

The aim of this study was to investigate the simultaneous presence of periodontal microbiota on inflammatory markers in gingival crevicular fluid from individuals with periodontal diseases.

METHODS

A total of 82 individuals with periodontal disease (mean age: 54.3 +/- 3.0 years) and 31 periodontally healthy individuals (mean age: 53.2 +/- 3.0 years) were randomly chosen and underwent clinical oral examinations in 2003 with the determination of the dental plaque index (PI), gingival index (GI), and periodontal probing depth (PD). The simultaneous presence of polymerase chain reaction (PCR)-assessed periodontal bacteria, levels of prostaglandin E(2) (PGE(2)), granulocyte elastase, interleukin 1-beta (IL-1beta), and total protein concentration were determined from the pockets. Marginal bone height percent was measured on x-rays. Analysis of variance and chi(2) tests were used to analyze the results.

RESULTS

In sites with Tannerella forsythensis, levels of PGE(2) (pg/site), granulocyte elastase (monoclonal antibodies (mAbs)/site), and total protein (mg/ml) were significantly higher than in sites without T. forsythensis (P <0.05, P <0.01, and P <0.05, respectively). Those with periodontal disease with simultaneous presence of T. forsythensis and Porphyromonas gingivalis, or T. forsythensis and Prevotella nigrescens, showed significantly higher PI and GI, deeper PD, more loss of attachment, and more release of PGE(2) and granulocyte elastase than did periodontitis patients without these bacteria.

CONCLUSION

The simultaneous presence of T. forsythensis and P. gingivalis, or T. forsythensis and P. nigrescens, seemed to promote the release of subgingival inflammatory mediators and seemed to be associated with more severe periodontal disease.

Salivary biomarkers of existing periodontal disease: a cross-sectional study

BACKGROUND

The authors conducted a study to determine if salivary biomarkers specific for three aspects of periodontitis--inflammation, collagen degradation and bone turnover--correlate with clinica features of periodontal disease.

METHODS

The relationship between periodontal disease and the levels of interleukin-1 beta (IL-1beta), matrix metalloproteinase (MMP)-8, and osteoprotegerin (OPG) in whole saliva of 57 adults (28 "case" subjects with moderate-to-severe periodontal disease and 29 healthy control subjects) was examined in a case-control trial.

RESULTS

Mean levels of IL-1beta and MMP-8 in saliva were significantly higher in case subjects than in controls. Both analytes correlated with periodontal indexes, whereas, after adjustment for confounders, OPG did not. Elevated salivary levels of MMP-8 or IL-1beta (more than two standard deviations above the mean of the controls) significantly increased the risk of periodontal disease (odds ratios in the 11.3-15.4 range). Combined elevated salivary levels of MMP-8 and IL-1beta increased the risk of experiencing periodontal disease 45-fold, and elevations in all three biomarkers correlated with individual clinical parameters indicative of periodontal disease.

CONCLUSION

Salivary levels of MMP-8 and IL-1beta appear to serve as biomarkers of periodontitis.

CLINICAL IMPLICATIONS

Qualitative changes in the composition of salivary biomarkers could have significance in the diagnosis and treatment of periodontal disease.

Salivary diagnostics powered by nanotechnologies, proteomics and genomics

BACKGROUND

The ability to monitor health status, disease onset and progression, and treatment outcome through noninvasive means is a highly desirable goal in health care promotion and delivery. Oral fluid is a perfect medium to be explored for health and disease surveillance.

METHODS

Two prerequisites exist before the goal of salivary diagnostics can be achieved: identification of specific biomarkers associated with a health or disease state and the development of technologies that can discriminate between the biomarkers. A recent initiative of the National Institute of Dental and Craniofacial Research has created a roadmap to achieve these goals through the use of oral fluids as the diagnostic medium to scrutinize the health and/or disease status of patients. This is an ideal opportunity to optimize state-of-the-art saliva-based biosensors for salivary biomarkers that discriminate between diseases.

RESULTS

Seven technology groups are developing point-of-care salivary diagnostic technologies. Three groups are working together toward deciphering the salivary proteome.

CONCLUSION

These collective efforts and the convergence of salivary diagnostic technologies and the salivary proteome will present unparalleled opportunities to explore the diagnostic potential of saliva for oral and systemic diseases.

Is there a relationship between juvenile idiopathic arthritis and periodontitis?

AIM

The aim was to compare the prevalence of periodontal conditions in patients with juvenile idiopathic arthritis (JIA) (n=78, age 14.4 years) with those revealed in a healthy control group (n=75, age 15.5 years).

MATERIAL AND METHODS

In both groups, the approximal plaque index (API), the modified sulcular bleeding index (SBI), and the clinical attachment loss (CAL) were determined. Laboratory parameters for JIA activity included the capsule-reactive protein (CRP) and the immunoglobulins A, G, M.

RESULTS

JIA patients had a significantly higher API (64.6%versus 49.9%, p=0.004) and slightly higher mean percentages of sites with CAL>3.5 mm (0.58%versus 0.22%, p=0.041). There was no significant difference in the prevalence of patients and controls who had sites with CAL >3.5 mm (25.6%versus 17.3%, p=0.212). The mean CAL was slightly greater (0.2 mm; p=0.030) in patients with CRP> or =5.0 mg/l compared with patients with CRP<5.0 mg/l. Patients who took non-steroidal anti-inflammatory drugs (NSAIDs) had a significantly decreased SBI (26.2%versus 51.1%, p=0.019).

