João Armando Brancher

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.

Effects of antidepressants and benzodiazepines on stimulated salivary flow rate and biochemistry composition of the saliva

OBJECTIVES To evaluate the effect of psychotropics on stimulated salivary flow rate (SSFR), total proteins, urea and calcium concentration, alpha-amylase activity, pH, saliva buffer capacity (SBC), and the prevalence of xerostomia in psychotropic users and its relationship with low SSFR and/or hyposalivation. STUDY DESIGN Thirty-three subjects were allocated to 4 groups: I (control): II (psychotropic users); III (subjects of group II using only selective serotonin reuptake inhibitors [SSRIs]); and IV (subjects of group II using SSRIs at recommended initial dose). The SBC was obtained by titrimetry and salivary composition by colorimetric method. RESULTS Group II presented a significant decrease (P = .0203), of 33.85% in SSFR compared with group I. Mean SSFR values in groups III and IV showed no significant difference compared with control group (P > .05). Xerostomia was observed in 37.50%, 38.46%, and 50% of subjects in groups II, III, and IV, respectively. Biochemical composition, pH, and SBC were not significantly affected (P > .05) by the use of psychotropics. CONCLUSIONS Xerostomia was associated with a decrease in SSFR and not with alterations in biochemical composition. Even when using the latest-generation drugs, there were complaints of xerostomia associated with decrease in SSFR.

Analysis of the association between lactotransferrin (LTF) gene polymorphism and dental caries

Objective The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. Material and Methods A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT≥1). DNA was obtained from a mouthwash with 3% glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. Results Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.030.76, p=0.01). Conclusion Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students.

Fine-Mapping of 5q12.1-13.3 Unveils New Genetic Contributors to Caries

Caries is a multifactorial disease and little is still known about the host genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified the interval 5q12.1–5q13.3 as linked to low caries susceptibility in Filipino families. Here we fine-mapped this region in order to identify genetic contributors to caries susceptibility. Four hundred and seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. DMFT scores and genotype data of 75 single-nucleotide polymorphisms were evaluated in the Filipino families with the Family-Based Association Test. For replication purposes, a total 1,467 independent subjects from five different populations were analyzed in a case-control format. In the Filipino cohort, statistically significant and borderline associations were found between low caries experience and four genes spanning 13 million base pairs (PART1, ZSWIM6, CCNB1, and BTF3). We were able to replicate these results in some of the populations studied. We detected PART1 and BTF3 expression in whole saliva, and the expression of BTF3 was associated with caries experience. Our results suggest BTF3 may have a functional role in protecting against caries.

Analysis of Polymorphisms in the Lactotransferrin Gene Promoter and Dental Caries

Regarding host aspects, there has been strong evidence for a genetic component in the etiology of caries. The salivary protein lactotransferrin (LTF) exhibits antibacterial activity, but there is no study investigating the association of polymorphisms in the promoter region of LTF gene with caries. The objective of this study was firstly to search the promoter region of the human LTF gene for variations and, if existent, to investigate the association of the identified polymorphisms with dental caries in 12-year-old students. From 687 unrelated, 12-year-old, both sex students, 50 individuals were selected and divided into two groups of extreme phenotypes according to caries experience: 25 students without (DMFT = 0) and 25 with caries experience (DMFT ≥ 4). The selection of individuals with extreme phenotypes augments the chances to find gene variations which could be associated with such phenotypes. LTF gene-putative promoter region (+39 to −1143) of the selected 50 individuals was analyzed by high-resolution melting technique. Fifteen students, 8 without (DMFT = 0) and 7 with caries experience (mean DMFT = 6.28), presented deviations of the pattern curve suggestive of gene variations and were sequenced. However, no polymorphisms were identified in the putative promoter region of the LTF gene.

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.

