The Effect of early physiotherapy on the recovery of mandibular function after orthognathic surgery for Class III correction: Part I—Jaw-motion analysis

A Comparative Analysis of Temporomandibular Disorders Using a Jaw Motion Analyzer and Surface Electromyography

INTRODUCTION

Quantification of mandibular movement allows both dynamic and static evaluation of temporomandibular joint (TMJ) status, which would provide important information in temporomandibular disorders (TMD) diagnosis and treatment. The ultrasonic Jaw Motion Analyzer (JMA; zebris) system could analyse the 3-dimensional motion of the mandible without any radiation. Using the JMA, this study aimed to investigate the differences in mandibular movements and masticatory muscle activities among patients with different diagnoses of anterior disc displacement based on TMJ magnetic resonance imaging (MRI).

METHODS

Seventy-four adult subjects with 148 TMJ were divided into 3 groups based on MRI: the No Disc Displacement (NDD), the Anterior Disc Displacement with Reduction (ADDWR), and the Anterior Disc Displacement without Reduction (ADDWoR). The JMA and surface electromyography (sEMG) were used to measure several mandibular movements and sEMG. Comparison and correlation analysis were performed among groups.

RESULTS

Significant differences were found between NDD, ADDWR, and ADDWoR in the following items: the incisal range of motion during right and left laterotrusion, maximum mouth opening, the surface area of Posselt envelope movement in the frontal plane, condylar range of motion in opening movement, and sEMG of masseter during maximum voluntary clenching.

CONCLUSION

Significant differences were found in mandibular movements and muscle activity between patients with NDD, ADDWR, and ADDWoR.

CLINICAL RELEVANCE

The JMA and sEMG provide important information on mandibular movement and muscle activities, which may provide additional insights into TMD diagnosis and treatment.

Perioperative care in orthognathic surgery - A systematic review and meta-analysis for enhanced recovery after surgery

The aim of this study was to determine whether implementing ERAS (Enhanced Recovery After Surgery) elements/protocols improves outcomes in orthognathic surgery (OGS) compared to conventional care. To achieve this, ERAS-specific perioperative elements were identified and literature on ERAS for OGS was systematically reviewed. Using PRISMA methodology and GRADE approach, 44 studies with 49 perioperative care elements (13 pre-, 15 intra-, 21 postoperative) were analyzed. While 39 studies focused on single elements, only five presented multimodal protocols, with three related to ERAS. Preoperative elements included antimicrobial and steroid prophylaxis and prevention of postoperative nausea and vomiting. Intraoperative aspects, especially anesthesiological, showed high evidence. Outcome parameters were heterogeneous: complications and postoperative pain were well-investigated with high evidence, while length of stay (LOS) and patient satisfaction received low to medium evidence. ICU LOS, healthcare costs, and readmission rates were underreported. The meta-analysis revealed significant results for pain reduction and trends towards fewer complications and shorter LOS in the ERAS group. Overall, ERAS protocols are not established in OMFS, particularly OGS. Further research is needed in pre- and postoperative care and standardized multimodal analgesia. The next step should be developing a comprehensive OGS protocol through a consensus conference and implementing it in clinical practice.

Effect of transcutaneous electrical nerve stimulation on maximum mouth opening after orthognathic surgery: a randomised controlled trial

Background

The present study aims to determine the effect of transcutaneous electrical nerve stimulation (TENS) on maximum mouth opening (MMO) after orthognathic surgery.

Materials and methods

This study is a randomised clinical trial. The samples of this study were class III patients who are candidates for Le Fort I osteotomy surgery for maxillary advancement and bilateral sagittal split osteotomy (BSSO) for mandibular setback surgery due to the lack of maxilla growth and mandibular prognathism using the Dalpont method. On the day following surgery, the intervention group received TENS physiotherapy and instructions to take analgesics. In the control group, patients only received analgesics. MMO was measured in both groups using a digital caliper preoperatively, 1 month, and 6 months postoperatively.

Results

A total of 82 patients participated in this study, who were divided into two groups of 41, intervention and control. The difference in the mean MMO in different periods after surgery of the intervention group (F=59733.350, P<0.001) and the control group (F=32.480, P<0.001) was significant. The pattern of MMO increase over time was not the same in the two groups. There was a steeper slope in the increase of MMO in the intervention group than in the control group.

Conclusion

It can be concluded from the results of this study, that the use of TENS after orthognathic surgery can be effective along with analgesics in reducing pain intensity and, subsequently, recovery in MMO in the short term.

