Role of periapical disease in bisphosphonates-related osteonecrosis of the jaw

Abstract

Objectives: To investigated the role of periapical disease in inducing BRONJ using an ovariectomized animal model. Methods: Forty animals were subjected to bilateral ovariectomy. Vehicle (sterile saline) or zoledronic acid (ZA) was administered via intraperitoneal injections for 8 weeks. Then all animals received a pulpal exposure on the first right lower molar. After another four weeks of vehicle or ZA administration, all animals were sacrificed for micro-CT and histological assessments. Results: Micro-CT analysis showed that bone mineral density (BMD) was significantly lower in the drilled teeth than non-drilled teeth when administered with vehicle (P < 0.005), but no differences between drilled and non-drilled teeth when animals received ZA (P =0 .538). ZA groups had a significant increased BMD compared to the control vehicle groups with or without pulpal exposure (P< 0.005). There was no significant interaction between the effects of ZA administration and pulpal exposure on alveolar bone microarchitecture. Pulpal exposure did not cause any significant change to the bone microstructure, while ZA treatment showed significantly increase BV/TV, Tb.Th and decrease in Tb.N. The width of periodontal ligament (PDL) space were significantly smaller in ZA groups than in vehicle groups when the teeth were drilled (P<.0005), but no differences between ZA and non-ZA groups without pulpal exposure (P=.868). Pulpal exposure significantly increased the width of PDL in both ZA and Vehicle groups (P<.05). Histological assessment showed combined ZA and pulpal exposure resulted in an increased number of non-viable osteocytes. Conclusions: Peiapical disease causes remarkable increased alveolar bone resorption and reduced bone density, while ZA administration inhibits periodontal bone resorption and increase the reduced BMD caused by periapical disease. ZA administration and periapical disease exacerbate subclinical osteonecrosis.