Effect of saliva substitutes on mineral content of demineralized and sound dental enamel

The aim of this in vitro study was to evaluate the effects of commercially available saliva substitutes on the mineral content of pre-demineralized and sound enamel. From 56 bovine incisors 224 enamel specimens were prepared and hand-polished. The specimens were partially covered with nail varnish (control of sound enamel). In group 1, 112 samples were demineralized (18 days; 37 degreesC; pH 5.0) and a portion of the demineralized area was likewise covered with nail varnish. Subsequently, 16 specimens were exposed (14 days; 37 degreesC) to 10 mi of each of several different saliva substitutes (Artisial; Glandosane; Oralube; Saliva medac), or mouthwash solutions (Biotene; Meridol), respectively. Noncarbonated, fluoride-containing mineral water (Eptinger) was used as control. In group 2, the 112 sound enamel specimens were immersed directly in the solutions (without a demineralization period). After immersion, the specimens were cut perpendicular to the surface, and slabs (110 mum) were ground. Contact microradiographs were obtained and studied with a digital image-analyzing system. A dedicated software (TMR 1.24) was used to calculate the mineral content. Sound enamel (group 2) was significantly demineralized after immersion in Biotene and Glandosane (P < 0.001; Kruskal-Wallis). In group 1, mineral loss after storage in Biotene and Glandosane was significantly increased (P < 0.001), compared with the mineral content after demineralization. All other solutions revealed a significant mineral gain (P < 0.01; Wilcoxon), with the most pronounced effects after use of Oralube and mineral water (both containing calcium, phosphates, and fluorides). Therefore, administration of products similar to the last named can be recommended for dentate patients with salivary gland hypofunction.