CONCLUSION

After adjustment for microbial plaque, JIA is not a risk factor for periodontitis.

Association of the IL1 gene cluster with susceptibility to ankylosing spondylitis: an analysis of three Canadian populations

OBJECTIVE

To examine the association between the IL1 gene cluster and susceptibility to ankylosing spondylitis (AS) in 3 independent case-control cohorts.

METHODS

We analyzed 394 patients and 446 controls from Alberta, Newfoundland, and Toronto, Canada. Samples were genotyped using a panel of 38 single-nucleotide polymorphism (SNP) markers within the IL1 gene cluster. Data from 20 informative and nonredundant SNP markers were analyzed using several association test strategies. First, we used the program WHAP to identify single-marker associations. Second, we used WHAP to analyze "sliding windows" of 3 contiguous markers along the entire extent of the IL1 gene cluster in order to identify haplotypic associations. Third, we used the linkage disequilibrium mapping program DMLE to estimate the posterior probability distribution of a disease locus.

RESULTS

A total of 14 SNP markers showed significant single-locus disease associations, the most significant being rs3783526 (IL1A) (P = 0.0009 in the Alberta cohort, P = 0.04 in the Newfoundland cohort) and rs1143627 (IL1B) (P = 0.0005 in the Alberta cohort, P = 0.02 in the Newfoundland cohort). Analysis of 3-marker sliding windows revealed significant and consistent associations with all of the haplotypes in the IL1A and IL1B loci in the Alberta cohort and with IL1B in the Newfoundland cohort, especially haplotypes rs1143634/rs1143630/rs3917356 and rs1143630/rs3917356/rs3917354 (P = 0.006-0.0001). With DMLE, a strong peak in the probability distribution was estimated near IL1A in both the Alberta and the Newfoundland populations.

CONCLUSION

These results indicate that the IL1 locus, or a locus close to IL1, is associated with susceptibility to AS.

Association of the IL-1RN2 allele with periodontal diseases

OBJECTIVES

Interleukin-1 receptor antagonist (IL-1Ra) gene (IL-1RN) polymorphism is associated with disease susceptibility and activity in several inflammatory diseases. The aim of this study was to investigate IL-1RN genotype and its associations with different periodontal diseases in a group of Turkish subjects.

DESIGN AND METHODS

A total of 293 subjects were included in this study. Genomic DNA was obtained from the peripheral blood of 52 patients with generalized aggressive periodontitis (G-AgP), 51 with chronic periodontitis (CP) and 190 reference subjects. A variable number tandem repeat (VNTR) polymorphism in the second intron of the IL-1RN gene was detected by PCR-based methods. Probing pocket depth, clinical attachment loss, plaque accumulation and bleeding on probing (BOP) were recorded. The data were analyzed by the chi(2) test, logistic regression and Mann-Whitney U test.

RESULTS

There were significant differences among the groups in the distribution of IL-1RN genotypes (P = 0.0001) and allele frequencies (P = 0.0001). The frequency of IL-1RN2 allele 2 positivity was higher in the AgP and CP group than the reference group [odds ratio (OR) 6.654, 95% CI: 3.023-16.648; OR 10.327, 95% CI: 4.758-22.412, respectively]. The percentage of sites with BOP was significantly higher in IL-1RN2+ compared to IL-1RN2- CP patients (P = 0.022).

CONCLUSION

These results suggest that IL-1RN2 allele positivity is associated with periodontal disease in a Turkish population.

The Interleukin-1beta +3953 Single Nucleotide Polymorphism: Cervical Protein Concentration and Preterm Delivery Risk

PROBLEM

To determine the associations between preterm delivery <37 weeks (PTD), cervical fluid interleukin-1beta (IL-1beta) concentration, and its +3953 single nucleotide polymorphism (SNP).

METHOD OF STUDY

Cervical fluid, peripheral blood, and cord blood samples were obtained from a cohort of women 23-32 weeks gestation with preterm labor symptoms and intact membranes.

RESULTS

Increased cervical fluid concentrations of IL-1beta were associated with PTD (P = 0.017) and spontaneous PTD (P = 0.001). Maternal IL-1beta +3953 SNP genotype was associated neither with PTD (P = 0.43) nor with cervical fluid IL-1beta concentrations (P = 0.35). Neonatal IL-1beta +3953 SNP genotype was associated neither with PTD nor cervical IL-1beta concentrations.

CONCLUSIONS

Cervical fluid concentrations of IL-1beta were elevated in symptomatic women destined to have a spontaneous PTD. The gene dosage of maternal IL-1beta +3953 allele 2 was associated neither with increased cervical fluid concentrations of IL-1beta nor with risk of PTD.

