This study evaluated the effects of local application of autologous platelet-rich plasma (PRP) on the tooth extraction site of rats presenting the main risk factors for medication-related osteonecrosis of the jaw (MRONJ). For seven weeks, senile rats were submitted to systemic treatment with vehicle (VEH and VEH-PRP) or 100 μg/Kg of zoledronate (ZOL and ZOL-PRP) every three days. After three weeks, the first lower molar was extracted. VEH-PRP and ZOL-PRP received PRP at the tooth extraction site. Euthanasia was performed at 28 days postoperatively. Clinical, histopathological, histometric and immunohistochemical analyses were carried out in histological sections from the tooth extraction site. ZOL showed lower percentage of newly formed bone tissue (NFBT), higher percentage of non-vital bone tissue (NVBT), as well as higher immunolabeling for TNFα and IL-1β. In addition, ZOL presented lower immunolabeling for PCNA, VEGF, BMP2/4, OCN and TRAP. VEH and ZOL-PRP showed improvement in the tooth extraction site wound healing and comparable percentage of NFBT, VEGF, BMP2/4 and OCN. Local application of autologous PRP proved a viable preventive therapy, which is safe and effective to restore tissue repair capacity of the tooth extraction site and prevent the occurrence of MRONJ following tooth extraction.

This study assessed the effectiveness of the local use of green propolis-loaded lipid nanoparticles (GPlnp) as an adjuvant therapy to scaling and root planing (SRP) to manage experimental periodontitis (EP) in ovariectomized rats treated with zoledronate. Ten weeks before the experiment, 48 female rats were ovariectomized. On day 0, a ligature was installed in the lower first molar to induce EP. From day 0 to day 42, half of the rats were treated with vehicle (VEH), while the other half were treated with 100μg/Kg of zoledronate (ZOL). On day 14, the rats were allocated into the following groups: VEH-NLT, VEH-SRP, VEH-SRP-GPlnp, ZOL-NLT, ZOL-SRP, and ZOL-SRP-GPlnp. VEH-NLT and ZOL-NLT received no local treatment. VEH-SRP and ZOL-SRP received SRP and irrigation with physiological saline solution. VEH-SRP-GPlnp and ZOL-SRP-GPlnp received SRP and irrigation with GPlnp. A single SRP session was carried out, and four irrigation sessions were conducted (on days 14, 16, 18, and 20). On day 42, all animals were euthanized. The hemimandibles were processed for histological, histometric (percentage of total bone tissue (PTBT) and non-vital bone tissue (PNVBT)) and immunohistochemical (TNFα, IL-1β, and TRAP) analysis. VEH-SRP-GPlnp showed better tissue repair, higher PTBT, and lower immunolabeling for TNFα and IL-1β compared to the groups treated with VEH. ZOL-SRP-GPlnp showed a favorable tissue repair, with lower PNVBT, less local inflammation, and lower immunolabeling for TNFα and IL-1β compared to the groups treated with ZOL. Irrigation with GPlnp proved to be effective as an adjuvant therapy to SRP in treating EP in ovariectomized rats treated with zoledronate.