Introduction: The aim of this study was to compare the osseointegration and the survival of dental implants (DIs) immediately placed in postextraction sites, in mandibles of minipigs that underwent radiotherapy (RT).
Materials and methods: Twelve Brazilian minipigs were divided into the following groups: A, control; B, implants placement 15 days before RT; C, implants placement 3 months after RT. Implant loss rate (ILR), fibrointegration rate (FIR), bone-implant contact (BIC), and bone density inside the threads (BDIT) were determined in each group 90 days after implantation.
Results: ILR was higher in group C (68.7%) than in groups B (28.1%) and A (21.9%), (P = 0.001). FIR was more frequent in group C (30%) than in groups B (21.7%) and A (4%), although not statistically significant. The averages of BIC and BDIT were, respectively, 33.1 and 41.5 in group C; 18.5 and 26.6 in group B; and 11.5 and 16.3 in group A (P = 0.003 for both variables).
Conclusions: RT showed a negative effect in periimplant bone regeneration. The implants placement before RT showed better results compared with the implants performed after RT, suggesting that DIs in head and neck cancer patients must be placed before RT or simultaneously during ablative tumor surgery.