Purpose: The present study aimed to evaluate and compare two types of implants: grit-blasted and acidetched implants (SLActive) and nanometer-scale hydroxyapatite-modified implants (NanoTite). Materials and Methods: Twenty-two SLActive and 22 NanoTite implants were inserted into the mandibles of 11 beagle dogs. The animals were divided into three groups according to healing time (group A, 2 weeks; group B, 4 weeks; group C, 8 weeks). Resonance frequency analysis (RFA) was performed immediately after implant placement and after 2, 4, and 8 weeks of healing. Two, 4, and 8 weeks after implantation, the animals were sacrificed and the amount of bone surrounding the implants was assessed using microcomputed tomography. Results: For SLActive and NanoTite implants, the RFA values decreased after 2 weeks and increased after 4 and 8 weeks of healing. After 8 weeks, the mean RFA value for SLActive implants was significantly higher than the mean RFA value for NanoTite implants. For the different healing periods, no significant differences in bone volume were seen for SLActive and NanoTite implants. Conclusions: SLActive and NanoTite implants evoked a similar bone response after implantation for 2, 4, and 8 weeks in a nonsubmerged position in the mandibles of dogs. In addition, the data confirmed that RFA is a reliable and noninvasive method to determine dental implant stability and the bone formation process at the clinical level. Schlagwörter: bone volume, dental implant, dog study, resonance frequency analysis, surface modification, titanium