title: The effect of rigid and non-rigid connections between implants and teeth on biological and technical complications: a systematic review and a meta-analysis.
abstract: OBJECTIVE
  To assess survival, as well as technical and biological complication rates of partial fixed dental prostheses (FDPs) supported by implants and teeth.
  
  
  METHODS
  An electronic Medline search was conducted to identify articles, published in dental journals from January 1980 to August 2015, reporting on partial FDPs supported by implants and teeth. The search terms were categorized into four groups comprising the PICO question. Manual searches of published full-text articles and related reviews were also performed.
  
  
  RESULTS
  The initial database search produced 3587 relevant titles. Three hundred and eighty-six articles were retrieved for abstract review, while 39 articles were selected for full-text review. A total of 10 studies were selected for inclusion. Overall survival rate for implants ranged between 90% and 100%, after follow-up periods with a mean range of 18-120 months. The survival of the abutment teeth was 94.1-100%, while the prostheses survival was 85-100% for the same time period. The most frequent complications were "periapical lesions" (11.53%). The most frequent technical complication was "porcelain occlusal fracture" (16.6%), followed by "screw loosening" (15%). According to the meta-analysis, no intrusion was noted on the rigid connection group, while five teeth (8.19%) were intruded in the non-rigid connection group [95% CI (0.013-0.151)].
  
  
  CONCLUSIONS
  The tooth-implant FDP seems to be a possible alternative to an implant-supported FDP. There is limited evidence that rigid connection between teeth and implants presents better results when compared with the non-rigid one. The major drawback of non-rigidly connected FDPs is tooth intrusion.
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Phoebus
authors.initials: P
authors.lastname: Tsaousoglou
authors.affiliation: Department of Prosthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece.|Department of Prosthodontics, School of Dental Medicine, Tufts University, Boston, MA, USA.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Michalakis
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, Tufts University, Boston, MA, USA.
authors.forename: Kiho
authors.initials: K
authors.lastname: Kang
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, Tufts University, Boston, MA, USA.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Weber
authors.affiliation: Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
mesh_terms: D000044:Dental Abutments; D015921:Dental Implants; D019232:Dental Restoration Failure; D003779:Denture Design; D003830:Denture, Partial, Fixed; D006801:Humans
chemical_list: D015921:Dental Implants
keywords: attachment; biological complication; dental implant; non-rigid connection; partial FDP; rigid connection; survival; technical complication; tooth-implant connection