title: Short-term clinical results of Nobel Direct implants: a retrospective multicentre analysis.
abstract: OBJECTIVE
  The present retrospective clinical study was undertaken to evaluate the survival rate and marginal bone conditions around Nobel Direct one-piece implants. The purpose was also to compare the results with when these implants are used for immediate/early loading with implants allowed to heal before loading.
  
  
  METHODS
  Forty-three consecutive patients previously treated with 117 Nobel Direct implants at four different centres were evaluated. The implants had been used in both jaws for treatment after loss of single and multiple teeth. Immediate/early loading (within 2 weeks) with a provisional crown/bridge was applied to 95 implants, while 22 implants healed unloaded for 6 weeks to 6 months before loading. Calculations of marginal bone loss were performed in radiographs taken at placement and after an average of 10.2 months (range 1-18 months) of loading.
  
  
  RESULTS
  Six (5.1%) of the 117 implants were removed during the follow up. All failed implants belonged to the immediate/early loading group giving a failure rate of 6.3% for this group and 0% for two-stage implants. The failure rate was higher for flapless (7.9%) than for flap surgery (0%). The marginal bone loss was -2.4 mm (SD 1.5) for all implants, while 37.6% showed more than 3 mm of loss during the follow up. Bone loss increased with time of follow up. Implants subjected to immediate/early loading showed more bone loss than two-stage implants: -2.6 mm (SD 1.5) vs. -1.6 mm (SD 1.1). Moreover, 41.3% of immediately loaded and 22.7% of two-stage implants presented with more than 3 mm of bone loss.
  
  
  CONCLUSIONS
  This short-term retrospective analysis showed a poor clinical outcome of Nobel Direct implants. Extensive marginal bone loss (>3 mm) was found around more than 1/3 of the implants evaluated. Less resorption and no failures were experienced when implants were allowed to heal from 6 weeks to 6 months before occlusal loading. Within the limitations of the present study design, data indicate that immediate loading, the use of this implant for multi-unit constructions and flapless surgery are risk factors for failure of Nobel Direct implants.
authors.affiliation: Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden. lars.sennerby@biomaterials.gu.se
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
authors.forename: Antonio
authors.initials: A
authors.lastname: Rocci
authors.forename: William
authors.initials: W
authors.lastname: Becker
authors.forename: Lars
authors.initials: L
authors.lastname: Jonsson
authors.forename: Lars-Ake
authors.initials: LA
authors.lastname: Johansson
authors.forename: Tomas
authors.initials: T
authors.lastname: Albrektsson
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000209:etiology; D003442:Crowns; D003758:Dental Implantation, Endosseous / Q000009:adverse effects* / Q000379:methods*; D015921:Dental Implants / Q000009:adverse effects*; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported / Q000009:adverse effects*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003831:Denture, Partial, Immediate / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013524:Surgical Flaps
chemical_list: D015921:Dental Implants