Comparison of muscle activity between subjects with or without lip competence: Electromyographic activity of lips, supra- and infrahyoid muscles

A simple home test to differentiate habitual from pathological mouth breathing

BACKGROUND

Mouth breathing (MB) is defined as breathing through the mouth alone or the mouth and the nose for more than six months. Unfortunately, after managing its mechanical causes, MB may continue due to habit, obscuring the results of surgical correction of nasal breathing and misleading to unnecessary or aggressive maneuvers.

OBJECTIVE

to develop and evaluate a new test to define children of habitual MB.

MATERIALS AND METHODS

Design: a prospective observational study conducted from May 2022 to February 2023.

SETTING

multicenter; outpatient university clinics and a private ENT center.

PARTICIPANTS

577 children aged 2-12 years and complaining of MB during sleep (±daytime) for ≥6 months were assessed for eligibility, 340 were excluded due to a lack of inclusion criteria, 29 declined or discontinued participation, and 208 were enrolled. Of these, 180 gave reliable data.

THE TEST

After about 1 h of the child's sleep, the parent applies one warmed hand to close the child's open mouth recording his awakeness time (AT) for a maximum of 3 min for three nights. On the next visit, the child's examination started for obstruction causes, including endoscopy, and the test results were collected.

MAIN OUTCOME AND MEASURES

The AT was compared to examination results aiming to find a significant diagnostic relation. Children with no abnormality in the clinical and endoscopic examination were considered habitual mouth breathers.

RESULTS

Among 94 males and 86 females aged 2-12 years, MB duration ranged from 6 to 42 months, with a mean of 15.9. The home test results were presented by the mean AT in seconds. The awakeness time (AT) could discriminate patients' abnormalities at a cut-off level of <133 s, with 98.5% sensitivity and 89.7% specificity. Results <133 s are considered positive. Positive results mean the presence of a cause of obstruction. Negative results suggest no reason could be detected by endoscope or clinical examination. True positive children were 120 (66.7%), and 12 (6.7%) were false positive. True negative children were 43 (23.9%), and 5 (2.8%) were false negative.

CONCLUSIONS

Test results ≥133 s are associated with habitual MB. We recommend the test for the initial assessment of night MB.

The Electrical Activity of the Orbicularis Oris Muscle in Children with Down Syndrome-A Preliminary Study

The aim of this study was to assess the electrical activity of the superior (SOO) and inferior (IOO) orbicularis oris muscles in children with Down syndrome (DS) and in children without DS. After applying the inclusion and exclusion criteria, 30 subjects were eligible to participate in the later stages of the research—15 subjects with DS (mean age 10.1 ± 1.1) and 15 healthy controls (mean age 9.8 ± 1.0). The electrical potentials of the SOO and IOO muscles were recorded using a DAB-Bluetooth electromyography machine (Zebris Medical GmbH, Germany) during the following tasks: At clinical rest, saliva swallowing, lip protrusion, lip compression, and production of the syllable/pa/. The Mann–Whitney U test was conducted to compare the study results between the groups. An analysis of the electromyographical (EMG) recordings showed that the electrical activity of the orbicularis oris muscle in children with DS and lip incompetence was significantly higher compared to healthy children during saliva swallowing, lip compression, and when producing the syllable/pa/, and this may suggest greater muscular effort due to the need to seal the lips during these functional conditions.

Lip-closing strength in children is enhanced by lip and facial muscle training

Objectives

Weakening of lip‐closing strength (LCS) associated with an incompetent lip seal (ILS) may affect the oral balance between the lip and tongue pressures. The purpose of this study was to evaluate the effects of lip‐closing training in children with lower LCS and/or abnormal habits across different age groups and to compare its effects on increasing LCS in children with malocclusion and/or oral habits.

Material and Methods

Lip‐closing training was performed by 154 Japanese children aged 3–12 years using a specialized training device at home for 3 months. Children with oral habits and/or exhibiting less than standard LCS were included. LCS was measured using a digital strain force gauge at a dental clinic at the beginning (T0) and after each month (after 3 months: T3).

