Objectives: To compare salivary stimulation and pH changes of a Gustatory Stimulant of Salivation (SST) (malic acid 4.2% and citric acid 2.1% w/w) in healthy volunteers and patients with Primary Sjögren Syndrome (PSS)
Methods: 30 healthy volunteers and 30 patients with PSS attending the Portuguese Institute for Reumathological Diseases or the Dental Clinic of a Portuguese University were to assigned to one of two groups according the presence or not of PSS: PSS Group (N) or Healthy Group (C). Unstimulated, mechanical and GSSS stimulated whole saliva flow rate and pH were measured by previously established methods. Time of GSSS induced pH drop below 4.5 was expressed in minutes as the mean ± 95% confidence interval. To better quantify risk differences of GSSS induced pH drop below 4.5 a contingency table compiling the counts of subjects with pH drops below 4.5 for over one minute was obtained (TSB), absolute risk increase (ARI) and number needed to harm (NNH) were also calculated. Means of salivary flow, salivary pH and time of pH drop below 4.5 were analysed with paired or independent Student's t-test or ANOVA and post hoc tests as appropriate. Informed consents and local ethical committee clearance was obtained.
Results: Significant differences were found for all parameters except unstimulated whole saliva pH. The PSS group presented a significant decrease for mechanical and GSSS stimulated salivary secretion and a significant increase in time of GSSS induced pH drop below 4.5 when compared to the N Group.. For TSB values over 1 min when compared to the healthy patients group the ARI was of 14% and the NNH was 8.
Conclusions: The results of this study suggest that PSS exerts a negative effect on saliva secretion and on the ability to counteract salivary pH drop stimulus.