title: Bone dimensional variations at implants placed in fresh extraction sockets: a multilevel multivariate analysis.
abstract: OBJECTIVE
  To use multilevel, multivariate models to analyze factors that may affect bone alterations during healing after an implant immediately placed into an extraction socket.
  
  
  METHODS
  Data included in the current analysis were obtained from a clinical trial in which a series of measurements were performed to characterize the extraction site immediately after implant installation and at re-entry 4 months later. A regression multilevel, multivariate model was built to analyze factors affecting the following variables: (i) the distance between the implant surface and the outer bony crest (S-OC), (ii) the horizontal residual gap (S-IC), (iii) the vertical residual gap (R-D) and (iv) the vertical position of the bone crest opposite the implant (R-C).
  
  
  RESULTS
  It was demonstrated that (i) the S-OC change was significantly affected by the thickness of the bone crest; (ii) the size of the residual gap was dependent of the size of the initial gap and the thickness of the bone crest; and (iii) the reduction of the buccal vertical gap was dependent on the age of the subject. Moreover, the position of the implant opposite the alveolar crest of the buccal ridge and its bucco-lingual implant position influenced the amount of buccal crest resorption.
  
  
  CONCLUSIONS
  Clinicians must consider the thickness of the buccal bony wall in the extraction site and the vertical as well as the horizontal positioning of the implant in the socket, because these factors will influence hard tissue changes during healing.
authors.affiliation: Department of Periodontology Institute of Odontology The Sahlgrenska Academy at University of Gothenburg, Box 450, SE 405 30 Göteborg, Sweden. cristiano.tomasi@odontologi.gu.se
authors.forename: Cristiano
authors.initials: C
authors.lastname: Tomasi
authors.forename: Mariano
authors.initials: M
authors.lastname: Sanz
authors.forename: Denis
authors.initials: D
authors.lastname: Cecchinato
authors.forename: Bjarni
authors.initials: B
authors.lastname: Pjetursson
authors.forename: Jorge
authors.initials: J
authors.lastname: Ferrus
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
authors.forename: Jan
authors.initials: J
authors.lastname: Lindhe
mesh_terms: D000328:Adult; D000539:Alveolar Process / Q000033:anatomy & histology* / Q000601:surgery*; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D014081:Tooth Extraction; D020390:Tooth Socket / Q000601:surgery*; D016896:Treatment Outcome; D014945:Wound Healing