The propensity of individual saliva to cause extrinsic staining in vitro—a developmental method

Objectives: To detect any differences in the propensity of individual saliva to cause in vitro staining by chlorhexidine and tea. Methods: Unstimulated human saliva was collected on a daily basis and used to coat optically clear Perspex specimens. Specimens were subjected to the original chlorhexidine/tea staining model described by Prayitno and Addy (Journal of Periodontal Research 1979;14:397–402), and cycles repeated until a maximum optical density of two was reached. Results: Stain development increased incrementally with increasing cycles. Differences in chlorhexidine/tea staining between subjects were obvious by cycle 3 where the lowest ‘stainer’ had 56% less stain than the highest ‘stainer’. Highly significant differences between subjects were seen during staining cycles 3–6, but not at cycles 7 and 8. Conclusions: In vitro stain formation using saliva from different individuals occurred at differing rates when all other variables were standardised. The properties of saliva accounting for this are still unknown, and warrant further study.