Three-dimensional motion analysis of facial movement during verbal and nonverbal expressions in healthy subjects.

Functional impairments of facial expressions alter the quality of life and their quantitative analysis is key to describing and grading facial function and dysfunction. The aim of this investigation was to quantify 3D lip movements in a group of healthy young subjects. Lip movements during five repetitions of common and random sequences of vowels and nonverbal expressions were recorded using an optoelectronic 3D motion analyzer. The mean maximum displacement of facial landmarks was used to compute 3D unilateral mobility and the symmetry indices (SI) separately for each sex. Facial mobility was significantly greater during open-mouth than closed-mouth smiles. Facial movement among the subjects was largest during articulation of the vowel /a/ and smallest for /i/. Lips were pursed with a SI very close to 95%, while smiles were slightly more asymmetric. The vowel /a/ was articulated with significantly greater symmetry than /e/, /i/ and /u/. The outcomes suggest that the proposed method characterized normal facial animations satisfactorily, so it could be a useful tool for assessing patients with facial lesions and dentofacial deformities. Patient assessment would profit from this quantitative approach, which would reduce discrepancies among several clinical examinations. Clin. Anat. 29:991-997, 2016. © 2016 Wiley Periodicals, Inc.

Evaluation of a Three-Dimensional Stereophotogrammetric Method to Identify and Measure the Palatal Surface Area in Children With Unilateral Cleft Lip and Palate.

OBJECTIVE: To assess a three-dimensional (3D) stereophotogrammetric method for area delimitation and evaluation of the dental arches of children with unilateral cleft lip and palate (UCLP). Obtained data were also used to assess the 3D changes occurring in the maxillary arch with the use of orthopedic therapy prior to rhinocheiloplasty and before the first year of life. DESIGN: Within the collaboration between the Università degli Studi di Milano (Italy) and the University CES of Medellin (Colombia), 96 palatal cast models obtained from neonatal patients with UCLP were analyzed using a 3D stereophotogrammetric imaging system. MAIN OUTCOME MEASURES: The area of the minor and greater cleft segments on the digital dental cast surface were delineated by the visualization tool of the stereophotogrammetric software and then examined. "Trueness" of the measurements, as well as systematic and random errors between operators' tracings ("precision") were calculated. RESULTS: The method gave area measurements close to true values (errors lower than 2%), without systematic measurement errors for tracings by both interoperators and intraoperators (P > .05). Statistically significant differences (P < .05) were noted for alveolar segment and time. CONCLUSIONS: Maxillary segments have the potential for growth during presurgical orthopedic treatment in the early neonatal period. The cleft segment delimitation on digital dental casts and area measurements by the 3D stereophotogrammetric system revealed an accurate (true and precise) method for evaluating the stone casts of newborn patients with UCLP.

Stair ascent and descent in assessing donor-site morbidity following osteocutaneous free fibula transfer: a preliminary study.

PURPOSE: The aim of this study was to investigate gait kinematic parameters during stair ascent and descent after fibula free flap removal for facial reconstruction. MATERIALS AND METHODS: Eight patients who underwent facial reconstruction with fibula free flap removal ascended and descended 3 standard steps. Their movements were recorded by a motion analyzer; gait kinematic parameters were obtained and compared with those calculated in 8 control subjects. RESULTS: Stride time, percentage of swing, and support phases did not differ among healthy and operated limbs and control subjects (Kruskal-Wallis, P > .05). No significant differences were found for hip and knee movements, pelvis rotation and tilt, and body center of mass displacements. During stair descent, the patients had significantly larger pelvis inclinations than the control subjects (P < .05). CONCLUSIONS: No functional limitations during stair performance were found. The only significant difference could indicate a minor control of the pelvis and should be used to define specific rehabilitative interventions.

Quantification of facial movements by optical instruments: surface laser scanning and optoelectronic three-dimensional motion analyzer.

The objective of this study was to assess the accuracy of displacements of tracing landmarks in standardized facial movements. Forty healthy persons were evaluated in 2 different groups (20 men and 20 women, aged 18-30 years) with optoelectronic motion analyzer and surface laser scanning. The displacements of tracing landmarks in brow lift and smile were calculated, and the 2 methods (optoelectronic motion analyzer and surface laser scanning) were compared in healthy persons. Side-related differences were found in the tracing landmark (superciliare) during brow lift movements between both methods (the largest movements were found on the right side, P = 0.044), whereas in smile movements the tracing landmark cheilion did not show significant differences between the 2 sides. In both movements, the differences of the tracing landmark displacements between the 2 systems and sexes were on average less than 2 mm, without statistically significant differences (P > 0.05). In conclusion, normal young adult men and women had similar standardized facial movements. The 2 analyzed movements can be measured by both optical instruments with comparable results.

Morphometry of the orbital region soft tissues in Down syndrome.

