Single nucleotide polymorphism rs4284505 in microRNA17 and risk of dental fluorosis.

OBJECTIVES: The aim of this study is to evaluate the association between the single nucleotide polymorphism (SNP) rs4284505 within the gene that codifies microRNA17 (miRNA17) and dental fluorosis (DF) in a group of children. METHODS: Children living in a city with fluoridation of public water supplies were included. DF was assessed in erupted permanent teeth by Dean's modified index. The miR-SNP rs4284505 was selected in miRNA17 and genotyping was carried out by real-time PCR. Genotype and allelic distributions between DF and control, and between DF phenotypes (mild, moderate and severe) and control were analysed. RESULTS: Among a total of 527 children enrolled for the study, 383 were DF free and 144 presented DF. In the dominant model analysis (AA + AG vs. GG) the miR-SNP rs4284505 was associated with moderate DF, with carriers of the GG genotype having an increased risk of more than two times for DF (p = 0.031; Odds Ratio = 2.26, Confidence Interval 95%= 1.04-4.73). Allelic distribution showed borderline statistical significance for moderate DF with the carriers of G allele having an increased risk for DF (p = .050; Odds Ratio = 1.75, Confidence Interval 95%= 1.00-3.12). CONCLUSION: The miR-SNP rs4284505 in miRNA17 was associated with an increased risk of DF.

Are mTOR and Endoplasmic Reticulum Stress Pathway Genes Associated with Oral and Bone Diseases?

The purpose of this cohort study was to identify associations between combined oral and bone disease phenotypes and genes present in cell regulatory pathways. The studied pathways play important roles in cellular growth, proliferation, differentiation, and homeostasis. DNA samples extracted from whole saliva of 3,912 individuals were genotyped and these data analyzed according to dental caries experience, periapical lesions, periodontitis, osteoporosis, or temporomandibular joint discomfort. Samples were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Twenty-seven polymorphisms in eight genes related to mTOR or endoplasmic reticulum stress pathways were selected for genotyping. Allele frequencies and Hardy-Weinberg equilibrium were calculated. Analyses were performed comparing genotypes between affected and unaffected individuals for each phenotype, as well as for the associated phenotypes combined. For all analyses, we used the software PLINK with an alpha of 0.002. Borderline associations with multiple variants of several genes were found, suggesting that both pathways may be involved in the susceptibility to multiple conditions affecting the oral cavity and bones. When combining patients that had concomitant dental caries, periodontitis, and periapical pathology, several markers in RHEB showed statistically significant association. Multiple conditions affecting bone and teeth (i.e., dental caries, periodontitis, periapical lesion formation, and osteoporosis) appear to share similar underlying genetic etiological factors, which allow us to hypothesize that instead of individually, they should be studied in conjunction in human populations.

Immunohistochemical expression of matrix metalloprotease-2 and matrix metalloprotease-9 in the disks of patients with temporomandibular joint dysfunction.

PURPOSE: Matrix metalloproteases (MMPs) are tissue-remodeling enzymes that function during the remodeling process, such as in immune-inflammatory diseases. Metalloprotease-2 (MMP-2) and metalloprotease-9 (MMP-9) are gelatinases that degrade several types of extracellular matrix collagen. It is hypothesized that in temporomandibular joint (TMJ) dysfunction, MMP-2 and MMP-9 expression levels may be elevated. Therefore, the objective of this study is to determine the association of MMP-2 and MMP-9 expression with temporomandibular joint dysfunction using an immunohistochemical approach to evaluate the joint disk. MATERIAL AND METHODS: A total of 45 human temporomandibular joint samples were collected, with 36 samples in the test group (patients with anterior disk displacement with reduction (n = 29) and without reduction (n = 7)) and nine samples in the control group. The immunostaining of the TMJ disks was statistically compared between the groups (P < 0.05). RESULTS: There was a statistically significant difference for the area of MMP-2 immunostaining between the control group and the displacement disks with reduction group (ADDwR) (P = 0.048) and between the groups with disk displacement and without reduction (ADDwoR) (P = 0.029). The expression of MMP-2 was significantly elevated in the ADDwoR group. CONCLUSION: No statistically significant difference was found between the variable area of MMP-9 expression in the disk with and without disk displacement, as determined by immunohistochemical analysis. However, there was an elevation of MMP-2 expression in the disks of patients with displacement and without reduction (more severe alteration).

