European Journal of Orthodontics, 2016, 227–234 doi:10.1093/ejo/cjv044 Advance Access publication 1 July 2015 Original Article The effect of orofacial myofunctional treatment in children with anterior open bite and tongue dysfunction: a pilot study Claire Van Dyck*, Aline Dekeyser**, Elien Vantricht**, Eric Manders**, Ann Goeleven**,***, Steffen Fieuws**** and Guy Willems* *Department of Oral Health Sciences-Orthodontics, KU Leuven and Dentistry, University Hospitals Leuven, **Research Group of Experimental Oto-Rhino-Laryngology, KU Leuven, ***ENT-department, University Hospitals Leuven, and ****Interuniversity Institute for Biostatistics and Statistical Bioinformatics, KU Leuven and University Hasselt, Belgium Correspondence to: Guy Willems, Department of Oral Health Sciences-Orthodontics, Katholieke Universiteit Leuven, Ka- pucijnenvoer 7 bus 7001, 3000 Leuven, Belgium. E-mail: [email protected] Summary Objectives: Insufficient attention is given in the literature to the early treatment of anterior open bite (AOB) subjects receiving orofacial myofunctional therapy (OMT), which aims to harmonize the orofacial functions. This prospective pilot study investigates the effects of OMT on tongue behaviour in children with AOB and a visceral swallowing pattern. Materials and methods: The study comprised of 22 children (11 boys, 11 girls; age range: 7.1– 10.6 years). They were randomly assigned into OMT and non-OMT subjects. The randomization was stratified on the presence of a transversal crossbite. At baseline (T0), at the end of treatment (T1) and at 6 months after T1 (T2) maximum tongue elevation strength was measured with the IOPI system (IOPI MEDICAL LLC, Redmond, Washington, USA). Functional characteristics such as tongue posture at rest, swallowing pattern and articulation and the presence of an AOB were observed. Results: OMT did significantly change tongue elevation strength, tongue posture at rest, and tongue position during swallowing of solid food. At T2 more OMT subjects had contact between the lower central incisors and their antagonists or palate (P = 0.036). More OMT subjects performed a physiological pattern of water swallowing than non-OMT children at T1 and T2, although the differences were not significant. Articulation of /s,l,n,d,t/ was not improved by OMT. No interaction between OMT and expansion was found for any of the parameters. Conclusion: OMT can positively influence tongue behaviour. However, further research is recommended to clarify the success of OMT as an adjunct to orthodontic treatment and to identify possible factors influencing the outcome. Introduction thrusting and posture, tooth ankylosis, and eruption disturbances. Malocclusions such as anterior open bite (AOB) are often associ- Some researchers have focused on the tongue as the primary factor ated with orofacial dysfunctions (1). It has a multifactorial etiology in the etiology of AOB. Proffit (2) and Proffit et al. (3, 4) measured comprising inherited skeletal pattern and environmental causes, force levels of the tongue against the maxillary incisors and palate such as thumb or dummy sucking, mouth breathing, lip or tongue during rest and normal swallowing. They concluded that the resting © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. 227 For permissions, please email: [email protected] 228 European Journal of Orthodontics, 2016, Vol. 38, No. 3 position of the tongue was a more contributing factor than the swal- Several treatment approaches with regard to early treatment of lowing position in determining dental arch form. The inadequate AOB can be found in the literature. Many authors agree that clini- tongue position during swallowing must then be regarded as a result cians should be able to distinguish an AOB of dental and dentoal- of a pre-existing morphological alteration, thus as a consequence veolar origin from a skeletal open bite so that treatment is directed and not as a cause of the AOB. Other investigators however have towards the cause of the problem. Unfortunately, in most cases this shown that functional tongue movements during deglutition are sig- distinction is not so clear and both dental and skeletal character- nificantly correlated with certain features of maxillofacial morphol- istics are present. The treatment modalities for early correction of ogy such as AOB (5–7). Individuals with partial AOB and incorrect AOB include functional, fixed, and removable appliances, with the tongue position exhibit impaired gnostic sensibility of the tongue (8, goals of impeding mechanical factors that maintain the open bite 9), which is a symptom of disturbed sensorimotor coordination and (like thumb sucking or tongue thrust) and limiting excessive vertical is connected with