title: A 4-year prospective clinical and radiological study of maxillary dental implants supporting single-tooth crowns using early and delayed loading protocols.
abstract: BACKGROUND
  Recent studies have showed that immediate/early loading of dental implants is a clinically feasible concept with results similar to those for standard two-stage procedures, especially in the mandible. However, there are only a few studies regarding the immediate/early loading of maxillary implants supporting single-tooth crowns.
  
  
  OBJECTIVE
  The aim of this study was to compare the clinical and radiological outcomes of early- and delayed-loaded dental implants supporting single-tooth crowns in the maxilla.
  
  
  METHODS
  Twenty-nine patients were consecutively treated between 2000 and 2002 with 59 Brånemark System MK III TiUnite implants (Nobel Biocare AB, Göteborg, Sweden) in the maxilla. Two groups were formed according to the loading protocols. In the test group, definitive implant-supported single crowns were delivered to 19 patients 6 weeks after the implant placement. In the control group, definitive implant-supported single crowns were delivered to 10 patients 6 months after the implant placement. Clinical and radiographic parameters were recorded at baseline, 1 to 4 years. Implant stability measurements have only been performed at 4-year follow-up recall.
  
  
  RESULTS
  Overall, three implants were lost during the study period. Two implants were lost in the test group including 36 implants, which indicated a survival rate of 94.4%. One of the lost implants was replaced and then osseointegrated successfully. One implant was lost in the control group during the healing period, which indicated a survival rate of 95.7%. The average marginal bone loss was 1.11 mm for 56 implants after 4 years. There were no significant differences in marginal bone levels, insertion torque, and resonance frequency values between the two groups.
  
  
  CONCLUSIONS
  The results of this study indicate that 6 weeks of early loading period for TiUnite-surface titanium implants in the maxilla is reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.
authors.affiliation: Department of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, Ohio 43218-2357, USA. turkyilmaz.1@osu.edu
authors.forename: Ilser
authors.initials: I
authors.lastname: Turkyilmaz
authors.forename: Mehmet
authors.initials: M
authors.lastname: Avci
authors.forename: Serkan
authors.initials: S
authors.lastname: Kuran
authors.forename: Esma Nida
authors.initials: EN
authors.lastname: Ozbek
mesh_terms: D000328:Adult; D016301:Alveolar Bone Loss / Q000209:etiology; D003442:Crowns; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D011446:Prospective Studies; D011861:Radiography, Dental; D018709:Statistics, Nonparametric; D013997:Time Factors; D019415:Torque; D014732:Vibration