Tooth position and speech--is there a relationship?

Speech adapts to differences in dentition within and across populations

We test the hypothesis that a specific anatomical feature, the dental malocclusion associated with reduced dental wear, causes languages to adapt by relying more heavily on labiodental consonants. In contrast to previous work on this topic, we adopt a usage-based approach that directly examines the relative frequency of such labiodental sounds within phonetically transcribed word lists and texts from thousands of languages. Labiodentals are shown to be very infrequent in the languages of hunter gatherers, who tend to have edge-to-edge bites as opposed to the overbite and overjet observed in populations that consume softer diets and rely heavily on eating utensils. This strong tendency is evident after controlling for Galton’s problem via multiple methods including frequentist and Bayesian linear mixed modeling. Additionally, we discuss data from Amazonian hunter gatherers with edge-to-edge bites. The languages of these populations are shown not to use labiodentals frequently, or to have only recently begun doing so. Finally, we analyze the speech of English speakers with varying bite types, demonstrating how the sounds used by individuals reflect the same phenomenon. The diverse findings converge on the same conclusion: speech adapts to anatomical differences within and across populations.

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

Objectives

To evaluate the acoustic properties of the /s/ sound in individuals with different occlusion types and to investigate relationships between these properties and cephalometric measurements.

Methodology

Sixty patients were divided into three groups based on malocclusion. Group 1 included 20 patients (mean age: 14.85±2.01 years) with Class I skeletal and dental relationships. Group 2 included 20 patients (mean age: 13.49±1.78 years) with Class II skeletal and dental relationships. Group 3 included 20 patients (mean age: 12.46±2.62 years) with Class III skeletal and dental relationships. Cephalometric tracings were obtained from cephalometric radiographs. All included patients were native speakers of Turkish. The /s/ sound was selected for center of gravity analysis. Correlations between cephalometric values and acoustic parameters were also investigated.

Results

The center of gravity of the /s/ sound had the lowest value in Group 2 (p<0.05). For the /s/ sound in Group 3, moderate positive correlations were found between center of gravity and Sella-Nasion to Gonion-Gnathion angle (p<0.05, r=0.444) Lower incisor to Nasion-B point (p<0.023, r=0.505), and Lower incisor to Nasion-B point angle (p<0.034; r=0.476). No correlation was found in other cephalometric measurements.

Conclusions

The /s/ sound was affected by malocclusion due to the changing place of articulation. Therefore, referral to an orthodontist for malocclusion treatment especially patients with class III in the early period is suggested for producing acoustically ideal sound.

Three-dimensional ultrasound evaluation of tongue posture and its impact on articulation disorders in preschool children with anterior open bite

Background Tongue posture plays an important role in the etiology of anterior open bite (AOB) and articulation disorders, and is crucial for AOB treatment planning and posttreatment stability. Clinical assessment of tongue posture in children is unreliable due to anatomical limitations. The aim of the study was to present functional diagnostics using three-dimensional ultrasound (3DUS) assessment of resting tongue posture in comparison to clinical assessment, and the associations between the improper tongue posture, otorhinolaryngological characteristics, and articulation disorders in preschool children with AOB. Patients and methods A cross-sectional study included 446 children, aged 3-7 years, 236 boys and 210 girls, examined by an orthodontist to detect the prevalence of AOB. The AOB was present in 32 children. The control group consisted of 43 children randomly selected from the participants with normocclusion. An orthodontist, an ear, nose and throat (ENT) specialist and a speech therapist assessed orofacial and ENT conditions, oral habits, and articulation disorders in the AOB group and control group. Tongue posture was also assessed by an experienced radiologist, using 3DUS. The 3DUS assessment of tongue posture was compared to the clinical assessment of orthodontist and ENT specialist. Results The prevalence of AOB was 7.2%. The AOB group and the control group significantly differed regarding improper tongue posture (p < 0.001), and articulation disorders (p < 0.001). In children without articulation disorders from both groups, the improper tongue posture occured less frequently than in children with articulation disorders (p < 0.001). After age adjustment, a statistical regression model showed that the children with the improper tongue posture had higher odds ratios for the presence of AOB (OR 14.63; p < 0.001) than the others. When articulation disorders were included in the model, these odds ratios for the AOB became insignificant (p = 0.177). There was a strong association between the improper tongue posture and articulation disorders (p = 0.002). The 3DUS detected the highest number of children with improper resting tongue posture, though there was no significant difference between the 3DUS and clinical assessments done by orthodontist and ENT specialist. Conclusions The 3DUS has proved to be an objective, non-invasive, radiation free method for the assessment of tongue posture and could become an important tool in functional diagnostics and early rehabilitation in preschool children with speech irregularities and irregular tongue posture and malocclusion in order to enable optimal conditions for articulation development.

