بررسي بافت شناسي سطح تماس استخوان با ميكروايمپلنت هاي ارتودنسي به دنبال اعمال نيروي فوري و تاخيري در استخوان فك پايين سگ

Histological evaluation of micro implant-bone interface following immediate versus delayed loading in a dogʹs mandibular bone

Background and Aim: Skeletal anchorage devices such as microimplants are successful attempts to have absolute anchorage. The aim of this study was to evaluate the effect of immediate and delayed orthodontic loading on maxillary and mandibular microimplants regarding histologic responses and bone implant contact (BIC) in a dog. Materials and Methodsʹ. Thirty-two microimplants (Abso Anchor) were bilaterally placed in the mandibular premolar regions of four adult male dogs. The microimplants were divided into loaded and unloaded (control) groups. The control group had two subgroups of 4 and 8 weeks and the loaded group comprised two subgroups of immediate and delayed (after 4 weeks healing period) loading. Loaded samples were subjected to 200g load provided by Ni-Ti coil spring for 4 weeks. The decalcified specimens were prepared for histological examination under light microscope. The microimplantsʹ surrounding tissue was observed histologically and the bone implant contact (BIC) percentage was calculated in each sample. Three way ANOVA was used to compare BICs in different groups. Results: Mobility was detected in two mandibular microimplants, so the survival rate was calculated as 93.7%. BIC values were not significantly different between loaded and unloaded groups, and between immediate and delayed loaded groups. Conclusion: Immediate or delayed loading of microimplants does not lead to significant difference in the bone- microimplant contact. Key words: Microimplant- Orthodontic loading-Anchorage. Corresponding Author: Dr. Dehghani-Mohammadabadi M., Assistant Professor, Department of Orthodontics, School of Dentistry, Yazd University of Medical Sciences. Yazd, Iran. e.mail: dehghanimm841@mums.ac. ir