This was a prospective pilot clinical observation on the comparison of crestal bone loss around the subcrestal dental implant system between using healing and customized titanium abutment during the osseointegration period. Fourteen patients who required a single posterior implant-supported prosthesis were randomly divided into two groups, which were the healing abutment group (Control group)and the customized titanium abutment group (Test group). Patients received one dental implant between 4.0 and 5.0 mm. diameter (Dentium Superline, Dentium, Seoul, Korea) with 8 to12 mm. in length. All patients had an implant placed 2 mm below the crestal bone using a surgical template. Customized titanium abutments were installed immediately after the implant placement while the healing titanium abutment was replaced with the final abutment 3 months later according to conventional prosthetic technique. XCP jig was fabricated for an individual patient to produce the same position of periapical film and x-ray tube to be able to compare periapical radiograph images during the evaluation period. Radiographs were taken to assess marginal bone loss immediately after surgery (day 0), then at 1-month, 3-month, and 6-month, respectively. All images were measured and compared for crestal bone loss in each patient. Results showed none of the specimens had a bone loss at the implant platform. Bone remodeling at crestal bone in 6 months has been found in both control and test groups, which were 1.507 ± 1.060 mm and 2.028 ± 0.790 mm, respectively. Within the limitation of this study, the customized titanium abutment has shown less marginal bone loss compared to the healing abutment. However, there was no statistically significant difference between healing and customized titanium abutment.