Single Implants in the Anterior Maxilla After 15 Years of Follow-up: Comparison with Central Implants in the Edentulous Maxilla

Purpose: To present long-term clinical and radiographic data on single-implant treatment in the anterior maxilla and to compare these results with comparable data of central implants supporting fixed prostheses in the edentulous maxilla. Materials and Methods: A total of 38 patients consecutively restored with 47 single-implant crowns in the anterior maxilla were included in the single-implant (study) group. The implants in the edentulous group (control) were included by randomly selecting one of the central implants (closest to midline) from 76 consecutively treated edentulous patients. Mean age was 25.4 years (SD: 10.0) and 60.1 years (SD: 11.6) at inclusion (P .001) for the study and control groups, respectively. Clinical and radiographic data were retrospectively retrieved from files holding up to 15 years of function in both groups. Results: No implants in the study group were lost (cumulative success rate: 100%), while 3 implants in the control group were lost (cumulative success rate: 95.4%). Ten single crowns were replaced (15-year cumulative survival rate: 77.0%), and the study group showed more mucosal problems and fistulas compared to the implants in the control group (P .05). Loose screws were a common problem in the single-implant group during the first 5 years of function, but bone loss did not differ significantly between patients with stable and loose screws/fistulas (P > .05) or between study and control implants after 15 years (P > .05). Conclusions: There is an obvious difference between the survival of the implants (100%) and original implant crowns (77%) in the study group. The present early single-implant restorations showed significantly more mechanical/fistula problems compared to central implants in the edentulous maxilla (P .05), but bone response was similar for both groups during 15 years of follow-up. Bone loss was not affected by the level of the implant head in relation to the cementoenamel junction of adjacent teeth, nor was it affected by mechanical or mucosal problems or persistent fistulas of the single implants during the entire follow-up period.