Association of the OGG1 Ser326Cys polymorphism with tooth loss

Although tooth loss is a serious health problem for elderly people, little is known about the genetic basis for susceptibility to it. In the present study we aimed to find a single nucleotide polymorphism (SNP) associated with tooth loss. DNA samples from 119 outpatients (mean age=78.8 years) were genotyped on seven polymorphisms (tumor necrosis factor-alpha -1031T/C, interleukin-1beta -511C/T, interleukin-6 -634C/G, macrophage migration inhibitory factor -173G/C, interleukin-1 receptor antagonist variable number of tandem repeat in intron 2, matrix metalloproteinase-1 -16071G/2G, and oxoguanine glycosylase 1 (OGG1) Ser326Cys (1245C/G)), and the results were statistically evaluated. Of the seven polymorphisms tested, only OGG1 Ser326Cys was revealed to associate with tooth loss at a statistically significant level (P=0.0086). In addition, a multivariate logistic regression analysis in which age, gender, body mass index (BMI), and ischemic heart disease were included as independent variables indicated that Ser326Cys could be an independent factor affecting tooth loss (OR, 3.191; 95%CI, 1.174-8.672). The data suggest that the OGG1 Ser326Cys polymorphism may be associated with tooth loss.

No Association Between Selected Candidate Gene Polymorphisms and Severe Chronic Periodontitis

BACKGROUND

Chronic periodontitis (CP) risk is influenced by environmental and genetic factors. Using a case-control design, we tested for associations between CP and selected DNA sequence variations (single nucleotide polymorphisms [SNPs]) in or near genes coding for proteins that play a role in the pathogenesis of this disease.

METHODS

DNA was analyzed from 219 whites who were examined clinically. Cases (N=137) were >or=35 years of age with eight or more teeth having >or=5 mm of proximal clinical attachment loss. Controls (N=82) were >or=45 years of age with minimal or no proximal attachment loss or pocketing. Nine diallelic polymorphisms (gene and SNP descriptor) were studied in subjects: cytotoxic T-lymphocyte antigen-4 (CTLA-4, 49 A>G), human beta-defensin-1 (DEFB1, 692 G>A), intercellular adhesion molecule-1 (ICAM-1, 1548 A>G), Fas ligand (fasL, -844 C>T), inducible costimulator (ICOS, 3990 G>T), interleukin-6 (IL-6, -174 G>C), cysteine-cysteine chemokine receptor-5 (CCR5, 59653 C>T), osteoprotegerin (OPG, 245 T>G), and osteopontin (OPN, 707 C>T). Genotypes were determined using an automated fluorogenic 5'-nuclease, polymerase chain reaction-based assay. Gender and smoking history (pack-years) were included as covariates in logistic regression analyses.

RESULTS

Heavy smoking (>10 pack-years) and male gender were significantly associated with disease (P<0.001). For all SNPs tested, the allele frequencies and distributions of genotypes did not differ between cases and controls (P>0.05). No unadjusted or adjusted odds ratios (comparing genotypes in cases versus controls) were significantly different than 1.0 (P>0.05) under any additive, dominant, or recessive inheritance model.

CONCLUSIONS

None of the SNPs tested were strongly associated with generalized severe chronic periodontitis in North American whites. A potentially more fruitful approach in future studies will be to test for associations between periodontitis and haplotype blocks constructed from either multiple SNPs in candidate gene regions or from panels of markers that span the entire genome.

Effect of myrrh oil on IL-1β stimulation of NF-κB activation and PGE2 production in human gingival fibroblasts and epithelial cells

Anecdotal and scientific evidence suggest that myrrh oil (MO) has anti-inflammatory properties. Subtoxic MO levels decrease interleukin (IL)-1beta-stimulated production of the inflammatory cytokine IL-6 by human gingival fibroblasts, but not epithelial cells. IL-1beta upregulates IL-6 via PGE(2), and via NF-kappaB, a transcription factor for many inflammatory mediator genes. NF-kappaB is inhibited by sesquiterpene compounds (from plants other than myrrh). This study determined MO effect on IL-1beta-stimulated PGE(2) production and NF-kappaB activation in gingival fibroblasts and epithelial cells. Cells were preincubated with MO, exposed to IL-1beta, cytoplasmic and nuclear fractions were isolated, and activated NF-kappaB was measured using an ELISA-based assay. IL-1beta increased nuclear activated NF-kappaB levels in fibroblasts and epithelial cells [10- and 2.5-fold over controls, respectively (p=0.0001)], and these increases were not significantly affected by MO. PGE(2) was measured in cell supernatants by ELISA, after preincubation with MO and exposure to IL-1beta. MO inhibited IL-1beta-stimulated PGE(2) production by fibroblasts (p=0.001), but not epithelial cells. The data suggest that gingival epithelial cells and fibroblasts may differ in the magnitude of NF-kappaB activation after IL-1beta stimulation, and that MO inhibition of IL-1beta-stimulated IL-6 production in fibroblasts is due in part to inhibition of PGE(2), but not NF-kappaB activation. (Supported by NIDCR DE-0725.).

Evidence for genetic variation as a factor in maintaining health

For many chronic diseases, the influence of genetics is subtle and complex and does not conform to simple Mendelian patterns of inheritance as is seen with single-gene disorders. Genetic variation can influence the propensity for the initiating event, the progression to a clinical disease state, and the trajectory of disease. One example of how genetic variations may affect complex diseases is provided by the interleukin 1 family of cytokines. This cytokine family plays a key role in mediating inflammation, which is a central component of many chronic diseases, including coronary artery disease and rheumatoid arthritis. Recent research has identified many sequence variations in the regulatory DNA of the genes coding for important members of the interleukin 1 family, and these variations are associated with differential effects on the inflammatory response. These in turn alter the risk of some diseases in which inflammation plays a role and also affect physiologic responses, such as the inflammatory response to exercise. As this new genetic knowledge is developed and extended, it may be possible to make health care interventions at an earlier stage, before clinical disease is established, rather than after tissues have been permanently damaged.

