Speech performance in lingual orthodontic patients measured by sonagraphy and auditive analysis

Esthetically appealing, externally invisible, lingually applied orthodontic brackets are in increasing demand. Because the brackets are placed lingually, however, they appear to cause some problems with respect to speech. This study is the first to present a prospective evaluation of the articulation of 23 patients with lingual brackets by means of an innovative combination of test methods. An acoustic, objective evaluation of articulation measured by digital sonagraphy was related to a semiobjective auditive evaluation by 10 speech professionals, to a semiobjective auditive evaluation by close contacts of the patients, and to a subjective auditive evaluation by the patients themselves, the latter 2 using standardized questionnaires. The tests were performed before (T1), within 24 hours after (T2), and 3 months (+/- 1 week) after (T3) the start of therapy. In comparison with the initial findings, a significant deterioration in articulation was recorded with all test methods at T2 and T3. Using a new combination of methods, our investigations show the need for detailed briefing of patients about the extent and duration of changes in speech resulting from lingual brackets.