Objective: Implant surface topography is a key element in achieving osseointegration. Nanostructured surfaces have shown promising results in accelerating and improving bone healing around dental implants. The main objective of the present clinical study is to compare, at 4 and 6w, bone-to-implant contact in implants having either machined surface (MAC), SLA medium roughness surface or a Nanostructured Calcium-Incorporated surface (XPEED®). Thirty five mini-implants with 3 different surface treatments (XPEED® (n=16) - SLA (n=13) - Machined (n=6)), were placed in the posterior maxilla of 11 patients then retrieved at either 4 or 6w in a randomized split-mouth study design.

Inclusion Criteria:

• • Height of the residual bone crest in the programmed implant site ≥ 9 mm and thickness ≥ 7mm.

  • Availability, in each sector, of sufficient mesio-distal space allowing placement of 2 standard-sized implants and at least 2 mini-implants (3.5x8.5mm) for retrieval.
  • Healed bone crest (≥ 3 months elapsed after extraction or tooth loss).
  • Age > 18 years.
  • Ability to examine and fully understand the study protocol.

Exclusion Criteria:

• • Myocardial infarction within the past 6 months.

  • Poorly controlled diabetes (HBA1c > 7.5%).
  • Coagulation disorders.
  • Radiotherapy to the head/neck area within the past two years.
  • Present or past treatment with intravenous bisphosphonates.
  • Immunocompromised patients.
  • Psychological or psychiatric problems.
  • Alcohol or drug abuse.
  • Poor oral hygiene and motivation (full mouth plaque score > 30% and/or full mouth bleeding score > 20%).
  • Uncontrolled periodontal disease.