GHR and IGF2R genes may contribute to normal variations in craniofacial dimensions: Insights from an admixed population.

INTRODUCTION: This study aimed to determine whether single nucleotide polymorphisms in the growth hormone receptor (GHR) and insulin-like growth factor 2 receptor (IGF2R) genes are associated with different craniofacial phenotypes. METHODS: A total of 596 orthodontic and 98 orthognathic patients from 4 cities in Brazil were included for analyses. Angular and linear cephalometric measurements were obtained, and phenotype characterizations were performed. Genomic DNA was collected from buccal cells and single nucleotide polymorphisms in GHR (rs2910875, rs2973015, rs1509460) and IGF2R (rs2277071, rs6909681, rs6920141) were genotyped by polymerase chain reactions using TaqMan assay. Genotype-phenotype associations were assessed in the total sample (statistical significance was set at P <8.333 × 10-3) and by a meta-analytic approach implemented to calculate the single effect size measurement for the different cohorts. RESULTS: Rare homozygotes for the GHR rs2973015 showed increased measurements for the lower anterior facial height (ANS-Me) and mandibular sagittal lengths (Co-Gn and Go-Pg). In contrast, common homozygotes for the IGF2R rs6920141 presented reduced measurements for these dimensions (ANS-Me and Go-Pg). Furthermore, the less common homozygotes for IGF2R rs2277071 had reduced maxillary sagittal length (Ptm'-A'). The meta-analytical approach replicated the associations of rs2973015 with ANS-Me, rs2277071 with Ptm'-A', and rs6920141 with Go-Pg. CONCLUSIONS: Our results provide further evidence that GHR contributes to the determination of mandibular morphology. In addition, we report that IGF2R is a possible gene associated with variations in craniofacial dimensions. Applying meta-analytical approaches to genetic variation data originating from likely underpowered samples may provide additional insight regarding genotype and/or phenotype associations.

BMP2 Is Associated with Caries Experience in Primary Teeth.

Bone morphogenetic proteins (BMPs) play an important role during the initial process of enamel development and therefore may play a role in caries susceptibility. The purpose of this study was to evaluate the association between the polymorphisms in the BMP2, BMP4 and BMP7 genes and their association with caries experience and primary enamel microhardness characteristics. DNA from buccal cells as well as clinical and demographic information from 1,731 subjects from three different data sets from Brazil were included. Polymorphisms in BMP2, BMP4 and BMP7 were analyzed by real-time polymerase chain reaction from genomic DNA. Association between caries experience, genotype, and allele distribution in both cohorts was evaluated using χ(2) and logistic regression analyses. In the family-based set, the association between caries experience and alleles was tested using the transmission disequilibrium test. In the Rio de Janeiro cohort, microhardness data on 108 exfoliated primary teeth before and after demineralization and remineralization challenges was included. Associations between microhardness values and genotype and allele distribution were evaluated using χ(2) and logistic regression analyses. Differences between caries experience and some risk factors were statistically significant. In the cohort from Nova Friburgo, BMP2 was associated with caries experience in primary dentition during logistic regression analysis (p = 0.023; OR = 2.58; 95% CI 1.13-5.86). There was no association between genotype and allele distribution for BMP polymorphisms and primary enamel microhardness alterations. Our result suggests that BMP2 may be involved in caries experience in primary dentition from a Nova Friburgo cohort.

Is there enough evidence that mouthguards do not affect athletic performance? A systematic literature review.

BACKGROUND: Although there is evidence that mouthguards prevent orofacial trauma occurrence during sport practice, the influence of this device on athletic performance has not been systematically quantified. OBJECTIVES: We aim to systematically review the literature to determine the effect of mouthguards on athletic performance and if the type of mouthguard influences this overcome. MATERIALS AND METHODS: A comprehensive search was performed in the Systematic Electronic Databases: Pubmed, Scopus, Web of Science and the Cochrane Library from their inception to February 2017. The publications were grouped based on their outcome: (i) the use of mouthguards; or (ii) the type of mouthguards. We conducted descriptive analyses and quality assessments of the included studies. RESULTS: The search identified 489 citations. After screening the studies, we identified 15 trials comprising a population of 312 athletes. According to the risk of bias evaluation, nine studies were considered 'high' risk of bias, and six 'low' risk of bias. Overall, custom-made mouthguards did not interfere or improve athletes' performance when compared with the control group (without mouthguard). Custom-made mouthguards showed the smallest range of changes in players' performance compared with other types of mouthguards. CONCLUSIONS: This systematic review provides evidence for sports professionals to advocate the use of custom-made mouthguards to prevent injury, and these devices do not impair performance. The scientific evidence should be interpreted carefully because there is a great variability in outcome measures and lack of important methodological details.

