This study compared two techniques for placing sealant in an elementary school setting. Eighty-five children in grades 1 to 4 in two schools were assigned randomly to two sealant treatment groups: 1) acid etch technique (AE), and 2) air abrasion with no acid etch (KCP-1000). Noncarious, nonfilled occlusal, distolingual and buccal pit surfaces of first permanent molars were sealed. A total of 300 teeth received sealants, and 230 were evaluated at 6 months. Rates of complete sealant retention at 6 months were: occlusal surfaces, 97% for AE and 96% for KCP-1000; distolingual surfaces, 82% for AE and 49% for KCP-1000; and buccal surfaces, 77% for AE and 7% for KCP-1000. Differences in complete retention at 6 months between AE and KCP-1000 were not significant for occlusal surfaces (P = 0.14) but were significant for buccal and distolingual surfaces (P < 0.0001). Results suggest that sealants placed with air abrasion have retention rates for occlusal surfaces similar to AE. More research is needed to identify factors contributing to low retention rates on other surfaces for KCP-1000.