The effect of tongue thrusting on tongue pressure production during swallowing in adult anterior open bite cases

Analyzing effects on anterior open bite in twins by PLS-SEM and sobel test

OBJECTIVE

This study aimed to assess the different pathways between predictor factors such as zygosity, atypical swallowing, mouth breathing, breastfeeding and bottle feeding related to anterior open bite (AOB) in twins.

METHODS

The study was conducted in monozygotic (MZ) and dizygotic (DZ) twin children aged 3-15 years. AOB, atypical swallowing, mouth breathing, feeding type, duration of bottle use, and mouth opening status during sleep were recorded during oral examination. Partial least squares structural equation model (PLS-SEM) and sobel tests were performed to assess the total and indirect effects among the variables on AOB.

RESULTS

A total of 404 children (29.2% MZ;70.8% DZ) participated in this study. The effect of zygosity on mouth breathing in the PLS-SEM model was statistically significant. Conversely, it was determined that mouth breathing effected that atypical swallowing (p = 0.001). Atypical swallowing triggered AOB (p = 0.001). The atypical swallowing has a mediation effect between AOB and mouth breathing (p = 0.020). Mouth breathing causes atypical swallowing and therefore indirectly increases the likelihood of AOB. While breastfeeding decreases AOB incidence (p = 0.023), bottle feeding increases AOB incidence (p = 0.046). The sobel tests show that the fully mediator variable feature of mouth breathing is statistically significant in the negative relation between zygosity and atypical swallowing.

CONCLUSION

The PLS-SEM model showed that mouth breathing triggers atypical swallowing and atypical swallowing triggers AOB. As a result of this chain of relationships, an indirect effect of zygosity on AOB was observed. According to sobel tests, zygosity has an indirect effect on atypical swallowing through mouth breathing, while mouth breathing has a positive indirect effect on AOB through atypical swallowing.

CLINICAL RELEVANCE

This study identified the relationships between different factors and the presence of AOB. The findings of this study demonstrate in detail the relationships between AOB and zygosity, atypical swallowing, mouth breathing, breastfeeding and bottle feeding. Brestfeeding has a reducing effect on the frequency of AOB. Among the nutritional forms, breastfeeding ensures the proper development of the stomatognathic system by working the oro-facial muscles.

Tongue pressure and maxillofacial muscle activities during swallowing in patients with mandibular prognathism

BACKGROUND

Coordination among lip, cheek and tongue movements during swallowing in patients with mandibular prognathism remains unclear.

OBJECTIVES

This study aimed to identify the temporal sequences of tongue pressure and maxillofacial muscle activities during swallowing in patients with mandibular prognathism and compared characteristics with those of healthy volunteers.

METHODS

Seven patients with mandibular prognathism (mandibular prognathism group) and 25 healthy volunteers with individual normal occlusion (control group) were recruited. Tongue pressures and masseter, orbicularis oris, mentalis and supra- and infrahyoid muscle activities while swallowing gel were measured simultaneously using a sensor sheet system with five measurement points and surface electromyography, respectively. Onset time, offset time and durations of tongue pressure and muscle activities were analysed.

RESULTS

In the mandibular prognathism group, tongue pressure was often produced first in more peripheral parts of the palate. Offset of tongue pressure in the posteromedian and peripheral parts of the palate and maxillofacial muscle activities except for orbicularis oris were delayed. Duration of tongue pressure in the anteromedian part of the palate was significantly shorter and durations of masseter, mentalis and suprahyoid muscle activities were significantly longer. Times to onset of orbicularis oris and suprahyoid muscle activities based on first onset of tongue pressure were significantly shorter.

CONCLUSION

These results suggest that patients with mandibular prognathism may exhibit specific patterns of tongue pressure production and maxillofacial muscle activities during swallowing.