Tooth agenesis-related GLI2 and GLI3 genes may contribute to craniofacial skeletal morphology in humans.

OBJECTIVE: The present cross-sectional, multi-centre, genetic study aimed to determine, whether single nucleotide polymorphisms (SNPs) in tooth agenesis (TA)-associated GLI2 and GLI3 genes contribute to the development of craniofacial skeletal morphology in humans. DESIGN: Orthodontic patients from an ethnically heterogeneous population were selected for the present study (n = 594). The presence or absence of TA was determined by analysis of panoramic radiography and dental records. The subjects were classified according to their skeletal malocclusion and facial growth pattern by means of digital cephalometric analysis. Genomic DNA was extracted from squamous epithelial cells of the buccal mucosa and SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs929387, rs846266) were analysed by polymerase chain reaction using TaqMan chemistry and end-point analysis. RESULTS: Class II skeletal malocclusion presented a significantly lower frequency of TA (P < 0.05). Subjects without TA showed significantly higher ANB angles (P < 0.05). Genotype and/or allele distributions of the SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs846266) were associated with the presence of TA (P < 0.05). The SNPs rs3738880, rs2278741 and rs929387 were also associated with some type of skeletal malocclusion (P < 0.05), but not with the facial growth pattern (P > 0.05). The G allele for TA-related GLI2 rs3738880 was strongly linked to the presence of Class III skeletal malocclusion (OR = 2.03; 95% CI = 1.37-3.03; P<3125 × 10-6). GLI2 rs2278741 C allele was overrepresented in individuals without TA, suggesting it as a protective factor for this dental phenotype (OR = 0.43; 95% CI = 0.24-0.78; P<625 × 10-5). CONCLUSION: The present study suggests that SNPs in TA-associated GLI2 and GLI3 genes may also play a role in the development of skeletal malocclusions. rs3738880 and rs2278741 in GLI2 seems to contribute to the genetic background for skeletal Class III and TA, respectively. TA could be an additional predictor of craniofacial morphology in some cases. Further research replicating the reported associations should be performed.

Evaluation of genetic polymorphisms in MMP2, MMP9 and MMP20 in Brazilian children with dental fluorosis.

Recent studies suggested that genetics contribute to differences in dental fluorosis (DF) susceptibility among individuals having the same environmental exposure. This study evaluated if MMP2, MMP9 and MMP20 are expressed during enamel development and assessed the association between polymorphisms in these genes with DF. Mice susceptible and resistant to DF were used to evaluate if MMPs were candidate genes for DF. The animals received fluoride and their enamels were used for immunohistochemistry. Additionally, 481 subjects from a city with fluoridation of public water supplies were recruited. Genotyping was performed using real time PCR. Allele/genotype frequencies were compared between groups. MMP2, MMP9 and MMP20 immunostaining was detected in both animal groups. DF was observed in 22.4% of the subjects. A borderline association was observed in MMP2 (rs243865), MMP9 (rs17576) and in MMP20 (rs1784418) (p = 0.06, p = 0.08 and p = 0.06 respectively). Briefly, MMPs were expressed during enamel maturation and genetic polymorphisms were not associated with DF.

Genetic variants in ACTN3 and MYO1H are associated with sagittal and vertical craniofacial skeletal patterns.

OBJECTIVE: This study aimed to evaluate the association of genetic variants inACTN3 and MYO1H with craniofacial skeletal patterns in Brazilians. DESIGN: This cross-sectional study enrolled orthodontic and orthognathic patients selected from 4 regions of Brazil. Lateral cephalograms were used and digital cephalometric tracings and analyzes were performed for craniofacial phenotype determination. Participants were classified according to the skeletal malocclusion in Class I, II or III; and according to the facial type in Mesofacial, Dolichofacial or Brachyfacial. Genomic DNA was extracted from saliva samples containing exfoliated buccal epithelial cells and analyzed for genetic variants inACTN3 (rs678397 and rs1815739) and MYO1H (rs10850110) by real-time PCR. Chi-square or Fisher's exact tests were used for statistical analysis (α = 5%). RESULTS: A total of 646 patients were included in the present study. There was statistically significant association of the genotypes and/or alleles distributions with the skeletal malocclusion (sagittal skeletal pattern) and facial type (vertical pattern) for the variants assessed inACTN3 (P < 0.05). For the genetic variant evaluated in MYO1H, there was statistically significant difference between the genotypes frequencies for skeletal Class I and Class II (P < 0.05). The reported associations were different depending on the region evaluated. CONCLUSION: ACTN3 and MYO1H are associated with sagittal and vertical craniofacial skeletal patterns in Brazilian populations.