Hyper-reactive mononuclear cells and neutrophils in chronic periodontitis

OBJECTIVES

Stimulated mono- and polymorphonuclear cells from patients with periodontitis have shown increased release of interleukin-1beta (IL-1beta) and oxygen radicals, respectively. The aim was to study whether this hyper-reactivity could be found both in mono- and polymorphonuclear cells from the same patient, and whether there was a relation to the gene coding for IL-1beta (IL-1beta(+3953)).

MATERIAL AND METHODS

Peripheral mononuclear cells from 14 non-smoking and well-treated patients and pair-matched controls were incubated with opsonized Staphylococcus aureus and lipopolysaccharide (LPS). Released IL-1beta and tumour necrosis factor (TNF)-alpha were determined with ELISA. Generation of oxygen radicals from the Fcgamma-receptor-stimulated neutrophils was measured with chemiluminescence and the polymorphism at IL-1beta(+3953) was measured with polymerase chainreaction.

RESULTS

The mononuclear cells from the patients released more IL-1beta after incubation with LPS (p<0.001) and with bacteria (p<0.05). The release of TNF-alpha tended to be higher in the patient group. The peripheral neutrophils from the patients generated more oxygen radicals (p<0.06). We found no differences between the study groups regarding the IL-1beta(+3953) polymorphism.

CONCLUSION

The similarity in systemic inflammation between patients and controls suggests that the increased release/generation of IL-1beta and oxygen radicals from peripheral leukocytes in periodontitis patients is of a constitutional nature and of pathogenic relevance.

Interleukin 1 genetics, inflammatory mechanisms, and nutrigenetic opportunities to modulate diseases of aging

Inflammation plays a central role in many diseases of aging, and genetic differences in the inflammatory response appear to influence different disease courses among individuals. Variations in the genes for the family of interleukin 1 (IL-1) proteins are inherited together in a small set of patterns and provide an example of the role of inflammatory genetics as a modifier of diseases of aging. The IL-1 genetic variations are associated with variation in both the inflammatory response and the clinical presentation of a range of diseases, including coronary artery disease, Alzheimer disease, gastric cancer, and periodontitis. This growing understanding of the role of genetic variation in inflammation and chronic disease presents opportunities to identify healthy persons who are at increased risk of disease and to potentially modify the trajectory of disease to prolong healthy aging. Nutrition represents one of the promising approaches to modulation of the risk of diseases of aging because of the effects of certain nutrients on gene expression. One of the most practical applications of nutritional modulation of chronic disease may be nutrients that regulate the expression of key inflammatory genes.

Periodontitis and rheumatoid arthritis: a review

Periodontitis and rheumatoid arthritis (RA) appear to share many pathologic features. In this review, the common pathologic mechanisms of these two common chronic conditions are explored. Emerging evidence now suggests a strong relationship between the extent and severity of periodontal disease and RA. While this relationship is unlikely to be causal, it is clear that individuals with advanced RA are more likely to experience more significant periodontal problems compared to their non-RA counterparts, and vice versa. A case is made that these two diseases could be very closely related through common underlying dysfunction of fundamental inflammatory mechanisms. The nature of such dysfunction is still unknown. Nonetheless, there is accruing evidence to support the notion that both conditions manifest as a result of an imbalance between proinflammatory and anti-inflammatory cytokines. As a result, new treatment strategies are expected to emerge for both diseases that may target the inhibition of proinflammatory cytokines and destructive proteases. The clinical implications of the current data dictate that patients with RA should be carefully screened for their periodontal status.

Single nucleotide polymorphisms in the human interleukin-1B gene affect transcription according to haplotype context

We questioned the significance of haplotype structure in gene regulation by testing whether individual single nucleotide polymorphisms (SNPs) within a gene promoter region [interleukin-1-beta (IL1B)] might affect promoter function and, if so, whether function was dependent on haplotype context. We sequenced genomic DNA from 25 individuals of diverse ethnicity, focusing on exons and upstream flanking regions of genes of the cluster. We identified four IL1B promoter region SNPs that were active in transient transfection reporter gene assays. To substantiate allelic differences found in reporter gene assays, we also examined nuclear protein binding to promoter sequence oligonucleotides containing different alleles of the SNPs. The effect of individual SNPs on reporter gene transcription varied according to which alleles of the three other SNPs were present in the promoter construct. The SNP patterns that influenced function reflected common haplotypes that occur in the population, suggesting functionally significant interactions between SNPs according to haplotype context. Of the haplotypes that include the four functional IL1B promoter SNPs (-3737, -1464, -511, -31), the four haplotypes that showed different contextual effects on SNP function accounted for >98% of the estimated haplotypes in Caucasian and African-American populations. This finding underlines the importance of understanding the haplotype structure of populations used for genetic studies and may be especially important in the functional analysis of genetic variation across gene regulatory regions.

Mikrobiologische Untersuchung zur Ermittlung des Erfolges der Sofortimplantation im parodontal geschädigten Gebiss

AIM

The aim of the present study was to investigate the prevalence of periodontal marker organisms and specific interleukin-1 (IL-1) gene polymorphisms (which show a close association with periodontitis) and their effect on the success of immediate implant placement postextraction in the patient with periodontal disease.

