Association of thalassemia major and gingival inflammation: A pilot study

ObjectivesThis cross-sectional study aimed to investigate the relationship between thalassemia major (TM) and gingival inflammation through the salivary, serum, and gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP)-8, MMP-9 and tissue inhibitor of MMP (TIMP)-1.MethodsBiofluid samples and full-mouth clinical periodontal recordings were obtained from 29 otherwise healthy patients with TM and 25 systemically healthy (SH) individuals. Biofluid samples were evaluated by immunofluorometric assay (IFMA) and enzyme-linked immunoassays (ELISAs). Data were tested statistically by Kolmogorov Simirnov, Mann–Whitney U tests, Spearman correlation analysis.ResultsAge, smoking status, bleeding on probing, plaque index were similar in the study groups, but probing depth, gender data exhibited significant differences (p = 0.037 for both). Salivary MMP-8, MMP-9, TIMP-1 concentrations were significantly higher in the TM than SH group (p = 0.014; p < 0.001; p = 0.042, respectively). Serum TIMP-1 concentrations were significantly higher; MMP-8/TIMP-1, MMP-9/TIMP-1 molar ratios were significantly lower in the TM than SH group (p < 0.001; p = 0.005; p = 0.022, respectively). Very few GCF samples revealed biochemical data above the detection limits. Numerous correlations were found between clinical periodontal parameters and biochemical data.ConclusionsIt may be suggested that TM may exacerbate the local inflammatory response as manifested in salivary MMP-8, MMP-9, TIMP-1 levels.     

Randomized clinical trial on effectiveness of silver diamine fluoride and glass ionomer in arresting dentine caries in preschool children

ObjectiveTo compare the effectiveness of annual topical application of silver diamine fluoride (SDF) solution, semi-annual topical application of SDF solution, and annual application of a flowable high fluoride-releasing glass ionomer in arresting active dentine caries in primary teeth.MethodsA total of 212 children, aged 3–4 years, were randomly allocated to one of three groups for treatment of carious dentine cavities in their primary teeth: Gp1-annual application of SDF, Gp2-semi-annual application of SDF, and Gp3-annual application of glass ionomer. Follow-up examinations were carried out every six months to assess whether the treated caries lesions had become arrested.ResultsAfter 24 months, 181 (85%) children remained in the study. The caries arrest rates were 79%, 91% and 82% for Gp1, Gp2 and Gp3, respectively (p = 0.007). In the logistic regression model using GEE to adjust for clustering effect, higher caries arrest rates were found in lesions treated in Gp2 (OR = 2.98, p = 0.007), those in anterior teeth (OR = 5.55, p < 0.001), and those in buccal/lingual smooth surfaces (OR = 15.6, p = 0.004).ConclusionAnnual application of either SDF solution or high fluoride-releasing glass ionomer can arrest active dentine caries. Increasing the frequency of application to every 6 months can increase the caries arrest rate of SDF application.Clinical significanceArrest of active dentine caries in primary teeth by topical application of SDF solution can be enhanced by increasing the frequency of application from annually to every 6 months, whereas annual paint-on of a flowable glass ionomer can also arrest active dentine caries and may provide a more aesthetic outcome.     

Matrix metalloproteinase 8 (MMP8) gene polymorphisms in chronic periodontitis

ObjectivePrevious studies have suggested that some functional polymorphisms in the matrix metalloproteinase (MMPs) genes are associated with the risk of periodontal disease. However, to date no study has investigated MMP8 gene variants in relation to chronic periodontitis (CP). The aim of this study was to analyse polymorphisms in the MMP8 gene and their associations with microbial composition and clinical manifestation of CP.DesignA total of 619 unrelated Czech subjects were included in the present study. Two polymorphisms [?799C/T (rs11225395) and +17C/G (rs2155052)] in the MMP8 gene were studied in 341 patients with CP and 278 unrelated non-periodontitis controls. Both polymorphisms were detected using the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) methods. Subgingival bacterial colonisation (occurrence of bacteria in subgingival pockets and gingival sulci) was investigated by a commercial semiquantitative kit in selected subjects (N = 169).ResultsOur results showed no differences in the allele and genotype frequencies of the MMP8 ?799C/T and +17C/G polymorphisms between patients with CP and controls (p > 0.05). Nevertheless, the haplotype T(?799)/C(+17) was significantly more frequent in patients with CP than in controls [43.7% vs. 37.6%, p < 0.05, OR = 1.273 (95% CI: 1.013–1.601)]. Despite significant differences determined in the occurrence of periodontal bacteria between patients with CP and non-periodontitis controls (from p < 0.000001 to p < 0.05), no significant relationships between periodontal pathogens, MMP8 polymorphisms and CP were found (p > 0.05).ConclusionsAlthough none of the investigated SNPs in the MMP8 gene was individually associated with periodontitis, specific haplotype showed association with clinical manifestation of chronic periodontitis in a Czech population.     

