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.     

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.     

Relationship between the IgA antibody response against Streptococcus mutans GbpB and severity of dental caries in childhood

ObjectiveExplore the associations between the severity of dental caries in childhood, mutans streptococci (MS) levels and IgA antibody response against Streptococcus mutans GbpB. Moreover, other caries-related etiological factors were also investigated.Design36–60 month-old children were grouped into Caries-Free (CF, n = 19), Early Childhood Caries (ECC, n = 17) and Severe Early Childhood Caries (S-ECC, n = 21). Data from socio-economic-cultural status, oral hygiene habits and dietary patterns were obtained from a questionnaire and a food-frequency diary filled out by parents. Saliva was collected from children for microbiological analysis and detection of salivary IgA antibody reactive with S. mutans GbpB in western blot.ResultsS-ECC children had reduced family income compared to those with ECC and CF. There was difference between CF and caries groups (ECC and S-ECC) in MS counts. Positive correlations between salivary IgA antibody response against GbpB and MS counts were found when the entire population was evaluated. When children with high MS counts were compared, S-ECC group showed significantly lower IgA antibody levels to GbpB compared to CF group. This finding was not observed for the ECC group.ConclusionsThis study suggests that children with S-ECC have reduced salivary IgA immune responses to S. mutans GbpB, potentially compromising their ability to modify MS infection and its cariogenic potential. Furthermore, a reduced family income and high levels of MS were also associated with S-ECC.     

The clinicopathologic relevance of RECK gene polymorphisms in ameloblastoma

ObjectiveTo investigate the relationship between RECK gene polymorphisms and the clinicopathologic features of ameloblastoma.DesignNormal gingival mucosa specimens were obtained from 10 healthy volunteers. Ameloblastomas were surgically removed from 30 patients and part of the tumor specimens were used to detect RECK gene polymorphisms by using PCR-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing analysis. Expression of RECK and MMP-9 protein was measured using western blot.ResultsThe overall SNP rate was 46.7% (14/30). Four polymorphisms were detected in exon 9, 11, 13, 15 of the RECK gene: two synonymous (P520P and R625R) and two missense SNPs (V275I and I395 V). RECK protein expression in specimens with minor RECK SNPs was lower than that in specimens without RECK SNPs (P < 0.05), and, RECK protein expression in specimens with and without RECK SNPs was lower than that in the normal gingiva specimens (P < 0.05). MMP-9 protein expression in specimens with minor RECK SNPs was higher than that in specimens without RECK SNPs (P < 0.05), and MMP-9 protein expression in specimens with and without RECK SNPs was higher than that in normal gingiva specimens (P < 0.05). RECK gene polymorphisms were closely associated with active proliferation, capsular invasion, and clinical recurrence of ameloblastoma.ConclusionThe rs16932912(G/A) SNP in the RECK gene was closely associated with active proliferation, capsular invasion, and clinical recurrence of ameloblastoma. RECK protein expression was closely associated with the presence of the rs16932912(G/A) SNP.     

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.     

Rs12941170 at SOX9 gene associated with orofacial clefts in Chinese

ObjectiveNon-syndromic orofacial cleftings (NSOCs) are considered as complex trait, which results from genetic and/or environmental modifiers. Current findings could only explain small portion of the NSOCs. SOX9 gene plays an important role during craniofacial development in animal models and the Pierre Robin sequence (PRS). However, its role in non-syndromic clefts remains unknown.DesignIn this study, we selected eight SNPs in and around SOX9 gene to make maximum coverage, and genotyped them by using RFLP-PCR and ligase detection reaction (LDR) methods to test its associations among 151 NSOCs (53 NSCLP, 52 NSCLO and 46 NSCPO) from Western Han Chinese population.ResultsAllelic TDT results showed that G allele at rs12941170 of SOX9 was under-transmitted among NSOCs (p = 0.00014, OR = 0.55 and 95%CI: 0.40–0.75), which could indicate that the G allele is protective against NSOCs; parent-of-origin effect analysis showed that G allele at rs12941170 was maternally under-transmitted (p = 0.002), while there was no statistically difference between the maternal and paternal transmission of it. To test if the adjacent SNPs travel together from parents to the affected individual, we carried out the sliding window haplotype analysis, it is interesting to find that the haplotypes carrying the G allele at rs12941170 also was under-transmitted for NSOCs, NSCL/P, NSCLP and NSCPO (lowest p = 0.00033).ConclusionsThis study suggested that G allele at rs12941170 was protective, which could decrease the risk for NSOCs from Western Han Chinese population, and it will provide new reference for future research and genetic counseling in NSOCs.     

