Effect of enamel matrix derivative on periodontal wound healing and regeneration in an osteoporotic model.BACKGROUND
 Despite the worldwide increased prevalence of osteoporosis, no data are available evaluating the effect of an enamel matrix derivative (EMD) on the healing of periodontal defects in patients with osteoporosis.  This study aims to evaluate whether the regenerative potential of EMD may be suitable for osteoporosis-related periodontal defects.


 An osteoporosis animal model was carried out by bilateral ovariectomy (OVX) in 20 animals.  Ten weeks after OVX, bilateral fenestration defects were created at the buccal aspect of the first mandibular molar.  Animals were randomly assigned to four groups of 10 animals per group: 1) control animals with unfilled periodontal defects; 2) control animals with EMD-treated defects; 3) OVX animals with unfilled defects; and 4) OVX animals with EMD-treated defects.  The animals were euthanized 28 days later, and the percentage of defect fill and thickness of newly formed bone and cementum were assessed by histomorphometry and microcomputed tomography (micro-CT) analysis.  The number of osteoclasts was determined by tartrate-resistant acid phosphatase (TRAP), and angiogenesis was assessed by analyzing formation of blood vessels.


 OVX animals demonstrated significantly reduced bone volume in unfilled defects compared with control defects (18.9% for OVX animals versus 27.2% for control animals) as assessed by micro-CT.  The addition of EMD in both OVX and control animals resulted in significantly higher bone density (52.4% and 69.2%, respectively) and bone width (134 versus 165μm) compared with untreated defects; however, the healing in OVX animals treated with EMD was significantly lower than that in control animals treated with EMD.  Animals treated with EMD also demonstrated significantly higher cementum formation in both control and OVX animals.  The number of TRAP-positive osteoclasts did not vary between untreated and EMD-treated animals; however, a significant increase was observed in all OVX animals.  The number of blood vessels and percentage of new vessel formation was significantly higher in EMD-treated samples.


 CONCLUSIONS
 The results from the present study suggest that: 1) an osteoporotic phenotype may decrease periodontal regeneration; and 2) EMD may support greater periodontal regeneration in patients suffering from the disease.  Additional clinical studies are necessary to fully elucidate the possible beneficial effect of EMD for periodontal regeneration in patients suffering from osteoporosis.
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