Finite element analysis of the effect of plate placement angle on cervical spine stability in anterior cervical fusion surgery / 中国骨伤

OBJECTIVE@#Using the method of finite element analysis, to compare the biomechanical properties between the plate deviating from the long axis of the cervical spine and the standard placement of the plate in the anterior cervical fusion surgery.@*METHODS@#A healthy female volunteer was selected and CT scan (C@*RESULTS@#The lower cervical spine (C@*CONCLUSION@#Little effect on the mechanical stability of the cervical spine was anticipated when the anterior cervical plate was not perfectly aligned with the long axis of the cervical spine. If the tilt of the plate in clinical surgery is less than 20°, there is no need to readjust the position of the plate.

Protraction of mandibular molars through a severely atrophic edentulous space in a case of juvenile periodontitis / 대한치과교정학회지

Moving the mandibular posterior teeth into a severely atrophic edentulous space is a challenge. A carefully designed force-and-moment system that results in bodily protraction of the posterior teeth with balanced bone resorption and apposition is needed in such cases. This report describes the treatment of a 19-year-old woman with missing mandibular first molars due to juvenile periodontitis. Miniscrews were used as absolute anchorage during protraction of the mandibular second and third molars. Bodily mesial movement of the mandibular second and third molars was achieved over a distance of 11 to 17 mm after 39 months of orthodontic treatment.

Effect of bicortical orthodontic microimplant on tooth movement in dogs / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the potential anchorage of bicortical microimplant for tooth movement.</p><p><b>METHODS</b>Five bicortical microimplants were inserted in the interradicular area of the second premolar (P2) in one side of the mandible (test side), 5 monocortical microimplant in the contralateral region (control side) in 5 beagle dogs. A total of 100 g force was generated between the implant and the fourth premolar (P4) in two sides. M1-P4, CA-IB and CA-M1 were measured biweekly. At the end of loading, specimens with P4 segments were cut and grounded to 70 microm to calculate the bone-to-implant contact (BIC).</p><p><b>RESULT</b>All the bicortical microimplants remained stable during the treatment periods, while 1 monocortical microimplant was lost within 1 week. Mesial movement of P4 was ( 3.92+/-0.22) mm in the test side, (2.03+/-0.15) mm in the control side (P<0.05). Analysis showed no difference of the BIC between the bicortical microimplants and the monocortical microimplants.</p><p><b>CONCLUSION</b>The bicortical microimplant may be used as orthodontic anchorage for mesial movement of posterior tooth.</p>