title: Comparison of implant stability by means of resonance frequency analysis for flapless and conventionally inserted implants.
abstract: BACKGROUND
  Resonance frequency analysis (RFA) is a noninvasive technique for the quantitative assessment of implant stability. Information on the implant stability quotient (ISQ) of transmucosally inserted implants is limited.
  
  
  OBJECTIVE
  The aim of this investigation was to compare the ISQ of conventionally inserted implants by raising a muco-periostal flap with implants inserted using a flapless procedure.
  
  
  METHODS
  Forty elderly patients with complete edentulous maxilla were consecutively admitted for treatment with implant-supported prostheses. A computer tomography was obtained for the computer-assisted implant planning. One hundred ten implants were placed conventionally in 23 patients (flap-group) and 85 implants in 17 patients by means of the flapless method (flapless-group) using a stereolithographic template. RFA measurements were performed after implant placement (baseline) and after a healing time of 12 weeks (reentry).
  
  
  RESULTS
  All implants exhibited clinically and radiographically successful osseointegration. Bone level did not change significantly neither for genders nor type of surgical protocol. Mean ISQ values of the flapless-group were significantly higher at baseline (p < .001) and at reentry (p < .001) compared with the flap-group. The ISQ values were significantly lower at reentry compared with baseline for the flap-group (p = .028) but not for the flapless-group. This group showed a moderate, but insignificant increase. RFA measurements of males resulted in ISQ values that were thoroughly higher as compared with females at both time-points in both groups. Correlation between RFA and bone level was not found.
  
  
  CONCLUSIONS
  The flapless procedure showed favorable conditions with regard to implant stability and crestal bone level. Some changes of the ISQ values that represent primary (mechanical) and secondary (bone remodeling) implant stability were observed in slight favor of the flapless method and male patients. In properly planned and well-selected cases, the minimal invasive transmucosal technique using a drill-guide is a safe procedure.
authors.affiliation: Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland. joannis.katsoulis@zmk.unibe.ch
authors.forename: Joannis
authors.initials: J
authors.lastname: Katsoulis
authors.forename: Marianna
authors.initials: M
authors.lastname: Avrampou
authors.forename: Christian
authors.initials: C
authors.lastname: Spycher
authors.forename: Marko
authors.initials: M
authors.lastname: Stipic
authors.forename: Norbert
authors.initials: N
authors.lastname: Enkling
authors.forename: Regina
authors.initials: R
authors.lastname: Mericske-Stern
mesh_terms: D016301:Alveolar Bone Loss / Q000175:diagnosis; D017076:Computer-Aided Design; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D008297:Male; D016348:Osseointegration; D013524:Surgical Flaps; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants