Flávio Zelante

Association between Caries Prevalence and Clinical, Microbiological and Dietary Variables in 1.0 to 2.5-Year-Old Brazilian Children

The association between caries prevalence and clinical (presence of visible plaque in the labial surfaces of maxillary incisors), microbiological (salivary levels of mutans streptococci) and dietary variables was evaluated in 142 1.0- to 2.5-year-old children attending public day-care nurseries in the city of Piracicaba – São Paulo. A significant difference in caries prevalence was observed between those children with and without visible plaque (χ2 = 12.08, p < 0.001). The mean ds (decayed surfaces) was significantly higher in children with visible plaque on the maxillary incisors than in children without it (p < 0.001). Mutans streptococci were detected in 114 (80.3%) of the children. A significantly higher caries prevalence was observed in children with high levels of mutans streptococci compared to children with low levels (χ2 = 28.67, p < 0.001). The mean ds was significantly higher in children with levels of mutans streptococci greater than 50 CFU when compared to children with 0 CFU or 1–50 CFU of mutans streptococci (p < 0.05). Children who were either never breast-fed or only until 3 months exhibited a significantly higher caries prevalence than those breast-fed for a longer time (χ2 = 4.11, p < 0.05). A significantly higher caries prevalence was also observed between children that used bottle containing milk with sucrose and cereal than children using bottle with milk with or without sucrose (χ2 = 6.24, p < 0.05). Children who started to eat salty meals at or after 7 months of age showed a significant higher caries prevalence than children who started earlier (χ2 = 10.30, p < 0.01). These data support the evidence of an association between caries prevalence in young children and mutans streptococci levels, clinical and dietary factors.

Effects of Subinhibitory Concentrations of Chemical Agents on Hydrophobicity and in vitro Adherence of Streptococcus mutans and Streptococcus sanguis

The aim of this investigation was to determine whether sublethal concentrations of chlorhexidine (Cx), hexetidine (Hx), cetylpyridinium chloride (Cc), sodium dodecyl sulfate (SDS), sanguinarine (Sg), sodium fluoride (NaF), and ammonium fluoride (NH4F) could affect hydrophobicity and adhesion of Streptococcus sanguis and Streptococcus mutans to saliva-coated hydroxyapatite (S-HA). Determination of the minimum inhibitory concentrations (MICs) showed that both species were susceptible to all agents tested. Growth in the presence of sub-MIC concentrations of Cx, SDS, Cc, NaF, or NH4F did not change significantly the hydrophobicity of S. sanguis cells when compared to the control which lacked any agent. However, growth in the presence of Hx or Sg resulted in a significant reduction in their hydrophobicity. Sub-MIC levels of SDS or Sg in the growth medium resulted in S. mutans cells with increased affinity for hexadecane compared with the control. The adherence of S. sanguis was changed significantly only by Hx or Sg, resulting in less cells adhering to S-HA. However, S. mutans cells previously incubated with NaF, NH4F, or Sg showed a higher adherence to S-HA than the control. The mechanisms of interference with adherence are at present not completely understood. Thus, antimicrobial agents at sub-MIC concentrations can interfere selectively with hydrophobicity and/or adhesion of oral streptococci.

Ocorrência simultânea de Staphylococcus aureus enterotoxigênicos nas mãos, boca e fezes em portadores assintomáticos

A possibilidade de ocorrencia simultânea de Staphylococcus aureus no nariz, boca, maos e fezes foi verificada em 112 individuos assintomaticos, residentes na cidade de Sao Paulo, SP, Brasil. De 40 (35,7%) deles a bacteria em questao foi isolada de, pelo menos, um dos nichos estudados. Entre estes portadores, 27 (67,5%) foram positivos em apenas um dos quatro nichos, 8 (20,0%) em dois e 5 (12,5%) em tres. Das 113 cepas de S. aureus identificadas, 28 (24,8%) isoladas de 9 (22,5%) dos portadores revelaram-se tox +. Entre essas cepas, 7 (25,0%) produziram enterotoxina do tipo A, 6 (21,4%) do tipo B, 11 (39,3%) do tipo C e 4 (14,3%) dos tipos A e C simultaneamente. A fagotipagem revelou a predominância de cepas sensiveis aos fagos do Grupo I/III/NC (16,8%) . Os resultados obtidos nao demonstraram a ocorrencia simultânea de cepas de Staphylococcus aureus em amostras colhidas de boca, maos e fezes do grupo estudado.

Staphylococcus aureus na boca e no nariz de indivíduos sãos: verificação de identidade entre as cepas isoladas

The material collected from nose and mouth (saliva and tongue smear, separately) in 130 clinically healthy individuals, enabled the characterization of 47 (36.15%) of them as carriers for S. aureus. Of these 21 were buccal carriers exclusively and 11 nasal carriers exclusively. Once it had been observed that nose and mouth shelter different phagotypes, it was discovered that the simultaneous collecting of material from two different niches (saliva and tongue, nose and tongue and nose and saliva) affords the identification of a larger number of carriers. It is recomended that, on the detection of S. aureus carriers, the isolation should be made starting with materials simultaneously collected from nasal and buccal areas (saliva or tongue).Material colhido do nariz e da boca (saliva e raspado lingual, isoladamente) de 130 individuos clinicamente sadios, permitiu caracterizar 47 (36,15%) deles como portadores de S. aureus, sendo 21 portadores exclusivamente bucais e 31 exclusivamente nasais. Tendo sido constatado que o nariz e a boca albergam cepas de diferentes fagotipos, foi verificado que a colheita simultânea de material de dois nichos distintos (saliva e lingua, nariz e lingua e nariz e saliva) proporcionava a determinacao de maior numero de portadores. Foi recomendado que, na deteccao de portadores de S. aureus, os isolamentos devem ser feitos a partir de materiais colhidos simultaneamente das areas nasal e bucal (saliva ou lingua).