BMP2 and BMP4 variations and risk of non-syndromic cleft lip and palate

ObjectiveNon-syndromic cleft lip with or without cleft palate (CL/P) is one of the most common congenital anomalies and arises from the interaction of environmental and genetic factors. The objective of this study was to investigate the association between the BMP2 (bone morphogenetic protein 2) and BMP4 (bone morphogenetic protein 4) polymorphisms with non-syndromic CL/P to clarify the potential role of these genes in the etiology of CL/P in Iranian population.DesignThe allelic and genotypic frequencies of BMP2 rs235768 A > T and BMP4 rs17563 T > C polymorphisms were determined in 107 unrelated Iranian subjects with non-syndromic CL/P and 186 control subjects using PCR and RFLP methods, and the results were compared with healthy controls. A p-value of <0.05 was considered statistically significant.ResultsThe BMP2 rs235768 AT genotype was significantly higher (P = 0.009, OR = 3, 95% CI = 1.3–7.0) in the CL/P (59.8%) than the control group (33.3%). Similarly, the BMP4 rs17563 TC genotype were significantly higher (P = 0.008, OR = 3.7, 95% CI = 1.4–9.9) in the CL/P (70.0%) than the control group (44.6%).ConclusionThe BMP2 rs235768 A > T and BMP4 rs17563 T > C polymorphisms could be considered as the risk factor for non-syndromic CL/P in Iranian population.     

The association of Enamelin,Lactoferrin, and Tumour necrosis factor alpha gene polymorphisms with high caries susceptibility in Chinese children under 4 years old

ObjectiveThe aim of this study was to assess the role of ENAM rs3796703, LTF rs1126478, and TNF-α rs1800629 in high caries susceptibility.DesignThe present case–control study included 1005 unrelated children under 4 years old: 505 with severe caries (dmft index ≥4) and 500 who were caries-free (dmft index = 0 and without white-spot lesions). Questionnaires were obtained from parents and gardians about the children’s diet and oral behavioural habits. All the children received dental examinations and oral swabbing for human genomic DNA collection. ENAM rs3796703, LTF rs1126478, and TNF-α rs1800629 were genotyped by Sanger sequencing.ResultsThe frequency of the ENAM rs3796703 T allele (6.7% in the caries group and 4.2% in the caries-free group), CT genotype (12.7% in the caries group and 8.4% in the caries-free group), TNF-α rs1800629 A allele (4.8% in the caries group and 6.8% in the caries-free group), and AG genotype (8.7% in the caries group and 13.2% in the caries-free group) were significantly different between the caries and caries-free groups (p < 0.05). No significant difference was found in the LTF rs1126478 allele frequency and genotype distribution between the two groups. The ENAM rs3796703 CT genotype increased caries susceptibility by 60.9% compared to the CC genotype (β = 0.746, OR = 1.609), and the TNF-α rs1800629 AG genotype reduced caries susceptibility by 47.4% compared to the GG genotype (β = −0.642, OR = 0.526). In terms of habits covariates, prolongation of night feeding time by 1 month increased caries susceptibility by 3.3% (β = 0.033, OR = 1.033); additionally, sweets and acidic drinks consumption 1–2 times per day increased caries susceptibility by 218.2% (β = 1.158, OR = 3.182), and consumption 3 or more times pe/r day increased susceptibility by 883.5% (β = 2.286, OR = 9.835) compared to non-consumption. Topical fluoride application decreased caries susceptibility by 43.0% (β = −0.562, OR = 0.570).ConclusionsThe ENAM and TNF-α genes are likely associated with caries experience in Chinese children. The ENAM rs3796703 CT genotype might be involved in caries susceptibility, while TNF-α rs1800629 AG genotype might be involved in caries protection.     

