Tooth polishing This outermost fluoride rich layer of enamel is removed when tooth polishing is provided. The mineral components of saliva and polishing pastes containing fluoride can assist in remineralizing this outer layer. The enamel surface is strong enough to withstand repeated tooth polishing, but it should be avoided on newly erupted teeth, exposed root surfaces and areas of demineralization. If polishing does occur on these surfaces, fluoride therapy can minimize the risk of dental caries. Excessive pressure can lead to frictional heat that may cause pulpal discomfort or necrosis of the dental pulp. Surfaces of restorations may be damaged by conventional
Human tooth mixed stage. The mixed stage lasts until the last primary tooth is lost and the remaining permanent teeth erupt into the mouth. There have been many theories about the cause of tooth eruption. One theory proposes that the developing root of a tooth pushes it into the mouth. Another, known as the cushioned hammock theory, resulted from microscopic study of teeth, which was thought to show a ligament around the root. It was later discovered that the "ligament" was merely an artifact created in the process of preparing the slide. Currently, the most widely held belief is that the periodontal