Glycerin

Dental products that advertise mineral content while also containing glycerin are considered internally contradictory, as the glycerin may prevent minerals from entering the teeth. Glycerin creates a film over tooth surfaces comparable to a bandage or plastic wrap, which can block minerals from re-entering enamel. The concern with glycerin is specifically its topical application on teeth, not the consumption of small amounts in food. Studies suggest glycerin may remain on the teeth for approximately 19 to 20 good swishes. Glycerin is a hidden issue because it appears in many natural dental products that otherwise avoid conventional additives. Glycerin's temporary reduction in tooth sensitivity may mask the underlying problem of impaired mineral uptake.