Probiotic intervention influences the salivary levels of Matrix Metalloproteinase (MMP)-9 and Tissue Inhibitor of metalloproteinases (TIMP)-1 in healthy adults

ObjectiveTo study the effect of orally administered Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus rhamnosus GG on the salivary levels of Matrix Metalloproteinases (MMP)-8, MMP-9 and of Tissue Inhibitor of Metalloproteinases (TIMP)-1 in healthy adults. Furthermore, the correlations between MMP-8, MMP-9 and TIMP-1 and plaque and gingival indices, salivary mutans streptococci and lactobacilli counts, and stimulated saliva secretion rate were analysed.DesignThe salivary samples originated from a randomized controlled trial where healthy student volunteers consumed probiotic or placebo lozenges twice a day for four weeks. The saliva samples were collected and clinical parameters measured at the baseline and at the end of the original study. For this study, the salivary levels of MMP-8, MMP-9 and TIMP-1 were analysed with immunofluorometric assay (IFMA) and enzyme-linked immunosorbent assay (ELISA).ResultsIn the probiotic group (n = 29), salivary MMP-9 levels increased (p < 0.01) and TIMP-1 levels decreased (p < 0.01) significantly during the intervention. Furthermore, MMP-9/TIMP-1 ratio differed significantly from the baseline level (p < 0.01). These changes were not observed in the control group (n = 31). In the whole data, salivary MMP-9 and gingival index correlated (r = 0.260, p < 0.05 at baseline and r = 0.354, p < 0.01 at the end of the study). Intergroup differences or correlations with other clinical parameters were not found. Probiotic consumption did not affect the saliva flow rate.ConclusionsIncreased MMP-9 and decreased TIMP-1 levels in saliva may indicate that probiotics have immunomodulatory effects in the oral cavity. Furthermore, increased salivary MMP-9 levels may be an indication of the defensive potential of matrix metalloproteinases.     

Are clustering effects accounted for in statistical analysis in leading dental specialty journals?

ObjectivesIn dental research multiple site observations within patients or taken at various time intervals are commonplace. These clustered observations are not independent; statistical analysis should be amended accordingly. This study aimed to assess whether adjustment for clustering effects during statistical analysis was undertaken in five specialty dental journals.MethodsThirty recent consecutive issues of Orthodontics (OJ), Periodontology (PJ), Endodontology (EJ), Maxillofacial (MJ) and Paediatric Dentristry (PDJ) journals were hand searched. Articles requiring adjustment accounting for clustering effects were identified and statistical techniques used were scrutinized.ResultsOf 559 studies considered to have inherent clustering effects, adjustment for this was made in the statistical analysis in 223 (39.1%). Studies published in the Periodontology specialty accounted for clustering effects in the statistical analysis more often than articles published in other journals (OJ vs. PJ: OR = 0.21, 95% CI: 0.12, 0.37, p < 0.001; MJ vs. PJ: OR = 0.02, 95% CI: 0.00, 0.07, p < 0.001; PDJ vs. PJ: OR = 0.14, 95% CI: 0.07, 0.28, p < 0.001; EJ vs. PJ: OR = 0.11, 95% CI: 0.06, 0.22, p < 0.001). A positive correlation was found between increasing prevalence of clustering effects in individual specialty journals and correct statistical handling of clustering (r = 0.89).ConclusionsThe majority of studies in 5 dental specialty journals (60.9%) examined failed to account for clustering effects in statistical analysis where indicated, raising the possibility of inappropriate decreases in p-values and the risk of inappropriate inferences.     

