Correlation between the cephalometric measurements and acoustic properties of /s/ sound in Turkish

Impacts of Development, Dentofacial Disharmony, and Its Surgical Correction on Speech: A Narrative Review for Dental Professionals

“…Perceptually, this imprecise articulation of sibilants [s] and [z] can be attributed to a reduced oral opening caused by the deep bite seen in many Class II patients [ 72 , 75 ]. Both our study at UNC and a Turkish study applied spectral moment analysis and found differences in [s] articulation in Class II patients compared with controls, indicating speech distortions are present at an increased prevalence among Class II patients, despite attempted compensation [ 44 , 50 ]. Though Class II DFD patients have documented articulation issues, their speech presentation may be milder than that in other DFD groups, with smaller shifts in consonant spectral moments (centroid frequency (M1) and spectral spread (M2)), compared to in AOB and Class III DFD cohorts [ 44 ].…”

“…Severe ‘handicapping’ malocclusions are associated with a 16- to 25-fold increased prevalence of speech distortions compared with Class I controls [ 48 – 50 ]. DFD subtypes (e.g., Class II, Class III and AOB) demonstrate distinct features on acoustic and perceptual evaluations.…”

“…DFD subtypes (e.g., Class II, Class III and AOB) demonstrate distinct features on acoustic and perceptual evaluations. This suggests that vertical and anterior–posterior disproportions have separate and potentially additive impacts on articulation [ 48 – 50 ]. Among DFD patients, 90% of Class III and 83% of open-bite patients suffer from SSDs compared with 4.9% of adolescents and 3.5% of adults in the general population, suggesting a link between jaw disproportion and articulation issues [ 24 ].…”

“…Class III : Speech distortions are well-documented in the Class III population [ 44 , 50 ]. A study of 451 Finnish students found that those with Class III malocclusions were 4.5 times more likely to produce consonants more anteriorly [ 66 ].…”

“…Compensation may help Class II patients approximate normal [s] and [z] articulation [ 48 ]. In some cases, attempting compensatory articulation contributes to distortions, with the protrusion of the tongue past the incisors (“interdental lisping”) during the production of /s/, leading to an audible lisp [ 48 , 50 ]. Perceptually, this imprecise articulation of sibilants [s] and [z] can be attributed to a reduced oral opening caused by the deep bite seen in many Class II patients [ 72 , 75 ].…”