Effects of Immediate Orthodontic and Orthopedic Forces on Peri-Miniscrew Bones: Histomorphologic and Histomorphometric Assessment in Dogs

Aim . The aim of this study was histomorphologic and histomorphometric evaluation of peri-screw bone after immediate orthodontic and orthopedic forces and comparing them with a control group. Materials and Methods . 18 dual-top miniscrews were inserted in the premolar region of three Iranian dogs. Screws were divided into three groups: (1) the first group undergoing immediate orthodontic force of 300 cN, (2) the second group undergoing immediate orthopedic force of 600 cN and (3) a control group. Screws were explanted with adequate amount of surrounding bone after three months. Bone-screw contact (BSC), percentage of lamellar bone, and percentage of woven bone were evaluated. Wilcoxon and Man Whitney tests were used to analyze the data using SPSS software ver. 15 ( α = 0.05). Results . There was no significant difference among the groups in terms of bone-screw contact ( P   value = 0.42), percentage of lamellar bone ( P   value = 0.83), and percentage of woven bone ( P   value = 0.88). Conclusion . By applying orthodontic and orthopedic forces to mini-screws the quality of surrounding bone and osseointegration will not be affected. Clinical Significance . Application of force to mini-screws is helpful in orthodontic-screw therapies.