Streptococcus pneumoniae is a pathogen responsible for high morbidity and mortality worldwide. The polysaccharide capsule confers protection against phagocytosis and influences many aspects of pneumococcal pathogenesis. The capsular polysaccharides (CPS) are highly immunogenic and exhibit great structural variability, with more than 100 serotypes described so far. Antimicrobial peptides (AMPs) are an important part of the innate defense mechanisms against many pathogens. Indolicidin is a cationic AMP produced by bovine neutrophils, with bactericidal effects against several bacteria. CPS has been shown to interfere with the ability of AMPs to kill pneumococci, but the effects of capsule variability on susceptibility to indolicidin have not been explored. The present work determined the effects of capsule on resistance to indolicidin in vitro. Using a bactericidal plate assay, we observed that different pneumococcal serotypes exhibited variable resistance to indolicidin, which correlated with the capsule net charge. Interestingly, the effect of capsule expression on resistance to indolicidin was dependent on the serotype; bacteria with lower zeta potential were more resistant to indolicidin when capsule was present, while those with less negative surface charge were more resistant in the absence of capsule. The addition of purified CPS partially rescued the bacteria from the bactericidal effects of indolicidin, while the addition of anticapsular antibodies accentuated the peptide’s bactericidal action, suggesting a possible new protective mechanism induced by polysaccharide-based pneumococcal vaccines.

Objective: To compare retention, preventive effectiveness and longevity of two different highviscosity glass-ionomer sealants Ketac Molar ® and Maxxion R ® in the sealing of erupting and out-of-occlusion first permanent molar in children aged 5-7 years. Material and Methods: Children with past caries experience with healthy erupting first permanent molar were included in the study. Teeth 16 and 46 were sealed with Ketac Molar ® and teeth 26 and 36 were sealed with Maxxion R ®. After 8 months, the retention of sealants was evaluated using the following criteria: total retention; presence of sealant in two thirds of the occlusal surface; presence of sealant in one third of the surface; and total absence of the sealant. Results: Statistical difference between materials was observed, and Ketac Molar ® retention was superior to that of Maxxion R ® (p<0.05). Regarding the development of caries in sealed first permanent molar, none of the teeth sealed with Ketac Molar ® or Maxxion R ® developed caries lesion. Conclusion: Ketac Molar ® retention is significantly superior to that of Maxxion R ® , but the preventive effectiveness in the development of carious lesions is similar for both, which is extremely interesting for the field of public health, since the cost of the material is significantly lower.