PATIENTS AND METHODS

A group of 59 patients (22 men and 37 women aged 20-81 years, median age 55 years, 18 smokers) with chronic adult periodontitis participated in the study which included a 1-year observation period postoperatively. Prior to tooth extraction two DNA samples were obtained for the microbiological diagnosis of five anaerobic gram-negative pathogens (Haemophilus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia sensu stricto, Treponema denticola) and to identify the IL-1 gene polymorphisms. Patients were treated with a total of 95 immediate dental implants (26 Ankylos/Friadent and 69 Camlog Root-Line/Camlog Biotechnologies) placed into extraction sites, 78 of which were loaded immediately. After 1 year four failures were observed; all of these patients were smokers.

RESULTS

None of these patients showed a positive IL-1 genotype; periodontal marker organisms were only found in one patient. No significant difference was seen in the microbiological pathogens between smokers and nonsmokers. Of 59 patients, 23 (39%) tested positive for IL-1 genotype polymorphism. Smoking was shown to increase the risk of implant failure. No association was observed between failures and the IL-1 gene polymorphisms or pathogens.

CONCLUSION

In conclusion, our study shows that periodontally infected sites do not seem to be a contraindication for immediate implantation.

Reasons for tooth extraction in Kuwait

OBJECTIVES

To investigate reasons for tooth extraction and its association with age and gender in Kuwait.

SUBJECTS AND METHODS

A record of all tooth extractions performed in 21 general dental practice centers during a 1-month period was logged on specially designed study forms. The patient's age and gender, number of teeth extracted, and the reason(s) for the extraction were recorded.

RESULTS

A total of 2,783 teeth were extracted in 1,604 patients (1.73 +/- 0.07 teeth per patient). Caries and periodontal disease were responsible for 43.7 and 37.4% of extractions, respectively. Caries was the principal cause for extraction in patients < or =40 years old (60.7%), while periodontal disease was the main cause of extractions in patients > or =40 years of age (63.0%). Extractions for caries and orthodontic reasons were more common in females, while extractions for periodontal disease were more prevalent in males. Molars and maxillary premolars were more commonly extracted due to caries, while mandibular premolars, and maxillary and mandibular anterior teeth (canines and incisors) were more commonly extracted due to periodontal disease.

CONCLUSIONS

The data show that caries is the principal cause for extractions in younger patients, while periodontal disease accounts for the majority of tooth extractions in patients older than 40 years. Furthermore, this study indicates that more teeth per patient are lost to periodontal disease than for any other reason.

Chronic periodontal disease is associated with single-nucleotide polymorphisms of the human TLR-4 gene

Periodontitis is an inflammatory disease affecting the connective tissue surrounding the teeth leading to tooth loss. Pathogens associated with periodontitis interact with Toll-like receptors (TLRs) to induce cytokines causing and aggravating disease. We screened 197 individuals suffering from generalized periodontitis for the presence of Asp299Gly and Thr399Ile of TLR-4 as well as Arg753Gln of TLR-2 in comparison to matched controls. Single-nucleotide polymorphisms (SNPs) of TLR-4 were elevated among patients (odd's ratio 3.650, 95% CI 1.573-8.467, P < or = 0.0001), while no difference was observed for TLR-2. TLR-4 SNPs were correlated with chronic periodontitis (odd's ratio 5.562, 95% CI 2.199-14.04, P < or = 0.0001), but not with aggressive periodontitis. This observation was confirmed employing a group of periodontally healthy probands over 60 years of age. These data demonstrate that genetic variants of TLR-4 may act as risk factors for the development of generalized chronic periodontitis in humans.

Controlled clinical and psychometric studies on the relation between periodontitis and depressive mood

BACKGROUND

Depressive mood is considered a risk factor for the development of periodontitis.

OBJECTIVES

Investigation of the relationship between periodontitis and psychopathology utilizing psychometry (both observer- and self-rating scales).

METHODS

Forty periodontitis patients were compared with 41 age- and sex-matched controls. The percentage of smokers was similar in both groups (30% versus 24.4%). Dental variables included probing depth, clinical attachment loss (CAL), radiographic loss of attachment, papillary bleeding index (PBI) and approximal plaque index (API). Psychometry comprised the Hamilton Depression Scale, the Zung Self-Rating Depression and Anxiety Scales, the von Zerssen Well-being and Complaint Scales, the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index, the Quality-of-Life Index, crystallized intelligence and the Freiburg Personality Inventory (FPI).

RESULTS

Multifactorial analysis of variance demonstrated increased depression and anxiety scores, reduced well-being, increased somatic complaints, deteriorated quality of life and introversion in periodontitis. Partial correlation analyses between psychometric measures and dental variables revealed positive correlations of periodontal disease severity/CAL with the depression/anxiety, subjective well-being and complaints scores, and a negative correlation with quality of life. The API was negatively correlated with social orientation, and the CAL was positively correlated with somatic complaints and introversion in the FPI.

CONCLUSION

Our clinical-psychometric studies confirm depressive mood as a relevant pathogenetic factor for periodontitis.

