Preventive Effect of Phosphodiesterase Inhibitor Pentoxifylline Against Medication-Related Osteonecrosis of the Jaw: An Animal Study

Purpose: The aim of this experimental study was to investigate the prophylactic effect of pentoxifylline (PTX) on medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: Female Sprague-Dawley rats (n=33) received zoledronic acid (ZA) for 8 weeks to create an osteonecrosis model. The left mandibular second molars were extracted and the recovery period lasted 8 weeks before sacrifice. PTX was intraperitoneally administered to prevent MRONJ. The specimens were histopathologically and histomorphometrically evaluated. Results: Histomorphometrically, between the control and ZA groups, there was no statistically significant difference in total bone volume (P=.999), but there was a statistically significant difference in bone ratio in the extraction sockets (P<.001). A comparison of the bone ratio of the ZA group with the ZA/PTX group (PTX administered after extraction) showed no statistically significant difference (P=.69), but there was a statistically significant difference with the ZA/PTX/PTX group (PTX administered before and after extraction; P=.008). Histopathologically, between the control and ZA groups, there were statistically significant differences for inflammation (P=.013), vascularization (P=.022), hemorrhage (P=.025), and regeneration (P=.008). Between the ZA and ZA/PTX groups, there were no statistically significant differences for inflammation (P=.536), vascularization (P=.642), hemorrhage (P=.765), and regeneration (P=.127). Between the ZA and ZA/PTX/PTX groups, there were statistically significant differences for inflammation (P=.017), vascularization (P=.04), hemorrhage (P=.044), and regeneration (P=.04). Conclusion: In this experimental model of MRONJ, it might be concluded that although PTX, given after tooth extraction, improves new bone formation that positively affects bone healing, it is not prophylactic. However, PTX given before tooth extraction is prophylactic. Therefore, PTX might affect healing in a positive way by optimizing the inflammatory response. (C) 2017 American Association of Oral and Maxillofacial Surgeons