Histomophometrical evaluation of biodegradable mini-implants for orthodontic anchorage in the mandibu-lar of beagle dogs / 实用医学杂志

ABSTRACT

Objective To investigate the biocompatibility and biodegradability of mini-implants of PLA-based composites in experimental animals by histomorphometry, and to study its clinical application in orthodontic treatment. Methods Six adult male Beagle dogs were randomly divided into 3 groups, a total of 72 mini-implants were implanted to the mandibular. Two Beagle dogs were sacrificed at 2 months、4 months and 6 months after surgery. Animals were intramuscularly injected with tetracycline on 14 and 4 days before sacrifice. Mandibular specimens and the surfaces of mini-implants were examined with Cone beam CT, CBCT and Scanning Electronic Microscopy and SEM respectively. Histopathologocal changes were observed with toluidine blue staining and HE staining. Results The results of CBCT assay showed that the mini-implants were gradually radiopacity with the extension of time. SEM assay showed that the morphology of mini-implants surface was significantly changed;micro-implants degradation occured gradually.New bone formation was observed around the micro-implants within 10 days.Toluidine blue staining showed the formation of new bone around the mini-implants. However, the inflamma-tion around the implants was not observed. Conclusion The biocompatibility of biodegradable mini-implant is good. This mini-implant is biodegradable in vivo and can promote the formation of the surrounding bone tissue.