Influence of kinetic cavity preparation devices on dental topography: an in vitro study.

AIM: The objectives of this study were to assess the influence of four different kinetic cavity preparation devices on cavity preparation taking into account tip angulation, internal tip diameter, and distance to the dental substrate. The dental topography itself was also evaluated after the use of these devices. METHODS AND MATERIALS: Quantitative parameters using pertinent statistical tests as well as qualitative parameters were used to assess the topography in terms of the dispersion halo effect (DHE), size, and depth of the preparation. RESULTS: The DHE did not present differences among the groups. In relation to the preparation size, the internal diameter influenced 120 masculine point angles, whereas distance influenced the 90 masculine ones. Considering the preparation depth, the 90 degrees point angle yielded the deepest. In the qualitative analysis, both angles provided cavity preparations with rounded cavosurface angles. The 120 masculine point angles yielded inclined, shallow V-shaped preparations, whereas the 90 masculine angles presented U-shaped preparations reaching the dentin. The enamel had an irregular aspect and exposed prisms; dentin had a loose smear layer with aluminum oxide residues. CONCLUSION: The kind of device may influence the kinetic cavity design. CLINICAL SIGNIFICANCE: It is the clinician that knows how to select the appropriate devices to adopt in order to achieve the desired cut, depth, and shape of cavity preparations.

Evaluation of Effect of Foraminal Enlargement of Necrotic Teeth on Postoperative Symptoms: A Systematic Review and Meta-analysis.

INTRODUCTION: The intentional enlargement of the apical foramen is designed to reduce the microbial load in the apical foramen, or even beyond, to levels more favorable for repair. This study provides a systematic review and meta-analysis to address the PICOS question: in adult patients who undergo endodontic treatment, does foraminal enlargement (FE) cause different postoperative symptoms in comparison with conventional endodontic treatment? METHODS: The PROSPERO registration number is CRD42017059921 and was conducted following the PRISMA statements. A broad search was conducted in the electronic databases PubMed, Web of Science, Scopus, Cochrane Library, and grey literature for articles published through May 2017. The MeSH terms "Pain," "Hyperemia," "Edema," "Hyperesthesia," "Fistula," "Root canal preparation," "Tooth apex," "Periapical periodontitis," "Dental pulp necrosis," and "Clinical study" were used. The reviewers evaluated the studies for eligibility criteria and performed data abstraction and risk of bias evaluations. A random-effects model was used for the meta-analysis. RESULTS: Five studies qualified for systematic review, and 3 studies were considered for meta-analysis. The results of the meta-analysis showed that postoperative pain is higher in the endodontic treatment with FE, with a statistically significant difference in the first, second, fourth, sixth, and seventh days. Limited data indicated that no significant difference was found in analgesic consumption, flare-up, and swelling between the groups. CONCLUSIONS: Postoperative pain was higher in the FE group compared with conventional endodontic therapy in the first days after treatment in teeth with necrosis and apical periodontitis.

Epidemiologic survey of traumatic dental injuries in children seen at the Federal University of Rio de Janeiro, Brazil.

This epidemiologic survey aimed at assessing the prevalence of traumatic dental injuries in children seen at the Federal University of Rio de Janeiro, Brazil. The records of a total of 111 children (aged 0 to 6 years) seen from 2004 to 2006 in the dental trauma clinic were surveyed, comprising a total of 201 traumatized primary teeth. Data pertaining to the child and to the trauma such as age, gender, etiology, teeth involved, type of traumatic injury, time elapsed between the trauma and seeking care, and the presence and kind of clinical and radiographic sequelae in the first visit were collected from the dental records. All variables studied were assessed by means of frequency analysis and the Chi-square test (p < 0.05). A higher prevalence of trauma was observed in boys (56.7%) and in the age group from 0-3 years (73.8%). The most affected teeth were the central incisors (84.7%) and the most common trauma etiology was a fall from the child's own height (63.0%). The supporting tissues were the most affected. Lateral luxation was the most frequent alteration observed (33.4%), followed by concussion (21.0%). Coronal discoloration (17.7%) and external resorption (18.3%) were, respectively, the most prevalent clinical and radiographic sequelae. Gender had no influence on the clinical (p = 0.54) and radiographic (p = 0.55) sequelae. Even though age had no influence on radiographic sequelae (p = 0.41), clinical sequelae were more prevalent in children aged 0 to 3 years (p = 0.03). In conclusion, traumatisms in primary teeth were more prevalent in boys, and in 0-3-year-old children. Luxation was the most frequent traumatic lesion, and coronal discoloration and external resorption were the most prevalent sequelae.

