Purpose: This study aimed to examine the effectiveness of a grafting technique using beta-tricalcium phosphate (ß-TCP) covered with different materials in alveolar bone defects with dehiscences. Materials and Methods: In five beagle dogs, all premolars in the mandible were extracted bilaterally. After a 12-week healing period, two bone defects (length, 5 mm; width, 5 mm; depth, 7 mm) were created on each side of the mandible, and the buccal bone plate was resected. The four bone defects were randomly assigned to one of the following treatments: group 1, ß-TCP alone (TCP group); group 2, ß-TCP graft covered with collagen sponge (TCP+collagen group); group 3, ß-TCP graft covered with free buccal mucosa (TCP+mucosa group); group 4, no treatment (control group). The microarchitecture of the regenerated bone was observed using microcomputed tomography, and the area of newly formed bone was measured. Specimens from each defect were selected and subjected to histologic and histomorphometric analysis; areas of newly formed bone and the ridge width were measured in the specimens. Results: Significant differences were found between the control group and all test groups. The median horizontal width of the ridge 2 mm from the top of the alveolar crest in the TCP+mucosa group was significantly greater than that of the TCP group. There was no significant difference between the TCP+mucosa and TCP+collagen groups in any measurement. Conclusions: Application of ß-TCP grafts to alveolar bone defects with dehiscence and covering of the open wound with free buccal mucosa or collagen sponge may be useful for ridge augmentation. Compared to no treatment or leaving the wound uncovered, these approaches resulted in more new bone formation and provided adequate horizontal mandibular width. Keywords: beta-tricalcium phosphate, canine mandible, open wound, ridge augmentation, socket preservation