Lactotransferrin Gene Polymorphism Associated with Caries Experience

Dental caries is a common multifactorial disease, resulting from the interaction of biofilm, cariogenic diet and host response over time. Lactotransferrin (LTF) is a main salivary glycoprotein, which modulates the host immune-inflammatory and antibacterial response. Although a genetic component for caries outcome has been identified, little is known over the genetic aspects underlying its susceptibility. Thus, the aim of this study was to investigate the association between LTF polymorphisms and caries susceptibility. Six hundred seventy seven 12-year-old students were selected: 346 with (DMFT ≥ 1) and 331 without caries experience (DMFT = 0). Also, individuals concentrating higher levels of disease (polarization group, DMFT ≥ 2, n = 253) were tested against those with DMFT ≤ 1 (n = 424). Along with clinical parameters, three representative LTF tag SNPs (rs6441989, rs2073495, rs11716497) were genotyped and the results were evaluated using univariate and multivariate analyses. Allele A for tag SNP rs6441989 was found to be significantly less frequent in the polarization group, conferring a protective effect against caries experience [AA + AG × GG (OR: 0.710, 95% CI: 0.514-0.980, p = 0.045)], and remained significantly associated with caries protection in the presence of gingivitis (p = 0.020) and plaque (p = 0.035). These results might contribute to the understanding of the genetic control of caries susceptibility in humans.

Prevalence of diagnosed temporomandibular disorders: A cross-sectional study in Brazilian adolescents

Background The prevalence of signs and symptoms of temporomandibular disorders (TMD) increases during adolescence and adulthood. Few studies have examined TMD prevalence in Brazilian adolescents. Aim To investigate the prevalence of TMD in Brazilian adolescents. Methods A representative population-based sample of 934 adolescents (10–14-years-old) was examined. TMD screening was performed using a questionnaire by the American Academy of Orofacial Pain. TMD diagnoses used research diagnostic criteria for temporomandibular disorders (RDC/TMD—Axis-I). Examinations were performed by a single calibrated examiner (kappa > 0.80). Results The prevalence of TMD symptoms was 34.9%; the most frequently reported symptoms were headache and neck ache (20.9%), followed by joint sounds (18.5%). Myofascial pain was the most prevalent type (10.3%), followed by disc displacement with reduction (8.0%) and arthralgia (3.5%). There was a significant association between sex and TMD symptoms; prevalence was significantly higher in girls (RP = 1.37; 95% CI = 1.14–1.65; p = 0.001). Myofascial pain of TMD and displacement with reduction were more prevalent in girls (RP = 1.76; p = 0.007 and RP = 2.06; p = 0.004, respectively). Conclusion TMD symptoms were present in 34.9% of adolescents, with myofascial pain being the most prevalent type (10.3%). TMD was significantly more common in girls. Routine pediatric dental care should include a TMD screening.

Genes Involved in the Enamel Development Are Associated with Calcium and Phosphorus Level in Saliva

Saliva components play a crucial role in the integrity of the dental enamel and in caries susceptibility. The saliva characteristics are controlled by many factors, including genetic factors. Therefore, this study aimed to evaluate the association between the genetic variations in genes expressed in enamel development with calcium and phosphorus levels in saliva. We collected 276 unrelated 12-year-old children from private and public schools. Saliva was collected for DNA extraction from oral cells and for measurement of calcium and phosphorus. Inductively coupled plasma-mass spectrometry determined calcium and phosphorus levels in whole saliva. Fifteen genetic variations in 9 genes were analyzed. The genotype was determined by real-time polymerase chain reactions. Data were analyzed using Plink with an alpha of 5%. Genetic variations in AMELX, AMNB and ESRRB were associated with the calcium level in saliva (p < 0.05). A borderline association was observed in ENAM allele distribution shown with phosphate level in saliva (p = 0.049). In conclusion, our results are the first to report that genetic variations contribute to calcium and phosphorus levels in saliva.

Sialometric analysis in young patients with chronic renal insufficiency

The present study aimed to evaluate whether or not quantitative changes occur in the salivary flow of patients with chronic renal insufficiency (CRI) who have been submitted to Hemodialysis. Twenty-nine chronic renal patients, between 4 and 25 years of age, submitted to Hemodialysis at Hospital Pequeno Príncipe in Curitiba, Paraná, Brazil participated in this study. The results form this study were compared with those of a group consisting of 29 healthy patients, paired by sex and age, whose parents sought out dental treatment at local health clinic in Campo Magro, Paraná. For Sialometric evaluations, samples were collected at the beginning, during and at the end of Hemodialysis, as well as after the analyses had been performed. Salivary flow was calculated by the Banderas-Tarabay formula (1997). The results revealed that the mean salivary flow values presented no difference between the groups. It could therefore be concluded that CRI did not determine quantitative alterations in salivary fluid.