Ten prospective studies (case series and cohort design, number not reported) (468 patients and 1,793 implants) were included in the review. Follow-up ranged from zero to 60 months.
Early surgical complications: Eight studies (428 patients, 1,581 implants) reported on early surgical complications. Thirty-nine patients (9.1%) experienced an early surgical complication. The most common complication was limited access in posterior areas (10 patients, 2.3%). Other common early surgical complications included primary bone augmentation necessary (eight patients, 1.9%), unexpected bony dehiscence (three patients, 0.7%), fracture of template (three patients, 0.7%) and infection at drill site pins (three patients, 0.7%)
Early prosthetic complications: Three studies (69 patients, 438 implants) reported on early prosthetic complications. Thirteen patients (18.8%) experienced an early prosthetic complication. The most common early prosthetic complication was misfit of abutment to bridge (five patients, 7.2% of patients). Other common early prosthetic complications included extensive adjustments of the occlusion (three patients, 4.3%) and incomplete seating of prosthesis (two patients, 2.9%).
Late implant failures: Six studies (138 patients, 721 implants) reported on implant failures after a minimum of 12 months. In four of these studies (101 patients, 537 implants), 37 implants (6.9%) failed during the follow-up period. The implant failure rate was reported to be higher in open flap surgery with delayed loading compared to flapless surgery with immediate loading procedures. Two studies (37 patients, at least 184 implants) had no implant failures.
Late prosthetic complications: Five studies (108 patients) reported on late prosthetic complications. Two studies (39 patients, at least 71 implants) had no prosthetic complications. In three studies (69 patients, 438 implants), all of which used a flapless procedure with immediate loading, 13 patients (12%) experienced complications.