Three-dimensional quantification of alveolar bone loss in Porphyromonas gingivalis-infected mice using micro-computed tomography

Background: Animal models are routinely used for the study of the pathogenesis of periodontal disease. However, some of the methods used for evaluating alveolar bone loss are limited to linear or two dimension measurements, while other methods, such as histology, are labor consuming. The present study was designed to evaluate a novel method for assessing the volume of alveolar bone loss in mice and to compare it to the traditional morphometric (linear) technique. Methods: Seven- to 8-week-old BALB/c mice were divided into three equal groups of six each; two groups were infected orally with Porphyromonas gingivalis (P gingivalis) 381 or 53977, while the third group was used as non-infected control. Forty-two days following infection, serum samples were obtained and maxillae were harvested. Bone loss was evaluated by micro-computed tomography (micro-CT) and by the morphometric technique. Results: Significant decrease in residual supportive bone volumes (RSBV) was observed in both P gingivalis-infected groups compared to the control group (P < 0.0001). The P gingivalis 53977-infected group showed less residual supportive bone volume compared to the P gingivalis 381-infected group, but there were no significant differences between these two groups. Using the morphometric technique, the differences between the three groups were not found to be statistically significant (P > 0.05). Conclusions: The present study describes a novel micro-CT technique for volumetric evaluation of alveolar bone loss in mice. This technique is relatively simple and accurate, and due to its high sensitivity, enables the investigator to reduce the number of animals needed in each experimental group.