459. The range of level of fluoride secreted by the glands into the mouth is_____________? September 27, 2025 by Admin A. 0.004-0.005 ppm B. 0.006-0.007 ppm C. 0.007-0.005 ppm D. 0.007-0.08 ppm ✅ The correct answer is option C. 0.007-0.005 ppm.