Intermediate long-term clinical performance of dental implants placed in sites with a previous early implant failure: a retrospective analysis.

Abstract

The aim of this retrospective case-control study was to evaluate the intermediate long-term clinical performance and success rate of dental implants inserted into sites of previous early implant failure. A retrospective evaluation was conducted on 6456 patients with 10,234 implants from January 2004 to December 2011. The patients with early implant failure retreated in previous failed sites were enrolled in the study. The collected data included patient's characteristics, implants characteristics (failed and replaced), and if was the case, any additional surgery performed prior or at the same of implant placement to obtain proper hard tissues dimensions. Moreover, peri-implant clinical parameters, marginal bone loss (MBL), and the implant quality scale (IQS) of the replacement implants were recorded after delivering of the final prosthesis and annually thereafter. Ninety-six patients (100 implants) showed initial early failure (failure rate=0.98%). Sixty-six patients (male: 38; female: 28; mean age: 42.3±18.2years old) with early implant failure received a total of 67 replacement dental implants. Three patients with three implants dropped out of the study during the mean follow-up of 69.4±27.0months. The implant length and diameter were varied for seven sites. The number of sites that required additional surgeries increased from 18 to 24 for first and replacement implant insertion, respectively. One of the 67 replacement implants failed before prosthesis delivery, and one implant failure occurred 20months after prosthesis delivery, which represented a cumulative survival rate of 94.6%. At last follow-up evaluation, the overall mean MBL was 1.7±1.3mm. Two of 64 implants failed according to IQS criteria, three implants showed satisfactory survival, and one implant showed compromised survival. No pain or tenderness was observed in the rest 58 implants evaluated, showing a success rate (optimum health) of 90.6%. Within the limits of the present study, early implant failure was not an obstacle for implant replacement at the same site after an adequate soft and hard tissues healing period.