title: Marginal bone level changes and prosthetic maintenance of mandibular overdentures supported by 2 implants: a 5-year randomized clinical trial.
abstract: BACKGROUND
  Documentation of early loading of mandibular overdentures supported by different implant systems is scarce.
  
  
  OBJECTIVE
  This study aimed to compare the biologic and prosthetic outcome of mandibular overdentures supported by unsplinted early-loaded one- and two-stage oral implants after 5 years of function.
  
  
  METHODS
  Twenty-eight consecutive patients were screened following an inclusion and exclusion criteria, and randomly allocated to treatment groups. Ball-retained mandibular overdentures were fabricated on two unsplinted Straumann (Institut Straumann AG, Basel, Switzerland) and Brånemark (Nobel Biocare AB, Göteborg, Sweden) dental implants and subjected to an early-loading protocol. During the 5-year period, prosthetic complications were recorded. At 5-years of function, plaque, peri-implant inflammation, bleeding, and calculus index scores were recorded, and standard periapical radiographs were obtained from each implant for measurement of marginal bone loss.
  
  
  RESULTS
  All implants survived during the observation period. The peri-implant inflammation, bleeding, and calculus index scores around Straumann and Brånemark implants were similar (p > .05). The marginal bone loss around Brånemark implants (1.21 +/- 0.1) was higher than Straumann implants (0.73 +/- 0.06) at 5 years of function (p = .002). Kaplan-Meier tests revealed that 1- and 5-year survival of overdentures on Straumann and Brånemark implants were similar (p = .85). Wear of the ball abutment in the Brånemark group was higher than in the Straumann group (p < .05). Complications regarding the retainer and the need for occlusal adjustments were higher in the Straumann group (p < .05). Chi-square test revealed that the frequency of retightening of the retainer was higher in the Straumann group than in the Brånemark group (p < .05).
  
  
  CONCLUSIONS
  Mandibular overdentures supported by unsplinted early-loaded Straumann and Brånemark implants lead to similar peri-implant soft tissue and prosthetic outcomes, although higher marginal bone loss could be observed around Brånemark implants after 5 years.
authors.affiliation: CosmORAL Oral and Dental Health Polyclinics, Section of Prosthodontics, Kavaklidere, Ankara, Turkey. mcehreli@hotmail.com
authors.forename: Murat Cavit
authors.initials: MC
authors.lastname: Cehreli
authors.forename: Serdar
authors.initials: S
authors.lastname: Uysal
authors.forename: Kivanc
authors.initials: K
authors.lastname: Akca
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology*; D016009:Chi-Square Distribution; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants / Q000009:adverse effects*; D003774:Dental Plaque Index; D017267:Dental Prosthesis Design / Q000009:adverse effects*; D017268:Dental Prosthesis Retention / Q000295:instrumentation*; D019094:Dental Prosthesis, Implant-Supported / Q000009:adverse effects*; D019554:Dental Restoration Wear; D003799:Dental Stress Analysis; D003834:Denture Precision Attachment; D003828:Denture, Overlay; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009911:Oral Hygiene Index; D010512:Periodontal Index; D011859:Radiography; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D013997:Time Factors; D057085:Tooth Wear / Q000209:etiology; D016474:Weight-Bearing
chemical_list: D015921:Dental Implants