Background: Hyposalivation is a highly prevalent condition in old persons.

Objectives: The aim of this study was to assess a novel tool for the diagnosis of hyposalivation using a sugar cube and to compare its reliability to other validated test methods.

Methods: Five tests were performed: unstimulated salivary flow test by draining method (USFT), oral moisture device Mucus® (MCS), sugar cube test (SCT), stimulated salivary flow test by chewing gum (CG) and Saxon test (SX). The sugar cube test consisted in measuring the time needed to disintegrate a standard-sized sugar cube N°4 (5.6 g) placed beneath the tongue. Bivariate correlation analyses were performed. ROC curve analysis and the Youden Index were used to determine the cut-off value. Sensitivity and specificity were calculated according to the determined cut-off point.

Results: A total of 121 participants were recruited, with an average age of 49.8 ± 18.2 years. The USFT was best correlated with the SCT. No correlation was found between SCT and the stimulated saliva tests (CG, SX) as well as the MCS test. According to the Youden index, 140 s is appropriate to diagnose hyposalivation. Sensitivity of .64 and specificity of .91 were found for SCT using USFT as gold standard. The mean subjective evaluation score of the SCT was 3.1 ± 1, significantly higher than USFT 2.6 ± 1.1 (p < .05).

Conclusions: The sugar cube test proved to be a useful method for assessing unstimulated salivation, reducing test execution time and causing less participant discomfort than the gold standard unstimulated salivary flow test.