Inhibition of endogenous human dentin MMPs by Gluma

ObjectiveThe objective of this study was to determine if Gluma dentin desensitizer (5.0% glutaraldehyde and 35% HEMA in water) can inhibit the endogenous MMPs of dentin matrices in 60 s and to evaluate its effect on dentin matrix stiffness and dry mass weight.MethodsDentin beams of 2 mm × 1 mm × 6 mm were obtained from extracted human third molars coronal dentin. To measure the influence of Gluma treatment time on total MMP activity of dentin, beams were dipped in 37% phosphoric acid (PA) for 15 s and rinsed in water. The acid-etched beams were then dipped in Gluma for 5, 15, 30 or 60 s, rinsed in water and incubated into SensoLyte generic MMP substrate (AnaSpec, Inc.) for 60 min. Controls were dipped in water for 60 s. Additional beams of 1 mm × 1 mm × 6 mm were completely demineralized in 37% PA for 18 h, rinsed and used to evaluate changes on the dry weight and modulus of elasticity (E) after 60 s of Gluma treatment followed by incubation in simulated body fluid buffer for 0, 1 or 4 weeks. E was measured by 3-pt flexure.ResultsGluma treatment inhibited total MMP activity of acid-etched dentin by 44, 50, 84, 86% after 5, 15, 30 or 60 s of exposure, respectively. All completely demineralized dentin beams lost stiffness after 1 and 4 weeks, with no significant differences between the control and Gluma-treated dentin. Gluma treatment for 60 s yielded significantly less dry mass loss than the control after 4 weeks.SignificanceThe use of Gluma may contribute to the preservation of adhesive interfaces by its cross-linking and inhibitory properties of endogenous dentin MMPs.     

The absence of an association between Interleukin 1β gene polymorphisms and recurrent aphthous stomatitis (RAS)

ObjectivesRecurrent aphthous stomatitis (RAS) is a chronic, ulcerative disease with a probable polygenic mode of inheritance and complex etiology with a strong immunological background. The aim of the present study was to determine the possible association between two single nucleotide polymorphisms (SNPs) of the IL-1β gene: IL-1β − 511 T > C (rs16944) and IL-1β + 3954C > T (rs1143634) and RAS susceptibility in a moderately large group of patients.DesignOne hundred and four patients with minor, major and herpetiform RAS and 75 healthy volunteers were genotyped at IL-1β − 511 T > C (rs16944) and IL-1β + 3954C > T (rs1143634) using the PCR-RFLP approach. The results were statistically analysed with chi-square test and test of difference between two rates of structure, with p < 0.05 assumed to be a statistically significance level (Statistica 10, StatSoft^®, Kraków, Poland).ResultsThere were no statistically significant differences in the genotype distribution for the IL-1β C[+3954]T polymorphism between the RAS and control groups. The frequency of IL-1β*T[-511]/*T[–511] homozygotes among the patients was significantly higher when compared to our study control (p < 0.0347). The results after stratification into carriers and non-carriers of C and T alleles did not clearly indicate which SNP may be considered a risk factor for RAS.ConclusionsThe genetic association between the studied SNPs of the IL-1β gene and RAS remains controversial and requires further investigation.     