Results

Children had higher LCS responses after lip‐closing training. The first month of lip‐closing training was more effective than the subsequent months. With lip‐closing training, the LCS increased from an average of 6.2 N (T0) to 11.4 N (T3) in Group I, 7.9 N (T0) to 12.8 N (T3) in Group II, and 6.8 N to 11.4 N in Group III. Anterior cross bite, including reverse bite, open bite, and tongue thrusting, significantly reduced training effects.

Conclusion

Our findings showed that lower LCS in children with ILS resulted in greater responses to lip‐closing training in a short period, but oral dysfunction, such as abnormal habits, inhibited the positive effects of training. Our results suggest that less detrimental effects of malocclusion and abnormal oral habits lip‐closing training enhances LCS in younger children.

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.

Effects of rehabilitation with complete dentures on bite force and electromyography of jaw and neck muscles and the correlation with occlusal vertical dimension

OBJECTIVES

The purpose of this study was to assess the effects of oral rehabilitation with complete dentures on bite force and electromyography of the suprahyoid and sternocleidomastoid muscles, and their correlation with occlusal vertical dimension (OVD). The research questions were "What are the effects of rehabilitation with complete dentures on bite force and electromyography of suprahyoid and sternocleidomastoid muscles, and how are they correlated with OVD?"

MATERIALS AND METHODS

Patients who are wearers of unsatisfactory removable complete dentures were attended in three sessions (T0, T1, and T2). At T0, while the patients still wore the old dentures, they were submitted to bite force and surface electromyographic exams of the suprahyoid and sternocleidomastoid muscles. These exams were repeated, and the OVD was measured while the patients wore their old and new prostheses, 30 days after insertion of the new prosthesis (T1). The exams were repeated 100 days after the insertion of the new prosthesis (T2). The data were submitted to the Shapiro-Wilk normality test, analysis of variance (ANOVA), and Pearson correlation and linear regression, all with 5% significance.

RESULTS

Fifteen patients participated in the study. No statistically significant difference was observed for bite force or electromyography in T0, T1, or T2. However, the correlation and regression tests showed important interactions between the OVD and maximum voluntary occlusal bite force, as well as the OVD and electromyography during deglutition for the suprahyoid muscles.

CONCLUSION

Rehabilitation did not impact bite force nor the activity of the assessed muscles (electromyography). On the other hand, OVD was shown to be an important factor for bite force, and deglutition of water after rehabilitation.

CLINICAL RELEVANCE

This study shows what are the influences of rehabilitation on oral functions and reinforces the importance of corrected reestablishment of OVD because it has been found to be an important factor for bite force and electromyography during deglutition.

Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments

Objective

The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.

Methods

In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations.

Results

Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle.

Conclusions

This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

Effects of sitting posture and bolus volume on activation of swallowing-related muscles

BACKGROUND

The pharyngeal phase is a particularly important clinical factor related to swallowing dysfunctions. Head and neck posture, as well as bolus volume, are important factors affecting the pharyngeal stages of normal swallowing.

OBJECTIVE

The aim of our study was to identify the effects of sitting posture and bolus volume on the activation of swallowing-related muscles.

MATERIALS AND METHODS

Twenty-four subjects participated in the study. The subjects were positioned in three sitting postures-slump sitting (SS), lumbo-pelvic upright sitting (LUS), and thoracic upright sitting (TUS). While sitting in the chair, the subject was instructed to swallow 10 and 20 mL of water. Surface electromyography (EMG) was used to measure the muscle activity of the supra-hyoid (SH) and infra-hyoid (IH) muscles. Also, sitting posture alignment (head, cervical and shoulder angle) was also performed. Data were analysed with a repeated measures analysis of variance (RMANOVA) using a generalised linear model.

