Is the main goal of mastication achieved after orthodontic treatment? A prospective longitudinal study

ABSTRACT Objective: To investigate the masticatory and swallowing performances in patients with malocclusions before and after orthodontic treatment, comparing them to an age- and gender-matched control group with normal occlusion. Methods: Twenty-three patients with malocclusions requiring orthodontic treatment were included in this prospective study. One month after appliance removal, seventeen patients completed a follow-up examination and the data were compared with those of a control group with thirty subjects with normal occlusion. Masticatory performance was determined by the median particle size for the Optocal Plus® test food after 15 chewing strokes, and three variables related to swallowing were assessed: a) time and b) number of strokes needed to prepare the test-food for swallowing, and c) median particle size of the crushed particles at the moment of swallowing. Results: At the baseline examination, the malocclusion group had a significantly lower masticatory performance and did not reach the particle size reduction at the moment of swallowing, when compared with the control group. After treatment, the masticatory performance significantly improved in the malocclusion group and the particle size reduction at swallowing reached the same level as in the control group. Conclusions: The present results showed that the correction of malocclusions with fixed appliances can objectively provide positive effects in both mastication and deglutition processes, reinforcing that besides aesthetic reasons, there are also functional indications for orthodontic treatment.摘要 研究目的：本研究旨在探究错𬌗畸形（malocclusions）患者正畸治疗前后的咀嚼与吞咽功能表现，并将其与年龄、性别匹配的正常𬌗（normal occlusion）对照组进行对比。 研究方法：本前瞻性研究纳入23例需接受正畸治疗的错𬌗畸形患者。矫治器拆除1个月后，共17例患者完成随访检查，将其数据与30名正常𬌗对照受试者的数据进行对比。咀嚼功能采用Optocal Plus®试验食物经15次咀嚼后的粒径中位数进行评估；吞咽相关指标共三项：a) 吞咽前制备试验食物所需的时间，b) 吞咽前制备试验食物所需的咀嚼次数，以及c) 吞咽瞬间破碎颗粒的粒径中位数。 研究结果：基线检查时，与正常𬌗对照组相比，错𬌗畸形组的咀嚼功能显著更低，且吞咽瞬间的粒径降幅未达到对照组水平。治疗后，错𬌗畸形组的咀嚼功能显著改善，吞咽瞬间的粒径降幅达到与对照组相同的水平。 研究结论：本研究结果显示，采用固定矫治器（fixed appliances）矫正错𬌗畸形，可客观改善咀嚼与吞咽功能，进一步佐证正畸治疗除美学需求外，亦存在功能层面的适应证。