Fluoride tablet programs in healthy elderly subjects: Distribution of fluoride in saliva and plaque with tablets in different sites

Based on root caries data and oral sugar clearance pattern, vestibular surfaces of upper incisors and lower molars may be regarded as risk areas along with the proximal surfaces. The aim of the present study was to use this information in improving fluoride tablet programs for the elderly. Six healthy elderly males with full dental arches took part. Flavored and unflavored tablets dissolved passively either under the tongue or in the vestibule close to the root caries risk areas. Salivary fluoride was determined at five to six intra-oral sites with a micro-sampling technique at intervals up to 10 min tablet use. Plaque samples were collected from single tooth surfaces before and after tablet use, and analyzed for total fluoride and total protein by microtechniques. Salivary fluoride exposure to root caries risk areas was strongly increased when fluoride tablets were placed in the vestibule in these areas. The unflavored tablet gave higher fluoride retention in saliva than did the flavored brand. Plaque fluoride levels tended to be above baseline in the first couple of hours after tablet use, and then to decline. In the caries risk areas, at vestibular surfaces of lower posterior and upper incisor teeth, most of the fluoride taken up in plaque had been lost after 5 h and a bread meal, whereas in the non-risk areas it was largely retained. The study demonstrated that fluoride exposures to the vestibular caries risk areas can be strongly increased by placing fluoride tablets close to them. An unflavored tablet seemed to give higher exposures than a flavored one. The rapid loss of fluoride from plaque in slow clearance risk areas indicates that more than one daily treatment would be required for elderly caries risk subjects.