Implant healing was studied with regard to the mineralization of the implant-tissue interface. Titanium discs were surface-modified and implanted in rat tibia for 4 weeks. After implantation, the bone was embedded in resin and cross sections of bone and implant were made using a low speed saw equipped with a diamond wafering blade. The sections were analyzed with imaging TOF-SIMS using a Bi-3(+) cluster ion source. This ion source has recently been shown to enable identification of hydroxyapatite (HA) fragments in bone samples. The area within 40 mm from the implant surface was selected for analysis, corresponding to bone-implant interface, from which positive spectra were recorded. In conclusion, differences were observed between the implants tested regarding signal intensity of fragments specific for HA. Coating of the implants with magnesium and porosity were shown to influence the mineral content of the bone-implant interface. This technique might be useful for biocompatibility assessment and for studying the mineralization process at implant surfaces. (c) 2008 Elsevier B.V. All rights reserved.