Virtual Dental Articulation Using Computed Tomography Data and Motion Tracking

Dental articulation holds crucial and fundamental importance in the design of dental restorations and analysis of prosthetic or orthodontic occlusions. However, common traditional and digital articulators are difficult and cumbersome in use to effectively translate the dental cast model to the articulator workspace when using traditional facebows. In this study, we have developed a personalized virtual dental articulator that directly utilizes computed tomography (CT) data to mathematically model the complex jaw movement, providing a more efficient and accurate way of analyzing and designing dental restorations. By utilizing CT data, Frankfurt's horizontal plane was established for the mathematical modeling of virtual articulation, eliminating tedious facebow transfers. After capturing the patients' CT images and tracking their jaw movements prior to dental treatment, the jaw-tracking information was incorporated into the articulation mathematical model. The validation and analysis of the personalized articulation approach were conducted by comparing the jaw movement between simulation data (virtual articulator) and real measurement data. As a result, the proposed virtual articulator achieves two important functions. Firstly, it replaces the traditional facebow transfer process by transferring the digital dental model to the virtual articulator through the anatomical relationship derived from the cranial CT data. Secondly, the jaw movement trajectory provided by optical tracking was incorporated into the mathematical articulation model to create a personalized virtual articulation with a small Fréchet distance of 1.7 mm. This virtual articulator provides a valuable tool that enables dentists to obtain diagnostic information about the temporomandibular joint (TMJ) and configure personalized settings of occlusal analysis for patients.

The effects of the size and strength of food on jaw motion and temporomandibular joints

Mastication displays much importance in people's lives. The masticatory mandibular motion associated with dental kinematics also impacts temporomandibular joint (TMJ) kinematics and even TMJ health status. How food properties impact kinematical parameters of TMJs is a meaningful question for the conservative treatment of temporomandibular disorders (TMD) and evidence for the diet recommendation of TMD patients. The aim of this study was to find the primary mechanical properties influencing the masticatory motion. The potato boluses with different boiling times and sizes were chosen. The optical motion tracking system was adopted to record the masticatory trials of chewing boluses with various mechanical properties. The mechanical experiments revealed that increasing boiling time could reduce compressive strength. Moreover, multiple regression models were built to find the primary property of food influencing the TMJ kinematics, including condylar displacement, velocity, acceleration, and crushing time. The results showed that the bolus size had a significant primary influence on condylar displacements. The chewing times had a significantly minor influence on condylar displacements, while bolus strength had only a small impact on condylar displacements. Furthermore, condylar displacements on the non-working side were more affected by bolus size and chewing times than on the working sides. The crushing time of the bolus was significantly influenced by the compressive strength. Meals with small sizes and soft properties were therefore advised to lessen condylar displacements and relax the crushing process, and further reduce the loadings in the TMJ.

Descriptions of the dynamic joint space of the temporomandibular joint

BACKGROUND

Clinical diagnosis and treatment depended heavily on the motion analysis of the human joints. Although the dynamic joint space (DJS) of other organs was widely used in academic investigations, they were not universally used in the temporomandibular joint (TMJ) field, which was also important for the motion evaluation of the TMJ. The objectives of this study are to introduce the DJS of the TMJ and characterize the DJS regulars of mandibular movements.

METHODS

Ten asymptomatic subjects were selected to instruct this application. The mouth opening and closing, mandibular protrusion, and left and right protrusions, were tracked by the optical motion tracking system. According to trajectories of markers and reconstructed models from computed tomography, the motions of the mandibles could be obtained. The DJSes, which were described as the minimum Euclidian distances, were subsequently calculated based on the geometrical surfaces between the condyle and fossa during the motions. Then, the DJS map could be drawn based on the calculated values.

RESULTS

The DJS map manifested a decreasing trend when the condyle crossed the glenoid fossa, while it generally increased after the condyle crossed the fossa during the mouth opening. The results showed that the average maximum and minimum anterior joint spaces were 5.39 mm and 2.07 mm during mouth opening respectively with a great discrepancy existing among the subjects. The average maximum and minimum anterior joint spaces were 4.74 mm and 2.19 mm during mandibular protrusion. As for left and right protrusions, the DJS of the contralateral side was greater than that of the ipsilateral side.

CONCLUSION

In comparison to morphological analyses or only mandibular motions, the DJS provides more dynamic and interactive information about the TMJ. The research and methodology may help us comprehend TMJ motions and temporomandibular disorders.

