This study examined by means of scanning electron microscopy (SEM), the attachment of Streptococcus mutans and the corrosion of cast commercially pure titanium, used in dental dentures. The sample discs were cast in commercially pure titanium using the vacuum-pressure machine (Rematitan System). The surfaces of each metal were ground and polished with sandpaper (#300-4000) and alumina paste (0.3 µm). The roughness of the surface (Ra) was measured using the Surfcorder rugosimeter SE 1700. Four coupons were inserted separately into Falcon tubes contained Mueller Hinton broth inoculated with S. mutans ATCC 25175 (10(9) cuf) and incubated at 37 °C. The culture medium was changed every three days during a 365-day period, after which the falcons were prepared for observations by SEM. The mean Ra value of CP Ti was 0.1527 µm. After S. mutans biofilm removal, pits of corrosion were observed. Despite the low roughness, S. mutans attachment and biofilm formation was observed, which induced a surface corrosion of the cast pure titanium.

Utilizando o método de difusão em ágar, este estudo avaliou in vitro a atividade antimicrobiana dos cimentos endodônticos comerciais: Acroseal e Epiphany, um cimento experimental à base do polímero da mamona, Polifil, e um agente primer (primer auto-adesivo do sistema Epiphany), contra Enterococcus faecalis. O cimento de óxido de zinco e eugenol (OZE) serviu como controle. Cinco poços por placa foram feitos em pontos eqüidistantes e imediatamente preenchidos com os materiais testados e controle. Após a incubação das placas aos 37ºC por 24 e 48 h foram medidas as zonas de inibição do crescimento bacteriano ao redor dos poços (em mm) com uma régua milimetrada. Após 48 h, os diâmetros das zonas de inibição do crescimento bacteriano foram os mesmos observados às 24 h, apenas as substâncias continuaram a se difundir. Epiphany e Polifil não apresentaram atividade antibacteriana (não ocorreu a formação das zonas de inibição do crescimento bacteriano). Os maiores halos de inibição foram atribuídos ao primer (17,62 mm), seguido do Acroseal (7,25 mm) e OZE (7,12 mm). E. faecalis foi resistente ao Epiphany e Polifil, enquanto que o primer e o cimento Acroseal foram eficientes contra esse microrganismo nas condições testadas.

Using the agar diffusion method, this study evaluated the in vitro antimicrobial activity of the commercial endodontic sealers Acroseal and Epiphany, a castor-oil based experimental sealer, Polifil, and a primer agent (Epiphany self-etching primer), against Enterococcus faecalis. Zinc oxide and eugenol cement (ZOE) served as control. Five wells per dish were made at equidistant points and immediately filled with the test and control materials. After incubation of the dishes at 37ºC for 24 h and 48 h, the diameter of the zones of microbial growth inhibition produced around the wells was measured (in mm) with a millimeter rule. After 48 h, the diameters of the zones of microbial growth inhibition were the same as those observed at 24 h, only the substances continued to diffuse. Epiphany and Polifil did not show antibacterial activity (no formation of zones of microbial growth inhibition). The primer produced the largest zones of inhibition (17.62 mm) followed by Acroseal (7.25 mm) and ZOE (7.12 mm). E. faecalis was resistant to Epiphany and Polifil, while the primer and Acroseal sealer were effective against this microorganism under the tested conditions.

O objetivo deste estudo foi determinar, através da técnica de reação em cadeia da polimerase com primers arbitrários (AP-PCR) a capacidade de diferenciar clones geneticamente distintos de Streptococcus mutans e estabelecer o grau de similaridade intrafamilial para os isolados. Para o presente estudo, foram selecionadas 22 famílias brasileiras. Amostras de saliva foram coletadas de todos os membros das famílias. Das crianças com idade entre 5-18 meses obteve-se amostras de placa dental. Após o isolamento das colônias com características morfológicas, realizou-se a identificação bioquímica com base na fermentação de carboidratos. O polimorfismo genético de Streptococcus mutans foi pesquisado através da técnica de AP-PCR utilizando-se o primer OPA-13. Os fragmentos de DNA obtidos foram amplificados e comparados através de eletroforese em gel de agarose. Dentre as espécies identificadas nas 22 famílias analisadas, o pai apresentou cepas com similaridade genética aos dos bebês em três das famílias analisadas; em 12 famílias a mãe apresentou cepas com similaridade com as cepas de Streptococcus mutans do bebê e 7 bebês apresentaram cepas de S. mutans com similaridade genética das cepas do irmão mais velho. A técnica de AP-PCR foi eficaz em demonstrar a heterogeneidade genética de Streptococcus mutans entre os membros das famílias brasileiras analisadas.

The aim of this study was to determine whether random amplified polymorphic DNA (AP-PCR) analysis is able to differentiate genetically different clones of mutans streptococci, in 22 Brazilian family members. Stimulated saliva samples were collected from fathers, mothers and infants. For 5-18 months babies with erupting primary dentition, plaque samples were collected using sterile tooth pick tips. From these samples, mutans streptococci were isolated on SB-20 agar plates. After growth, representative colonies were identified by biochemical methods on the basis of carbohydrate fermentation. Streptococcus mutans isolates were obtained from all family members and AP-PCR typed separately with a random primer (OPA-13). Bacterial cell lysates were used as template in PCR reactions and the amplified DNA fragments obtained were compared by agarose gel electrophoresis. Results demonstrated that the father shared the baby's genotype in three families and the mother shared the baby's genotype in 12 families seven babies harbored Streptococcus mutans strains similar to those of their siblings. The technique was able to demonstrate the genetic Streptococcus mutans in Brazilian family members.