Abstract: Objective To study the clinical application of the keykey attachment used in the bilateral molar missing cases (Kennedy I).Methods 26 patients with bilateral molar missing (Kennedy I) were selected and were repaired with keykey attachment denture.And at the beginning,3 month,6 month,12 month and 24 month,the masticatory efficiency,attachment retentive force,and periodontics index(GI,PD) were investigated and were analysised by stastic software.Results 26 patients treated with keykey way attachment were satisfied with the denture.The masticatory efficiency statistically increased at the time of 3 month,6 month,12 month and 24 month.The retentive force decreased with time,and at the 24 month it had statistically significant compared with the first time.The gingival index (GI) statistically inceased at the time of 3 month.The periodontics probing depths (PD) had no significant change.Conclusions The key-key attachment is a kind of esthetic,stable prosthetics restoration method with high efficiency.

Key words: Key-Key way attachment denture , masticatory effciency, attachment retentive force , gingival index, periodontics probing depths attachment level.