Sleep bruxism and related risk factors in adults: A systematic literature review

ObjectiveThe aim of this article was to systematically review the literature to assess the relationship between risk factors and sleep bruxism (SB) in adults (age ≥18 years).DesignA systematic search of the following databases was carried out: PubMed, Embase, Scopus, Cochrane Oral Health Group’s Trial Register and Cochrane Register of Controlled Trials, Web of Science, LILACs and SciELO. Nine out of the 4583 initially identified articles were selected. This review was conducted according to the guidelines from the Cochrane Handbook for Systematic Reviews of Interventions, with reporting in agreement to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.ResultsAmong the nine analyzed articles, associations between SB and gastro-esophageal reflux disease (GERD) (OR = 6.6, CI = 1.4–30.9) was found in one randomized clinical trial (RCT). Four cross-sectional studies suggested history of SB during childhood (OR = 8.1 CI = 5.4–12–2), age (OR = 3.1, CI = 2.3–4.1) and chronic migraine (OR = 3.8, C.I = 1.8–7.8) as determinant factors for the development of SB. In one case-control study, patients with genetic polymorphisms were more likely to present SB (OR = 4.3, CI = 1.6–11.3). Smoking (OR = 2.8, CI = 2.2–3.5) and alcohol intake (OR = 1.9, CI = 1.2–2.8) showed moderate association in two case-control studies.ConclusionsHistory of SB during childhood, gastro-esophageal reflux disease and genetic polymorphisms seem to be important risk factors associated to SB in adults. Dry mouth on awakening seems to be a protective factor. Association does not infer with causality. Even if the evidence emerged from the considered studies was clinically relevant, further studies are requested to better understand the biological mechanisms behind the described associations.     

Positional factors affecting the bond failure rates in orthodontic treatment: A systematic review and meta-analysis

PurposeThe purpose of this study was to make a systematic review and meta-analysis of studies investigated the effects of positional factors on the bonding failure of brackets.MethodsElectronic databases (PubMed, Web of science, Scopus) were searched by 3 independent researchers. Randomized studies comparing maxilla-mandibular region, anterior–posterior segments, and right-left arch were included in the meta-analysis. The odds ratio was used as the effect size. A two-tailed test was performed to compare the factors. Heterogeneity was calculated with the Cochran Q test and I² statistics.ResultsAssociation was found between bonding failure and dental regions (OR = 1.24, 95% CI: 1.05, 1.46) (p = 0.009) and between bonding failure and anterior–posterior segments, too (OR = 1.96, 95% CI: 1.58, 2.45) (p < 0.001). But, no association was found bonding failure and arch sides (OR = 1.11, 95% CI: 0.96, 1.29) (p = 0.26).ConclusionClinicians should more care, especially when operating in the mandibular region and posterior segment. However, there is no difference between the left and right arch in terms of the loss of the bracket.     

Human neutrophil peptide-1 affects matrix metalloproteinase-2, -8 and -9 secretions of oral squamous cell carcinoma cell lines in vitro

ObjectivesThe present study aimed to investigate the effect of HNP-1 on the matrix metalloproteinase (MMP)-2, -8 and -9 secretions of two oral squamous cell carcinoma (OSCC) cell lines (UT-SCC-43A and UT-SCC-43B).DesignIn all experiments, the two OSCC cell lines were incubated with graded concentrations (0, 1, 5, and 10 μg/ml) of HNP-1 for 24 and 48 h. Cell viability was measured using a colorimetric proliferation test and cell death was analyzed with a colorimetric cytotoxicity detection kit. Enzyme activity of MMP-2 and MMP-9 was detected by using gelatin zymography, and molecular weight forms of MMP-8 were determined by Western-blot and a densitometric quantitation method.ResultsBoth cell lines showed a significant increase in LDH toxicity at 24 h (UT-SCC-43A: p = 0.005 & UT-SCC-43B: p = 0.014). Reduced gelatinolytic activities of proMMP-2 were detected in UT-SCC-43B cell line after 24 and 48 h of incubation with HNP-1 (1 μg/ml: p < 0.001, 5 μg/ml: p < 0.001, and 10 μg/ml: p = 0.0225). MMP-8 levels of both cell lines decreased at 200–250 kDa after 24 h of incubation, while after 48 h only UT-SCC-43B decreased at 45–50 kDa.ConclusionsOur results indicate that HNP-1 suppresses the secretion of MMP-2, -8, and -9 in OSCC cell lines.     

