Salivary Testing in Daily Practice: Poor Correlation With Clinical Findings

Objectives: Saliva has been extensively studied as a potential diagnostic tool over the last decade due to its ease and non-invasive accessibility along with its abundance of biomarkers. However, whether current salivary testing provides information useful for clinical practice remains under debate.
This pilot study evaluates the correlation between salivary testing and a number of currently-used indexes or the presence of caries in a ‘practice-based’ scenario.

Methods: In total, 37 non-smoker adult patients (mean age 27 years; 70% females) were enrolled. A commercial salivary test kit (Saliva-Check Buffer) was used to measure salivary quantity, consistency, flow, pH and buffering ability, according to manufacturer’s instructions. The decayed, missing, filled teeth (DMFT) index, the plaque index and the supragingival calculus index were then calculated by standard assessments. The presence of caries was evaluated. The reported results were then correlated.

Results: According to the salivary test, saliva quantity was low in 20 patients (54%) and normal in the remaining ones. Six patients (16%) had increased salivary viscosity. Salivary flow was low in 12 patients (32%). pH was below normal values in 11 patients (30%), and buffering ability was below standard range in 28 subjects (76%).
Mean DMFT was 8.6±6.0, with higher values in patients with increased salivary viscosity (10.1±6.6 vs 8.3±5.4 in those with normal viscosity). Counterintuitively, plaque and calculus indices were higher in patients with normal salivary quantity. No correlations between any parameter measured with the testing kit and the presence of caries were reported.

Conclusions: In a ‘practice-based’ scenario, a standard commercial salivary testing kit did not provide clinically-relevant information. More sensitive tools and protocols, and the establishment of defined evidence-based guidelines are advisable to allow routine use of salivary diagnostics as chair-side tests.