Comparisons of salivas collected and stored under different conditions

Objectives:

To simplify saliva-sampling procedures in clinical studies involving geographically spread out dental clinics.

Methods:

Pilot study with 10 subjects.

Day 1: A Dentocult® SM Strip Mutans (SM) test was performed and whole paraffin-stimulated saliva was collected while time taken was noted. For estimation of Lactobacilli, a Dentocult® LB (LB) test was used and Dentobuff® Strip (DS) for the buffer capacity (Orion Diagnostica). The whole paraffin-stimulated saliva sample was then divided into two portions: one portion was stored at –20º C and one at room temperature (rt) for 48 hours. Chewing gum-stimulated saliva was also collected and stored at rt. Chewing gum might be easier to accept for small children.

Day 3: The frozen saliva was thawed. Frozen and rt stored salivas were then analysed using SM, LB and DS tests. The total amount of immunoglobulin A (IgA) was measured using an ELISA and specific IgA reactions to antigens of S. mutans were analysed with immunoblot.

Results: For all subjects the SM, LB and DS scores showed no dissimilarities between the differently stored salivas. However, the chewing gum-stimulated saliva showed a one step decrease in SM score, though the LB and the DS scores were stable. For nine subjects chewing gum-stimulation resulted in a double fold secretion rate. No difference in total IgA was noted, but the IgA reactions to S mutans antigen were weaker for the rt salivas.

Conclusion: The results indicate that salivas stored at rt for 48 hours could be used for estimation of mutans streptococci, lactobacilli, buffer capacity and total IgA. However, the specific IgA reactions have to be further investigated since they were markedly altered after storing saliva at rt.

The study was supported by The Crafoord Foundation, Sweden