Different contribution of BRINP3 gene in chronic periodontitis and peri-implantitis: a cross-sectional study.

BACKGROUND: Peri-implantitis is a chronic inflammation, resulting in loss of supporting bone around implants. Chronic periodontitis is a risk indicator for implant failure. Both diseases have a common etiology regarding inflammatory destructive response. BRINP3 gene is associated with aggressive periodontitis. However, is still unclear if chronic periodontitis and peri-implantitis have the same genetic background. The aim of this work was to investigate the association between BRINP3 genetic variation (rs1342913 and rs1935881) and expression and susceptibility to both diseases. METHODS: Periodontal and peri-implant examinations were performed in 215 subjects, divided into: healthy (without chronic periodontitis and peri-implantitis, n = 93); diseased (with chronic periodontitis and peri-implantitis, n = 52); chronic periodontitis only (n = 36), and peri-implantitis only (n = 34). A replication sample of 92 subjects who lost implants and 185 subjects successfully treated with implants were tested. DNA was extracted from buccal cells. Two genetic markers of BRINP3 (rs1342913 and rs1935881) were genotyped using TaqMan chemistry. Chi-square (p < 0.05) compared genotype and allele frequency between groups. A subset of subjects (n = 31) had gingival biopsies harvested. The BRINP3 mRNA levels were studied by CT method (2(ΔΔCT)). Mann-Whitney test correlated the levels of BRINP3 in each group (p < 0.05). RESULTS: Statistically significant association between BRINP3 rs1342913 and peri-implantitis was found in both studied groups (p = 0.04). The levels of BRINP3 mRNA were significantly higher in diseased subjects compared to healthy individuals (p = 0.01). CONCLUSION: This study provides evidence that the BRINP3 polymorphic variant rs1342913 and low level of BRINP3 expression are associated with peri-implantitis, independently from the presence of chronic periodontitis.

Association of interleukin 4 gene polymorphisms with dental implant loss.

PURPOSE: The purpose of this study was to investigate the association between interleukin 4 (IL4) polymorphisms/haplotypes and dental implant loss. MATERIALS AND METHODS: Two hundred and seventy eight (n = 278) unrelated patients were divided into 2 groups: (1) control group (C) composed of 186 individuals presenting at least 1 osseointegrated implant and (2) study group (S) composed of 94 individuals presenting at least 1 implant loss. After DNA collection, IL4 polymorphisms were investigated by polymerase chain reaction (PCR)-restriction fragment length polymorphism and for the variable number of tandem repeat (VNTR) only by PCR. RESULTS: No association between alleles/genotypes of -590 (C/T) (P = 0.9704/P = 0.5992) and VNTR (P = 0.7155/P = 0.8789) polymorphisms and implant loss were found between the groups. Regarding +33 (C/T) polymorphism, no difference was found in genotype frequency (P = 0.1288), but the C allele was associated with implant loss (P = 0.0236, odds ratio = 1.61, 95% confidence interval = 1.1-2.4). Haplotype analysis showed no statistical differences between the groups. CONCLUSION: The C allele of the +33 (C/T) polymorphism in the IL4 gene was associated with susceptibility to dental implant loss in Brazilians in the studied population.

Role of TRAV locus in low caries experience.