Early colonization of non-submerged dental implants in patients with a history of advanced aggressive periodontitis

The aim of the study was to evaluate the early colonization of non-submerged implants over a 6-month period in partially edentulous patients treated for advanced aggressive periodontal disease. In 22 patients treated for advanced aggressive periodontitis and in a supportive maintenance program for a period between 12 and 240 months at implant surgery, a total of 68 non-submerged dental implants were installed. Patients had a plaque score below 20%, and less than 20% of the pockets around the teeth were bleeding on probing (BOP). Using DNA-probes (micro-IDent), the presence and concentration of five periodontal pathogens (Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf) and Treponema denticola (Td)) were determined in the five deepest pockets of the rest dentition pre-operatively and after 6 months as well as five places around each implant 10 days, 1 month, 3 months and 6 months after surgery. In each patient, a test to determine the genotype interleukin-1 (IL-1) was performed (PST - micro-IDent). After 6 months, no difference in microbial composition as compared with baseline was found around the teeth in five patients, in 12 minute differences and in five patients important differences were observed. Ten days after surgery, three patients had a complete similar bacterial composition between teeth and implants. In 14 patients, the composition was fairly similar, while large differences in composition and concentration occurred in five patients. This microbiota around the implants remained almost unchanged over a 6-month period and did not hamper the clinical and radiographic osseointegration and did not lead to peri-implantitis, mucositis or initiation of bone destruction.

Periodontal diseases

The periodontal diseases are highly prevalent and can affect up to 90% of the worldwide population. Gingivitis, the mildest form of periodontal disease, is caused by the bacterial biofilm (dental plaque) that accumulates on teeth adjacent to the gingiva (gums). However, gingivitis does not affect the underlying supporting structures of the teeth and is reversible. Periodontitis results in loss of connective tissue and bone support and is a major cause of tooth loss in adults. In addition to pathogenic microorganisms in the biofilm, genetic and environmental factors, especially tobacco use, contribute to the cause of these diseases. Genetic, dermatological, haematological, granulomatous, immunosuppressive, and neoplastic disorders can also have periodontal manifestations. Common forms of periodontal disease have been associated with adverse pregnancy outcomes, cardiovascular disease, stroke, pulmonary disease, and diabetes, but the causal relations have not been established. Prevention and treatment are aimed at controlling the bacterial biofilm and other risk factors, arresting progressive disease, and restoring lost tooth support.

Genetic Control of the Immune Response in Pathogenesis

BACKGROUND

Epidemiological studies have suggested that there is a genetic component to susceptibility to chronic periodontitis. Studies in humans and in animal models have suggested that some of the important components may be polymorphisms in key immunological genes.

METHODS

This paper summarizes previously published data from a mouse model in which alveolar bone loss is induced by oral infection with Porphyromonas gingivalis. Mice of different inbred immune-normal strains were used, as well as the F1 heterozygotes from crosses between strains. In addition, tissue expression of an array of immunological genes was measured in the gingiva and spleen of these mice by quantitative reverse transcription-polymerase chain reaction (QPCR).

RESULTS

Not all strains of mice are susceptible to bone loss. Intercross experiments demonstrate that susceptibility is an inherited trait. A subset of immunological genes tested showed differential basal expression in the gingiva or spleens (or both). Tumor necrosis factor and osteoprotegerin mRNAs are more highly expressed in the gingiva and interleukin-1 mRNA is more highly expressed in both the gingiva and the spleens of susceptible mice than resistant mice. In the resistant mice, interleukin-15 mRNA in the gingiva and Selp mRNA in the spleen are present at higher levels. In the resistant mice no genes changed expression after P. gingivalis infection, while mRNA for interleukin-1, osteoprotegerin, and STAT6 all increased in the susceptible mice.

CONCLUSIONS

Susceptibility and resistance are heritable traits. Strain differences in basal mRNA expression correlate with differences in susceptibility. Genes that change expression in response to infection also correlate with differences in susceptibility.

Risk Indicators for Tooth Loss Due to Periodontal Disease

BACKGROUND

Several risk indicators for periodontal disease severity have been identified. The association of these factors with tooth loss for periodontal reasons was investigated in this cross-sectional comparative study.

METHODS

All extractions performed in 21 general dental practice clinics (25% of such clinics in Kuwait) over a 30-day period were recorded. Documented information included patient age and gender, medical history findings, dental maintenance history, toothbrushing frequency, types and numbers of extracted teeth, and the reason for the extraction. Reasons were divided into periodontal disease versus other reasons in univariate and binary logistic regression analyses.

RESULTS

A total of 1,775 patients had 3,694 teeth extracted. More teeth per patient were lost due to periodontal disease than for other reasons (2.8 +/- 0.2 versus 1.8 +/- 0.1; P <0.001). Factors significantly associated with tooth loss due to periodontal reasons in logistic regression analysis were age >35 years (odds ratio [OR] 3.45; 95% confidence interval [CI] 2.79 to 4.26), male gender (OR 1.42; 95% CI 1.17 to 1.73), never having periodontal maintenance (OR 1.48; 95% CI 1.23 to 1.78), never using a toothbrush (OR 1.81; 95% CI 1.49 to 2.20), current or past smoking (OR 1.56; 95% CI 1.28 to 1.91), anterior tooth type (OR 3.23; 95% CI 2.57 to 4.05), and the presence of either of the following medical conditions: diabetes mellitus (OR 2.64; 95% CI 2.19 to 3.18), hypertension (OR 1.73; 95% CI 1.41 to 2.13), or rheumatoid arthritis (OR 4.19; 95% CI 2.17 to 8.11).

