The objective of this study was to evaluate the effect of absorbable atelocollagen sponge on healing of hard tissue of buccal dehiscence defects in mongrel dogs. The mandibular second and fourth premolars of 12 dogs were extracted. Group 1 and Group 2 consisted of dogs without and with an inserted atelocollagen sponge after extraction with buccal plate preservation; Group 3 and Group 4 consisted of dogs without and with an inserted atelocollagen sponge after removing two thirds of the buccal wall. At 10 weeks, Group 4 presented a significantly greater increase in the height of the alveolar bone crest than that of Group 3. Histologically, Group 2 and Group 4 showed better new bone formation ability than Groups 1, 3 at 6 weeks after extraction. The new bone formation ability of Group 3 was the poorest at 10 weeks. The results showed that the transplantation of absorbable atelocollagen sponge in the extraction socket can promote new bone formation and compensate marginal ridge reconstruction.