Quantitative assessment of salivary oral bacteria according to the severity of dental caries in childhood

This study aimed to assess differences in selected oral bacteria in children according to the severity of dental caries. One hundred and thirty-six children, 36–60 months old were divided into three groups according to caries status: caries-free (CF) (n = 47), early childhood caries (ECC) (n = 40) and severe-early childhood caries (S-ECC) (n = 49). Saliva was collected for detection and quantification of selected oral streptococci, Actinomyces naeslundii, Lactobacillus spp., Bifidobacterium spp., and Scardovia wiggsiae by quantitative-polymerase chain reaction. The results showed that the detection and quantitative levels of S. mutans, S. sobrinus, Bifidobacterium spp. and S. wiggsiae were significantly higher in S-ECC children compared to CF and ECC children, while for S. salivarius were significantly higher in CF compared to ECC and S-ECC children. There was no statistical difference among the clinical groups for S. mitis, S. oralis, A. naeslundii and Lactobacillus spp. levels and detection. S-ECC children had a lower monthly family income, started tooth brushing later and were breastfeed for a longer duration compared to CF children. S. mutans levels were positively correlated with S. wiggsiae and Bifidobacterium spp. levels, lower mother’s education and child bottle-feeding before sleeping and negatively correlated with S. salivarius. It was concluded that in addition to S. mutans, other bacterial species, including bifidobacteria, Scardovia wiggsiae and S. sobrinus, are associated with severity of early childhood caries, although their role in the progress of dental caries remains unclear.     

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.     

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.     

Sex differentials in caries frequencies in Medieval London

ObjectiveTooth decay is one of the most common oral infections observed in skeletal assemblages. Sex differentials in caries frequency are commonly examined, with most studies finding that females tend to have a higher frequency of carious lesions (caries) compared to males. Less research has examined differences in caries between males and females with respect to age in past populations. Findings from living populations indicate that caries frequencies are higher in females, at least in part, because of the effects of estrogen and pregnancy. We are interested in the interaction of age, sex, and caries in medieval London, during a period of repeated famines, which might have exacerbated underlying biological causes of caries sex differentials.DesignWe examined caries in adults from two medieval London cemeteries dating to c. 1120–1539 AD: St. Mary Spital (n = 291) and St. Mary Graces (n = 80) to test the hypothesis that males and females have different caries frequencies irrespective of age. The association between maxillary molar caries and sex was tested using hierarchical log-linear analysis to control for the effects of age on caries frequencies.ResultsThe results indicate a higher frequency of maxillary molar caries in females (P < 0.00), and that the age distribution of caries differs between the sexes (P = 0.01), with a consistent increase in frequency with age for females until late adulthood, but not males.ConclusionsThe difference in caries frequencies is not explained by differences in the age distributions of the sexes. Differences in the age patterns of caries for males and females could be the result of biological factors that present during reproductive age, differences in diet, or differential access to resources during famine.     

Effect of arginine on the growth and biofilm formation of oral bacteria

BackgroundAlkali production via arginine deiminase system (ADS) of oral bacteria plays a significant role in oral ecology, pH homeostasis and inhibition of dental caries. ADS activity in dental plaque varies greatly between individuals, which may profoundly affect their susceptibility to caries.ObjectiveTo investigate the effect of arginine on the growth and biofilm formation of oral bacteria.Methods and resultsPolymicrobial dental biofilms derived from saliva were formed in a high-throughput active attachment biofilm model and l-arginine (Arg) was shown to reduce the colony forming units (CFU) counts of such biofilms grown for various periods or biofilms derived from saliva of subjects with different caries status. Arg hardly disturbed bacterial growth of Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis and Streptococcus gordonii in BHI medium, but only inhibited biofilm formation of S. mutans. Scanning electron microscope (SEM) showed S. mutans biofilms harboured fewer cells grown with Arg than that without Arg, even in the initial 2 h and 8 h phase. Confocal laser scanning microscope (CLSM) images of poly-microbial dental and S. mutans biofilms revealed the biofilms grown with Arg had lower exopolysaccharide (EPS)/bacteria ratios than those without Arg (P = 0.004, 0.002, respectively). Arg could significantly reduce the production of water-insoluble EPS in S. mutans biofilms (P < 0.001); however, quantitative real-time PCR (qRT-PCR) did not show significantly influence in gene expression of gtfB, gtfC or gtfD (P = 0.32, 0.06, 0.44 respectively).ConclusionsArg could reduce the biomass of poly-microbial dental biofilms and S. mutans biofilms, which may be due to the impact of Arg on water-insoluble EPS. Considering the contribution to pH homeostasis in dental biofilms, Arg may serve as an important agent keeping oral biofilms healthy thus prevent dental caries.     

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.     