CONCLUSION

Tooth loss due to periodontal disease is associated with the risk indicators of age, male gender, smoking, lack of professional maintenance, inadequate oral hygiene, diabetes mellitus, hypertension, rheumatoid arthritis, and anterior tooth type.

Disease progression: identification of high-risk groups and individuals for periodontitis

AIMS

While the role of bacteria in the initiation of periodontitis is primary, a range of host-related factors influence the onset, clinical presentation and rate of progression of disease. The objectives of this review are (1) to present evidence for individual predictive factors associated with a patient's susceptibility to progression of periodontitis and (2) to describe the use of prognostic models aimed at identifying high-risk groups and individuals in a clinical setting.

METHODS

Relevant publications in the English language were identified after Medline and PubMed database searches. Because of a paucity of longitudinal studies investigating factors including clinical, demographic, environmental, behavioural, psychosocial, genetic, systemic and microbiologic parameters to identify individuals at risk for disease progression, some association studies were also included in this review.

FINDINGS AND CONCLUSIONS

Cigarette smoking is a strong predictor of progressive periodontitis, the effect of which is dose related. High levels of specific bacteria have been predictive of progressive periodontitis in some studies but not all. Diabetics with poor glycaemic control have an increased risk for progression of periodontitis. The evidence for the effect of a number of putative factors including interleukin-1 genotype, osteoporosis and psychosocial factors is inconclusive and requires further investigation in prospective longitudinal studies. Specific and sensitive diagnostic tests for the identification of individuals susceptible to disease progression are not yet a reality. While factors assessed independently may not be valuable in predicting risk of future attachment loss, the combination of factors in a multifactorial model may be useful in identifying individuals at risk for disease progression. A number of multifactorial models for risk assessment, at a subject level have been developed but require validation in prospective longitudinal studies.

Effect of genetic variability on the inflammatory response to periodontal infection

AIM

To review the association between genetic variability and the inflammatory response induced by periodontal infection.

MATERIAL AND METHODS

A search of MEDLINE-PubMed was performed from January 2000 up to and including March 2005. The search included all types of publications, published in English without other limitations. The following search terms were used: "cytokine polymorphism", "gene polymorphism", "periodontitis", "gingivitis", "inflammation" and "host-response". The papers resulting from the above search were used as an additional source for relevant articles.

RESULTS

Genetic variability was examined for the correlation to clinical indicators of inflammation such as bleeding on probing (BOP), gingival inflammation, cytokine in gingival crevicular fluid (GCF) and cytokine production by inflammatory cells. According to the current literature, most of the studies found no association between genetic variability and BOP, gingival inflammation or cytokine concentrations in the GCF. These studies were hampered by inappropriate study designs and the use of inflammatory parameters as secondary rather than primary outcome variables. The data suggest that the production of inflammatory mediators by inflammatory cells may be affected by different genetic traits but further studies are needed in order to establish this association.

CONCLUSIONS

To date, there is no clear correlation between any of the gene polymorphisms and clinical indicators of inflammation. The powering of studies to reveal associations between single or multiple nucleotide polymorphisms and inflammatory parameters will need to involve a much larger number of subjects than were used in the past. The available data (including the interleukin-1 composite genotype) do not currently support the utility of such tests in the diagnosis and prognostic assessments of periodontal diseases.

Identification of genetic risk factors for periodontitis and possible mechanisms of action

AIM

To review the literature for genetic risk factors associated with periodontitis.

METHODS

Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk.

RESULTS AND CONCLUSIONS

Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.

Analytical epidemiology of periodontitis

AIMS

To review the literature related to the analytical epidemiology of periodontitis generated over the past decade. This review does not deal with descriptive epidemiologic studies of the prevalence, extent and severity of periodontitis with respect to global geography, but focuses exclusively on analytical epidemiology issues, including the challenges posed by the use of different case definitions across studies, current theories and models of disease progression, and risk factors associated with the onset and progression of periodontitis.

METHODS

Relevant publications in the English language were identified after Medline and PubMed database searches.

FINDINGS AND CONCLUSIONS

There is a conspicuous lack of uniformity in the definition of periodontitis used in epidemiologic studies, and findings from different research groups are not readily interpretable. There is a lack of studies that specifically address the distinction between factors responsible for the onset of periodontitis versus those affecting its progression. Colonization by specific bacteria at high levels, smoking, and poorly controlled diabetes have been established as risk factors for periodontitis, while a number of putative factors, including specific gene polymorphisms, have been identified in association studies. There is a clear need for longitudinal prospective studies that address hypotheses emerging from the cross-sectional data and include established risk factors as covariates along with new exposures of interest. Intervention studies, fulfilling the "targeting" step of the risk assessment process, are particularly warranted. Obvious candidates in this context are studies of the efficacy of elimination of specific bacterial species and of smoking cessation interventions as an alternative to the traditional broad anti-plaque approach in the prevention and control of periodontitis. Ideally, such studies should have a randomized-controlled trial design.

The Relationship Between Interleukin-10 Gene Polymorphism at Position –1082 and Susceptibility to Gingivitis in Children

BACKGROUND

Interleukin (IL)-10 is an anti-inflammatory cytokine. The protective role of this cytokine against different diseases has been demonstrated in several studies. However, no such study has been carried out on gingivitis. The objective of this study was to determine whether differences exist between Caucasian children with and without gingivitis in the distribution of IL-10 alleles at position -1082.