Orthodontic Perspective for Face Asymmetry Correction

Facial symmetry affects the perception of facial beauty. Overall, facial harmony with an appropriate facial proportion and satisfactory midline facial symmetry are crucial factors for facial attractiveness. The role of orthodontists in correcting facial asymmetry begins with providing suitable diagnosis of the condition and identifying patients’ expectations. Through a thorough, subjective clinical evaluation of dentofacial asymmetry, the procedures for the surgical orthodontic management of facial asymmetry are discussed. The aim of this clinical review is to provide information on surgical indications for facial asymmetry, optimal treatment goals, presurgical orthodontic preparation, the surgery-first approach, three-dimensional (3D) surgical simulation, postsurgical orthodontic finishing, and treatment outcome evaluation. A comprehensive 3D diagnosis with appropriate planning, accurate transference of surgical simulation to real surgery, slight overcorrection, periodic assessment of treatment outcomes, and awareness of treatment limitations are essential to improve treatment outcomes of facial asymmetry.

Efficacy of Kinematic Parameters for Assessment of Temporomandibular Joint Function and Disfunction: A Systematic Review and Meta-Analysis

The aim of this review was to answer the following PICO question: "Do TMJ kinematic parameters (intervention and comparison) show efficacy for assessment of mandibular function (Outcome) both in asymptomatic and TMD subjects? (Population)". PubMed, Scopus, Web of Science, Embase, Central databases were searched. The inclusion criteria were (1) performed on human, (2) English only, (3) on healthy, symptomatic or surgically altered TMJ, (4) measured dynamic kinematics of mandible or TMJ (5) with six degrees of freedom. To assess the Risk of Bias, the Joanna Briggs Institute tool for non-randomised clinical studies was employed. A pairwise meta-analysis was carried out using STATA v.17.0 (Stata). The heterogeneity was estimated using the Q value and the inconsistency index. Ninety-two articles were included in qualitative synthesis, nine studies in quantitative synthesis. The condylar inclination was significantly increased in female (effect size 0.03°, 95% CI: -0.06, 0.12, p = 0.00). Maximum mouth opening (MMO) was increased significantly in female population in comparison with males (effect size 0.65 millimetres (0.36, 1.66). Incisor displacement at MMO showed higher values for control groups compared with TMD subjects (overall effect size 0.16 millimetres (-0.37, 0.69). Evidence is still needed, considering the great variety of devices and parameters used for arthrokinematics. The present study suggests standardising outcomes, design, and population of the future studies in order to obtain more reliable and repeatable values.

Use of Transcutaneous Electrical Nerve Stimulation (TENS) for the Recovery of Oral Function after Orthognathic Surgery

The oral functions of patients are markedly diminished immediately after orthognathic surgery, and novel approaches are needed to accelerate their recovery. The aim of this study was to examine the usefulness of weekly applications of transcutaneous electrical nerve stimulation (TENS) for this purpose, based on the evidence of its effectiveness in other types of patients with muscle alterations. Maximum jaw opening, bite force, pain, and facial inflammation were compared between patients receiving TENS and those receiving sham-TENS for 30 min at baseline and weekly over a four-week period after orthognathic surgery and were also compared between the before and after of each procedure. TENS was applied at 220 Hz, applying the maximum intensity tolerated by each individual patient. The TENS procedure was identical for all patients, but the device was not turned on in the sham-TENS group. Patients were blinded to their group membership. Results were analyzed separately in skeletal class II and III patients. Improvements in jaw opening and inflammation were significantly greater in the TENS than in the sham-TENS group, attributable to the muscle relaxation achieved with the procedure. Research is warranted on the benefits of a more frequent application of TENS.

Establishment of a new rehabilitation program using masticatory training food for jaw deformity patients

Background/purpose

Patients with jaw deformities may show a reduction in masticatory function as a result of postoperative hypofunction. This study aimed to establish a novel rehabilitation program using a commercially available masticatory training food for patients with jaw deformities after orthognathic surgery.

Materials and methods

Nine patients with mandibular prognathism (the training group: n = 5, and the non-training group: n = 4) and 6 control participants with normal occlusion were included in this study. For the rehabilitation program with masticatory exercise, patients were instructed to chew the training food once a day for 60 days starting from 10 days after the surgery. The effects of the rehabilitation program were assessed by determining the maximum bite force (MBF) and the masticatory performance (MP). Clinical assessments were performed just before orthognathic surgery (Pre) and at 10 days (T0), 1 month (T1), 2 months (T2), and 3 months (T3) after surgery.

Results

Compared with the non-training group, the training group showed a trend toward greater recovery amount of MBF from Pre to T3, and a significantly greater recovery amount in MP (p < 0.05) from Pre to T3. When the time-series change of MP was evaluated in both groups from T0 to T3, a significant difference was observed in the interaction terms (p = 0.03). This result indicates that the effectiveness of the training may be demonstrated by following the postoperative course further.

Conclusion

The rehabilitation using this training food may become a useful method for postoperative hypofunction in patients with jaw deformities.

Early recovery after surgery protocol in orthognathic surgery: a randomized, blind clinical study

A randomized, blind and prospective clinical trial was conducted to compare two clinical rehabilitation protocols in patients submitted to orthognathic surgery, during the first 60 days after surgery. Pain, edema, mandibular movement, masticatory efficiency and quality of life were evaluated. Nineteen (19) patients were separated into control and experimental groups. The control group consisted of 10 patients followed by oral and maxillofacial surgeons and submitted to a rehabilitation protocol that involved active and passive mouth opening exercises. The experimental group had 9 patients and followed the surgeons' protocol, in addition to an Early Recovery After Surgery (ERAS) protocol performed by speech therapists, and involving specific motricity exercises and lymphatic drainage. The Student's t-test was applied to compare the results, and the Fisher's exact test of independence, to analyze the quality of life and the masticatory efficiency variables. The statistical significance was set at 5% (p < 0.05) for all the tests. The results showed that the ERAS protocol made a positive difference in pain perception in the first 14 days. However, it did not improve the other variables. Although many variables showed no significant difference, it was concluded that the surgeons can delegate patient rehabilitation to qualified professionals, so that they can optimize their postoperative clinical time.

Additively manufactured scan body for transferring a virtual 3-dimensional representation to a digital articulator for completely edentulous patients

A technique is described for obtaining a virtual 3-dimensional representation of completely edentulous patients with the virtual definitive casts mounted on the virtual articulator. An additively manufactured intraoral scan body was developed to record the definitive maxillary and mandibular casts and gothic arch interocclusal registration. The intraoral scan body guided the integration of the digital definitive casts and facial scans to obtain the virtual 3-dimensional patient's representation and facilitated the transfer of the definitive casts to the virtual articulator.

Effect of botulinum toxin-A on pain and mouth opening following surgical intervention in oral submucous fibrosis - A controlled clinical trial

The purpose of this trial was to study the effect on pain and mouth opening of intramuscular injection of botulinum toxin-A into masticatory muscles following surgical intervention in oral submucous fibrosis (OSMF) cases. Injections of either botulinum toxin A (BTX-A) (study group) or normal saline (control group) were given 2 weeks prior to surgical intervention in OSMF patients, into the bilateral masseter and temporalis muscles. All patients were evaluated for pain and ease of active physiotherapy at 1 week and 1, 3, and 6 months after surgery using a numerical rating scale and appropriate questionnaires, with comparisons made between the study and control group patients. Electromyographic studies of the masticator muscles were also carried out in all patients before injection, and at 1 month and 6 months after injection. 20 OSMF patients were equally divided into study and control groups (n = 10 each). At 1, 3, and 6 months after surgery, the study group patients showed significantly greater decreases in pain (p-values of 0.007, 0.001, and 0.005, respectively) and greater ease in physiotherapy compared with the control group. EMG recordings of masticator muscles showed a transient drop in microvolt value in the study group 1 month after injection, unlike the control group recordings. It was concluded that preoperative BTX-A injection was a good addition to surgical therapy in the patient group.

Measurement of normal and pathological mandibular and temporomandibular joint kinematics: A systematic review

Motion of the mandible and temporomandibular joint (TMJ) plays a pivotal role in the function of the dentition and associated hard and soft tissue structures, and facilitates mastication, oral communication and access to respiratory and digestive systems. Quantification of TMJ kinematics is clinically relevant in cases of prosthetic rehabilitations, TMJ disorders, osteoarthritis, trauma, tumour resection and congenital abnormalities, which are known to directly influence mandibular motion and loading. The objective of this systematic review was to critically investigate published literature on historic and contemporary measurement modalities used to quantify in vivo mandibular and TMJ kinematics in six degrees of freedom. The electronic databases of Scopus, Web of Science, Medline, Embase and Central were searched and 109 relevant articles identified. Publication quality was documented using a modified Downs and Black checklist. Axiography and ultrasonic tracking are commonly employed in the clinical setting due to their simplicity and capacity to rapidly acquire low-fidelity mandibular motion data. Magnetic and optoelectronic tracking have been used in combination with dental splints to produce higher accuracy measurements while minimising skin motion artefact, but at the expense of setup time and cost. Four-dimensional computed tomography provides direct 3D measurement of mandibular and TMJ motion while circumventing skin motion artefact entirely, but employs ionising radiation, is restricted to low sampling frequencies, and requires time-consuming image processing. Recent advances in magnetic tracking using miniature sensors adhered to the teeth in combination with intraoral scanning may facilitate rapid and high precision mandibular kinematics measurement in the clinical setting. The findings of this review will guide selection and application of mandibular and TMJ kinematic measurement for both clinical and research applications.

