The Effect Of Zoledronic Acid-loaded Gelatin Nanoparticles On The Restitution Of Teeth Extraction Socket

Residual alveolar ridge absorption is a common complication after clinical extraction.It is characterized by chronic and progressive absorption of residual alveolar bone after tooth extraction or tooth loss.This absorption not only affects the chewing function,the appearance of the face,but also seriously affects the physical and mental health of the patient.Severe alveolar ridge absorption also poses greater difficulties for the restoration and use of dentures.Local or systemic application of.chemicals is a common method of preventing residual alveolar resorption.Zoledronic acid is an analog of pyrophosphate in its chemical structure and is currently the most powerful nitrogen-containing bisphosphonate.Gelatin is a mixture of polypeptides formed by collagen denaturation,which has the advantages of being degradable,non-toxic and non-antigenic.In this experiment,gelatin was combined with zoledronic acid to prepare nanoparticles,which were applied locally to the extraction socket to observe the effect of sustained release of zoledronic acid on bone healing of the extraction socket.In the experiment,we prepared the zoledronic acid gelatin nanoparticles by a modified two-step solvent removal method.Using acetone as a coagulant,the gelatin precipitate obtained after desolvation in the first step is dissolved in zoledronic acid solution,and the solution is added’ to acetone under ultrasonication to be desolvated again to obtain gelatin nanoparticles.Glutaraldehyde is used for crosslinking of the zoledronic acid-loaded gelatin nanoparticles.The product was centrifuged and lyophilized in vacuo.90 Wistar rats(6 weeks,180g-200g)were used as experimental animals.The incisors were extracted and then,according to the drug loading efficiency of zoledronic acid-loaded gelatin nanoparticles,3μg,6μg and 12μg zoledronic acid were implanted into the extraction sockets of the three experimental groups,and the healing of the alveolar bone was observed by histological sections at 15d,30d and 60d.Bone density of the teeth extraction sockets was examined to evaluate bone formation.The material implanted into the alveolar fossa of the rat in the control group was blank gelatin nanoparticles,and the other conditions were the same as those of the experimental grou p.The results showed that the gelatin nanoparticles implanted in the extraction socket was well dissolved.After 15 days,the area of trabecular bone in the extraction socket of the experimental group was significantly larger than that of the control group.The trabecular bone grew toward the center of the extraction socket and was larger than that of the control group.The statistical data of the bone mineral density measurement showed that the bone density of the extraction socket of the experimental group was significantly higher than that of the control group.The experiment shows that the improved two-step desolvent method is an ideal method for preparing zoledronic acid-loaded gelatin nanoparticles;the zoledronic acid-loaded gelatin nanoparticles can be implanted into the extraction socket and promote the restitution of the alveolar bone by sustained release.