OBJECTIVE The aims of the study were to evaluate the clinical performance and the complications of combined tooth-implant supported 3 unit fixed partial dentures in the posterior mandible. METHODS 78 partially edentulous patients in the posterior mandible were recruited for the study (n=26/group). Group 1 served as the control group and received 2 dental implants for supporting 3 unit fixed partial dentures (FPD). Groups 2 and 3 were the experimental groups where an implant was combined with a tooth. As stated by the dental implant company, standard implants (8 mm or longer) were included in Group 2, while short implants (shorter than 8 mm) were included in Group 3. Periapical radiographs were taken for evaluation of marginal bone resorption (CBL). Modified plaque index (MPI), bleeding index (BI) and sulcus depth of abutment teeth was recorded at the time of FPD insertion, 6 months after FPD insertion and annually. Abutment tooth intrusions, cementation failures of the restorations, porcelain chipping/delamination, framework fracture, abutment screw loosening, abutment and abutment screw fracture, implant fracture were also recorded as complications. RESULTS Statistically significant different was observed between group 1 (.06 .17) and group 2 (.18 .32) and group 1 and group 3 (.17 .30) in terms of MPI (p≤0.05). No difference was observed between group 2 (.11 .34) and group 3(.14 .36) and group 1(.04 .22) and group 2 in terms of BI. There was statistically significant difference in terms of CBL between group 1 (.259 .05 mm) and group 3 (.11 .03 mm), and group 2 (.03 .03 mm) and group 3 (p≤0.05).The mean abutment tooth sulcus depth was 1.11 .31 mm for group 2 and 1.20 .46 mm for group 3. CONCLUSIONS Within the limitations of the current study, it was concluded that combined tooth-implant supported prostheses (CTISP) is a predictable treatment choice in posterior mandible. When CTISP is planned, it is more predictable to use short dental implant rather than a standard-length dental implant.