The effect of dietary intervention on paraffin-stimulated saliva and dental health of children participating in a randomized controlled trial

ObjectivesThe aim was to study the impact of dietary intervention on the properties of paraffin-stimulated saliva, and on dental caries.Study designAt 7 months of age 1062 infants (540 intervention; 522 controls) started in the prospective, randomized Special Turku Intervention Project (STRIP) aimed at restricting the child's saturated fat and cholesterol intake to prevent atherosclerosis of adult age (www.clinicaltrials.gov NCT 00223600). At 3 years of age, every fifth child was invited to an oral sub-study, and 148 (78 boys) children attended. At 6, 9, 12 and 16 years of age 135, 127, 114 and 88 children were restudied, respectively. Dietary intakes of carbohydrates, protein, saturated fat, calcium, phosphate, and fibre were regularly recorded using 4-day food records. Height and weight were regularly monitored. Paraffin-stimulated saliva samples were collected at 6, 9, 12 and 16 years of age, and analyzed for flow rate, buffer capacity, calcium, phosphate and proteins. Dental health was recorded and expressed as d₃mft/D₃MFT, and as time of caries onset.ResultsDietary intakes of calcium, phosphate and fibre, and salivary flow rate increased with time in both groups (p < 0.001, GLM for repeated measures). Fibre intake and salivary flow rate were higher in the intervention than in the control group (p = 0.042 and p = 0.0394, respectively, GLM for repeated measures). There were no correlations between dietary intakes and salivary concentrations of calcium or phosphate. Children who did not have caries experience (d₃mft/D₃MFT = 0) during the entire follow-up had higher salivary calcium than those who had caries already at 3 years of age. The association between salivary calcium and caries onset was significant up to 12 years of age. Toothbrushing frequency was statistically significantly associated with caries-onset at ages 6 (gamma statistic 0.457, p = 0.046) and 12 years (gamma statistic 0.473, p = 0.019).ConclusionsThe current long-term dietary intervention increased children's paraffin-stimulated salivary flow rate. The concentration of salivary calcium was directly correlated to dental health. Higher salivary flow rate in the intervention group is believed to be due to higher fibre intake in the intervention group.     

Promotion of enamel caries remineralization by an amelogenin-derived peptide in a rat model

ObjectiveAn amelogenin-derived peptide has been shown to promote remineralization of demineralized enamel in an in vitro model of initial caries induced by pH cycling. The present study examines whether the peptide exerts similar effects within the complex oral environment in vivo.DesignSpecific pathogen-free Sprague-Dawley rats (n = 36) were infected with Streptococcus mutans, given ad libitum access to Diet 2000 and drinking water supplemented with sucrose (10%, w/v), and then randomly divided into three groups treated with 25 μM peptide solution, 1 g/L NaF or deionized water. Molar teeth were swabbed twice daily with the respective solutions for 24 days. Then animals were killed, their jaws were removed and caries lesions were analyzed using the quantitative light-induced fluorescence-digital (QLF-D) technique to measure changes in mineral content. To verify QLF-D results, caries were scored for lesion depth and size using the Keyes method, and analyzed using polarized light microscopy (PLM).ResultsMineral gain was significantly higher in teeth treated with peptide or NaF than in teeth treated with water (p < 0.05), based on the QLF-D results (ΔF and ΔQ). Incidence of smooth-surface and sulcal caries based on Keyes scores was similar in rats treated with peptide or NaF, and significantly lower in these groups than in rats treated with water (p < 0.05). Lesions on teeth treated with peptide or NaF were shallower, based on PLM. No significant differences were observed between molar enamel caries treated with peptide or NaF.ConclusionsThis amelogenin-derived peptide can promote remineralization in a rat caries model, indicating strong potential for clinical use.     

Risk behaviors and its association with caries activity and dental caries in Japanese children

The aim of this study was to assess risk behaviors and its association with caries activity and dental caries in Japanese children. The subjects were 392 young Japanese children who underwent dental health check-up at 18, 30 and 42 months of age. Oral examinations, Cariostat tests and dental health questionnaires were carried out at each time. The caries prevalence of children was 1.5% at 18 months, 9.9% at 30 months and 28.1% at 42 months. Caries activity based on the Cariostat scores of children was correlated with caries status (caries-free/carious) at 42 months. In children with caries during each examination period at 42 months, eating snacks while playing was ranked as the most important behavioral risk (P < 0.001), followed by breast-feeding (P < 0.01), non setting of time for snacks (P < 0.05) and frequency of snacks (P < 0.05) at 18 months old; non brushing by mother (P < 0.05) and eating snacks while playing (P < 0.05) were ranked highest at 30 months old. In addition, eating snacks while playing (P < 0.001) at 42 months old was the only a significant factor for children with caries. Caries activity and risk behaviors were associated with caries experience at different age periods of childhood.     

