title: Factors associated with failure of surface-modified implants up to four years of function.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Periodontology and Oral Implantology, University of Ghent, Faculty of Medicine and Health Sciences, Ghent, Belgium. jan.cosyn@ugent.be
authors.forename: Jan
authors.initials: J
authors.lastname: Cosyn
authors.forename: Edward
authors.initials: E
authors.lastname: Vandenbulcke
authors.forename: Hilde
authors.initials: H
authors.lastname: Browaeys
authors.forename: Georges
authors.initials: G
authors.lastname: Van Maele
authors.forename: Hugo
authors.initials: H
authors.lastname: De Bruyn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016025:Bone Transplantation; D016009:Chi-Square Distribution; D002983:Clinical Competence; D003430:Cross-Sectional Studies; D003757:Dental Implantation / Q000193:education; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants / Q000009:adverse effects; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading / Q000009:adverse effects; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013499:Surface Properties; D055815:Young Adult
chemical_list: D015921:Dental Implants