The aim of this study was to investigate the surface characteristics and evaluate the bone–implant interfaces of injection molded zirconia implants with or without surface treatment and compare them with those of conventional titanium implants. Four different zirconia and titanium implant groups (n = 14 for each group) were prepared: injection-molded zirconia implants without surface treatment (IM ZrO2); injection-molded zirconia implants with surface treatment via sandblasting (IM ZrO2-S); turned titanium implants (Ti-turned); and titanium implants with surface treatments via sandblasting with large-grit particles and acid-etching (Ti-SLA). Scanning electron microscopy, confocal laser scanning microscopy, and energy dispersive spectroscopy were used to assess the surface characteristics of the implant specimens. Eight rabbits were used, and four implants from each group were placed into the tibiae of each rabbit. Bone-to-implant contact (BIC) and bone area (BA) were measured to evaluate the bone response after 10-day and 28-day healing periods. One-way analysis of variance with Tukey’s pairwise comparison was used to find any significant differences. The significance level was set at α = 0.05. Surface physical analysis showed that Ti-SLA had the highest surface roughness, followed by IM ZrO2-S, IM ZrO2, and Ti-turned. There were no statistically significant differences (p > 0.05) in BIC and BA among the different groups according to the histomorphometric analysis. This study suggests that injection-molded zirconia implants are reliable and predictable alternatives to titanium implants for future clinical applications.