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Objectives@#This study aimed to compare the effects of systemic administration of levofloxacin or cephalexin on fracture healing in rats. @*Materials and Methods@#In this animal study, tibial fractures not requiring fixation were artificially induced in 30 male Wistar albino rats using a 1.1 mm surgical bur. The rats were randomly divided into 6 groups (n=5). Groups 1 and 2 received daily subcutaneous saline injections. Groups 3 and 4 received subcutaneous injections of 25 mg/kg levofloxacin twice daily. Groups 5 and 6 received daily subcutaneous injections of 20 mg/kg cephalexin.The rats in Groups 1, 3, and 5 were sacrificed after 1 week, while the rats in Groups 2, 4, and 6 were sacrificed after 4 weeks. The score of fracture healing was determined through histological assessment of sections from the fracture site according to Perry and colleagues. Data were analyzed by Kruskal–Wallis and Mann–Whitney tests. @*Results@#The mean score of fracture healing at 4 weeks was significantly higher than that at 1 week in the saline, levofloxacin, and cephalexin groups P<0.001). At 1 week, no significant difference was noted among the three groups of saline, levofloxacin, and cephalexin in the mean score of fracture healing (P=0.360). However, this difference was significant at 4 weeks (P=0.018), and the mean score in the saline group was significantly higher compared to that in the levofloxacin group (P=0.015). @*Conclusion@#It is recommended not to prescribe levofloxacin for more than 1 week after surgical management of bone fractures due to its possible adverse effects on fracture healing.
RESUMO
Objectives@#Melatonin induces human stem cells, converts pre-osteoblasts to mature osteoblasts, and reduces the duration of this transition. However, melatonin itself prevents activation of osteoclasts. Here, we evaluate the role of melatonin in prevention of bisphosphonate-related osteonecrosis of the jaw. @*Materials and Methods@#In this experimental-interventional study, 30 rats were evaluated in 3 groups. The first and second groups received saline and zoledronic acid, respectively, for 4 weeks and the third group received 4 weeks of zoledronic acid and 3 weeks of melatonin simultaneously. Firstright-maxillary-molar extraction was performed for all animals, which were sacrificed after 4 weeks of recovery. The extraction sockets were examined histologically for the presence of osteonecrosis, number of osteoclasts and fibroblasts, severity of inflammation, and vascularization. Data were ana-lyzed by chi-square, one-way ANOVA, Tukey, Kruskal–Wallis and Fisher’s exact statistical tests (α=0.05). @*Results@#Osteonecrosis was observed in 20%, 90%, and 70% of the first, second and third groups, respectively (p=0.008). The lowest number of osteoclasts and fibroblasts was seen in the third group. @*Conclusion@#Melatonin may effectively prevent some undesirable side effects of bisphosphonates. However, further studies are required to confirm the results of this study.