title: Immediately loaded distally cantilevered fixed mandibular prostheses supported by four implants placed in both in fresh extraction and healed sites: 2-year results from a prospective study.
abstract: OBJECTIVE
  To evaluate the outcome of immediately loaded distally cantilevered mandibular full-arch prostheses according to the 'all-on-four' concept supported by implants placed in both fresh extraction and healed sites.
  
  
  METHODS
  A prospective study was conducted in 24 patients with extraction of all remaining mandibular teeth and placement of 4 implants per patient (2 mesial axial and 2 distal tilted) for full-arch mandibular restorations. Implants were inserted in fresh extraction sockets 2.3 ± 1.0 per patient and 1.7 ± 1.0 implants in healed sites. Implants placed in fresh extraction sites (n = 55) were significantly (P <0.01) more deeply inserted than implants (n = 41) placed in healed sites (peri-implant alveolar crest: +1.6 ± 0.8 mm vs +0.6 ± 0.7 mm). Patients received an immediate provisional fixed dental prosthesis and, 3 months later, a definite resin veneered prosthesis with metal framework. At the 12-and 24-month follow-up, patients were evaluated for implants and prosthesis success, for prosthodontic maintenance efforts and patient satisfaction. At both follow-up examinations, peri-implant marginal bone level, implant pocket depth, plaque, bleeding, gingival and calculus indices were evaluated and compared between implants placed in fresh extraction and healed sites.
  
  
  RESULTS
  At the 24-month follow-up, no implant failed and all prostheses were stable. There were five fractures of the provisional prosthesis in 5 patients but no fracture of the definite prostheses. For the definite prostheses, 15 acrylic teeth had to be renewed/repaired (in 10 patients) and 18 patients presented the need for the implant-supported prosthesis to be rebased. Peri-implant marginal bone level after 12 and 24 months was -0.18 ± 0.20 mm and -0.40 ± 0.29 mm for all implants (P <0.001) representing bone level differences of 0.35 mm between implants placed in healed and post-extractive sites at both the 1st year (95%-CI:-0.49 to -0.20) and the 2nd year (95%-CI: -0.57 to -0.14) assessment. Plaque (1st year: 1.17 ± 0.48 versus 0.5 ± 0.6; P <0.001; 2nd year: 1.21 ± 0.51 versus 0.55 ± 0.6; P <0.001) and calculus indices (1st year: 0.92 ± 0.28 versus 0.45 ± 0.51; P <0.001; 2nd year: 1.00 ± 0.42 versus 0.5 ± 0.51; P <0.001) were significantly higher for implants placed in fresh extraction than in healed sites. Patients' subjective satisfaction score rating assessed by 5 items was high at the 1- (score: 4.6 ± 0.4) and 2-year evaluation (score: 4.7 ± 0.36).
  
  
  CONCLUSIONS
  Within the limits of this study, immediately loaded full-arch prostheses can be supported by four implants placed simultaneously into healed and fresh extraction sites.
authors: Stefan
authors: S
authors: Krennmair
authors: Rudolf
authors: R
authors: Seemann
authors: Michael
authors: M
authors: Weinländer
authors: Gerald
authors: G
authors: Krennmair
authors: Eva
authors: E
authors: Piehslinger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000145:classification; D015331:Cohort Studies; D003728:Dental Calculus / Q000145:classification; D015921:Dental Implants; D003774:Dental Plaque Index; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003801:Dental Veneers; D003779:Denture Design; D003823:Denture Rebasing; D003780:Denture Repair; D003825:Denture, Complete, Immediate; D003826:Denture, Complete, Lower; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D057893:Immediate Dental Implant Loading; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000145:classification; D011446:Prospective Studies; D020390:Tooth Socket / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants