Orofacial Muscles Research Articles

The effect of tongue-to-palate on deep neck flexor activity

Deep neck flexor (DNF) muscles contribute to cervical stability and proprioception. Reduced muscle strength and endurance lead to faulty movement patterns, muscle imbalances, and dysfunction. Potentially, the orofacial muscles contribute to cervical strength by providing stability through muscular connections. This study examined effects of tongue muscle activity on cervical spine muscular stiffness. Twenty-three healthy subjects assumed three supine positions [at rest (AR), chin tuck (CT), and head lift (HL)] with and without tongue-to-palate pressure. The DNF stiffness was measured using shear wave elastography. Without tongue-to-palate, stiffness increased with CT and HL compared to AR (p <0.001) but not between CT and HL (p = 0.22). Tongue-to-palate increased stiffness AR (p <0.001) but not during CT (p = 0.95) or HL (p = 0.67). Stiffness levels between the AR and HL conditions during tongue-to-palate performance did not differ (p = 0.734), but CT stiffness was significantly greater than AR (p = 0.029) with tongue-to-palate. Tongue-to-palate AR increases DNF stiffness to a similar level as HL with or without tongue-to-palate, while CT with or without tongue-to-palate resulted in the highest stiffness levels. Tongue-to-palate pressure AR or with CT performance may be alternatives to HL strengthening in healthy necks. This may be a useful strategy to increase cervical stability during loads on the cervical spine.

Tongue and Lip Strength and Endurance in Healthy Young Adults With and Without Orofacial MyofunctionalDisorders.

Based on the premise that tongue and lip force is affected in individuals with orofacial myofunctional disorders (OMDs), orofacial myofunctional therapy (OMT) programs typically include the strengthening of orofacial muscles through isometric and isotonic exercises. The purpose of this study is to examine whether there is indeed a measurable difference in maximum tongue and lip strength and endurance between subjects with and without OMDs, as well as to explore Oral Health-Related Quality of Life (OHRQoL) in this population. Sixty healthy young adults (mean age 18.9 years, SD 0.69 years, range 18.0-21.4 years) participated in this study. Perceptual evaluation of orofacial functions was conducted using the Orofacial Myofunctional Evaluation with Scores (OMES) protocol. Participants were divided into three groups, namely those with physiological orofacial functions (POF; n = 20), those with inconsistent orofacial functions (IOF; n = 11), and those with consistent OMDs (OMD; n = 29). Maximum isometric pressure and endurance of tongue and lips were measured using the Iowa Oral Performance Instrument (IOPI). OHRQoL was assessed using the Oral Health Impact Profile (OHIP-14). The OMES total scores did not differ significantly between the three groups, though the subscale 'function' showed significant differences (13.637; p = 0.001). No statistically significant differences in maximum isometric pressure or endurance for tongue and lips, nor for OHIP scores, were measured between the three groups. Although orofacial muscle strengthening is commonly part of OMT, current findings suggest the superfluity of these types of exercises in the treatment of OMDs in healthy young adults and may indicate the need to focus on awareness and rehabilitation of pathological functions in these individuals. Re-evaluation of the efficacy of OMT programs in different populations may be an important strategy going forward.

The other face of facioscapulohumeral muscular dystrophy: Exploring orofacial weakness using muscle ultrasound.

One of the most distinct clinical features of facioscapulohumeral muscular dystrophy (FSHD) is facial weakness. It leads to diminished facial expression and functional impairments. Despite its clinical relevance, little else is known about orofacial muscle involvement. We therefore evaluated orofacial muscle involvement in a sizeable cohort of FSHD participants with muscle ultrasound. Muscle ultrasound images of the following orofacial muscles were scored visually and quantitatively: depressor anguli oris (DAO), orbicularis oris (OO), buccinator, temporalis, masseter, digastric, zygomaticus major and minor bilaterally, and the geniohyoid. Reliability analyses of both visual and quantitative evaluations were performed. Ultrasound results were correlated with other measures: the FSHD clinical score, facial weakness score, and facial function scale. We included 107 FSHD participants (male 54%; age 52 ± 14 years), of whom 92% showed signs of facial weakness. The reliability of visual ultrasound analysis varied widely (κ 0.0-1.0). Quantitative ultrasound reliability was high (intraclass correlation analysis ≥ 0.96). The DAO, buccinator, OO, temporalis, and zygomaticus minor muscles were affected most often (15%-39%). The digastric, geniohyoid, zygomaticus major, and masseter muscles were least often affected (<5%). The ultrasound compound score correlated weakly to moderately with other outcome measures used (ρ = 0.3-0.7). This study adds to the understanding of orofacial weakness in FSHD, confirming the involvement of the muscles of facial expression in FSHD using ultrasound. We showed that orofacial muscle ultrasound is feasible and reliable when quantitatively assessed. Future studies should evaluate orofacial muscle ultrasound longitudinally, alongside clinical and patient-reported facial weakness outcome measures, to assess their potential as outcome measures.

A Prospective Randomized Control Trial of Lingual Frenuloplasty with Myofunctional Therapy in Patients with Maxillofacial Deformity in a Polish Cohort.

Introduction: There are few publications concerning ankyloglossia in mixed-aged groups utilizing myofunctional therapy and frenuloplasty in patients undergoing orthodontic treatment and maxillofacial surgery. While it is well known that ankyloglossia is mainly diagnosed in babies, research on functional and structural disorders in different age groups is less common. Thus, there is a high need for specific information about the influence and effectiveness of frenuloplasty with myofunctional therapy on the stomatognathic function and final treatment outcome for a wider variety of patients, especially those with maxillofacial deformities. Aim: This paper aims to evaluate the impact of lingual frenuloplasty as an adjunct to myofunctional therapy for the treatment of ankyloglossia in children and adults with maxillofacial deformity. Methods: Prospective randomized control trial with 155 subjects. Methods were based on visual observation and examination of the oral cavity. There were two groups: myofunctional therapy vs. myofunctional therapy and lingual frenuloplasty. Patients were randomized based on order of entry into the study. χ2 test, Kruskal-Wallis, ANOVA, Student's t-test and others were used for statistical analyses. Results: The presented protocol with myofunctional therapy and surgical procedures proved to be significantly more effective in improving tongue mobility and stomatognathic functions such as swallowing, breathing, and oral resting postures as compared to the reference group who underwent myofunctional therapy only. Conclusions: Lingual frenuloplasty with myofunctional therapy is highly effective in restoring the equilibrium of the orofacial muscles and the skeleton, which is often disturbed and may lead to unstable functional effects among patients considering orthodontic and orthognathic treatments for maxillofacial deformities.

Impact of the orofacial muscular rehabilitation exercise on facial expression recovery post-orthognathic surgery

ObjectiveThis study aimed to evaluate the impact of myofunctional rehabilitation of the orofacial muscles through specific exercises on the recovery of facial expression in patients following orthognathic surgery. Material and MethodsThe study included 62 patients who underwent Le Fort I and sagittal split ramus osteotomy (SSRO). Patients were divided into two groups: the first group started immediate post-operative myofunctional rehabilitation of the orofacial muscles through specific exercises. In contrast, patients in Group II did not undergo any myofunctional rehabilitation post-operative exercises. The recovery of facial expressions postoperatively was evaluated in both calm and smiling states by comparing the differences between 3D facial scanning data of chosen facial anatomical structures collected at five key time points: pre-surgery (D0), 2 days (D2), 14 days (D14), 1 month (D30), and 3 months (D90) postoperatively. ResultsThe analysis revealed that characteristic angles and lengths experienced significant changes post-surgery, with ∠chRnchL and ∠chRsnchL decreasing at D2 and normalizing by D30 in the experimental group, while the control group showed a slower recovery, normalizing by D90. The ChL-R length decreased at D2, returning to normal by D30 in the experimental group and D90 in the control group. The height Li-Ls increased at D2 and normalized by D30 in calm and smiling expressions across single and double jaw surgery patients. These findings underscore the more rapid recovery in the experimental group compared to the control group (P < 0.05; P < 0.005; P < 0.0001). ConclusionInitiating myofunctional rehabilitation immediately following orthognathic surgery enhances facial muscle function recovery, improves patient confidence, and expedites social reintegration. This approach is crucial for functional and psychological benefits.