Genes expressed in dental enamel development are associated with molar-incisor hypomineralization

Genetic disturbances during dental development influence variation of number and shape of the dentition. In this study, we tested if genetic variation in enamel formation genes is associated with molar-incisor hypomineralization (MIH), also taking into consideration caries experience. DNA samples from 163 cases with MIH and 82 unaffected controls from Turkey, and 71 cases with MIH and 89 unaffected controls from Brazil were studied. Eleven markers in five genes [ameloblastin (AMBN), amelogenin (AMELX), enamelin (ENAM), tuftelin (TUFT1), and tuftelin-interacting protein 11 (TFIP11)] were genotyped by the TaqMan method. Chi-square was used to compare allele and genotype frequencies between cases with MIH and controls. In the Brazilian data, distinct caries experience within the MIH group was also tested for association with genetic variation in enamel formation genes. The ENAM rs3796704 marker was associated with MIH in both populations (Brazil: p = 0.03; OR = 0.28; 95% C.I. = 0.06–1.0; Turkey: p = 1.22e?012; OR = 17.36; 95% C.I. = 5.98–56.78). Associations between TFIP11 (p = 0.02), ENAM (p = 0.00001), and AMELX (p = 0.01) could be seen with caries independent of having MIH or genomic DNA copies of Streptococcus mutans detected by real time PCR in the Brazilian sample. Several genes involved in enamel formation appear to contribute to MIH.     

Genetic and immunological markers predict titanium implant failure: a retrospective study

This study evaluates diagnostic markers to predict titanium implant failure. Retrospectively, implant outcome was scored in 109 subjects who had undergone titanium implant surgery, IL1A ?889 C/T (rs1800587), IL1B +3954 C/T (rs1143634), IL1RN +2018 T/C (rs419598) and TNFA ?308 G/A (rs1800629) genotyping, in vitro IL-1β/TNF-α release assays and lymphocyte transformation tests during treatment. TNF-α and IL-1β release on titanium stimulation were significantly higher among patients with implant loss (TNF-α: 256.89 pg/ml vs. 81.4 pg/ml; p < 0.0001; IL-1β: 159.96 pg/ml vs. 54.01 pg/ml; p < 0.0001). The minor alleles of the studied polymorphisms showed increased prevalence in the implant failure group (IL1A: 61% vs. 42.6% in controls, IL1B: 53.7% vs. 39.7% in controls, TNFA: 46.3% vs. 30.9% in controls, IL1RN: 58.5% vs. 52.9% in controls). Increasing numbers of risk genotypes of the studied polymorphisms were associated with an increasing risk of implant loss, suggesting an additive effect. Multiple logistic regression analysis showed positive IL-1β/TNF-α release assay scores (p < 0.0001, OR = 12.01) and number of risk genotypes (p < 0.046, OR = 1.57–6.01) being significantly and independently associated with titanium implant failure. IL-1/IL1RN/TNFA genotyping and cytokine release assay scores provide prognostic markers for titanium implant outcome and may present new tools for individual risk assessment.     

Association study for the role of Matrix metalloproteinases 2 and 3 gene polymorphisms in dental caries susceptibility

ObjectiveVarious exogenous and endogenous risk factors have been described as contributing to dental caries susceptibility. In the last decade it has been established that both pro and active forms of host derived Matrix metalloproteinases (MMPs) are present in the oral cavity. MMPs role in caries development has been hypothesized. The aim of this study was to analyse MMP2 (rs2287074) and MMP3 (rs679620) single nucleotide polymorphisms (SNPs) and their role in caries susceptibility.DesignThe two SNPs were analysed by PCR- restriction fragment length polymorphism (RFLP) in a sample of 102 ethnic Bulgarian volunteers (42 males and 60 females), all students in Sofia Medical University.ResultsStatistical analysis of the MMP2 SNP showed significant differences for the genotype frequencies between the caries free (CF, DMFT = 0) and low caries experience (LCE, DMFT ≤ 5) groups. Analysis for the non-synonymous MMP3 SNP found significant differences between both CF vs caries experience groups (LCE+ high caries experience (HCE, DMFT ≥ 5)) and LCE vs HCE groups. The presence of allele G decreased the risk of HCE about 4 times.ConclusionsMMP2 and MMP3 genes are likely to be involved in caries susceptibility in our population. However, as dental caries is a multifactorial disorder and several genes are likely to have influence on it, it is reasonable to expect that SNPs, even those proven to be functional like rs679620, potentially play a significant, but not major role in the disease outcome.     

