FLUORIDE PROFILES OF PERIKYMATA IN ENAMEL SURFACES OF HUMAN PREMOLARS

Twenty-five premolars (from Nagoya, Japan <0.1 parts/10(6) F in drinki ng water) were sampled to determine the fluoride content in imbricatio n lines of Retzius between the grooves and ridges of perikymata on the enamel surface. Eight small windows were formed on each surface in gr oove and ridge regions using an etched microsampling technique. By usi ng a regression curve, y = ax(-b), fluoride concentrations were compar ed at depths of 1, 3, 5, 10, 20, 30 and 50 mu m in the perikymata regi ons. Fluoride concentrations increased gradually from the age of 10 to 12 years on the premolar surfaces, but were significantly higher in 1 2-year-olds or older (erupted teeth) than in 10-year-olds or younger ( unerupted teeth). No obvious difference in fluoride concentrations was found between males and females. In the outermost enamel (<5 mu m dep th), fluoride concentrations were significantly higher in the grooves than the ridges of the perikymata, Comparison of the exponential regre ssion coefficients (-b) of the fluoride profiles showed a significant difference between the grooves and ridges. It was concluded that fluor ide concentrations and profiles were higher in grooves than in ridges of perikymata, probably because they are naturally porous and are stag nation areas attracting dental plaque. (C) 1998 Elsevier Science Ltd. Ail rights reserved.