universidade de são paulo - Faculdade de Odontologia - Unesp

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have observed that the preconditioning with saliva either does not significantly
affect [22-26] or decreases C. albicans colonization [4, 27-31].
In these studies, diverse protocols have been used for collection and
preparation of saliva samples, with differences in the nature (e.g. the quality of
saliva from different individuals) and in the centrifugation parameters. It is
therefore conceivable that these factors may have affected the outcomes and that
this variability may have accounted partly for the conflicting data reported by
different authors [32]. All these show the importance of quality control of saliva
in studies of this nature and point out the need for standardization [22]. However,
to date, no information is available concerning how different methods of
collection and preparation of saliva samples affect the adhesion of Candida spp.
cells to denture materials.
Different methods have been used to investigate the adhesion of Candida
to biomaterials, among them XTT and cell staining assays. For XTT assay, the
water-soluble tetrazolium salt [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-
[(phenylamino) carbonyl]-2H-tetrazolium-hydroxide] is taken up by living cells
and is reduced by mitochondrial dehydrogenase to colored tetrazolium formazan
products that are determined spectrophotometrically [20, 22, 26, 33-35]. In the
staining assay, the fungal cells that adhered to the material surface are fixed,
stained with a basic dye, crystal violet, and then counted under a microscope [1,
26-27, 30-31, 36-37].
Therefore, the aim of the present study was to evaluate the effect of
variations in the centrifugation parameters and number of donors of saliva on C.