RESULTS

There was no significant difference in terms of the head angle (P = .395). However, significant differences were found in relation to the cervical angle (P < .001) and shoulder angle (P < .001). The TUS produced the lowest SH EMG activity (P = .001), in comparison to SS and LUS. The bolus volume for 20 mL showed greater SH and IH EMG activity (P < .001) than did the bolus volume for 10 mL.

CONCLUSIONS

Correcting sitting posture from SS to TUS may better assist swallowing-related muscles with less effort, irrespective of the bolus volume.

Swallowing patterns after adenotonsillectomy in children

IMPORTANCE

Hypertrophy of the pharyngeal and palatine tonsils can interfere with breathing, physical and cognitive development, and quality of life, including sleep quality. There are important relationships between the muscles of the airways, the anatomy, and the pattern of breathing and swallowing.

OBJECTIVE

The aims of the present study were to evaluate the swallowing process in children after adenotonsillectomy undertaken to treat obstructive breathing disorders.

METHODS

Subjects were 85 children or adolescents who underwent adenotonsillectomy in a reference hospital between 2003 and 2007. For the clinical evaluation of swallowing, the protocol of orofacial myofunctional evaluation with scores (OMES) was used, videofluoroscopy of deglutition was performed, and the Dysphagia Outcome and Severity Scale (DOSS) and Classification for Severity of Dysphagia to Videofluoroscopy Scale were applied for analysis.

RESULTS

Out of the 85 evaluated children, 43 were male (50.59%), the average age at evaluation was 12.11 years, the average age at the time of surgery was 6.73 years, and post-surgery time was 3.00-8.00 years. In the clinical evaluation of swallowing, half the sample (50.59%) recorded the poorest score for lip and tongue behavior. A score of 1 was observed in 67.06% of subjects for other behaviors, and in 15.30% of subjects for efficiency of swallowing. Videofluoroscopic analysis demonstrated that the most frequent swallowing alterations were labial sealing (50.59%), residue in vallecula (51.76%), and use of compensatory maneuvers (61.18%). Analysis of DOSS showed that normal swallowing was attributed to 48.31% of subjects at level 7, 44.95% at level 6, and 6.74% at level 5. For the Classification for Severity of Dysphagia to Videofluoroscopy, 75.28% were classified as having mild dysphagia.

INTERPRETATION

Alterations in the dynamics of swallowing are common in children who have undergone surgery of the tonsils, even at late follow-up.

Analysis of the stomatognathic system of children according orthodontic treatment needs

PURPOSE

The present study evaluated electromyographic activity (EMG), masticatory performance, and tongue strength in children without and with orthodontic treatment needs.

PATIENTS AND METHODS

A total of 90 children were screened and divided into the following groups: Group I (no treatment needed; mean age: 8.00 ± 0.43 years; n = 26), Group II (few malocclusions, treatment needed; mean age: 8.89 ± 0.43 years; n = 28), and Group III (slight-to-borderline treatment needed; mean age: 8.44 ± 0.22 years; n = 36). Orthodontic treatment need was classified on the basis of IOTN-DHC (Index of Orthodontic Treatment Need - Dental Health Component). The electromyographic Trigno EMG Systems was used for muscle analysis and the Iowa Oral Pressure Instrument (IOPI) was used to measure tongue strength. Data were analyzed using normality tests and one-way analysis of variance with a Bonferroni post hoc test (p ≤ 0.05).

RESULTS

EMG in almost all mandibular movements was higher in Group III with statistically significant differences compared to position at rest: right masseter (p = 0.03); protrusion: left temporal (p = 0.02); saliva swallowing: left temporal (p = 0.05) and water swallowing: orbicularis oris mouth, right upper segment (p = 0.05). Lower masticatory performance was found in Group III, but the difference compared to Group I and II was not significant. There were no significant differences between the groups in terms of tongue strength.

CONCLUSIONS

Children with borderline orthodontic treatment needs show functional disorders of the stomatognathic system.