30th Euro Dentistry Congress
Sichuan University, China
Title: Effectiveness and Effciency of Molar Distalization in Orthodontic Treatment
Biography: : Xianglong, HAN
Molar distalization is a frequently used non-extraction option for orthodontic camulflage. Extraoral appliances such as headgear, and intraoral appliances such as pendulums, have been used and achieved effective results. The effect of extraoral appliances depend on patients’ co-operation, and intraoral appliances can have side effects like distal tipping, rotation and anchorage loss. Therefore, anchorage loss can be resist through skeletal anchorage devices in conjunction with intraoral movers. In addition, clear aligners have become common alternatives under aesthetic and comfort considerations, providing Class II correction with high predictability through continuous distalization. However, molars can only be distalized with adequate bony envelope to house the roots, exceeding which will result in dehiscence, root-resorption and even tooth mobility. The boundaries of molar distalization refers to the posterior alveolar region. To date, there is no universal consensus describing the posterior alveolar regions of the maxilla in the context of molar distalization. We then quantitatively analyzed the influence of vertical growth patterns on retromolar regions of mild skeletal Class II patients through measuring cone-beam computed tomography (CBCT) images of 60 patients with hypo-, hyper- and normo-divergent. After standardized orientating images in Mimics 16.0 software, the available distance between second molar root and inner/outer cortical bone as well as the bone volume of reconstructed slices were measured. The results showed significant differences in the maxilla among three vertical growth patterns. In conclusion, vertical growth patterns affect distalization potential, and the patient with hyperdivergent growth pattern is indicative of less potential for distalization.