Mouth Breathing and Its Impact on Atypical Swallowing: A Systematic Review and Meta-Analysis

The aim of this systematic review is the assessment of the effect of mouth breathing on the prevalence of tongue thrust. The review was performed according to the PRISMA 2020 checklist guidelines, and the protocol was registered with PROSPERO (CRD42022339527). The inclusion criteria were the following: studies of clinical trials and cross-sectional and longitudinal descriptive studies that evaluate the appearance of tongue thrust in patients with mouth breathing; healthy subjects of any age, race or sex; and studies with a minimum sample group of five cases. The exclusion criteria were the following: studies with syndromic patients, articles from case reports, and letters to the editor and/or publisher. Searches were performed in electronic databases such as The National Library of Medicine (MEDLINE via PUBMED), the Cochrane Central Register of Controlled Trials, Web of Science and Scopus, including studies published until November 2023, without a language filter. The methodological quality of the included case-control studies was assessed using the Newcastle-Ottawa Scale (NOS), and the Joanna Briggs Institute (JBI) tool was used for descriptive cross-sectional studies and cross-sectional prevalence studies. A meta-analysis was conducted on studies that provided data on patients' classification according to mouth breathing (yes/no) as well as atypical swallowing (yes/no) using Review Manager 5.4. From 424 records, 12 articles were selected, and 4 were eligible for meta-analysis. It was shown that there is no consensus on the diagnostic methods used for mouth breathing and tongue thrust. The pooled risk ratio of atypical swallowing was significantly higher in the patients with mouth breathing (RR: 3.70; 95% CI: 2.06 to 6.66). These studies have several limitations, such as the heterogeneity among the individual studies in relation to the diagnostic tools and criteria for the assessment of mouth breathing and atypical swallowing. Considering the results, this systematic review shows that patients with mouth breathing presented higher risk ratios for atypical swallowing.

Differences in the factors associated with tongue pressure between children with class I and Class II malocclusions

Background

The relationship between tongue pressure and masticatory performance during the mixed dentition period in cases of Class II malocclusion has not been clarified. The aim of this study was to determine differences in tongue pressure-related factors, including maxillofacial morphology and masticatory performance, between Class I and Class II malocclusions during the mixed dentition period.

Methods

A total of 56 children with Class I malocclusion (12 boys, 16 girls) or Class II malocclusion (16 boys, 12 girls) with mixed dentition were included in the present study. Height, body weight, hand grip strength, maximum occlusal force, maximum tongue pressure, masticatory performance, and the number of decayed, missing, and filled teeth were measured in all participants. Their lateral cephalograms were also evaluated. The means of all measurements were compared between Class I and Class II malocclusions. Pearson’s correlation coefficients were used to determine associations between maximum tongue pressure and other variables for each type of malocclusion.

Results

The maximum tongue pressure, hand grip strength, and maximum occlusal force in the Class II malocclusion group were significantly lower than those in the Class I malocclusion group (all, p < 0.05). The maximum tongue pressure was significantly positively correlated with hand grip strength, maximum occlusal force, masticatory performance, and SNB (sella, nasion, B point) angle in the Class I group (all, p < 0.05), and with height, body weight, and labial inclination of the central incisors in the Class II group (all, p < 0.05).

Conclusions

The maxillofacial morphometric factors associated with tongue pressure were clearly different between cases of Class I and Class II malocclusion with mixed dentition. Masticatory performance and tongue pressure were significantly positively correlated in cases of Class I malocclusion, but not in cases of Class II malocclusion.

Oral Myofunctional and Articulation Disorders in Children with Malocclusions: A Systematic Review

BACKGROUND

Relationships between malocclusion and orofacial myofunctional disorders (OMD), as well as malocclusions and articulation disorders (AD) have been described, though the exact relationships remain unclear. Given the high prevalence of these disorders in children, more clarity is needed.

SUMMARY

The purpose of this study was to determine the association between OMD (specifically, bruxism, deviate swallowing, caudal resting tongue posture, and biting habits), AD, and malocclusions in children and adolescents aged between 3 and 18 years. To conduct a systematic review, 4 databases were searched (MEDLINE, Embase, Web of Science, and Scopus). The identified articles were screened for the eligibility criteria. Data were extracted from the selected articles and quality assessment was performed using the tool of Munn et al. [Int J Health Policy Manag. 2014;3:123-81] in consensus. Using the search strategy, the authors identified 2,652 articles after the removal of duplicates. After reviewing the eligibility criteria, 17 articles were included in this study. One of the included articles was deemed to have an unclear risk of bias, whereas all other articles were considered to have a low risk of bias. The articles showed a relationship between anterior open bite and apico-alveolar articulatory distortions, as well as between anterior open bite and deviate swallowing. For the biting habits, bruxism, and low tongue position no clear conclusions could be drawn. Key Messages: The current review suggests a link between specific types of malocclusion and OMD and AD. However, more high-quality evidence (level 1 and level 2, Oxford Levels of Evidence) is needed to clarify the cooccurrence of other OMD, AD, and malocclusions.

