A Clinical Study Of Skeletal Angle Ⅲ Malocclusion In Mixed Dentition On Articulation

[Objective] To investigate the effects of skeletal Class III malocclusion in mixed dentition on speech articulation and to look for which factors lead to the sound errors. [Methods]Thirty-eight children with skeletal Angle III malocclusion in mixed dentition were selected as a sample group, 40 children with normal occlusion in mixed dentition were selected as a control group .Two phoneticians evaluated their articulations and wrote down error phonemes and error types respect ively. The acoustical analysis of the discorded speech sounds were done by means of Computerized Speech Lab. The correlated analysis was done between the number of errors and the measurements of patients' cephalometry. [Results] :Most Class III malocclusion patients in mixed dentition have mi sarticulations, the sound errors focused on sibilants (c, s, z etc.). The numbers of errors were correlated with overbite, UI-LI, OBJ and TD-PW significantly. The voice onset time(VOT) of resonant note sibilants ofmaloccl ussion group is zero while that of the normal group is positive. [Conclusion] :There is articulatory misfunction in most skeletal Angle III malocclusion patients in mixed dentition.