Fatores de virulência do Actinobacillus actinomycetemcomitans: outros possíveis fatores

Actinobacillus actinomycetemcomitans is implicated as the causative agent of localized juvenile periodontitis. This organism possesses a large number of virulence factors with a wide range of activities and also interfere with tissue repair. Fifty isolates of A. actinomycetemcomitans from 20 periodontal patients were examined to evaluate other putative virulence factors. In this study, the capsule, DNase, coagulase, fibrinolysin, proteolytic, haemolysin and bacteriocin production, haemagglutination, serum sensitivity, epithelial cells attachment, hydrophobicity and virulence of the A. actinomycetemcomitans isolates were evaluated. All the isolates were resistant to the different tested sera. 70% to 94% were alpha-haemolytics and agglutinated all blood types. Most of isolates produced antagonistic substances and they had a low hydrophobicity. None of the isolates was pathogenic for mice. Little is known as to wether these factors may act in the development of periodontal disease, and further studies are required for an application in pathogenic and systematic terms.

Observação sobre o padrão fágico de cepas de Staphylococcus aureus isoladas da boca e do nariz de indivíduos sãos

Sixty-eight Staphylococcus aureus strains, isolated from mouth and nose in clinically healthy individuals were submitted to phagetyping. Although the three niches, togne, saliva and nose, showed equivalent percentual of isolation, the nose and the mouth harbour different phage patterns from the International Phagetyping Set. The strains isolated from the nose were more sensitive to the phages from group I, whereas the strains isolated from the tongue were more sensitive to the phages from group III. Based on these observations, research on nose and mouth (tongue and saliva) simultaneously is recommended, where S. aureus carriers are detected.Foram analisadas 68 cepas de Staphylococcus aureus isoladas da boca (saliva e lingua) e nariz de portadores assintomaticos que albergavam essa bacteria nos tres nichos, simultaneamente. Embora os tres nichos apresentassem equivalencia quanto ao percentual de isolamentos, foi constatado que as cepas isoladas do nariz diferiam, quanto ao seu padrao fagico, principalmente daquelas isoladas da lingua. No primeiro caso, as cepas apresentaram-se mais sensiveis aos fagos do grupo I enquanto que, as isoladas do segundo nicho, foram mais sensiveis aos fagos do grupo III. Considerando estas observacoes e recomendavel, quando da deteccao de portadores de Staphylococcus aureus, a pesquisa dessa bacteria em material colhido do nariz e da boca, simultaneamente.

Possível interferência da antitoxina tetânica pré-existente, na vacinação antitetânica

Estudou-se qual a possivel interferencia no desenvolvimento da imunidade antitetânica ativa em cobaias e camundongos, filhos de femeas vacinadas contra o tetano em diferentes epocas durante o periodo da prenhes. Verificou-se que a vacinacao das femeas, em gestacao nao interferiu, negativamente, no desenvolvimento da imunidade ativa dos animais filhos, quando submetidos a vacinacao ao redor de 60 dias apos o nascimento. A presenca de baixos niveis de anticorpos circulantes, recebidos congenitamente, parece ter, em determinadas condicoes, estimulado a resposta imunitaria quando, posteriormente, os animais filhos foram vacinados contra o tetano. Sugere-se que o complexo antigeno-anticorpo formado seja capaz de melhorar a resposta imunitaria induzida pelo toxoide.

Occurrence of microorganisms at different levels of the pulp: Contribution to endodontic techniques

Microorganisms were absent in the remaining pulp stumps of twenty teeth which had been exposed to caries and contaminated at the pulpal chamber level. We have demonstrated that microorganisms are not carried to the deepest areas of the pulp when the basic procedure is strict antisepsis applied to the living pulp stump. A sterile and living pulp stump wound contributes to an adequate biologic sealing of the apical foramen. Of all the isolated microorganisms, the alpha hemolytic Streptococcus was most frequently found in all examined cases, in pure or mixed cultures, demonstrating once again he prodominance of that type of microorganism when pulpal injury occurs.

Prevalência de estreptococos do grupo mutans em crianças de 12 a 31 meses de idade e sua associação com a freqüência e severidade de cárie dental

The prevalence of mutans streptococci (MS) was evaluated in samples of unstimulated saliva from 142 12-31-month-old children. Initial and manifest caries of all teeth surfaces were recorded. Mutans streptococci were detected in 80.3% (n = 114) of the studied children, and 21.8% of all children (n = 31) presented high levels of these microorganisms. The salivary levels of mutans streptococci depended on the number of erupted teeth (c2 = 19.03; p < 0.001). There was a positive association between the number of caries affected children and the salivary levels of MS (c2 = 28.67; p < 0.001). In addition, there was a positive correlation between the salivary levels of these microorganisms and the number of caries lesions which was higher when initial caries were considered (r = 0.537; p < 0.001). These data show a high prevalence of mutans streptococci in children with 12 to 31 months of age and its positive association with the frequency and severity of dental caries.