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 analyzed 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.
RESUMO
BACKGROUND: The aim of this research was to evaluate the effect of adipose derived stem cells on bone repair in through and through mandibular bone defects of canine. MATERIALS AND METHODS: In this prospective comparative study, adipose-derived stem cells were isolated from subcutaneous fat of lateral thoracic area of 4 dogs. The isolated cells were cultured and expanded through 3 passages. The undifferentiated stem cells were seeded in Collatamp and transferred into mandibular bone through-and-through defects. Similar defects on control group were filled with cell-free Collatamp. After 6 weeks, biopsies were taken and histomorphometric analysis was performed. The percentage of new bone formation was measured in each case. The data were subject to statistical analysis using the Wilcoxon test. Differences at P≤0.05 were considered significant. RESULTS: H and E staining of decalcified samples revealed more bone formation in the group, which stem cells were seeded. Cell-free collatamp group revealed an average bone regeneration of %41±13.21, while adipose derived stem cell-seeded collatamp group showed %49±8.24. CONCLUSION: The use of stem cell seeded collatamp scaffold in mandibular defects caused more bone regeneration.