Occurrence of complications in patients restored with implants

To determine the occurrence and clustering of complications in subjects restored with fixed implant-supported prostheses.

In the present retrospective case series, 241 subjects treated at one clinical centre and provided with 729 implants were included. A clinical and radiographic examination was performed after a mean follow-up period of 4.8 ± 2.0 years. Additional information on occurrence of technical (chipping, loss of retention, fracture of components) and biological complications (marginal bone loss, implant loss) during follow-up was extracted from patient records. For each type of complication and complications overall, regression analyses were performed to identify potential risk factors. Cox regression analyses were used to evaluate time to event for implant loss and technical complications.

In all, 30% of the 241 patients presented with at least one complication of technical and/or biological character during the follow-up period. Technical complications affected 19.5% of subjects, while 14.1% presented with marginal bone loss >2 mm. Implant loss occurred in 4.6% of subjects. While technical complications were noted already early during the maintenance period (<1200 days), implant loss typically occurred during a later phase. A small subgroup of subjects (7.9%) experienced more than one type of complication.

Complications occurred frequently and the most common type of complication was of technical character. Technical and biological complications occurred independently of each other.