Levels and complexity of IgA antibody against oral bacteria in samples of human colostrum.

Streptococcus mutans (SM) have three main virulence antigens: glucan binding protein B (gbpB), glucosyltransferase (Gtf) and antigens I/II (Ag I/II) envolved in the capacity of those bacteria to adhere and accumulate in the dental biofilm. Also, the glycosyltransferases 153 kDa of Streptococcus gordonii (SGO) and 170kDa of Streptococcus sanguinis (SSA) were important antigens associated with the accumulation of those bacterias. Streptococcus mitis (SMI) present IgA1 protease of 202 kDa. We investigated the specificity and levels IgA against those antigens of virulence in samples of human colostrum. This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the Western blot. The mean concentration of IgA was 2850.2 (±2567.2) mg/100 mL followed by IgM and IgG (respectively 321.8±90.3 and 88.3±51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

The use of bur and laser for root caries treatment: a comparative study.

This research analyzed the influence of bur and erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser caries removal on cavity characteristics and marginal seal of composite resin restorations. One hundred and forty human dental root samples were used. After in vitro root caries induction using Streptococcus mutans, the carious lesions were removed either by a conventional technique using burs (G1=control) or by using an Er,Cr:YSGG laser (λ=2.78 µm, 20 Hz, pulse duration is approximately equal to 140 µs, noncontact mode using a 600-µm tip) with the following power outputs: G2: 1.0 W; G3: 1.25 W; G4: 1.5 W; G5: 1.75 W; G6: 2.0 W; G7: 2.25 W; G8: 2.5 W; G9: 2.75 W; G10: 3.0 W; G11: 3.25 W; G12: 3.5 W; G13: 3.75 W; and G14: 4.0 W. Samples in the 14 groups (n=10) were conditioned with Clearfil SE Bond and restored with a flowable composite. They were then thermocycled (1000 cycles) and immersed into a 2% methylene blue solution for microleakage analysis. The data were statistically compared (analysis of variance or Spearman correlation tests; p≤0.05). The lased groups showed significantly greater microleakage indexes, cavity depths, and presence of residual caries than did those of the control group. There was a strong positive correlation between residual caries and microleakage. The results indicate that Er,Cr:YSGG laser irradiation is not a good alternative to the use of burs for root caries removal since it may cause a significant loss of marginal sealing in composite resin restorations.