Does a change in bone mineral density occur in the mandible of Göttingen minipigs after irradiation in correlation with radiation dose and implant surgery?

PURPOSE

To date, studies have not agreed on the effects of irradiation on bone mineral density. The aim of our study was to investigate the changes in mandibular bone mineral density after irradiation at various doses with and without surgery.

MATERIALS AND METHODS

We implemented a descriptive animal experiment. The sample included 16 female Göttingen Minipigs, randomly assigned to 4 groups and irradiated with equivalent doses of 0, 25, 50, and 70 Gy to the mandibular region. At 3 months after irradiation, the mandibular left premolars and molars were removed, and dental implants were placed. Computed tomography scans were taken before and 6 months after irradiation. The measured bone density was related to a bone phantom to calculate the bone mineral density quotient (BMDQ). The outcome variable was the BMDQ. Other study variables were the radiation dose and surgery. Descriptive and univariate analyses were computed, and significance was set at P ≤ .05.

RESULTS

In the left hemimandible, compared with the control group, a significant decrease in BMDQ was observed: 0.01 at 0 Gy, -0.01 at 25 Gy, -0.06 at 50 Gy, and -0.11 at 70 Gy (P = .023). The right hemimandible compared with the control group also showed a significant decrease in BMDQ: -0.02 at 0 Gy, -0.08 at 25 Gy, -0.09 at 50 Gy, and -0.11 at 70 Gy (P = .007).

CONCLUSIONS

The present study used a large animal model to simulate the tissue reactions induced by various radiation doses in the mandible. We found a significant decrease in the BMDQ after irradiation, but no significant correlation could be found between the irradiation dose and a decrease in the BMDQ.