Purpose: The aim of the present study was to correlate the staging of bisphosphonate-related osteonecrosis of the jaws (BRONJ) with serum C-terminal cross-linking telopeptide of type I collagen (CTX), which is under debate as an index of risk prediction. Stage I BRONJ was defined as asymptomatic osteonecrotic bone. Stage II BRONJ includes infection, and stage III includes additional complications such as fracture or extraoral fistulas.
Patients and methods: The serum CTX values of 18 patients (mean age 74 years) who were diagnosed with osteonecrosis of the jaws caused by oral bisphosphonate were investigated.
Results: The serum CTX values ranged from 10 to 262 pg/mL (mean 112 +/- 76.1). The mean duration of bisphosphonate therapy was 3.9 years, and 17 of the 18 patients had received once weekly 70 mg aldendronate and 1 patient once weekly 35 mg risedronate. The risk assessment was rated according to the CTX values of the individual patient (minimal risk, more than 150 pg/mL; moderate, 100 to 150 pg/mL; and high, less than 100 pg/mL). Next, the BRONJ scores were calculated according to the number of the BRONJ lesions and their stage. The risk assessment and BRONJ scores were correlated. The result was statistically significant (P = .019).
Conclusions: BRONJ is relatively rare but has been increasingly recognized in our clinic. The usefulness of the serum CTX value as an index of risk prediction continues to be debated. Considering the staging of lesions and the number of lesions, we found a significant correlation between the disease severity and the risk assessment using serum CTX.