Background and aims. The aims of this study were to assess the prevalence of anterior open bite (AOB) and articulation disorders (AD) in deciduous dentition and their association with low tongue posture, orofacial disorders and impaired ENT condition. The aim was to assess the resting tongue posture in subjects with and without AOB and AD using a three-dimensional ultrasonography (3DUS) and to compare the method to orthodontic and ENT assessment. These findings would allow us to supplement basics of national preventative protocol for early developmental interception of both, AOB malocclusion and AD.
Subjects and methods. The subjects were 446 children aged 3 - 7 years, 236 boys and 210 girls visiting local kindergartens in Posočje, Slovenia. The survey has 4 different studies. The subjects were orthodontically examined for AOB malocclusion, orofacial and ENT impairment, oral habits, AD and questionnaires were answered by their parents. Participants presenting AOB in deciduous dentiton were allocated to the research group, the rest were included to the control group (CG). Further orthodontic clinical examinations, facial and oral photographs and dental casts were obtained in AOB subjects only. An experienced ENT specialist the ENT condition and a speech therapist examined the AD. A 3DUS assessment of resting tongue posture was assessed by an experienced radiologist and an orthodontist independently. The device used was 3DUS Voluson 730 (General Electrics Healthcare). The 3DUS data were analysed by 4D View Programe 5.0. The R-Programe was used for collated data statistical analysis with descriptive statistic, Mann-Whitney, chi-square or Fisher's exact test, McNemar test and the multiple logistic regression model. Statistical significancy was set at p < 0.05.
Results. The 32 preschool children aged 3.5 -7 years (mean 5.0 years ± 0.9 y) presented AOB in the deciduous dentition; the prevalence of AOB was 7.2 % and the prevalence of AD was 30,2 %. The subjects with AOB presented higher occurrence of orofacial and ENT irregularities and AD, mostly sigmatism, rhotacism and their combinations. In children without AD from both groups, the improper tongue posture occured less frequently than in children with AD. The 3DUS detected the highest number of AOB subjects with low tongue posture and there was no significant difference among the three clinical assessments.
Conclusions. The results confirmed a strong relationship among AOB, low tongue posture and AD. The 3DUS assessment is objective, reliable, non-invasive, radiation free, no time consuming and child-friendly method for functional assessment of the tongue posture in preschool children and should become a useful tool in everyday clinical practice for functional diagnostics, prevention of the development of dentofacial deformities, and for treatment planning of early rehabilitation in preschool children with AOB and AD. The child and his/her parents should get the early information about the proper resting tongue posture, lip closure and nasal breathing. In this way, an optimal condition in the oral cavity for proper orofacial and articulation development can be created. Preventative procedures for early AOB development interception should be included into all three levels of national preventative protocol to enhance early interception of sucking and non-sucking habits, orofacial or ENT impairment and a timely PLP 5 screening for referrals to orthodontists and speech therapists.