title: Radiographic evaluation of crestal bone levels of delayed implants at medium-term follow-up.
abstract: OBJECTIVE
  The aim of this study was to evaluate the radiographic bone level changes after delayed implant placement at medium-term follow-up, with three elements kept constant: keratinized gingiva thickness, implant axes perpendicular to the opposing occlusal surface, and implants with a collar of 2 mm.
  
  
  METHODS
  Patients treated in a private practice setting were retrospectively enrolled in the study. They underwent delayed placement (4 to 8 weeks after extraction) of dental implants in edentulous premolar or molar regions. Implants followed a delayed loading protocol. Crestal bone levels were measured at baseline; at provisional prosthesis placement; at 1, 3, and 5 years; and at medium-term follow-up of healing from implant placement.
  
  
  RESULTS
  One hundred twenty patients received 135 implants (one or two implants per patient); 3 implants were lost. After a mean follow-up period of 9.71 ± 4.88 years, a survival rate of 97.76% was reported. At 1 year after implant placement, mean bone loss of -1.5 ± 0.62 mm was found. At almost 3 years post-implant placement, a mean bone gain of +1.20 ± 0.49 mm was seen, which was statistically significantly different compared with 1 year. After this point, the bone levels remained stable; similar values were reported over time, with no significant differences.
  
  
  CONCLUSIONS
  The mean vertical bone gain of +1.20 ± 0.49 mm seen at almost 3 years after implant placement in this study may be supported by both clinical parameters as presence of sufficiently thick keratinized gingiva (3 mm), implants with a 2-mm collar, and the axis of implant insertion perpendicular to the opposing occlusal surface.
authors.forename: Giovanni B
authors.initials: GB
authors.lastname: Bruschi
authors.forename: Roberto
authors.initials: R
authors.lastname: Crespi
authors.forename: Paolo
authors.initials: P
authors.lastname: Capparè
authors.forename: Nicola
authors.initials: N
authors.lastname: Grande
authors.forename: Ernesto
authors.initials: E
authors.lastname: Bruschi
authors.forename: Enrico
authors.initials: E
authors.lastname: Gherlone
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001861:Bone Regeneration; D003758:Dental Implantation, Endosseous; D015921:Dental Implants / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013524:Surgical Flaps; D013997:Time Factors
chemical_list: D015921:Dental Implants