Rossi Moara de, Rossi Andiara de, Abrão Jorge
Department of Pediatric Clinics, Preventive and Community Dentistry, Ribeirão Preto Dental School, USP -- University of São Paulo, Ribeirão Preto, SP, Brazil.
Braz Dent J. 2011;22(4):334-9. doi: 10.1590/s0103-64402011000400013.
Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.
有人提出，固定式上颌扩弓矫治器可控制快速上颌扩弓（RME）后面部垂直维度的增加。然而，关于其真正的骨骼效应，文献中仍未达成共识。这项前瞻性研究的目的是纵向评估使用固定式上颌扩弓矫治器进行RME后的垂直和矢状向头影测量变化。样本包括26名儿童，平均年龄8.7岁（范围：6.9 - 10.9岁），患有后牙骨骼性反颌且有RME指征。上颌扩弓后，固定式矫治器作为固定保持器使用3.4个月，随后更换为可摘保持器。头影测量研究在治疗开始前及拆除固定式矫治器6.3个月后拍摄的侧位片上进行。组内比较采用配对t检验。结果显示，治疗结束时矢状向骨骼无显著变化。在评估的11项头影测量指标中，有5项出现了较小的垂直向骨骼增加。上颌向下移位，但未改变面部生长模式或下颌生长方向。在本研究的特定条件下，可以得出结论，使用丙烯酸固定式上颌扩弓矫治器进行RME确实促进了显著的垂直或矢状向头影测量变化。使用固定式矫治器发现的垂直变化较小且可能是暂时的，与使用带环扩弓矫治器时出现的变化相似。
