This study was undertaken to evaluate the effect of microthread geometry of scalloped design implant on marginal bone resorption. Four types of scalloped design titanium implant specimens were prepared. The type 1 implant had a machined scalloped collar, type 2 had a sandblasted and acid-etched scalloped collar, type 3 had horizontal microthreads, and type 4 had parabolic microthreads, which are parallel with the scalloped conical margin. Two implants of a type were randomly installed immediately after extraction in the mandible of a beagle dog. Definitive prostheses were delivered immediately after surgery. After 12 weeks of healing, the dog was sacrificed and microtomography was performed. Type 4 specimens showed a marginal bone loss pattern definitively analogous to the scalloped margin. In this preliminary study, microthread geometry affected the marginal bone resorption pattern of scalloped design implants. However, additional specimens and more controlled conditions should be applied in future studies to confirm these results.