comparison of speech performance in labial and lingual orthodontic patients: a prospective study

background: the intensity and duration of speech diffi culty inherently associated with lingual therapy is a signifi cant issue of concern in orthodontics. this study was designed to evaluate and to compare the duration of changes in speech between labial and lingual orthodontics. materials and methods: a prospective longitudinal clinical study was designed to assess speech of 24 patients undergoing labial or lingual orthodontic treatment. an objective spectrographic evaluation of/s/sound was done using software praat version 5.0.47, a semiobjective auditive evaluation of articulation was done by four speech pathologists and a subjective assessment of speech was done by four laypersons. the tests were performed before (t1), within 24 h (t2), after 1 week (t3) and after 1 month (t4) of the start of therapy. the mann-whitney u-test for independent samples was used to assess the signifi cance difference between the labial and lingual appliances. a speech alteration with p < 0.05 was considered to be signifi cant. results: the objective method showed a signifi cant difference to be present between the two groups for the/s/sound in the middle position (p < 0.001) at t3. the semiobjective assessment showed worst speech performance in the lingual group to be present at t3 for vowels and blends (p < 0.01) and at t3 and t4 for alveolar and palatal consonants (p < 0.01). the subjective assessment also showed a signifi cant difference between the two groups at t3 (p < 0.01) and t4 (p < 0.05). conclusion: both appliance systems caused a comparable speech diffi culty immediately after bonding (t2). although the speech recovered within a week in the labial group (t3), the lingual group continued to experience discomfort even after a month (t4). key words: articulation, labial orthodontics, lingual orthodontics, spectrography, speech