Effects of Hawley retainers on consonants and formant frequencies of vowels

Abstract

Objective: To assess (1) whether Hawley retainers cause speech disturbance and (2) the duration of speech adaptation to Hawley retainers with objective and subjective tests. Materials and Methods: Twelve adolescents, aged 11.11 to 18.03 years, were included in this study. The assessment of speech sounds were done subjectively using an articulation test and objectively using acoustic analysis before and after Hawley retainer application. Results: After wearing Hawley retainers, patients showed statistically significant speech disturbances on consonants [ş] and [z]. Regarding the vowels, statistically significant changes were recorded with [i], while F1 increased and F2 and F3 decreased. Conclusions: The tongue changes its target position with the application of a foreign body within the mouth; however, in time it adapts to that new situation. (Angle Orthod. 2012;82:14-21.)

The effects of rapid maxillary expansion on voice function

“…Kayıkcı et al 17 used Hawley retainers and found statistically significant speech disturbances in consonants [s ] and [z]. In addition, the authors found that the F 1 frequency of the vowel /i/ increased, whereas F 2 and F 3 decreased.…”

“…In addition, the /a/ vowel serves as the phonological core of many syllables. 9,16,17 Thus, we have examined the parameters of the /a/ vocal in evaluating the voice.…”

A Prospective Evaluation of Speech Distortion among Patients Wearing Hawley Retainer Using Acoustics Approach

“…Majority population in Malaysia is Malay (60%) and the national language was Bahasa Malaysia [13]. In this study, the consonant sounds of /t d k n s/ were analyzed as these phonemes were the most likely to have distortion of speech in patients according to literature review done [7][8][9][10]. Furthermore, analysis was limited to the consonants because these sounds are much less affected by differences in dialect [14].…”

“…The design is Adam's clasps with 0.7 mm diameter stainless steel wire on the first molars and a labial bow with 0.7mm diameter stainless steel wire which span from canine to canine (Figure 1). The acrylic part (Impact Orthodontic Resin) was kept at a uniform thickness of 2 to 3mm on the palatal for each retainer, as suggested by Kulak Kayikci et al [10]. All retainers were constructed by a single technician.…”

“…However, the assessments of speech sounds were done subjectively (perceptual phonetics) using an articulation test which was conducted by an experienced speech therapist. Kulak Kayikci et al [10] was the first study looking at the effect of the Hawley appliance on speech clarity objectively by using acoustic analysis. PRAAT (Dutch for 'talk'), created by Paul Boersma and David Weenink of the Institute of Phonetic Sciences, University of Amsterdam, is currently among the most popular spectrography analysis software packages and it can be freely downloaded from the following website: It is a very flexible tool that can do acoustic analysis of speech and voice samples.…”