title: A longitudinal retrospective study of the analysis of the risk factors of implant failure by the application of generalized estimating equations.
abstract: OBJECTIVE
  Many studies have identified risk factors for dental implant failure, although few have investigated the correlation among implant fixtures within single patients. A better analytical method may include repeated measures analysis including generalized estimating equations (GEE). This retrospective cohort study aimed to (1) identify the risk factors for failure of dental implantation and (2) evaluate an analytical method using GEE analysis.
  
  
  METHODS
  We analyzed data on early and late implant failures in 296 patients providing 721 rough surface dental implants (2.44 implants per patient). Potential predictors of implant failure included age, gender, smoking, location of implant, use of bone augmentation, number of remaining teeth, opposing tooth condition, fixture length, fixture diameter and type of suprastructure (fixed or removable partial denture). The likelihood of early and late implant failure was estimated by GEE.
  
  
  RESULTS
  The early failure rate was 1.5% (11/721 implants, 7/296 patients) and the 10-year cumulative survival rate was 94.0% (7/710 implants, 5/293 patients). The GEE analysis revealed that a significant risk factor for early implant failure was smoking (p<0.01), whereas significant risk factors for late failure were maxillary implant (p=0.02), posterior implant (p<0.01), number of remaining teeth (≥20) (p<0.01), opposing unit being a removable partial denture or nothing (p=0.04) and having a removable type suprastructure (p<0.01).
  
  
  CONCLUSIONS
  GEE analysis showed that smoking was a risk factor for early implant failure, and several risk factors were identified for late implant failure.
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Kinji
authors.initials: K
authors.lastname: Noda
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Arakawa
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kimura-Ono
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Seiya
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Emilio Satoshi
authors.initials: ES
authors.lastname: Hara
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Sonoyama
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Maekawa
authors.affiliation: Department of Stomatognathic Function and Occlusal Reconstruction, Institute of Health Biosciences, Tokushima University Graduate School, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okura
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Osaka University, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Shintani
authors.affiliation: Department of Stomatognathic Function and Occlusal Reconstruction, Institute of Health Biosciences, Tokushima University Graduate School, Japan.
authors.forename: Yoshizo
authors.initials: Y
authors.lastname: Matsuka
authors.affiliation: Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan. Electronic address: kuboki@md.okayama-u.ac.jp.
authors.forename: Takuo
authors.initials: T
authors.lastname: Kuboki
mesh_terms: D000368:Aged; D000540:Alveolar Ridge Augmentation / Q000009:adverse effects; D015331:Cohort Studies; D015921:Dental Implants; D019232:Dental Restoration Failure / Q000706:statistics & numerical data*; D003832:Denture, Partial, Removable / Q000009:adverse effects; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008437:Maxilla / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013997:Time Factors
chemical_list: D015921:Dental Implants
keywords: Generalized estimating equations; Implant fixture failure; Removable denture; Smoking