Caries is the most common chronic, multifactorial disease in the world today; and little is still known about the genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified five loci related to caries susceptibility: 5q13.3, 13q31.1, 14q11.2, 14q 24.3, and Xq27. In the present study, we fine mapped the 14q11.2 locus to identify genetic contributors to caries susceptibility. Four hundred seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. An additional 387 DNA samples from unrelated individuals were used to determine allele frequencies. For replication purposes, a total of 1,446 independent subjects from four different populations were analyzed based on their caries experience (low versus high). Forty-eight markers in 14q11.2 were genotyped using TaqMan chemistry. Transmission disequilibrium test was used to detect over transmission of alleles in the Filipino families, and Chi-square, Fisher's exact and logistic regression were used to test for association between low caries experience and variant alleles in the replication data sets. We finally assessed the mRNA expression of TRAV4 in the saliva of 143 study subjects. In the Filipino families, statistically significant associations were found between low caries experience and markers in TRAV4. We were able to replicate these results in the populations studied that were characteristically from underserved areas. Direct sequencing of 22 subjects carrying the associated alleles detects one missense mutation (Y30R) that is predicted to be probably damaging. Finally, we observed higher expression in children and teenagers with low caries experience, correlating with specific alleles in TRAV4. Our results suggest that TRAV4 may have a role in protecting against caries.

Limited fatty infiltration due to apoptosis in human degenerated temporomandibular joint disks: an immunohistochemical study.

In this study, we hypothesized that caspase 3, which plays a central role in the execution phase of cell apoptosis, could be involved in limiting fatty degeneration of the temporomandibular joint (TMJ) disks and therefore inhibit the TMJ disk tissue from completely degenerating into fatty tissue. Therefore, caspase 3 immunohistochemical expression in human TMJ degenerated disks was studied. Fifty-nine degenerated TMJ disks were stained with Harry's hematoxylin, and they were then examined with light microscopy to detect any pathologic changes typical of fatty degeneration. Sections from the same TMJ disk were immunostained also by a polyclonal anti-caspase 3 antibody. On morphologic observations, 11 disks of 59 degenerated ones also presented a fatty infiltration. Immunostaining with caspase 3 antibody was detected on adipocytes in the cytoplasm as well as the nuclei. Our results sustain the hypothesis that fatty degeneration is limited by apoptosis, being adipocytes immunolabeled by caspase 3 antibody. Hence, apart from the several factors that can trigger degeneration changes in TMJ disk, their appearance, spread, and permanence, at least for fatty degeneration, seem to be influenced by apoptosis.

The broad effects of the functional IL-10 promoter-592 polymorphism: modulation of IL-10, TIMP-3, and OPG expression and their association with periodontal disease outcome.

Periodontal diseases are infectious diseases, in which periodontopathogens trigger chronic inflammatory and immune responses that lead to tissue destruction. It occurs through the generation of metalloproteinases and the activation of bone resorption mechanisms. Anti-inflammatory cytokines such as IL-10 seem to attenuate periodontal tissue destruction through the induction of tissue inhibitors of metalloproteinases (TIMPs) and the inhibitor of osteoclastogenesis osteoprotegerin (OPG). A high individual variation in levels of IL-10 mRNA is verified in periodontitis patients, which is possibly determined by genetic polymorphisms. In this study, the IL-10 promoter -592C/A single nucleotide polymorphism (SNP), which is associated with a decrease in IL-10 production, was analyzed by RFLP in 116 chronic periodontitis (CP) patients and 173 control (C) subjects, and the IL-10, TIMPs, and OPG mRNA expression levels in diseased gingival tissues were determined by real-time-PCR. The IL-10-592 SNP CA (P=0.0012/OR=2.4/CI:1.4-4.1), AA (P=0.0458/OR=2.3/CI:1.1-4.9), and CA+AA (P=0.0006/OR=2.4/CI:1.4-3.4) genotypes and the allele A (P=0.0036/OR=1.7/CI:1.2-2.4) were found to be significantly more prevalent in the CP group when compared with control subjects. Both CA and AA genotypes were associated with lower levels of IL-10, TIMP-3, and OPG mRNA expression in diseased periodontal tissues and were also associated with disease severity as mean pocket depth. Taken together, the results presented here demonstrate that IL10-592 SNP is functional in CP, being associated with lower levels of IL-10 mRNA expression, which is supposed to consequently decrease the expression of the downstream genes TIMP-3 and OPG, and influence periodontal disease outcome.

Genetic susceptibility to dental implant failure: a critical review.

