Factors Associated with Failure of Surface-Modified Implants up to Four Years of Function

Objectives: The relative impact of innovative treatment concepts on the failure of surface-modified implants is not well understood. This retrospective study aimed to explore this using data obtained in a university postgraduate training center. Material and Methods: Patients treated with implants for a variety of indications over a 3-year period were included. All implants had been at least 1 year in function. Clinical records were evaluated for implant failure and in reference to implant length/diameter/location, time from tooth loss to implant placement, bone condition (native/grafted), surgical protocol (two-/one-stage), loading protocol (delayed/early/immediate), type of prosthesis (removable/fixed), surgeon's experience level (resident/trainee) and specialty (periodontist/oral surgeon). The impact of each covariate on failure was tested using the Fisher's exact test. Kaplan-Meier survival functions were constructed and Mantel-Cox log-rank tests were used to compare survival functions. To correct for possible interaction, Cox proportional Hazards regression was adopted. Results: Forty-one of 1,180 (3.5%) implants were lost in 34/461 (7.4%) patients (245 ♀, 216 ♂; mean age 51, range 18-90). Factors showing significant impact on failure on the basis of univariate analyses were implant location (p=.015), surgical protocol (p=.002), loading protocol (p=.002), surgeon's experience level (p=.035) and specialty (p=.001). When controlling for other covariates, only the loading protocol had a significant influence (p=.049) with early loading more prone to failure (p=.014) when compared with delayed loading. Immediate loading and delayed loading showed comparable implant survival (p=.311). Conclusions: Implant therapy may be highly successful in a training center where inexperienced clinicians are strictly monitored and personally guided. Implant specific variables do not affect implant survival but early loading is a risk indicator for implant failure, whereas immediate loading is not. © 2010 Wiley Periodicals, Inc.