Early bone formation around immediately loaded implants with nanostructured calcium-incorporated and machined surface: a randomized, controlled histologic and histomorphometric study in the human posterior maxilla

Clin Oral Investig. 2017 Nov;21(8):2603-2611. doi: 10.1007/s00784-017-2061-y. Epub 2017 Feb 2.


Objective: The aim of this randomized, controlled histologic/histomorphometric study was to compare the early bone formation around immediately loaded implants with nanostructured calcium-incorporated (NCI) and machined (MA) surface, placed in the human posterior maxilla.

Materials and methods: Fifteen fully edentulous patients (six males; nine females; mean age 57.9 ± 6.7 years) were selected for this study. Each patient was installed with two temporary transmucosal implants, with different surfaces: one NCI (test) and one MA (control) implant. All temporary implants were placed in the posterior maxilla, according to a split-mouth design, to help to support an interim complete maxillary denture. After 8 weeks, all temporary transmucosal implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed-rank test was used to evaluate differences (BIC%, BD%) between the surfaces. The level of significance was set at 0.05.

Results: Eight weeks after placement, 24 clinically stable implants (12 test, 12 control) were subjected to histologic/histomorphometric evaluation. In the MA implants, the histomorphometric evaluation revealed a mean BIC(±SD)% and BD(±SD)% of 21.2(±4.9)% and 29.8(±7.8)%, respectively. In the NCI implants, the histomorphometric analysis revealed a mean BIC(±SD)% and BD(±SD)% of 39.7(±8.7)% and 34.6(±7.2)%, respectively. A statistically significant difference was found between the two surfaces with regard to BIC% (p < 0.001), while no significant difference was found with regard to BD% (p = 0.09).

Conclusions: The NCI surface seems to increase the peri-implant endosseous healing properties in the native bone of the posterior maxilla, under immediate loading conditions, when compared with the MA surface.

Clinical relevance: Under immediate loading conditions in the human posterior maxilla, the nanostructured calcium-incorporated surface has led to better histologic and histomorphometric results than the machined surface; therefore, the clinical use of implants with nanostructured calcium-incorporated surface may be beneficial in the posterior maxilla, under immediate loading protocol.

Keywords: Early bone formation; Human histology; Immediate loading; Implant surface.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Bone-Implant Interface*
  • Calcium / chemistry*
  • Dental Implants*
  • Female
  • Humans
  • Immediate Dental Implant Loading*
  • Jaw, Edentulous / rehabilitation*
  • Male
  • Maxilla / surgery*
  • Middle Aged
  • Nanostructures
  • Osseointegration / physiology*
  • Surface Properties


  • Dental Implants
  • Calcium