Effect of DNA/protamine complex paste on bone augmentation of the mandible: A pilot study on dogs

Objective Our previous studies found that a salmon DNA-based scaffold containing protamine promoted bone regeneration of the calvarial defects of rats. The aim of the present pilot study was to examine the influence of the DNA/protamine (DP) complex on bone regeneration of a saddle type, alveolar ridge defects of the dog mandible. Design Alveolar ridge defects were performed in the mandibles of five adult female beagles. The following three treatment modalities were randomly allocated: (1) the DP complex paste, (2) a beta-tricalcium phosphate (β-TCP), and (3) a blank (control). Healing of bone defects were evaluated by periapical radiography, micro-computed tomography (micro-CT), and histology. Results Periodical radiographic images revealed that a higher percentage of regenerated bone height was consistently achieved in the DP group, as compared with blank controls. All three-dimensional, sagittal, and coronal images of micro-CT showed increased amounts of newly formed bone and a greater bone volume/ tissue volume ratio, as compared with the blank and β-TCP groups. In contrast, there was no significant difference in bone mineral density among the groups. Histological analysis confirmed that the alveolar bone defects were filled with newly formed bone with mature and compact properties in the DP group. Conclusions These findings indicate that the DP complexes enhanced regeneration of vertical alveolar bone defects of the dog mandible.