DEFB1 polymorphisms and salivary hBD-1 concentration in Oral Lichen Planus patients and healthy subjects

ObjectivesThe aetiology of Oral Lichen Planus (OLP), a chronic inflammatory disease of oral mucosa, is not yet well understood. Since innate immunity may be hypothesized as involved in the susceptibility to OLP, we studied human beta defensin 1 (hBD-1) an antimicrobial peptide constitutively expressed in the saliva, looking at functional genetic variants possibly able to diminish hBD-1 production an consequently conferring major susceptibility to OLP.DesignWe analysed three DEFB1 polymorphisms at 5′ UTR, −52G > A (rs1799946), −44C > G (rs1800972), −20G > A (rs11362) and two DEFB1 polymorphisms at 3′UTR, c*5G > A (rs1047031), c*87A > G (rs1800971), with the aim of correlating these genetic variants and hBD-1 salivary level in a group of OLP patients and in healthy subjects. We also evaluated hBD-1 salivary concentrations, using ELISA, in OLP and healthy controls.ResultsWe compared hBD-1 concentrations in OLP and healthy subjects: hBD-1 concentration was significantly higher in OLP patients respect to control.When considering the correlation between DEFB1 polymorphisms genotypes and hBD-1 expression levels, significant results were obtained for SNPs −52G > A (p = 0.03 both in OLP patients and healthy individuals) and −44C > G (p = 0.02 in OLP patients).ConclusionshBD-1 production was different between OLP and healthy subjects (not age-matched with OLP). DEFB1 gene polymorphisms, −52G > A and −44C > G, correlated with hBD-1 salivary concentrations.     

Interleukin-1 receptor antagonist polymorphism (rs2234663) and periodontitis susceptibility: a meta-analysis

ObjectiveThe results of recent published studies focusing on interleukin-1 receptor antagonist (IL-1RN) gene variable number of tandem repeats (VNTR) polymorphism in periodontitis susceptibility are often conflicting. We performed a meta-analysis in order to investigate the potential association of IL-1RN VNTR polymorphism with susceptibility to either chronic (CP) or aggressive (AgP) periodontitis.DesignNineteen studies involving a total of 2011 cases and 1719 controls were searched without any language restriction. Odds ratios (ORs) along with their 95% confidence intervals (CIs) were calculated to compare the distribution of alleles and genotypes between cases and controls. Both fixed and random effects models were used to pool the data.ResultsThe IL-1RN VNTR polymorphism was marginally associated with an elevated risk of CP in overall populations (22 versus LL (L means the long alleles): OR = 1.47, 95% CI 1.00–2.18, p = 0.05), and the association was consistently significant in severe CP subgroup (OR = 4.02, 95% CI 1.84–8.80, p < 0.0005). Further stratified analysis restricted to Hardy–Weinberg equilibrium studies showed evidence for an increased risk with CP in Asians (2 allele versus L allele: OR = 1.82, 95% CI 1.31–2.54, p < 0.0005), however, a decreased risk with AgP in Caucasians (L2 versus LL: OR = 0.50, 95% CI 0.32–0.78, p = 0.002).ConclusionsThis meta-analysis suggested that IL-1RN VNTR polymorphism might contribute to an increased risk on CP and a decreased risk on AgP. However, further well-designed studies with large sample size are needed to determine the robustness of these observations in different populations.     

