The Effect of Bisphosphonates’ Oncologic dose on the Static and Dynamic Bone Parameters of the Temporomandibular Joint’s Condyle (A Randomized Animal Controlled Trial)

The present study was conducted to assess the effect of oncologic dose of bisphosphonate on the condylar temporomandibular joint’s (TMJ’s) static and dynamic bone parameters. Forty adult male albino rats were utilized in the study. Animals were randomly assigned into four groups, each included ten rats that were intraperitoneally injected with saline (control groups I and II), or 0.2 mg.kg-1 Zoledronic acid (experimental groups I and II). The rats were sacrificed at the end of 6 weeks (groups I) and 12 weeks (groups II). The right side TMJs condyles were used in histological and histomorphometric analysis while the left side condyles were utilized for assessing dynamic bone parameters. Bone volume/ Tissue volume (BV/TV) and trabecular thickness (Tb.Th) were significantly increased in ZOL group II as compared to control and Zoledronic acid (ZOL) group I (p=<0.001) while trabecular separation (Tb.Sp) was markedly increased in ZOL group I as compared to both control and ZOL group II (p=0.001 and 0.012, respectively). The ZOL group II showed a significant increase in mineral apposition rate as compared to the ZOL group I (p < 0.001). Our results demonstrated that oncologic dose of Zoledronic could have a catabolic effect on TMJ’s condyles after six weeks which is reversed after 12 weeks as evidenced by enhanced endochondral and intramembranous ossification.