Electromyographic features and efficacy of orofacial myofunctional treatment for skeletal anterior open bite in adolescents: an exploratory study

BACKGROUND

Due to the multifactorial aetiology and unpredictable long-term stability, skeletal anterior open bite (SAOB) is one of the most intractable conditions for orthodontists. The abnormal orofacial myofunctional status (OMS) may be a major risk factor contributing to the development and relapse of SAOB. This study is aimed at evaluating the OMS and the efficacy of orofacial myofunctional therapy (OMT) alone for SAOB subjects.

METHODS

Eighteen adolescents with SAOB (4 males, 14 females; age: 12-18 years) and eighteen adolescents with normal occlusion (2 males, 16 females; age: 12-18 years) were selected. The electromyographic activity (EMGA) associated with mastication and closed mouth state was measured. Lateral cephalography was used to evaluate craniofacial morphology. Wilcoxon signed rank tests and t-tests were performed to evaluate myofunctional and morphological differences. Pearson or Spearman correlation analysis was used to investigate the correlations between EMGA and morphological characteristics. SAOB subjects were given OMT for 3 months, and the EMGA was compared between before and after OMT.

RESULTS

During rest, anterior temporalis activity (TAA) and mentalis muscle activity (MEA) increased in SAOB subjects, but TAA and masseter muscle activity (MMA) decreased in the intercuspal position (ICP); and upper orbicularis activity (UOA) and MEA significantly increased during lip sealing and swallowing (P < 0.05). Morphological evaluation revealed increases in the FMA, GoGn-SN, ANS-Me, N-Me, L1-MP, U6-PP, and L6-MP and decreases in the angle of the axis of the upper and lower central incisors and OB in SAOB subjects (P < 0.05). TAA, MMA and anterior digastric activity (DAA) in the ICP were negatively correlated with vertical height and positively correlated to incisor protrusion. MEA was positively correlated with vertical height and negatively correlated with incisor protrusion; and the UOA showed a similar correlation in ICP, during sealing lip and swallowing. After SAOB subjects received OMT, MEA during rest and TAA, MMA and DAA in the ICP increased, while UOA and MEA decreased (P < 0.05).

CONCLUSION

SAOB subjects showed abnormal OMS features including aberrant swallowing patterns and weak masticatory muscles, which were interrelated with the craniofacial dysmorphology features including a greater anterior facial height and incisor protrusion. Furthermore, OMT contributes to OMS harmonization, indicating its therapeutic prospect in SAOB.

Impact of Oral Myofunctional Therapy on Orofacial Myofunctional Status and Tongue Strength in Patients with Tongue Thrust

INTRODUCTION

Tongue thrust is a frequent clinical condition characterized by abnormal patterns of movements and altered tongue posture on the mouth floor. It might contribute to determining alterations in the maxillofacial morphology and in the development of malocclusion. Several therapeutic options are available for treatment. In particular, the orofacial myofunctional therapy (OMT) is frequently adopted even if only few studies have analyzed its efficacy using validated instruments and no information is available regarding the effect of dentition on the results obtained with OMT.

OBJECTIVE

To evaluate the effect of OMT through a validated instrument and explore the role of dentition on its efficacy.

METHODS

A total of 22 consecutive patients with tongue thrust were enrolled. According to the presence of mixed or complete dentition, the cohort of patients was divided into 2 groups. Each patient underwent OMT according to the Garliner method (10 weekly sessions of 45 min each in hospital and daily exercises at home). The efficacy of OMT was evaluated using the Orofacial Myofunctional Evaluation with Scores (OMES), a validated protocol developed for the assessment of orofacial myofunctional disorders, and the Iowa Oral Performance Instrument (IOPI) to measure the peak isometric pressure exerted by the anterior and posterior part of the tongue. Both OMES and IOPI were administered before and at the end of the treatment.

RESULTS

A significant improvement in the OMES scores was demonstrated after OMT. No significant differences between the patients with intermediate and mixed dentition obtained in both the pre- and post-treatment conditions were demonstrated in the OMES scores. Similarly, a significant increase in the peak isometric tongue pressure in both the anterior and posterior parts of the tongue was demonstrated after OMT in the groups. No differences between the two groups in both the pre- and post-treatment conditions were demonstrated in the IOPI scores.

CONCLUSIONS

OMT improves orofacial motricity and tongue strength in patients with tongue thrust regardless of the type of dentition.