Sealing of preventively enlarged fissures

The occlusal fissures of 156 permanent first molars in 63 children, 7--8 years of age, were sealed with a chemically polymerizing material (Delton). Deep and narrow fissures were opened up with a pointed diamond before etching and sealing. The treatment was performed by untrained dental students. The patients were called back for treatment every 6 months. 2/3 of the patients were followed up for a period of 2 1/2 years. After that period the retention of sealants was 93% (74 sealants) in ground deep fissures and 88% (28 sealants) in unground shallow fissures.