Diabetes Mellitus (DM) is a recognized factor affecting implant complication rates, including peri-implantitis and peri-implant bone loss, and the apico-coronal position of implants seems interfere on the conditions of peri-implant tissues. However, the influence of the vertical implant position in type 2 diabetics (T2DM) is unclear. This split-mouth randomized controlled trial evaluated the impact of implants of machined-collar placed at crestal level or supracrestally in T2DM rehabilitated with implant-retained overdentures on the clinical, tomographic and immunoinflammatory peri-implant outcomes after implant loading.

Considering the outcomes achieved with implants with machined-collar inserted supracrestally, it would be relevant to investigate whether this therapeutic strategy could be considered as a more effective approach in the rehabilitation with dental implants of individuals with type 2 DM, since these patients may be more disposed to peri-implant changes, both from the point of view of marginal bone remodeling as related to local variations in immunoinflammatory response. Thus, the propose of this split-mouth randomized controlled trial was to compare the impact of crestal level or supracrestally implant platform in T2DM rehabilitated with implant-retained overdentures on the clinical, tomographic and immunoinflammatory peri-implant outcomes after implant loading.

Inclusion Criteria:

• The inclusion criteria included: patients aged between 50 and 80 years old, 2) totally edentulous in the mandible with previous mandibular dentures for at least 6 months and indicated for rehabilitation with overdenture, 3) patients with diabetes had to have had T2DM, diagnosed by a physician, for at least the past 5 years. Such individuals were either under a dietary regimen and/or were using oral hypoglycaemic agents (metformin or glybenclamin).

Exclusion Criteria:

• Exclusion criteria were: 1) pregnancy, 2) lactation, 3) current smoking or ex-smokers, 4) other systemic conditions that could affect bone metabolism (e.g., immunologic disorders), 5) use of anti-inflammatory, immunosuppressive and anti-resorptive medications, 6) patients that required bone grafts before or concomitantly with implant surgery and 7) a history of previous regenerative procedures in the area designated for implant therapy. Patients with major complications of DM (i.e., cardiovascular and peripheral vascular diseases [ulcers, gangrene, and amputation], neuropathy, and nephropathy) were also excluded.