Monitoring the bacterial load of saliva can be useful in predicting caries onset. Studies have shown that high caries activity populations have >1 × 10 6 mL -1 of S. mutans and/or 1 × 10 5 mL -1 of Lactobacillus in their saliva, while low caries activity populations have <1 × 10 5 mL -1 of S. mutans and/or 1 × 10 4 mL -1 of Lactobacillus. Salivary bacteria such as Prevotella have been studied as potential predictive markers for caries onset. Furthermore, studies have associated periodontal diseases with increased levels of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in saliva. Periodontal diseases are characterized by inflammation and tissue destruction around teeth. Saliva can be used to monitor oral bacteria levels, which have been associated with increased prevalence of periodontal diseases. Periodontitis has also been associated with increased levels of aspartate AST and ALP in saliva, which can be used as markers for monitoring the disease.