title: Stability evaluation of implants integrated in grafted and nongrafted maxillary bone: a clinical study from implant placement to abutment connection.
abstract: BACKGROUND
  Clinical studies have shown a higher degree of implant failures in grafted bone compared with normal nongrafted maxillary bone. Additionally, a prolonged time for integration of titanium implants in grafted block bone has been shown by means of resonance frequency analysis (RFA).
  
  
  OBJECTIVE
  The aim of this prospective study was to compare the stability of implants placed in particulate bone, onlay block bone, interpositional bone, and nongrafted maxillary bone during the early phase of osseointegration using RFA and implant failure.
  
  
  METHODS
  Thirty-five patients with edentulism in the maxilla were included in the study. In all, 260 Astra Tech TiOblast implants (Astra Tech AB, Mölndal, Sweden) were installed. Twenty-five of these patients had severe maxillary atrophy and were treated with iliac bone grafts 5 to 6 months prior to implant placement, 19 with lateral onlay block grafts on one side (group A, 38 implants) and particulate bone for lateral augmentation on the other (group B, 38 implants). These 19 patients also got bilateral sinus floor augmentation with particulate bone (group C, 76 implants). Six patients had an unfavorable sagittal relation between the jaws and underwent a LeFort I operation with interpositional bone blocks grafted to the nasal and sinus floors (group D, 48 implants). The remaining 10 patients could be treated with implants without bone augmentation and served as control (group E, 60 implants). RFA was performed at implant placement and abutment connection 6 months later and an implant stability quotient (ISQ) value was given for each implant.
  
  
  RESULTS
  Four implants (1.5%) were found mobile at abutment connection and removed (two in group A and two in group D). RFA showed a slight increase in stability from installation to abutment connection but the differences were not statistically significant in any of the groups (Wilcoxon signed rank test for comparison of paired data). Implants installed in group D had a significantly lower ISQ value at both measurements compared with the other groups (Wilcoxon Rank Sum test for comparisons of independent samples, p = .05).
  
  
  CONCLUSIONS
  It is concluded that TiO(2)-blasted implants placed in nongrafted and grafted maxillary bone using a two-staged protocol show similar stability during the early phase of osseointegration. Patients reconstructed with interpositional bone graft after a LeFort I osteotomy showed lower implant stability values than nongrafted patients and other grafting techniques.
authors.affiliation: Department of Oral and Maxillofacial Surgery, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. lars.rasmusson@gu.se
authors.forename: Lars
authors.initials: L
authors.lastname: Rasmusson
authors.forename: Andreas
authors.initials: A
authors.lastname: Thor
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000534:rehabilitation / Q000601:surgery; D016025:Bone Transplantation / Q000009:adverse effects / Q000379:methods*; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation / Q000601:surgery; D008297:Male; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D016348:Osseointegration; D019340:Osteotomy, Le Fort / Q000009:adverse effects; D011446:Prospective Studies; D011859:Radiography; D018709:Statistics, Nonparametric; D014025:Titanium; D014732:Vibration
chemical_list: D015921:Dental Implants; C009495:titanium dioxide; D014025:Titanium