ABSTRACT
The objective of this study was to analyze the genotypic diversity, frequency of serotypes and the detection of mutacins from Streptococcus mutans isolates in caries-free and caries-active individuals.A total of 260 S. mutans isolated from 28 individuals with and without dental caries were subjected to AP-PCR and PCR screening of glucosyltransferase B, mutacin and serotype genes, which showed the presence of. 70 different genotypes. There was no statistically significant association between the presence of genes for serotypes and mutacins with dental caries. However, there was a statistically significant and a strong association between the higher genotypic diversity in the subjects with caries (r = 0.72, p = 0.001). There was an increase in the number of genotypes with increasing age (p <0.01).
ABSTRACT
Silorane-based composite, an epoxy material, was marketed as promising less polymerization contraction than conventional restorative materials. The aim of this study was to evaluate, by means of photoelasticity, the polymerization stress generated by a silorane-based composite. Thirty photoelastic rings with orifices measuring 5 mm (d) × 3 mm (h) were prepared and divided into 6 groups (n = 5) according to the material tested. The inside walls of the rings were sandblasted with aluminum oxide, after which the restorative materials were inserted into the orifices and photoactivated according to the manufacturer's instructions. The specimens were analyzed and the visual representation of the stress was measured considering the isochromatic ring of first order. The data were converted to MPa and subjected to ANOVA and Tukey's test (α= 0.05). The adhesive Filtek P-90 (G5) showed high contraction stress (p < 0.05) when compared to G1, G2, G3, G4, and G6, which did not differ from each other (p > 0.05). The composite Filtek P-90 showed similar contraction stress compared to the conventional composite and, additionally, its adhesive showed higher stress than did the etch-and-rinse 2-step adhesive.
Subject(s)
Composite Resins/chemistry , Dental Stress Analysis/methods , Dentin-Bonding Agents/chemistry , Analysis of Variance , Elastic Modulus , Elasticity , Materials Testing , Polymerization , Stress, MechanicalABSTRACT
Os avanços no conhecimento da biologia molecular e do genoma humano forneceram evidências de que a maioria das doenças humanas é influenciada por alterações em estruturas genéticas. Inúmeros estudos investigando a contribuição genética à cárie dentária são realizados. Novas técnicas e novos métodos de avaliações para as informações genéticas surgiram, criando novas terapias e tratamentos.O cirurgião-dentista deve estar preparado e informado sobre as novas possibilidades, para incorporá--las no cotidiano de sua clínica. O presente trabalho tem como objetivo atualizar o cirurgião-dentista,abordando conceitos e técnicas da biologia molecular na odontologia e na prevenção da cárie dentária.
The advances in the knowledge of molecular biology and the human genome provide evidence that themajority of the human diseases are influenced by alterations in genetic structures. Several studies investigatingthe contribution of genetics in the dental caries are made. New techniques and methods ofevaluation emerged, creating new therapies and treatments. The dentist clinician must be prepared andinformed about the new possibilities, in order to incorporate it into the evolving discipline of dentistry. Thepresent study aims to update the dentist clinician, approaching new concepts and techniques in molecular biology, in dentistry and in the prevention of dental caries.
Subject(s)
Molecular Biology , Dental Caries/prevention & control , DentistryABSTRACT
A reabsorção radicular apical externa (RRAE) é uma sequela indesejada dotratamento ortodôntico. Estudos prévios sugerem que a RRAE apresenta um componente genético substancial. Este trabalho teve como objetivo avaliar a relação entre o polimorfismono gene da interleucina-1b (lL-1b)e a reabsorção radicular apical externa em 50 pacientes entre 12 a 30 anos, tratados ortodonticamente durante os anos de 1999 a 2000. Os dadosforam coletados a partir dos prontuários dos indivíduos e avaliação radiográfica. O DNA foi obtido a partir das células epiteliais da mucosa bucal. O polimorfismo foi avaliado pelareação em cadeia da polimerase (PCR), seguido de digestão por enzima de restrição, pela técnica do polimorfismo do comprimento do fragmento de restrição (RFLP). Os produtosforam analisados em gel de agarose a 2% e corados com brometo de etídeo. Foi verificada associação entre a RRAE e o polimorfismo no gene da IL-1b,assim como quando se analisou a RRAE e o polimorfismo segundo a inclinação dos incisivos superiores. Houve diferençasignificativa nas frequências alélicas e genotípicas do gene IL-1b entre os indivíduos com RRAE e sem esta condição. Os dados deste estudo sugerem que o alelo 1 do gene IL-1baumenta significativamente o risco para RRAE.
External apical root resorption (EARR)is an undesirable sequei of orthodontictreatment. Previous studies have suggested that EARR has a substantial genetic component. The aim of this study was to examine the relationship between the EARR and the interleukin-1B gene polymorphism in 50 subjects between 12 and 30 years old who had undergone orthodontic treatment from 1999 and 2000. Data were collected from the subject's dental charts and radiographic exams. DNA was obtained from epithelial cells of buccal mucosa.The polymorphism was evaluated by polymerase chain reaction (PCR)and restriction fragment length polymorphism (RFLP). An association between EARR and the interleukin-1b gene polymorphism was found, as well as EARR and inclinations of upper incisors. There was a significant difference between allelic and genotypic frequency and the interleukin-1b genepolymorphism among subjects with and without EARR. The study suggests that the allele 1 from the IL-1b gene significantly increases the risk for EARR.