| Alongwith the development of technology, people’s healthy consciousness iscontinuously improved. More and more people’s requirement is not only function of teeth,they pay much more attention to visual aesthetic pursuit.Influence and endangerment ofmalocclusion has caught people’s eyes day by day, so malocclusion has been accepted andrespected. But longer time during teeth treatment has been a new problem while they go tosee the doctor.So,how to accelerate construction and reconstruction of periodontal tissureto reduce orthodontic retention period is a new difficulty that should be overcame to all thedoctors.Osteoprotegerin was found in1997, which is the secreted protein which is released byosteoblast. It is belong to tumor necrosis factor receptor family. As a result of the functionof refrain osteoclast’s formation,it is named as osteoprotegerin, together with function ofincrease bone’s density. Osteoprotegerin vias to specific combine with RANKL in order toemulative refrain the combination between RANK with RANKL, which is to restrainosteoclast ’s formation and activity,by which it can adjust bone’s density.In recently years,drug which is used in orthodontic retention period has been a newhot research direction. Bisphosphonates depend on these abilities such that highlyappetency to bones, prior moved to serious damaged aera of bones and refrainosteoclasts’activity,so they are used to treat osteoporosis and win great therapeutic effect.Among them, ibandronate is the third generation drug, it is the most highly safety andefficiency, which is still in experiment and trial phase in oral treatment area. People’sresearch mainly focus on retraint of osteoclasts’function. This experiment aims to researchthat Ibandronate has the function of positive regulation about stimulating osteoclasts torelease Osteoprotegerin,so as to verify feasibility about reducing orthodontic retentionperiod.maybe it can be afford a bit reference for other experiments.Objective: To examine the effect of local injection of ibandronate on the periodontaltissues during orthodontic retention. Methods: Fifty-five8-week-old male Sprague-Dawley rats were divided randomlyinto a blank control group, control group and experimental group. Maxillary first molar(right side) was drawn to mesial movement under50g forces in all rats, lasting21days.Rats in the blank group were directly executed without any preparation. Rats in the experiment and control groups were locally administrated with ibandronate and normal saline1day before retention, and then the retainers were placed. Five rats from the experimentaland control groups were executed at1,3,7,14,21days, respectively. Tissue samples fromall groups were cut and stained with hematoxylin-eosin and immunohistorchemistry stainingResult and conclusion: Hematoxylin-eosin staining showed the osteoclasts in theexperimental group decreased as compared with the control group. At the same point, osteoprotegerin expressed higher in the experimental group than the control group. However, there was no significant difference in osteoprotegerin level between the experimental group and control group at days1and3(P>0.05); a significant difference was found betweenthe two groups at days7,14and21(P <0.05). Expression of osteoprotegerin exhibited anincreasing trend in the experimental group. As compared with the blank control group, theexpression of osteoprotegerin was significantly higher in the experimental and control groups (P <0.05). Local injection of ibandronate can stimulate osteoblasts to secrete osteoprotegerin and indirectly restrain osteoclast formation, thereby accelerating bone reconstruction. |
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