A study compared two alternative methods for the clinical treatment of occlusal pits and fissures in the early posteruption state. On contralateral pairs of permanent first and second molars, one molar was given a preventive treatment with pit and fissure sealant, and the paired molar surfaces were restored with amalgam. The retreatment rate for sealant was highest after 6 months (20%) and declined to 11% or less during the 7 years. A generalized margin deterioration was seen in more than 50% of amalgam restorations, whereas 55% of the sealant margins remained not detectable clinically. The data from this study support the application of pit and fissure sealant as a treatment within the specific limitations of a controlled preventive program and professional supervision.