The observation that clinical factors alone do not explain why some patients develop implant loss; the understanding of the osseointegrated implant failure as a complex, multifactorial process; and the observed aggregation of repetitive failure in certain individuals raise interesting questions related to host susceptibility to dental implant failure. Genetic analysis applied to dental implants began in the late 1990s, and since then, increased interest in genetic susceptibility to the phenotype has been demonstrated by several studies. These studies, however, have been based on and limited to candidate gene association analysis and were intended to find associations between specific alleles and/or genotypes of genetic markers and susceptibility to implant failure. The aim of this review is to provide a brief description of the current methodology for genetic analysis of complex traits, followed by a comprehensive review of the literature related to genetic susceptibility to dental implant failure and a discussion of different aspects of the applied methodology. Moreover, a novel approach of genome wide, case-control analysis is discussed as an alternative method to access genetic influence to dental implant failure mechanisms. Advances toward the elucidation of the genetic basis of dental implant loss may contribute to the understanding of why some patients do not respond to currently available treatments while others do and provide potential targets for effective screening, prevention, and treatment. For example, clinicians might be able to estimate, before the elective surgical procedure, the risk of a given patient to develop a negative individual host response.

Analysis of MMP-1 and MMP-9 promoter polymorphisms in early osseointegrated implant failure.

PURPOSE: Polymorphisms, such as a guanine inserted at position -1607 in the promoter region of human matrix metalloprotenase 1 (MMP-1) or a C-1562T substitution in the MMP-9 gene, have been shown to increase the transcriptional activity of these MMPs. The objective of this study was to investigate the possible relationship between these polymorphisms and early implant failure. MATERIALS AND METHODS: Genomic DNA from oral mucosa was amplified by polymerase chain reactions (PCRs) and analyzed by restriction endonucleases. The significance of the differences in observed frequencies of polymorphisms was assessed by the chi-square and Fisher exact tests. RESULTS: The test group comprised patients with early failure of osseointegrated oral implants. In the MMP-1 gene, 2G allele was observed in 25% of the control group and in 50% of the test group (P = .013). The genotype 1G/1G was found in 61.5% of the control group, while all patients in the test group had the genotype 1G/2G (P < .001). No differences were seen in the allele and genotype frequencies in the MMP-9 gene among the groups (P = .15 and P = .13, respectively). DISCUSSION AND CONCLUSION: These results suggest that polymorphism in the promoter region of the MMP-1 gene may be associated with early implant failure, while polymorphism in the promoter region of the MMP-9 gene may not have a relationship with implant loss.

Association among oral health parameters, periodontitis, and its treatment and mortality in patients undergoing hemodialysis.

BACKGROUND: Chronic periodontitis (CP) is a continuous, reversible source of inflammation with a potential impact on mortality in patients undergoing hemodialysis (HD). This study investigates the impact of oral health indicators, CP, and its treatment on survival rates in a group of patients undergoing HD. METHODS: Clinically stable patients undergoing HD were referred for a dental examination. All patients were prospectively followed in the dialysis clinic, and all-cause mortality was recorded. Three groups of patients were analyzed: those who received CP treatment, those who did not, and patients without CP as a control group. RESULTS: A total of 122 patients (79 males and 43 females, aged 23 to 77 years; mean age: 50 years; range: 23 to 77 years) were enrolled. Forty percent reported having rarely been evaluated by a dentist, and 59% had CP. There were 34 fatal events during a mean follow-up time of 64.1 ± 11.2 months. Oral factors associated with death in the univariate analysis were decreased frequency of dental visits; non-use of dental floss; increased decayed, missing, and filled teeth index; presence of CP; and absence of CP treatment. Patients with CP had a higher risk of death from all causes compared with patients without CP in the univariate analysis for untreated patients (hazard ratio 2.65 [95% confidence interval 1.06 to 6.59]; P = 0.036) and to a lesser extent for treated patients (2.36 [1.01 to 5.59]; P = 0.047). These significant differences were not maintained after adjustments for confounders in the multivariate model. CONCLUSIONS: These results suggest that poor oral health, including CP, is a common finding in patients undergoing HD. The results of this study call for intervention trials to test the hypothesis that treatment of CP improves survival in maintenance of patients undergoing HD.