Inhibition of enamel mineral loss by fissure sealant: An in situ study

ObjectivesThis study evaluated the effect of fluoride and non-fluoride sealants on hardness decrease (HD) and marginal adaptation (MA) on enamel substrates after cariogenic challenge.MethodsOcclusal enamel blocks, from human third molars, were randomly divided into six groups (n = 12), according to occlusal fissures condition (S – sound; C – caries-like lesion; CF – caries-like lesion + topical fluoride) and sealants (F – FluroShield; H – Helioseal Clear Chroma). Lesion depths were 79.3 ± 33.9 and 61.3 ± 23.9 for C and CF groups, respectively. Sealants were placed on occlusal surface and stored at 100% humidity (37 °C; 24 h/d). HD was measured by cross-sectional microhardness analysis at the sealant margin distances: ?1 (under sealant), 0 (sealant margin), 1, 2 (outer sealant). Sealant MA was observed by polarized light microscopy and scored according to: 0 – failure (no sealant MA or total sealant loss); 1 – success (sealant MA present). MA and HD were analysed by ANOVA-R and mixed model analysis, respectively.ResultsFor HD (ΔS), F values (6900.5 ± 3686.6) were significantly lower than H values (8534.6 ± 5375.3) regardless of enamel substrates and sealant margin distances. Significant differences were observed among sealant margin distances: ?1 (5934.0 ± 3282.6) < 0 (8701.5 ± 6175.7) = 1 (8473.2 ± 4299.4) = 2 (7761.5 ± 4035.1), regardless of sealant and substrate. MA was similar for all groups (p ≥ 0.05).ConclusionMA was not affected by sealant type or substrate condition, whereas enamel HD was favourably impacted by fluoride in the sealant. In addition, sealants were more effective as a physical barrier than as its chemical potency in reducing enamel HD.Clinical significanceSealing with a fluoride material is a recommended procedure to prevent caries of occlusal permanent molars in high-caries-risk patients, even though those exhibiting white spot lesions, since the enamel hardness decrease when fluoride sealant was used in vitro.     

Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes

ObjectivesNickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro.MethodsIn accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n = 6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1β) and additionally stimulated with different Ni(II) concentrations (400 and 4000 ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control.ResultsOur experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p > 0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p < 0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p < 0.001), MMP expressions were in line with our findings (p < 0.001). The mRNA data were supported by proliferation and wound closure assays (p < 0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB.SignificanceOur in vitro study implicated that Ni(II) has various modifying effects on IL-1β-induced inflammatory processes depending on the concentration.     

Non-syndromic cleft lip with or without cleft palate in Asian populations: Association analysis on three gene polymorphisms of the folate pathway

ObjectiveOrofacial clefts (OFCs) are one of the most common birth defects in humans. They are the subject of a number of investigations aimed at elucidating the bases of their complex mode of inheritance involving both genetic and environmental factors. Genes belonging to the folate pathway have been among the most studied. The aim of the investigation was to replicate previous studies reporting evidence of association between polymorphisms of folate related genes and the occurrence of non-syndromic cleft lip with or without cleft palate (NSCL/P), using three independent samples of different ancestry: from Tibet, Bangladesh and Iran, respectively.DesignSpecifically, the polymorphisms rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were tested.ResultsA decreased risk of NSCL/P was observed in patients presenting the C677T variant at MTHFR gene (relative risk for heterozygotes = 0.53; 95% confidence interval [C.I.] = 0.32–0.87). The investigated polymorphisms mapping at TCN2 and CBS genes did not provide any evidence of association.ConclusionOverall, these results indicate that NSCL/P risk factors differ among populations and confirm the importance of testing putative susceptibility variants in different genetic backgrounds.