In this study were investigated salivary cells directly (cariogenic microorganisms) and indirecttly (defence cells) implicated in cavity etiopathogeny, correlated with stress represented by a final test. The study was performed on a group of 18 students, aged between 20-21. There were investigated Decay Missed Filled (DMF index) and saliva samples were collected. Were determined salivary flow, neutralising capacity and salivary pH. Cavity risk was appreciated by the salivary levels of Streptoccocus mutans and Lactobacillus. DMF index was 1,56 showing the existance of odontal caries. Buffer capacity of saliva was medium, and the level of Streptoccocus mutans was very high at 33% of cases. Lactobacillus was normal in most of the cases. Salivary flow (0.82±0.2 ml/min) and pH (7.1±0.54) were lower before the exam. Those can be explained by activation of sympathetic system before the exam. The increase of salivary flow (1±0.49 ml/min) after the exam was correlated with increased pH (7.6±0.11). Local defence system may be shown by the number of oral epithelial cells, leucocytes, and theirs viability. From this study it was revealed that salivary factors related with caries are increased during stress periods. It was recomanded an increased attention for oral hygiene during this periods.