Perceptual characteristics of consonant errors associated with malocclusion

The characteristics of articulation errors made by subjects having a class II, class II with open-bite, class III, or class III with open-bite malocclusion were compared. Regardless of the type of occlusal defect, errors occurred primarily on the sibilants /s, z/ and “sh, ch, j, dz,” which were characterized mostly by combined visual and auditory distortions. Errors on the stop consonants /p, b, m, t, d, n/ occurred less frequently and, in all cases, consisted of isolated visual distortions. The type of malocclusion had a specific influence on the nature of the sound error. Subjects having a class II malocclusion, with or without an open bite, were able to assume a variety of tongue and mandibular postures that allowed them to approximate an /s/ or /z/. These compensations did not occur in subjects with a class III malocclusion. In these cases, the tongue remained distal to the mandibular incisors, causing the air stream to scatter. This study suggests that certain groups of sounds were more susceptible to specific types of misproductions and to particular types of occlusal defects.