the incorrect position of the tongue. This results growth of the craniofacial skeleton (24–31). However, few publi- in imprecise action and reduced vertical movement of the tongue. cations exist on early interceptive treatment in AOB patients with Cayley et al. (10) reported that children who swallow incorrectly a persistent aberrant swallowing pattern using orofacial myofunc- very rarely touch the anterior part of the palate with the tip of the tional therapy (OMT) (32–35). Some authors question the clinical tongue. They perform predominantly horizontal tongue movements use of OMT (22). Others support the reestablishment of a normal and place the tongue between their anterior teeth while speaking and oral function after OMT in patients with myofunctional disorders swallowing (11). Although studies have demonstrated that tongue such as tongue thrusting (36, 37). thrust plays an important role in the etiology of AOB as well as in The aim of a myofunctional program is to establish a new neu- the relapse of treated AOB patients, the exact etiological connection romuscular pattern and to correct abnormal functional and resting between malocclusion and malfunction during swallowing remains postures. Cayley et al. (38) demonstrated that normal swallowing controversial (12). This applies in particular to the extent to which function resumes after OMT in subjects with AOB. Also the improve- orofacial dysfunctions foster the development of malocclusions and ment of the resting position of the tongue has been described (35). It how a dysfunction can be positively influenced by a change in struc- has been suggested that an OMT therapist should train the patient ture (13). to lift the body of the tongue in order to learn a normal resting posi- From the standpoint of developmental physiology, a distinction tion of the tongue. Other treatment objectives are strengthening of is drawn between visceral, somatic, and inconstant swallowing (12, the orofacial muscles to pave the way for mouth closure, establish 14). Visceral swallowing exists at birth and is also termed ‘infan- nasal breathing, and learn a physiological swallowing pattern (39). tile swallowing’. It is characterized by a forward movement of the However, Smithpeter and Covell (40) cited the following reasons for tongue tip and pressure against the lingual surfaces of the anterior the lack of enthusiasm for OMT: 1. limited office space for provid- teeth. A visceral type of swallowing can persist well after the fourth ing therapy, 2. absence of OMT providers, 3. difficulty and amount year of life and is then considered as a dysfunction or abnormal- of time required, 4. inadequate training, 5. hope that a change in ity because of its association with certain malocclusions (12, 14). function will be induced by a change in form, 6. belief that there is Normally, the visceral swallowing pattern changes gradually into a insufficient scientific evidence to support OMT and 7. observation mature or somatic swallowing pattern. The latter is characterized that not all OMT providers have the same expertise, so successful by a cranial movement of the tongue and pressure on the incisive results are unpredictable. papilla (12). Inconstant swallowing is characterized as a pattern The aim of the present pilot study is to investigate the effects of swallowing during the transitional period between infantile and of OMT on tongue behaviour in children with AOB and a visceral somatic swallowing. According to Christensen and Hanson, a vis- swallowing pattern. ceral swallowing pattern is seen in 50% of 5-year olds and in 33% of 8-year olds (15). In the age range between 6 and 8 years, AOB is a predominant Subjects and methods type of malocclusion (16). A prevalence of 1–17.7% of AOB (defined Twenty-two children (11 males, 11 females; age range: 7.1– as the lack of overlap between the upper and lower incisors) in the 10.6 years) were included in this prospective pilot randomized mixed dentition is reported in the literature (1, 16–19). In the mixed study. The inclusion period started in February 2012 and ended in dentition AOB is registered more often in girls (1, 19). Keski-Nisula February 2013. The inclusion and exclusion criteria are described et al. (17) reported in their study that at the onset of the early mixed in Table 1. All children were seen at the orthodontic department of dentition, 39.1% of the children had no contact either between the the University Hospitals Leuven and informed consent was obtained. mandibular incisors and maxillary incisors or palatal gingiva. In The research project was approved by the Ethics Committee of the 4.6% no incisal overlap was present. Some authors mention that the University Hospitals Leuven (B322201316750).