Genetic association study between Interleukin 10 gene and dental implant loss.

OBJECTIVE: Three single nucleotide polymorphisms (SNPs), -1082, -819 and -592, located on the promoter region of IL10 gene have been associated with high in vitro IL-10 production and autoimmune diseases. We aim to investigate whether polymorphisms in the IL10 gene would influence dental implant loss. METHODS: We evaluated a total of 277 unrelated patients, including 185 individuals presenting at least one osseointegrated implant in function for six months or more and with no implant failure, and 92 individuals presenting at least one implant loss. DNA was extracted from buccal mucosa cells and SNPs were genotyped using TaqMan(®) probes-based assays. RESULTS: Multiple logistic regression showed association between dental implant failure with -819(C/T) genotype (OR=3.27; 95% CI=1.02-10.46; p=0.0334). However, considering the statistical significance level α=0.004 (adjusted by Bonferroni correction of multiple comparisons), these results lost their significance. No association of dental implant loss with genotypes and alleles of the -1082 and -592 SNPs, as well as IL10 haplotypes in genotype/allele forms were found (p=0.9400; p=0.8861). CONCLUSIONS: Neither the IL10 gene polymorphisms, nor haplotypes or other covariates were associated with susceptibility to dental implant failure in the studied population.

Analysis of the association of an MMP1 promoter polymorphism and transcript levels with chronic periodontitis and end-stage renal disease in a Brazilian population.

UNLABELLED: Chronic periodontitis (CP) and end-stage renal disease (ESRD) are complex inflammatory conditions. Higher levels of MMP-1 were found in fluids and gingival tissues from CP patients and in the blood and tissues from ESRD patients. MMP1-1607 (1G/2G) is a functional polymorphism, as it alters MMP-1 expression. OBJECTIVE: The aim of this study was to investigate the association of the MMP1-1607 (1G/2G) polymorphism with CP and ESRD and evaluate differences in transcript levels between the groups. DESIGN: A total of 254 individuals were divided into four groups: Group 1, without CP and without chronic kidney disease (CKD) (n = 67); Group 2, with CP and without CKD (n = 60); Group 3, without CP and with CKD stage 5 (ESRD) (n = 52), and Group 4, with CP and with ESRD (n = 75). The MMP1-1607 polymorphism was analysed by PCR-RFLP. MMP1 gene transcripts from gingival tissues were analysed by real-time PCR. RESULTS: No association was found between the MMP1-1607 polymorphism and CP or ESRD. Increased levels of MMP1 transcripts were observed in CP patients with or without ESRD. No differences were observed in the transcript levels according to the genotypes. CONCLUSION: It was concluded that the MMP1-1607 polymorphism was not associated with either CP or ESRD. However, higher levels of MMP1 gene transcripts were found at gingival sites of CP in patients both with and without ESRD.

Enamel formation genes influence enamel microhardness before and after cariogenic challenge.

There is evidence for a genetic component in caries susceptibility, and studies in humans have suggested that variation in enamel formation genes may contribute to caries. For the present study, we used DNA samples collected from 1,831 individuals from various population data sets. Single nucleotide polymorphism markers were genotyped in selected genes (ameloblastin, amelogenin, enamelin, tuftelin, and tuftelin interacting protein 11) that influence enamel formation. Allele and genotype frequencies were compared between groups with distinct caries experience. Associations with caries experience can be detected but they are not necessarily replicated in all population groups and the most expressive results was for a marker in AMELX (p=0.0007). To help interpret these results, we evaluated if enamel microhardness changes under simulated cariogenic challenges are associated with genetic variations in these same genes. After creating an artificial caries lesion, associations could be seen between genetic variation in TUFT1 (p=0.006) and TUIP11 (p=0.0006) with enamel microhardness. Our results suggest that the influence of genetic variation of enamel formation genes may influence the dynamic interactions between the enamel surface and the oral cavity.

