Unstimulated salivary flow and oral streptococci in pediatric patients with hematological tumors: A longitudinal study

Aims: To evaluate the unstimulated salivary flow (USF) and salivary colonization of total Streptococcus spp. (TS) and mutans-group (MS) in pediatric patients with hematological tumors. Correlations of salivary and microbiological changes with chemotherapy and patient-related factors were also verified. Methods and Results: Eligible children (n = 31) were evaluated before (control) and after (2, 5, and 10-weeks) the chemotherapy protocol was applied. Saliva samples were collected by the traditional spitting method to determine the USF (ml /min). Salivary TS and MS were determined by colony-forming units (CFU ) counts in a selective medium. The caries experience was evaluated by DMFT/dmft indexes. Data were submitted to Student's t-test, one-way ANOVA, and correlation tests (alpha = 0.05). The USF rate at baseline was 0.89 (+/- 0.73) ml/min with up to 20% reduction during the follow-up and did not differ statistically during chemotherapy (p > .05). Chemotherapy did not modify the salivary TS load (p > .05), but induced a dysbiotic shift with higher MS counts (similar to 5 fold-increase) at 10-weeks (p < .05). There is a correlation of USF with age (r = .390) and SM load with caries experience (r(s) = -.540) at 5-weeks. Conclusion: Chemotherapy may promote a specific increase of mutans-group streptococci without changing the Streptococcus spp. load and unstimulated saliva flow. Correlation reinforced the need for further enlightenment about the chemotherapy mechanisms in the salivary and microbiological parameters.