Influence of a Brazilian wild green propolis on the enamel mineral loss and Streptococcus mutans’ count in dental biofilm

ObjectiveThis study investigated the anti-demineralizing and antibacterial effects of a propolis ethanolic extract (EEP) against Streptococcus mutans dental biofilm.DesignBlocks of sound bovine enamel (n = 24) were fixed on polystyrene plates. S. mutans inoculum (ATCC 25175) and culture media were added (48 h–37 °C) to form biofilm. Blocks with biofilm received daily treatment (30 μL/1 min), for 5 days, as following: G1 (EEP 33.3%); G2 (chlorhexidine digluconate 0.12%); G3 (ethanol 80%); and G4 (Milli-Q water). G5 and G6 were blocks without biofilm that received only EEP and Milli-Q water, respectively. Final surface hardness was evaluated and the percentage of hardness loss (%HL) was calculated. The EEP extract pH and total solids were determined. S. mutans count was expressed by log₁₀ scale of Colony-Forming Units (CFU/mL). One way ANOVA was used to compare results which differed at a 95% significance level.ResultsG2 presented the lowest average %HL value (68.44% ± 12.98) (p = 0.010), while G4 presented the highest (90.49% ± 5.38%HL) (p = 0.007). G1 showed %HL (84.41% ± 2.77) similar to G3 (87.80% ± 6.89) (p = 0.477). Groups G5 and G6 presented %HL = 16.11% ± 7.92 and 20.55% ± 10.65; respectively (p = 0.952). G1 and G4 differed as regards to S. mutans count: 7.26 ± 0.08 and 8.29 ± 0.17 CFU/mL, respectively (p = 0.001). The lowest bacterial count was observed in chlorhexidine group (G2 = 6.79 ± 0.10 CFU/mL) (p = 0.043). There was no difference between S. mutans count of G3 and G4 (p = 0.435). The EEP showed pH 4.8 and total soluble solids content = 25.9 Brix.ConclusionThe EEP seems to be a potent antibacterial substance against S. mutans dental biofilm, but presented no inhibitory action on the de-remineralization of caries process.     

Vertical and horizontal polymerization shrinkage in composite restorations

ObjectivePolymerization shrinkage developed in vertical and horizontal directions after light activation of light-curing composite restorative materials. The purpose of this study was to examine the effects of vertical and horizontal polymerization shrinkage on: (a) dimensional changes of resin composites in tooth cavities; (b) shear bond strengths to enamel and dentin; and (c) marginal gap width in a non-reacting Teflon mold.MethodsVertical and horizontal polymerization shrinkage in tooth cavities were measured immediately (3 min) after light activation. With the same time lapse, shear bond strengths to enamel and dentin and marginal gap widths in Teflon mold were also measured.ResultsThere was a significant correlation between vertical and horizontal polymerization shrinkage (r = 0.647, p = 0.043) in the tooth cavity. Composite materials which produced small vertical shrinkage also produced smaller horizontal shrinkage. Composite materials which produced small vertical shrinkage in the tooth cavity exhibited greater shear bond strengths to both enamel (r = −0.697, p = 0.025) and dentin (r = −0.752, p = 0.012). Composite materials which produced smaller horizontal shrinkage produced smaller marginal gap widths in the Teflon mold (r = 0.829, p = 0.003). No relationships were observed between horizontal shrinkage in the tooth cavity and shear bond strengths to both enamel and dentin (p > 0.05).SignificanceDuring the early stage of setting (<3 min) in tooth cavities, the vertical shrinkage of light-activated composite restorative materials was correlated with horizontal shrinkage.     

Repair genes expression profile of MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers

ObjectiveThe aim of this study was to evaluate the effect of chronic smoking on the expression profile of the repair genes MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers and never smokers.Materials and methodsThe sample consisted of thirty exfoliative cytology smears per group obtained from Smokers and Never Smokers. Total RNA was extracted and expression of the MLH1, MSH2 and ATM genes were evaluated by quantitative real-time and immunocytochemistry. The gene and protein expression data were correlated to the clinical data. Gene expression was analyzed statistically using the Student t-test and Pearson’s correlation coefficient, with p < 0.05.ResultsMLH1, MSH2 and ATM genes were downregulated in the smoking group compared to the control with significant values for MLH1 (p = 0.006), MSH2 (p = 0.0001) and ATM (p = 0.0001). Immunocytochemical staining for anti-MLH1, anti-MSH2 and anti-ATM was negative in Never Smokers; in Smokers it was rarely positive. No significant correlation was observed among the expression of MLH1, MSH2, ATM and age, number of cigarettes consumed per day, time of smoking during life, smoking history or levels of CO in expired air.ConclusionThe expression of genes and proteins related to DNA repair mechanism MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers was reduced.     

