To date there has been no evidence concerning the need for adjusting the occlusion after sealant placement. Thus, this study investigated the occlusal effects of filled and unfilled sealants. For each of 18 subjects a sealant was applied and the occlusion monitored for 1 week. Each participant received a filled and an unfilled sealant for the specified period. With the filled sealant, nearly all subjects experienced a perceptable occlusal change and most were unable to abrade the interferences to a comfort level. These results indicate that the occlusion should be routinely verified and, if necessary, adjusted immediately after placement of a filled sealant.