A new study introduces a simple saliva test that could detect early signs of tooth decay long before cavities form. The findings deliver a clear message: individuals with more cavities tend to have weaker salivary defenses. Their saliva flows slowly, is more acidic and viscous, and less effective at neutralizing acids that erode tooth enamel. Overall, the study underscores a key point: salivary testing has the potential to make dental care more predictive, help to prevent cavities, reduce treatment time, and lower costs.