Heilungshindernis bei klaffender Tube – ein Fallbericht

A 65-year-old female patient presented with a diagnosis of PET (patulous Eustachian tube). For years, she had been suffering from severely disabling autophonia and had already undergone various unsuccessful treatments. Surgery was discussed as the last resort.The osteopathic treatments I carried out primarily only led to a short-lasting improvement in the symptoms. An unconscious permanent tension of the cervical muscles, shoulder – and temporomandibular joint muscles – subjectively unperceived by the patient – in combination with a coordination disorder of the orofacial muscles prevented a lasting healing success. In addition to the osteopathic treatment an intensive perception training and daily coordination excercises were necessary for a successful treatment.

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

ObjectiveThis 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.MethodsThe 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.ResultsA 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.ConclusionThe 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 relevanceThis 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.

Effect of Dry Needling on Suboccipitalis Muscle and Orofacial Muscles in TMD Related Headache

Effect of Dry Needling on Suboccipitalis Muscle and Orofacial Muscles in TMD Related Headache

MyotonPRO as a new valid tool for measuring cervical muscle tension. A reliability study

Objective The main objective of this study is to test the reliability of a non-invasive objective method for the measurement of biomechanical parameters of cervicofacial muscle groups, with the purpose of diagnosis and evaluation of voice disorders’ treatments, especially focused on muscle tension dysphonia. Study design Prospective study. Methods The device used is a handheld myotonometer (MyotonPRO) that measures biomechanical and viscoelastic properties in superficial soft tissues frequency, stiffness, elasticity, relaxation time and creep. It is used in the field of medicine, sport and research. This pilot study includes 10 subjects, who have been measured in the masseter, sternocleidomastoid, orbicularis oris, semispinalis capitis, suprahyoid, infrahyoid and trapezius muscles on each side. Measurements were performed by 2 evaluators to assess inter-evaluator reliability. Subsequently, one of them repeated the measurements to assess intra-evaluator reliability. Results The results revealed good to excellent inter-rater reliability for the masseter, sternocleidomastoid, trapezius and suprahyoid muscles, with lower ICCs for the stiffness and creep properties. Intra-rater reliability was good to excellent for the masseter, sternocleidomastoid, semispinalis capitis and suprahyoid muscles. The lowest ICCs were found in the stiffness and creep properties. Conclusion The use of a myotonometer to measure the mechanical properties of selected cervical and orofacial muscles is a reliable and reproducible method. Future research is needed to establish an association between the properties of these muscles and their role in voice disorders, as well as to determine whether this tool can aid diagnosis with quantifiable and objectifiable indicators, and for monitoring and treatment efficacy.

Evaluating the Impact of Myofunctional Therapy on Orthodontic Treatment Outcomes

ABSTRACT Background: Myofunctional therapy has gained attention as a potential adjunct to orthodontic treatment, focusing on improving orofacial muscle function and balance. Despite its increasing popularity, the precise impact of myofunctional therapy on orthodontic treatment outcomes remains to be fully elucidated. Materials and Methods: A retrospective cohort study was conducted, involving 80 orthodontic patients aged 8–18 years, divided into two groups: Group A received orthodontic treatment alone, while Group B received orthodontic treatment combined with myofunctional therapy. Orthodontic treatment outcomes were assessed based on occlusal stability, facial aesthetics (evaluated through standardized photographs), and patient-reported satisfaction scores. Posttreatment stability of occlusion was assessed using the peer assessment rating (PAR) index, with lower scores indicating better occlusal outcomes. Results: The results indicated a significant improvement in orthodontic treatment outcomes among patients who received myofunctional therapy in addition to orthodontic treatment. Group B demonstrated a mean decrease of 25% in PAR index scores compared to Group A, indicating superior occlusal stability posttreatment. Facial aesthetics were also notably enhanced in Group B, with a higher percentage of patients achieving harmonious facial profiles than Group A. Additionally, patient satisfaction scores were significantly higher in Group B, with 85% of patients reporting high satisfaction levels, compared to 60% in Group A. Conclusion: Myofunctional therapy as an adjunct to orthodontic treatment has a positive impact on treatment outcomes, including improved occlusal stability, enhanced facial aesthetics, and increased patient satisfaction.

Myo-optogenetics: optogenetic stimulation and electrical recording in skeletal muscles.

Complex movements involve highly coordinated control of local muscle elements. Highly controlled perturbations of motor outputs can reveal insights into the neural control of movements. Here we introduce an optogenetic method, compatible with electromyography (EMG) recordings, to perturb muscles in transgenic mice. By expressing channelrhodopsin in muscle fibers, we achieved noninvasive, focal activation of orofacial muscles, enabling detailed examination of the mechanical properties of optogenetically evoked jaw muscle contractions. We demonstrated simultaneous EMG recording and optical stimulation, revealing the electrophysiological characteristics of optogenetically triggered muscle activity. Additionally, we applied optogenetic activation of muscles in physiologically and behaviorally relevant settings, mapping precise muscle actions and perturbing active behaviors. Our findings highlight the potential of muscle optogenetics to precisely manipulate muscle activity, offering a powerful tool for probing neuromuscular control systems and advancing our understanding of motor control.

Locus coeruleus activation contributes to masseter muscle overactivity induced by chronic restraint stress in mice.

It is commonly accepted that exposure to stress may cause overactivity in the orofacial muscles, leading to consistent muscle pain, which is the main symptom of temporomandibular disorders. The central neural mechanism underlying this process, however, remains unclear. The locus coeruleus is considered to play an important role in stress-related behavioral changes. Therefore, the present study was designed to examine the role of locus coeruleus neurons in masseter overactivity induced by stress. C57BL/6 mice were subjected to chronic restraint stress for 14 days to establish an animal model. The behavioral changes and the electromyography of the masseter muscle in mice were measured. The expression of Fos in locus coeruleus was observed by immunofluorescence staining to assess neuronal activation. A chemogenetic test was used to inhibit locus coeruleus neuronal activity, and the behavioral changes and electromyography of the masseter muscle were observed again. The results exhibited that chronic restraint stress could induce anxiety-like behavior, overactivity of the masseter muscle, and significant activation of locus coeruleus neurons in mice. Furthermore, inhibition of noradrenergic neuron activity within the locus coeruleus could alleviate stress-induced anxiety behavior and masseter muscle overactivity. Activation of noradrenergic neurons in locus coeruleus induced by stress may be one of the central regulatory mechanisms for stress-induced anxiety-like behaviors and overactivity of masseter muscles.

The feasibility of visualizing and quantifying muscle changes in postoperative oral cancer patients using Quantitative Muscle Ultrasound (QMUS)

PurposeQuantitative muscle ultrasound (QMUS) is a patient friendly tool for examining orofacial muscles. Resection of tissue can have an effect on the architecture and function of these muscles. The aim of this study is to investigate the feasibility of visualizing and quantifying muscle changes in postoperative oral cancer patients and to relate the findings to tumor and patient characteristics.MethodsAdult patients with a resected first primary pT1 or T2 oral squamous cell carcinoma, at least one year post operatively, where included. Ultrasound data were collected of the geniohyoid muscle, digastric muscles, masseter muscle, transverse muscle and genioglossus muscle. Ultrasound images were labeled as clearly visible, questionable or unclear. Of the clear muscles, echogenicity and muscle thickness were measured.Results37 patients were included. The masseter muscle was clearly visible in all ultrasound images, both intrinsic tongue muscles had the lowest visibility (45.9%). There was a significant correlation between visibility and tumor localization for the genioglossus (p = 0.029). Age correlated with the visibility of the genioglossus muscle, BMI with the genioglossus and transverse muscles. Echogenicity and muscle thickness of the clearly identified muscles did not differ from normative values.ConclusionQMUS of orofacial muscles is feasible in postoperative oral cancer patients with relatively small tumor sizes. Tongue resections negatively affected the visibility of the two intrinsic tongue muscles. These preliminary results for particular muscles indicate that the use of ultrasound might be promising in oral cancer patients to help determine targeted goals in post-operative rehabilitation.

High prevalence of orofacial pain in juvenile fibromyalgia as detected by a novel tool specifically devised for children and adolescents.

To examine the prevalence of temporomandibular disorders (TMD) in patients with juvenile fibromyalgia syndrome (JFS) and identify TMD characteristics specifically associated to JFS. Signs and symptoms of TMD were assessed using a novel clinical tool specifically devised for children that consists of: 1. a self-report multiple-choice questionnaire; 2. a protocol for the clinical examination of the orofacial region. Multivariate logistic regression model was used to identify TMD features associated with JFS. Thirty JFS patients (median age 15.5 years) and 45 healthy controls (median age 15.0 years) were included in this cross-sectional study. Orofacial pain was reported by 26 of 30 JFS patients (86.7%) and by 3 of 45 controls (6.7%; p<0.001). Pain on TMJ palpation was present in 18 of 30 JFS patients (60%) and in 5 of 45 controls (11.1%; p<0.001). Median values of maximum spontaneous mouth opening, voluntary active opening and assisted passive opening were significantly higher in JFS patients than in controls. On multiple regression analysis spontaneous orofacial pain (OR: 21.0; p=0.005), diffuse tenderness on palpation of the masticatory muscles (OR: 14.9; p=0.026) and TMJ hypermobility (OR 1.42; p=0.008) were independently associated with JFS. The high prevalence of TMD in JFS highlights the need for a broader interdisciplinary evaluation of JFS patients. TMJ hypermobility, in addition to orofacial and masticatory muscle pain, is an important clue for the diagnosis of TMD in adolescents with JFS. Elucidating the link between these disorders will advance individualised management and improve treatment efficacy.

3D Printer-Assisted Layered Fabrication of a Novel Appliance for Oral Myofunctional Therapy and Functional Evaluation of Its Effects on Orofacial Muscles During Wear.