Oral chemical burns caused by self-medication in a child: case report.

There are few published reports that discuss oral burns in children. Electrical, chemical, and thermal agents are the main causative agents of these burns. Some chemicals can cause burning in the mucosa of cheeks, lips, tongue, and palate. Because of the clinical state of acute pain associated with lack of or inadequate care to relieve the symptoms, some patients use self-medication. The purpose of this work is to report the case of oral chemical burns caused by topical self-medication for tooth pain relief, and also to discuss the clinical presentation and the treatment performed.

Epidemiologic survey of traumatic dental injuries in children seen at the Federal University of Rio de Janeiro, Brazil

This epidemiologic survey aimed at assessing the prevalence of traumatic dental injuries in children seen at the Federal University of Rio de Janeiro, Brazil. The records of a total of 111 children (aged 0 to 6 years) seen from 2004 to 2006 in the dental trauma clinic were surveyed, comprising a total of 201 traumatized primary teeth. Data pertaining to the child and to the trauma such as age, gender, etiology, teeth involved, type of traumatic injury, time elapsed between the trauma and seeking care, and the presence and kind of clinical and radiographic sequelae in the first visit were collected from the dental records. All variables studied were assessed by means of frequency analysis and the Chi-square test (p < 0.05). A higher prevalence of trauma was observed in boys (56.7 percent) and in the age group from 0-3 years (73.8 percent). The most affected teeth were the central incisors (84.7 percent) and the most common trauma etiology was a fall from the child's own height (63.0 percent). The supporting tissues were the most affected. Lateral luxation was the most frequent alteration observed (33.4 percent), followed by concussion (21.0 percent). Coronal discoloration (17.7 percent) and external resorption (18.3 percent) were, respectively, the most prevalent clinical and radiographic sequelae. Gender had no influence on the clinical (p = 0.54) and radiographic (p = 0.55) sequelae. Even though age had no influence on radiographic sequelae (p = 0.41), clinical sequelae were more prevalent in children aged 0 to 3 years (p = 0.03). In conclusion, traumatisms in primary teeth were more prevalent in boys, and in 0-3-year-old children. Luxation was the most frequent traumatic lesion, and coronal discoloration and external resorption were the most prevalent sequelae.

A cárie dentária e suas condicionantes em crianças de uma escola pública municipal em Niterói, RJ / Dental caries and its circumstances amongst schoolchildren of a Niterói public

Objetivo: Avaliar a manifestação da cárie entre alunos de 4 a 12anos de uma escola da rede pública municipal de Niterói (RJ), em1990 e 2005, e apontar quais são os hábitos alimentares e dehigiene bucal mais freqüente entre esses alunos em 2005.Método: A amostra contou com 370 indivíduos, divididos em 3grupos: Grupo 1 (G1) com 150 crianças, entre 4 e 12 anos deidade, de ambos os sexos que foram alunos da referida escola em1990; grupo 2 (G2), semelhante ao primeiro, mas com alunosmatriculados em 2005; Grupo 3 (G3) composto por 70 pais ouresponsáveis das crianças pertencentes ao G2, que responderama um questionário sobre hábitos alimentares e higiene bucal. Foramobtidas as médias dos dentes cariados, perdidos e obturados, arelação estatística através do teste não paramétrico Mannn-Whitney,e as freqüências percentuais para os hábitos de higiene ealimentares.Resultados: A cárie dentária foi o valor mais expressivo, nos doisperíodos estudados, no entanto, ocorreu um declínio quando secomparou 1990 e 2005 (p<0,05), não houve alteração significativaentre os dentes perdidos e obturados nos dois períodos (p>0,05).Quanto aos hábitos alimentares e de higiene bucal, constatou-seque a maioria das crianças fez uso de mamadeira até 1 ano ou umpouco mais, o consumo de açúcar acontecia de 3 a 4 vezes ao diae o horário mais freqüente era entre as refeições. Em relação àhigienização, o início da escovação se deu quando já existiamvários dentes, geralmente era a própria criança que realizava esseprocedimento, sendo que a escova era individual e grande partenão usava o fio dental.Conclusão: Os programas educativos e preventivos na escolasão importantes e devem ser adequados a realidade da população,já que a saúde é um relevante medidor de qualidade de vida.