METHODS: Eligibility criteria for sample selection were: 20-40-year subjects with acceptable occlusion, native speakers of Portuguese. The volunteers (n=21) were divided in four groups randomized with a 1:1:1:1 allocation ratio. The four groups used, in random order, the four types of retainers full-time for 21 days each, with a washout period of 7-days. The removable maxillary retainers were: conventional wraparound, wraparound with an anterior hole, U-shaped wraparound, and thermoplastic retainer. Three volunteers were excluded. The final sample comprised 18 subjects (11 male; 7 female) with mean age of 27.08 years (SD=4.65). The speech evaluation was performed in vocal excerpts recordings made before, immediately after, and 21 days after the installation of each retainer, with auditory-perceptual and acoustic analysis of formant frequencies F1 and F2 of the vowels. Repeated measures ANOVA and Friedman with Tukey tests were used for statistical comparison.
RESULTS: Speech changes increased immediately after conventional wraparound and thermoplastic retainer installation, and reduced after 21 days, but not to normal levels. However, this increase was statistically significant only for the wraparound with anterior hole and the thermoplastic retainer. Formant frequencies of vowels were altered at initial time, and the changes remained in conventional, U-shaped and thermoplastic appliances after three weeks.
CONCLUSIONS: The thermoplastic retainer was more harmful to the speech than wraparound appliances. The conventional and U-shaped retainers interfered less in speech. The three-week period was not sufficient for speech adaptation.
方法:样本选择的合格标准是:具有可接受闭塞的20-40岁受试者,以葡萄牙语为母语的人。志愿者(n=21)分为四组,随机分配比例为1:1:1:1。使用的四组,以随机顺序,四种类型的固位器分别全职21天,冲洗期为7天。可移除的上颌固位体是:常规的环绕,周围有一个前孔,U形环绕,和热塑性固定器。三名志愿者被排除在外。最终样本包括18名受试者(11名男性;7名女性),平均年龄为27.08岁(SD=4.65)。语音评估是在之前制作的声乐摘录录音中进行的,紧接着,每个固定器安装后21天,对元音共振峰频率F1和F2进行听觉感知和声学分析。重复测量ANOVA和Friedman与Tukey检验用于统计比较。
结果:在常规环绕和热塑性固定器安装后,语音变化立即增加,并在21天后减少,但没有达到正常水平。然而,这种增加仅在具有前孔和热塑性固定器的环绕中具有统计学意义。元音的共振频率在初始时间被改变,变化仍然是传统的,三周后的U型和热塑性器具。
结论:热塑性固定器比环绕式矫治器对言语的危害更大。常规和U形固定器对语音的干扰较小。三周的时间不足以适应语言。