Aim Balanced function of the orofacial muscles is important for normal occlusion and dentition; however, patients with malocclusion often present with myofunctional disorder (MFD). Myofunctional therapy (MFT) has received much attention as a method for reducing MFD. Moreover, prefabricated functional appliances (PFAs) have been developed as a method to eliminate abnormal muscle pressure and guide the tongue into the correct position. However, PFAs have disadvantages, such as poor intraoral retention, limited usage time due to discomfort and poor patient compliance, and changes in the axis of the mandibular anterior teeth.Therefore, this study aimed to develop a new custom-made splint-type orthodontic appliance with CAD/CAM technology. Moreover, we evaluated the characteristics of the appliance and conducted functional tests to determine the effects of the appliance on the orofacial muscles and the discomfort associated with its use. Materials and methods Twenty-five volunteers (nine females and 16 males; mean age 28.4 ± 3.4 years) with normal swallowing function were included in the study. Lip-closing strength (LCS), electromyogramduring swallowing, oxygen saturation, and pulse rate were measured and compared when the appliance was not worn and when it was worn. In addition, tongue habits were evaluated, and the maximum tongue pressure was measured when the appliance was not worn. The subjects were asked to answer a questionnaire using a numerical rating scale (NRS) regarding discomfort when wearing the appliance. The evaluation items were swallowing difficulty, speaking difficulty, and breathlessness, which were rated on an 11-point scale ranging from 0 to 10. Statistical tests were conducted using IBM SPSS version 28.0.1 (IBM, Armonk, NY, USA) with the Shapiro-Wilk and Levene's test, followed by the Wilcoxon signed rank sum test. The significance level was set at α = 0.05. The measurement error for each measurement item was evaluated using an intraclass correlation coefficient. Results A new custom-made splint-type orthodontic appliance was fabricated for each subject. The fit and retention of the appliance in the mouth were good when fitted, and a comparison of the functional test measurements of 25 subjects with and without the appliance showed that the LCS decreased significantly (p<0.05) before and after wearing the appliance. However, no statistically significant differences were found for the other items. The Mann-Whitney U test regarding the effects of sex, previous orthodontic treatment, or MFT, and oral habits did not statistically significantly influence the effects of wearing the device. In the NRS results, "difficulty swallowing" was observed in half of the subjects, "difficulty breathing" was rarely observed, and "difficulty speaking" was observed in all subjects. Conclusions A novel custom-made splint-type orthodontic appliance was designed and fabricated using digital workflow and 3D printing technology. This appliance was designed to correct oral habits and was made from a new material classified as a class II medical appliance according to the international harmonized classification.

Identification of the Biomechanical Response of the Muscles That Contract the Most during Disfluencies in Stuttered Speech.

Stuttering, affecting approximately 1% of the global population, is a complex speech disorder significantly impacting individuals' quality of life. Prior studies using electromyography (EMG) to examine orofacial muscle activity in stuttering have presented mixed results, highlighting the variability in neuromuscular responses during stuttering episodes. Fifty-five participants with stuttering and 30 individuals without stuttering, aged between 18 and 40, participated in the study. EMG signals from five facial and cervical muscles were recorded during speech tasks and analyzed for mean amplitude and frequency activity in the 5-15 Hz range to identify significant differences. Upon analysis of the 5-15 Hz frequency range, a higher average amplitude was observed in the zygomaticus major muscle for participants while stuttering (p < 0.05). Additionally, when assessing the overall EMG signal amplitude, a higher average amplitude was observed in samples obtained from disfluencies in participants who did not stutter, particularly in the depressor anguli oris muscle (p < 0.05). Significant differences in muscle activity were observed between the two groups, particularly in the depressor anguli oris and zygomaticus major muscles. These results suggest that the underlying neuromuscular mechanisms of stuttering might involve subtle aspects of timing and coordination in muscle activation. Therefore, these findings may contribute to the field of biosensors by providing valuable perspectives on neuromuscular mechanisms and the relevance of electromyography in stuttering research. Further research in this area has the potential to advance the development of biosensor technology for language-related applications and therapeutic interventions in stuttering.

Tongue pressure production and orofacial muscle activities during swallowing are related to palatal morphology in individuals with normal occlusion

ABSTRACT Purpose The relationships between motor function, including the orofacial muscles coordinated with the tongue during swallowing, and palatal morphology are still unclear. This study aimed to identify the relationships between tongue pressure production and orofacial muscle activities during swallowing and palatal morphology. Materials and methods The participants were 20 healthy volunteers with individual normal occlusion (8 men, 12 women; mean age: 25.0 ± 2.9 years). Tongue pressure and masseter, orbicularis oris, mentalis and supra-infrahyoid muscle activities during 4 ml gel swallowing were recorded simultaneously by a sensor sheet system, with five measuring points and surface electromyography, respectively. Onset, offset and duration of each parameter and the maximum magnitude of tongue pressure were analysed. Palatal width and depth were measured using three-dimensional digital images of maxillary dental models and examined for correlations with tongue pressure and orofacial muscle activities. Results The temporal coordination between tongue pressure production and orofacial muscle activities during swallowing was observed. The maximum magnitude of tongue pressure was significantly positively correlated with the palatal width. Palatal depth showed significant correlations with the time sequences of tongue pressure and orbicularis oris and mentalis muscle activities. Conclusion These results suggest that tongue pressure production and orofacial muscle activities during swallowing are related to palatal width and depth.

