Methods: 120 patients, attending a Portuguese University dental clinic were recruited for this study and randomized to one of two groups and then administered either a NAL or a C lozenge. Saliva collection was obtained by established methods at different times ranging from 0 till 20 minutes. Salivary secretion rate (SSR) was expressed as mean +- SD of the difference between lozenge stimulated and basal salivary flow in ml.min-1. The salivary pH of the samples was determined with a pH meter and a microelectrode. Erosive potential was defined as the mean ± SD time interval (in minutes) of salivary pH below 5.5. The 95 % confidence intervals (CI) for absolute risk reduction (ARR) and number needed to treat (NNT) were obtained in order to better quantify erosive potential differences between the two groups. Paired or unpaired Student t test were employed for testing of mean differences as appropriate, significance level was set at 5%. This study was approved by the local ethical committee.
Results: SSR for group NAL and C was 0.904 ± 0.434 and 0.968 ± 0.459 ml.min-1 respectively. The ARR for patients in the NAL group was 78% ± 11 and the NNT 1 for 95% CI.
Conclusions: In this study both lozenges presented similar salivary stimulation rates while the NAL presented a significant reduction in dental erosion potential when compared to C.