Impact of implant diameter on bone level changes around platform switched implants: preliminary results of 18 months follow-up a prospective randomized match-paired controlled trial

Clin Oral Implants Res. 2012 Oct;23(10):1142-6. doi: 10.1111/j.1600-0501.2011.02297.x. Epub 2011 Nov 24.


Objective: This prospective randomized match-paired controlled trial aimed to evaluate the impact of implant platform diameter on marginal bone level around implants restored according to the platform switching (PS) concept.

Material and methods: A total of 24 implants were examined in 12 patients. All patients received two adjacent implants inserted at the crestal level: 4.3 mm (control group) and 4.8 mm (test group) in diameter. Mesio-distal implant position was randomly performed. According to the PS concept, for restoration, a 3.8 and 4.3 mm diameter abutment was used, respectively in the control and test groups, resulting, in both groups, with 0.25 mm of implant/abutment mismatching. Implant restorations were splinted. Eighteen months after final restoration, periapical standardized digital radiographs were taken to evaluate marginal bone level alterations after loading. The Wilcoxon Signed-Rank Test was selected to identify differences between groups.

Results: At the last follow-up, control implants exhibited a mean bone loss value of 1.10 mm (SD: 0.47 mm); the test group showed a mean value of 1.09 mm (SD: 0.08 mm). No statistically significant differences were found between test and control groups.

Conclusions: Within the limits of this study, the present results suggest that bone resorption is mostly related to biologic (biologic width re-establishment) rather than to biomechanical factors (implant platform diameter). Furthermore long-term studies with a wider sample size are needed to confirm the platform diameter influence on hard tissue response around implants restored according to the PS concept.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Alveolar Bone Loss / diagnostic imaging
  • Alveolar Bone Loss / physiopathology*
  • Bone Resorption*
  • Dental Implant-Abutment Design
  • Dental Implants*
  • Dental Prosthesis, Implant-Supported
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Osteotomy
  • Prospective Studies
  • Radiography
  • Risk Factors
  • Statistics, Nonparametric


  • Dental Implants