Digital Concepts for the Care of Newborns with Craniofacial Anomalies

The treatment of newborns with craniofacial abnormalities such as cleft lip and/or palate poses special challenges for healthcare providers. Often, the collaboration of an interdisciplinary team of pediatricians, orthodontists, and oral and maxillofacial surgeons is necessary. Therapy using feeding or stimulation plates can improve feeding and strengthen orofacial muscle tone. The treatment of patients with cleft lip and palate using conventionally manufactured feeding plates as well as the treatment of patients with reduced orofacial muscle tone through stimulation plates therapy are established and widely used methods. The conventional production of these plate appliances can lead to serious complications such as swallowing of impression material and airway obstruction due to aspiration. Through an innovative, entirely digital workflow using computer-assisted design and manufacturing of the appliances in a 3D printer, risks can be minimized and time and costs can be saved. This article aims to explain the digital workflow of treating newborns with 3D CAD/CAM feeding and stimulation plates through two case studies.

A critical size volumetric muscle loss model in mouse masseter with impaired mastication on nutrition.

Orofacial muscle defect due to congenital anomalies, tumour ablation or traumatic accident that exceeds endogenous regeneration capacity may lead to sustained deficits in masticatory function and nutrition intake. Functional recovery has always been the goal of muscle tissue repair, but currently, there is no suitable model for quantitative analyses of either functional consequences or treatment efficacy of orofacial muscle defect. This study proposed a critical size volumetric muscle loss (VML) model in mouse masseter with impaired mastication on nutrition. Full-thickness VML defects in diameter of 1.0, 1.5, 2.0 and 3.0 mm were generated in the centre of the mouse masseter using a biopsy punch to determine the critical size for functional impairment. In the VML region, myogenesis was dampened but fibrogenesis was activated, as long with a reduction in the density of the neuromuscular junction and an increase in vascular density. Accordingly, persistent fibrosis was observed in the centre region of VML in all diameters. The 2.0 mm diameter was the critical threshold to masticatory function impairment after VML in the masseter. VML of 3.0 mm diameter led to a significant impact on nutrition intake and body weight gain. Autologous muscle graft effectively relieved the fibrosis and functional deficit after VML injury in the masseter. This model serves as a reliable tool in studying functional recovery strategies for orofacial muscle defects.

Neurobiology of bruxism: The impact of stress (Review).

Bruxism is a non-functional involuntary muscle activity that affects more than one-third of the population at some point in their lives. A number of factors have been found to be related to the etiopathogenesis of bruxism; therefore, the condition is considered multifactorial. The most commonly accepted factor is stress. Stress has long been considered to increase muscle tone and to reduce the pain threshold. Current evidence indicates that exposure to chronic stress, distress and allostatic load ignite neurological degeneration and the attenuation of critical neuronal pathways that are highly implicated in the orofacial involuntary muscle activity. The present review discusses the negative effects that chronic stress exerts on certain parts of the central nervous system and the mechanisms through which these changes are involved in the etiopathogenesis of bruxism. The extent of these morphological and functional changes on nerves and neuronal tracts provides valuable insight into the obstacles that need to be overcome in order to achieve successful treatment. Additionally, particular emphasis is given on the effects of bruxism on the central nervous system, particularly the activation of the hypothalamic-pituitary-adrenal axis, as this subsequently induces an increase in circulating corticosterone levels, also evidenced by increased levels of salivary cortisol, thereby transforming bruxism into a self-reinforcing loop.