Purpose: To evaluate the usefulness of ridge augmentation using a customized titanium mesh (CTM) that was preformed by trimming and bending the commercial titanium mesh on a virtually reconstructed 3D acrylic resin model using clinical, radiologic, histologic, and histomorphometric analyses. Materials and Methods: This study was designed prospectively for patients who required vertical ridge augmentation using a staged approach before implant surgery. After installation of the CTM, grafting was performed using deproteinized porcine bone mineral covered with an absorbable membrane. Computed tomography was performed preoperatively and 6 months after simultaneous/staged guided bone regeneration to measure planned, reconstructed, and lacking bone volume, and the reconstruction rate was calculated based on these values. Clinical complications were also recorded, particularly the mesh exposure rate. At re-entry, the bone core was obtained using a trephine bur, and histologic and histomorphometric analyses were performed. Results: A total of 10 sites in eight patients were used for the study analysis. The mean planned bone volume was 1.15 cm3 (range: 0.78 to 1.56 cm³), mean lacking bone volume was 0.13 cm³ (range: 0 to 0.59 cm3), and mean reconstructed bone volume was 1.02 cm³ (range: 0.56 to 1.43 cm³). The exposure rate was 30% (3 out of 10 sites). The reconstruction rate was over 80%, except for one case that showed suppuration. From histomorphometric analysis, 27.52% ± 16.87% of new bone, 7.62% ± 5.19% of residual graft, and 64.86% ± 23.76% of connective tissue were observed. The core biopsy samples demonstrated different pseudoperiosteum layer appearances based on the healing stage of the augmented sites. In the premature bone, the inner osteogenic layer consisted of multiple layers of osteoblast cells with adjacent large blood vessels. However, in the mature augmented site, there was no specific inner osteogenic layer, and the outer fibrous layer was dominant. Conclusions: The fabrication of CTM based on the application of the 3D-printing technique makes vertical ridge augmentation easier and can reduce complications and achieve target bone acquisition. In addition, it is expected that quantitative analysis of the pseudoperiosteum layer will be facilitated using the CTM.