Radiographic and histologic observations of sequential healing processes following ridge augmentation after tooth extraction in buccal-bone-deficient extraction sockets in beagle dogs

Objectives: To evaluate dimensional ridge alterations and sequential healing processes following ridge augmentation after tooth extraction in damaged extraction sockets with buccal-bone-deficiency. Material and methods: Bilateral dental roots of three mandibular premolars were extracted with entire removal of the buccal-bone plate in eight beagle dogs. Unilateral sites were grafted with biomaterials (test group) and contralateral sites were healed without grafting (control group). Observations were made after 1, 2, 4, and 8 weeks, and all sites were distributed evenly (n = 6 for each group and period). Radiographic/histomorphometric analyses were performed. Results: In spontaneous healing of damaged extraction sockets, the dimension of regenerated alveolar ridge gradually increased until 4 weeks and then remained stable, but radiographic/histomorphometric analyses revealed evident dimensional shrinkage compared to the pristine tissue at 8 weeks in the coronal and middle areas. Bone grafting retained the pristine dimension of alveolar ridge, and newly formed bone area within the augmented space continuously expanded during the observational period to the outermost border of the space. Conclusions: Spontaneous healing of damaged extraction sockets caused substantial dimensional shrinkage. However, ridge augmentation can provide space into which new bone may grow continuously, resulting in the final dimensions comparable to those of the pristine alveolar ridge.