Prevalence of dyslalias in 8 to 16 year-old students with anterior open bite in the municipality of Envigado, Colombia

Background

Anterior open bite AOB is the most common malocclusion associated with speech disorders and the literature has shown that problems of occlusion involve all oral functions. AOB not only produce aesthetic and occlusal problems for the patient and modifies the union of the lips, tongue, teeth, palate, palatal rugae and oropharynx, and thus affecting the ability to communicate well with their surroundings.

The prevalence of AOB in children and adolescent in our population is unknown. Furthermore, the most frequent type of dyslalias in children with this malocclusion is also unknown. Therefore, the aim of the study was to describe the frequency and types of dyslalia in students between 8-16 years with AOB, as well as the difference in the types of dyslalia according to the magnitude of AOB.

Methods

A cross-sectional study was conducted. Clinical assessment of AOB in students from the municipality of Envigado, Colombia, was performed. Students from 8 to16 years of age were examined during the second semester of 2011 and first semester of 2012. Phonoaudiological assessment was carried out in students in the mixed or permanent dentition. Exclusion criteria included children with history of systemic disease, altered skeletal development, neurological and psychiatric disorders, and residents in other departments. In addition, students undergoing orthodontic treatment at the time of evaluation or with history of previous orthodontic treatment, as well as those who did not cooperate with the oral cavity evaluation, were excluded.

Results

Six thousand one hundred sixty five children were evaluated. One hundred sixty six presented AOB (prevalence: 2.7 %; 95 % CI: 2.28–3.10). Thirty four students were excluded. 26.5 % of the sample presented mild AOB, 66.7 % moderate, and 6.8 % severe. Some type of dyslalia was found in 77.4 % of the students, being distortion (75.8 %) the most common. The most frequently altered phonemes were: / d / t / s / ch / ñ /. No significant association between different types of dyslalia and AOB severity (p-value = 0.974) was found.

Conclusion

Prevalence of AOB in Envigado is low (2.7 %). Phonation alterations are very common in children with AOB (77.8 %), and distortion is the most frequent type of dyslalia (75.8 %). In order to diagnose and treat occlusal and phonetic problems, and to avoid possible recurrence, interdisciplinary approach is recommended.

Speech acoustics: How much science?

Human vocalizations are sounds made exclusively by a human vocal tract. Among other vocalizations, for example, laughs or screams, speech is the most important. Speech is the primary medium of that supremely human symbolic communication system called language. One of the functions of a voice, perhaps the main one, is to realize language, by conveying some of the speaker's thoughts in linguistic form. Speech is language made audible. Moreover, when phoneticians compare and describe voices, they usually do so with respect to linguistic units, especially speech sounds, like vowels or consonants. It is therefore necessary to understand the structure as well as nature of speech sounds and how they are described. In order to understand and evaluate the speech, it is important to have at least a basic understanding of science of speech acoustics: how the acoustics of speech are produced, how they are described, and how differences, both between speakers and within speakers, arise in an acoustic output. One of the aims of this article is try to facilitate this understanding.