Study of the participation of MMP-7, EMMPRIN and cyclophilin A in the pathogenesis of periodontal disease

Background and objectivePeriodontal disease is an infectious disease resulting from the immunoinflammatory response of the host to microorganisms present in the dental biofilm which causes tissue destruction. The objective of this study was to evaluate the immunohistochemical expression of matrix metalloproteinase 7 (MMP-7), extracellular matrix metalloproteinase inducer (EMMPRIN) and cyclophilin A (CypA) in periodontal disease.DesignGingival tissue samples were divided as follows: clinically healthy gingiva (n = 32), biofilm-induced gingivitis (n = 28), and chronic periodontitis (n = 30). Histological sections of 3 μm were submitted to immunoperoxidase method and undergone quantitative analysis. The results were analyzed statistically by the Mann-Whitney and Spearman correlation tests, with the level of significance set at 0.05 (α = 0.05).ResultsImmunopositivity for MMP-7, EMMPRIN and CypA differed significantly between the three groups, with higher percentages of staining in chronic periodontitis specimens, followed by chronic gingivitis and healthy gingiva specimens (p < 0.05). Immunoexpression of CypA and MMP-7 was higher in the intense inflammatory infiltrate observed mainly in cases of periodontitis (p < 0.05). CypA expression was positively correlated with MMP-7 (r = 0.831; p < 0.001) and EMMPRIN (r = 0.289; p = 0.006). In addition, there was a significant positive correlation between probing depth and expression of MMP-7 (r = 0.726; p < 0.001), EMMPRIN (r = 0.345; p = 0.001), and CypA (r = 0.803; p < 0.001).ConclusionThese results suggest that MMP-7, EMMPRIN and CypA are associated with the pathogenesis and progression of periodontal disease.     

Frequency of periodontal pathogens in equivalent peri-implant and periodontal clinical statuses

ObjectivesThis study tested the hypotheses that there is: (1) higher bacterial frequency in peri-implantitis/periodontitis, followed by mucositis/gingivitis and peri-implant/periodontal health; (2) similar bacterial frequency between comparable peri-implant and periodontal clinical statuses.Design of studyThe presence of Porphyromonas gingivalis, Tannerella forsythia, Campylobacter rectus, Prevotella intermedia, Treponema denticola and Aggregatibacter actinomycetemcomitans was evaluated in peri-implant (n = 53) and periodontal (n = 53) health; mucositis (n = 50), gingivitis (n = 50), peri-implantitis (n = 50) and periodontitis (n = 50).ResultsThe pattern of peri-implant bacterial frequency was not as expected (peri-implantitis > mucositis > health). Except for P. intermedia (p > 0.05), bacterial frequency was higher in peri-implantitis than health (p < 0.05). The frequency of P.gingivalis and red complex species were higher in peri-implantitis than mucositis (p < 0.05). In periodontal samples, T. forsythia and T. denticola showed the expected pattern of frequency (periodontitis > gingivitis > health). The frequencies of C. rectus and T. forsythia were higher in healthy teeth/gingivitis than healthy implants/mucositis, respectively (p < 0.05). The frequency of P. gingivalis and A. actinomycetemcomitans were similar between periodontitis and peri-implantitis (p > 0.05) while all other species occurrences were higher in periodontitis than peri-implantitis (p < 0.05).ConclusionsBacterial frequency increased from peri-implant/periodontal health to peri-implantitis/periodontitis but not from mucositis/gingivitis to peri-implantitis/periodontitis. There was a trend towards higher bacterial frequency in teeth than implants.