Association of IL1 gene polymorphisms with chronic periodontitis in Brazilians.

UNLABELLED: Chronic periodontal disease (PD) is an infectious immune-inflammatory illness. Polymorphisms in IL1 genes play a role in inflammatory diseases through the modulation of cytokine levels. OBJECTIVE: this study aimed to investigate the association between polymorphisms in the IL1 gene cluster and chronic periodontitis in a Brazilian population. DESIGN: a sample of 113 subjects over 25 years (mean age 41.2) were grouped into: 44 healthy individuals, 31 subjects with moderate and 38 with severe periodontitis. DNA was obtained through a mouthwash and oral mucosa scraping. PCR-RFLP was used to identify the following polymorphisms: IL1A C-889T (rs1800587), IL1B C-511T (rs16944), IL1B C+3954T (rs11436340), IL1RN intron 2 (rs2234663). Differences in the allele/genotype/haplotype frequencies were assessed by Chi-square test (p<0.05). The risk associated with alleles, genotypes and haplotypes was calculated as odds ratio (OR) with 95% confidence intervals (CI). RESULTS: neither IL1A (C-889T) nor IL1B (C+3954T) polymorphisms was associated with chronic PD. Allele T for IL1B (C-511T) only associated with PD in the group of blacks and mulattos. Moreover, genotype 2/2 for IL1RN (intron 2) was associated with severe PD. CONCLUSIONS: genotype 2/2 of IL1RN for the whole Brazilian population and allele T of IL1B (C-511T) in a subgroup of Afro-Americans and mulattos were suggested as putative risk indicators for chronic periodontitis.

Occurrence and regional distribution of TRAIL and DR5 on temporomandibular joint discs: comparison of disc derangement with and without reduction.

BACKGROUND: Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is an apoptosis-inducing member of the TNF gene family which triggers apoptotic signals by interaction with its receptors. It has been suggested to be a major contributing factor to tissue degeneration. OBJECTIVE: The present study investigated, through immunohistochemistry, the regional expression of TRAIL and in temporomandibular joint (TMJ) disc of anterior disc displacement with reduction (ADDwR) and without reduction (ADDwoR) patients, to help determine the relationship between TMJ disc displacement and apoptosis. STUDY DESIGN: We studied 18 TMJ diseased discs affected by disc displacement without or with reduction and 4 normal TMJ discs. Specimens were processed for immunohistochemistry to evaluate TRAIL and its receptor DR5 expression. RESULTS: Disc tissues from internal derangements (both ADDwR and ADDwoR) exhibited a much higher percentage of TRAIL- and DR5-positive cells as well as stain intensity compared with normal tissue though with regional variation according to the portion of the disc. There was a significantly higher percentage of stained cells in the posterior disc attachment compared with the anterior or intermediate bands of both ADDwR and ADDwoR discs for TRAIL and DR5. CONCLUSIONS: TRAIL and DR5 are overexpressed in displaced human TMJ disc, especially in the posterior disc attachment. These results suggest a possible pivotal role of the TRAIL/DR5 system in TMJ disc degeneration.

Histologic and histomorphometric analysis of posterior region of the human temporomandibular disc.

OBJECTIVE: The aim of this study was to analyze histologic and histomorphometric features of the articular disc in groups with and without disc displacement. STUDY DESIGN: A sample of 39 temporomandibular joints TMJs (31 case specimens, 8 control specimens) from 28 patients (mean age 31.2 years) were recruited for this study. The patients were considered to be affected and treated surgically with disc repositioning when presenting painful clinical signs of disc displacement after unsuccessful nonsurgical treatment for at least 6 months. Of the control patients, 4 presented condyle fracture which required opening to be reduced for treatment, and 4 displayed active condyle hyperplasia. The posterior region of the disc was removed and sent for histologic and histomorphometric analysis. Histologic (hematoxylin-eosin) and histomorphometric (picro-Sirius red) analyses were performed. Statistically significant differences between the analyzed groups were accessed through the chi-squared test (P

Oral health in Brazilian patients with chronic renal disease.

