Purpose: This study aimed to assess and compare the effectiveness of 3D-printed pre-formed resorbable polycaprolactone/β-tricalcium phosphate (PCL/β-TCP) membrane and collagen membrane, combined with demineralized bovine bone mineral (DBBM), for guided bone regeneration (GBR) for peri-implant dehiscence defects. Materials and Methods: Twelve patients underwent GBR using either a PCL/β-TCP membrane with DBBM (PM group) or a collagen membrane with DBBM (CM group). Clinical assessments, including measurements of vertical defect height and width after implant placement (baseline) and re-entry surgery, were conducted. Cone-beam computed tomography imaging was performed to measure the augmented horizontal bone width (HW0, HW2, and HW4 at 0, 2, and 4 mm apical to the implant shoulder), vertical thickness (VT), and VT at a 45° angle (VT-45) at both time points. Results: No adverse effects, such as soft tissue dehiscence, membrane exposure, or severe postoperative complications, were observed during the healing period. The mean reductions in the defect height and width were 89% and 80% in the PM group and 73% and 71% in the CM group, respectively. The horizontal bone width and vertical thickness between the two groups were statistically significant (p < .05) at HW0, VT, and VT-45, both at baseline and re-entry surgery. Meanwhile, the changes in bone augmentation between baseline and re-entry surgeries were not significantly different (p > .05) between the two groups. Conclusion: Based on the findings of this study, pre-formed resorbable 3D-printed PCL/β-TCP membrane with DBBM could be an effective treatment option for peri-implant dehiscence defects, providing stability and vertical and horizontal bone augmentation.