Biomechanical behaviour of temporomandibular joints during opening and closing of the mouth: A 3D finite element analysis

Temporomandibular joints (TMJs) constitute a pair of joints that connect the jawbone to the skull. TMJs are bilateral joints which work as one unit in conducting daily functions such as speaking, mastication, and other activities associated with the movement of the jaw. Issues associated with the TMJs may arise due to various factors-one such factor being the internal load on the TMJ. These issues may contribute to temporomandibular disorders (TMD). This study aims to evaluate the mandibular trajectories and the associated stress changes during the process of opening the mouth on the TMJs of an asymptomatic subject. The mouth opening motion was recorded by a motion capturing system using models of the mandible and maxilla constructed based on the computed tomography (CT). Two discs constructed based on magnetic resonance imaging (MRI). Finite element analysis was performed on the relative motion of the mandible to the maxilla and validated. The process modelled by these displacements provided less than 10% error in terms of deformation. The simulation results indicate that the lateral intermediate zone-the head and neck of the mandible-and the articular eminence sustained the most significant stresses during the mouth opening motion. The results also suggested that the stresses increase as the range of opening increases with the greatest von Mises stress, tensile, and compressive stress found at the position of maximal opening.

Short-term changes in muscle activity and jaw movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry

Objective

To evaluate the short-term changes in masticatory muscle activity and mandibular movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry.

Methods

Twenty-seven skeletal Class III adult patients were divided into two groups based on the degree of facial asymmetry: the experimental group (n = 17 [11 male and 6 female]; menton deviation ≥ 4 mm) and control group (n = 10 [4 male and 6 female]; menton deviation < 1.6 mm). Cephalography, electromyography (EMG) for the anterior temporalis (TA) and masseter muscles (MM), and mandibular movement (range of motion [ROM] and average chewing pattern [ACP]) were evaluated before (T0) and 7 to 8 months (T1) after the surgery.

Results

There were no significant postoperative changes in the EMG potentials of the TA and MM in both groups, except in the anterior cotton roll biting test, in which the masticatory muscle activity had changed into an MM-dominant pattern postoperatively in both groups. In the experimental group, the amount of maximum opening, protrusion, and lateral excursion to the non-deviated side were significantly decreased. The turning point tended to be shorter and significantly moved medially during chewing in the non-deviated side in the experimental group.

Conclusions

In skeletal Class III patients with facial asymmetry, the EMG activity characteristics recovered to presurgical levels within 7 to 8 months after the surgery. Correction of the asymmetry caused limitation in jaw movement in terms of both ROM and ACP on the non-deviated side.

[Effects of Active Mandibular Exercise for Mouth Opening Limitation Patients after Maxillomandibular Fixation Release: A Non-Randomized Controlled Trial]

PURPOSE

The aim of this study was to evaluate the effects of active mandibular exercise (AME) in patients with limited mouth opening after maxillomandibular fixation (MMF) release.

METHODS

The study used a quasi-experimental, nonequivalent control group and a pre test-post test design. Sixty-two patients with Maxillomandibular Fixation Release were assigned to the experimental (n=31) or control group (n=31). The AME was performed in the experimental group for 4 weeks. The exercise AME consisted of maximal mouth opening, lateral excursion and protrusive movement. These movements were repeated ten times a day. After the final exercise of the day, the number of tongue blades used for mouth opening was noted. The effect of AME was evaluated after MMF release at different time intervals: a) immediately, b) after 1 week, c) after 2 weeks, d) after 4 weeks, and e) after 12 weeks. The exercise was assessed using the following criteria: a) mandibular movements, b) pain scores associated with maximal mouth opening, c) discomfort scores associated with range of movement, and d) daily life activities that involve opening the mouth.

RESULTS

The experimental group showed significant improvement regarding the range of mandibular movements (maximal mouth opening (F=23.60, p<.001), lateral excursion to the right side (F=5.25, p=.002), lateral excursion to the left side (F=5.97, p=.001), protrusive movement (F=5.51, p=.001)), pain score (F=39.59, p<.001), discomfort score (F=9.38, p<.001). Daily life activities that involve opening the mouth were more favorable compared to those in the control group.

CONCLUSION

The AME in patients after MMF release is helpful for increasing mandibular movement range, decreasing pain and discomfort, and improving day life activities that involve opening the mouth. Therefore, AME is highly recommended as an effective nursing intervention.