BACKGROUND: Poor oral health status may have an impact on the health status of patients with chronic renal failure. AIM: To describe the oral health status of a group of Brazilian patients with chronic renal failure. MATERIAL AND METHODS: Retrospective review of the medical records of patients with chronic renal failure, of whom 13 (4.5%) were in a predialysis stage, 158 (55%) were on hemodialysis, 23 (8.4%) were on peritoneal dialysis and 92 (32.1%) were transplanted. General oral health, presence of dental calculus, and halitosis were recorded. The number of decayed, missed and filled teeth was analyzed by means of DMF-T (Decayed, Missed and Filled Teeth) index. RESULTS: The sample was composed of 152 men (53%) and 134 women (47%), aged 42+/-13 years. Oral health status was considered defective in most patients (83%). Eighty-seven percent had dental calculus and 55% had halitosis. Transplant patients reported significantly less halitosis (40.2%) than the rest of the groups. The DMF-T for the whole population was 20.6 and had a positive correlation with age. CONCLUSIONS: This group of patients with chronic renal failure presented a poor oral health status. Dental treatment programs for these patients should be implemented to avoid the exposure to dental pathogens.

Evaluation of the relationship between interleukin-1 gene cluster polymorphisms and early implant failure in non-smoking patients.

OBJECTIVE: The aim of the present study was to investigate the relationship between specific polymorphisms of the interleukin-1 gene cluster and the early failure of osseointegrated implants. MATERIAL AND METHODS: The subject population was composed by a test group comprising 28 non-smoking patients (mean age 52.7) that had suffered one or more early implant failures and by a control group consisting of 34 individuals (mean age 43.3) with one or more healthy implants. Genomic DNA from buccal mucosa was amplified by the polymerase chain reaction (PCR), followed by restriction fragment length polymorphism (RFLP) and submitted to polyacrylamide gel electrophoresis to distinguish the alleles of the interleukin-1A (-889), interleukin-1B (+3953), interleukin-1B (-511) and interleukin-RN (intron 2) gene polymorphisms. Differences in the allele and genotype frequencies between control and test groups were assessed by chi(2) test or by Monte Carlo simulations (P<0.05). Haplotype frequencies, linkage disequilibrium and Hardy-Weinberg equilibrium were also estimated. RESULTS: No statistically significant differences were found in the genotype distribution or allelic frequencies of the polymorphisms. No differences were observed between control and test groups when different interleukin-1 gene cluster haplotypes were compared. Nevertheless, the interleukin-1A (-889) and interleukin-1B (+3953) polymorphic sites were in strong linkage disequilibrium (P=0.00014 for control group and P=0.0238 for the test group). CONCLUSION: This study suggests that polymorphisms in the interleukin-1 gene cluster are not associated with early implant failure in a non-smoking Brazilian population.

Investigation of an IL-2 polymorphism in patients with different levels of chronic periodontitis.

BACKGROUND: Interleukin-2 (IL-2) is a pro-inflammatory cytokine derived from Th1 cells. This cytokine is involved in B-cell activation and stimulates macrophages, natural killer cells, T-cell proliferation and osteoclast activity. IL-2 has been also implicated in the stimulation of osteoclast activity in bone resorption. OBJECTIVE: In this study the relationship between the polymorphism - 330 (T-->G) in the IL-2 gene and different levels of chronic periodontal disease was investigated. MATERIAL AND METHODS: DNA was extracted from buccal epithelial cells of 113 unrelated adult individuals acting as controls and with different levels of periodontitis. The PCR-RFLP technique was used to investigate the polymorphism in the promoter of IL-2 gene. RESULTS: When comparing the data of three groups of patients (Control, Moderate and Severe) we did not find significant differences between the studied IL-2 polymorphism and severity levels of PD. However, when the Control and Moderate phenotypes were grouped together and compared with genotypes TT vs. TG/GG, a significant difference was observed. CONCLUSION: We conclude that the - 330 (T-->G) polymorphism in the IL-2 gene is associated with the severity of periodontal disease. The results presented in this study suggest an active role of IL-2 in the pathogenesis of periodontal disease.