The purpose of this study was to evaluate 6 years cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with $Br{aa}nemark$ $TiUnite^{(R)}$ implant system. The findings from this study were as followed ; 1. The 112 (111 persons) single implants that were placed in the mandibular posterior region were successful except 4 cases and showed 96.42% CSR. 2. The 55 (55 persons) single implants that were placed in the mandibular first molar region were successful except 2 cases and showed 96.36% survival rate. And, among the 57 (56 persons) single implants replacing the mandibular second molar. 2. failed showing 96.49% survival rate. There was no significant statistical difference. 3. Among the total 112 implants, 5.0mm wide diameter implants were placed in 96 cases(85.7%) showing 96.9% survival rate. 4.0mm standard diameter implants were placed in 16 cases showing 93.8% survival rate. There was no significant statistical difference. 4. Long implants above 10.0mm length were placed 103 cases(91.0%) and showed 96.1% survival rate. Short implants within 8.5mm length were placed 9 cases and showed 100% survival rate. There was no significant statistical difference. 5. 37 implants placed in type I, II bone quality were showed higher survival rate(100%) than that of 52 implants placed in type III, IV bone quality(92.3%). But, there was no significant statistical difference. In conclusion, $Br{aa}nemark$ $TiUnite^{(R)}$ implant showed successful results when replacing manbibular single molar.