METHODS

A total of 260 Caucasian children (86 controls, 174 patients), aged 8 to 12 years, from the University Dental Hospital of Manchester, U.K., were examined. Plaque (PI), calculus (CI), gingival (GI), and bleeding on probing (BOP) indices were used to assess gingival health. DNA was obtained from buccal epithelial cells. Amplification refractory mutation system polymerase chain reaction (ARMS-PCR) was used for genotyping IL-10 polymorphism. Chi square tests were carried out to test the association between allele and genotype frequencies and the severity of gingivitis. Multiple logistic regression was used to determine the role of IL-10 gene polymorphism at position -1082 while adjusting for potential confounders such as plaque, age, and gender.

RESULTS

Gingivitis was present in 67% of the children examined. Frequencies of alleles -1082*A and -1082*G were 45% and 55%, respectively. An increased risk of having gingivitis was found in allele A positive children (G/A, A/A); 75% versus 25% in allele A negative children (G/G); (P = 0.01). The -1082*A allele was significantly more common in children with gingivitis; 49% versus 37% in controls (P = 0.01). Multivariate logistic regression analysis showed that allele A remained a risk factor for gingivitis in children (P = 0.03) regardless of plaque or age. Also, allele A positive children were at increased odds of having gingivitis of 1.8 (95% confidence interval [CI]: 1.05 to 3.06) compared to allele A negative children after adjusting for plaque, age, and gender.

CONCLUSION

These data suggest that the -1082*A allele could be a risk factor for gingivitis.

A comparative study of the efficacy of AphthealTM in the management of recurrent minor aphthous ulceration

BACKGROUND

Recurrent minor aphthous ulceration (RAU) is a common condition which is multifactorial in origin.

METHODS

This study, firstly, aimed to treat the prodromal stage of RAU with Aphtheal (5% amlexanox paste) to determine if ulcer development could be prevented. A second arm of the study investigated treatment of RAU with Aphtheal once ulceration had developed. Ulcer duration, ulcer size and associated pain were measured. Both groups of subjects had previously undergone a no-treatment run-in period to establish these parameters over an untreated episode of ulceration.

RESULTS

By day 3, only 35% of the prodromal group had developed an ulcer compared with 97% of the ulcer group (P < 0.001). In the treated ulcer group only 66% had an ulcer present by day 3. Treatment at the onset of prodromal symptoms reduced the maximum ulcer size score by 84% (P < 0.01), extent of ulceration by 88% (P < 0.01), maximum pain score by 69% (P < 0.01) and extent of pain by 85% (P < 0.01) compared to no treatment.

CONCLUSION

Treatment with Aphtheal at the onset of prodromal RAU symptoms can prevent progression to ulcer development and significantly reduced symptoms if ulcers do develop.

Application of oral implants to the general dental practice

BACKGROUND

The use of dental implants has become a management strategy for replacing missing teeth. As new implant surface technologies develop and prosthetic options increase, the field of dental implantology continues to change. General dentists con sidering the use of this treatment modality in their practices should understand the vital role treatment planning plays in achieving predictable outcomes.

OVERVIEW

This article reviews specific issues the general dentist typically faces when considering patients for single-tooth, partially-edentulous-arch and full-arch tooth replacement using dental implants. The author analyzes patient-based assessments, as well as diagnostic criteria and steps, to help practitioners predict patient-specific issues that may signal complications. He also discusses approaches for resolving complications. The article emphasizes the importance of careful evaluation in predicting patient-specific issues that can lead to gingival recession and suggests approaches to manage these situations.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Dental implants have become an increasingly common treatment option for missing dentition. Because innovations in implant surfaces continue to promote faster bone growth with better predictability, general dentists should be aware of the importance of treatment planning, assessment and teamwork in achieving successful outcomes.

A functional interleukin-1beta gene polymorphism is associated with chronic periodontitis in a sample of Brazilian individuals

BACKGROUND

Interleukin-1 beta (IL-1 beta) is a potent inflammatory mediator and an important polymorphism in the locus +3954 (C/T) of the human IL1 B gene has been shown to affect the levels of this cytokine. This functional polymorphism has been associated with the establishment of inflammatory diseases, including periodontal disease, in European, Asian and North American populations.

OBJECTIVE

The aim of this study was to investigate the association between the IL1 B (+3954) gene polymorphism and the occurrence of different clinical forms of periodontitis in a sample of Brazilian individuals.

METHODS

This study employed a cross-sectional design involving individuals from the State of Minas Gerais in the south-eastern region of Brazil. Genomic DNA was obtained from oral swabs of 129 individuals and amplified using the polymerase chain reaction (PCR) with specific primers flanking the locus +3954 of IL1 B. PCR products were submitted to restriction endonuclease digestion and analyzed by polyacrylamide gel electrophoresis, to distinguish alleles T and C of the IL1 B gene, allowing for the determination of the genotypes and detection of the polymorphism.

RESULTS AND CONCLUSIONS

The chronic periodontitis group displayed a higher percentage of the T allele (28%) when compared to the aggressive periodontitis group (10.7%, chi(2)=5.24, p=0.02, OR=0.31, CI=0.11--0.88) and to control group (8.7%, chi(2)=7.11, p=0.007, OR=0.24, CI=0.08--0.73). Our data suggested that the polymorphism in the locus +3954 of IL1 B gene could be a risk factor for chronic periodontitis in a sample of Brazilian individuals.