The orbital region of subjects with Down syndrome (DS) has been scanty described so far. We wanted to detail the morphologic characteristics of the soft tissue orbital region in Italian and North Sudanese subjects with DS. The three-dimensional coordinates of 10 landmarks on the orbital soft tissues were obtained using computerized anthropometry in 53 Italian and 64 North Sudanese subjects with DS aged 4 to 52 years, and in 461 (Italian) and 682 (North Sudanese) sex- and age-matched controls. From the landmarks, linear distances, ratios, areas, and angles were calculated, z scores computed, and compared by t-tests and analyses of covariance. In North Sudanese DS subjects, intercanthal width and height-to-length ratio were increased; biorbital width, eye height, length, and area were reduced. Eye fissure and orbital inclinations relative to Frankfort plane were reduced, whereas orbital inclinations versus the true horizontal were increased. In Italian DS men, orbital height and height-to-length ratio were increased, eye length was decreased; orbital inclination versus the true horizontal was increased. For almost all measurements, a significant effect of age was found. No effects of sex were found. Ethnic group influenced orbital height, area, and orbital inclination versus Frankfort plane. All paired measurements had similar discrepancies on both sides. The orbital soft tissues of North Sudanese DS subjects differed from those of their reference subjects, but this was only partially true for Italian subjects. The 2 ethnic groups had different alterations in their soft tissue orbital regions that were influenced by age, but not by sex.

Consistency and Reliability Analyses of a Comprehensive Index for the Evaluation of Teeth Alignment Performance.

(1) Introduction: The purpose of this work was to describe a method and propose a novel accuracy index to assess orthodontic alignment performance. (2) Methods: Fifteen patients who underwent orthodontic treatment using directly printed clear aligners were recruited. The study sample included 12 maxillary and 10 mandibular arches, whose pre-treatment, predicted and post-treatment digital models were superimposed on the untreated posterior teeth by means of a best-fit surface-based registration, which was also used to transfer three anatomical landmarks, digitally labeled on the crown of each anterior moving tooth, from the pre-treatment to the predicted and post-treatment models. The Teeth Alignment Performance (TAP) index, quantifying how close the final landmarks were to their expected final position, was proposed as an accuracy index of both individual tooth and group of teeth movement, and its inter-examiner repeatability was tested. (3) Results: No systematic inter-rater discrepancy associated with TAP was observed (p > 0.05), not even when a slight systematic inter-rater difference in landmark labelling was detected (for the upper central incisors, p < 0.001). In addition, all Intra-class Correlation Coefficient (ICC) values showed excellent inter-rater agreement (>0.95), and the small Random Error of Measurement (REM), ranging from 1% for the arch TAP to 3% for the lower canine TAP, indicated that this accuracy index is highly repeatable. (4) Conclusions: The TAP index was proven to be comprehensive, consistent and reliable in assessing the performance of teeth alignment according to a digital plan. The proposed method is also suitable to be implemented in the clinical digital workflow.

Direct 3D Printing of Clear Orthodontic Aligners: Current State and Future Possibilities.

The recent introduction of three-dimensional (3D) printing is revolutionizing dentistry and is even being applied to orthodontic treatment of malocclusion. Clear, personalized, removable aligners are a suitable alternative to conventional orthodontic appliances, offering a more comfortable and efficient solution for patients. Including improved oral hygiene and aesthetics during treatment. Contemporarily, clear aligners are produced by a thermoforming process using various types of thermoplastic materials. The thermoforming procedure alters the properties of the material, and the intraoral environment further modifies the properties of a clear aligner, affecting overall performance of the material. Direct 3D printing offers the creation of highly precise clear aligners with soft edges, digitally designed and identically reproduced for an entire set of treatment aligners; offering a better fit, higher efficacy, and reproducibility. Despite the known benefits of 3D printing and the popularity of its dental applications, very limited technical and clinical data are available in the literature about directly printed clear aligners. The present article discusses the advantages of 3D printed aligners in comparison to thermoformed ones, describes the current state of the art, including a discussion of the possible road blocks that exist such as a current lack of approved and marketed materials and limited existence of aligner specific software. The present review suggests the suitability of 3D direct printed aligners is superior to that of thermoformed manufactured aligners because of the prior's increased accuracy, load resistance, and lower deformation. It is an overall more stable way to produce an aligner where submillimeter movements can make a difference in treatment outcome. Direct 3D printing represents a complex method to control the thickness of the aligner and therefore has a better ability to control the force vectors that are used to produce tooth movement. There is currently no other approved material on the market that can do this. The conclusion of this article is that we encourage further in vitro and in vivo studies to test these new technologies and materials.

Translation and rotation movements of the mandible during mouth opening and closing.

To assess the relative contribution of rotation and translation of the temporomandibular condyle-disc assembly during opening and closing movements, free movements of maximum mouth opening and closing were recorded in healthy subjects (12 men, 14 women) using an optoelectronic three-dimensional motion analyzer. For each subject, the displacement of the lower interincisal point, the path of the condylar reference point, the degree of rotation around the three orthogonal rotational axes, and the relative contribution of translation and rotation were calculated during all movement of mouth opening and closing. The distance covered by the interincisor point and the rotational angle about the transverse axis at maximum mouth opening were larger in men than in women, but the difference cancelled after correcting for mandibular radius in the sagittal plane; mandibular rotation was always larger than translation, but never approaching 100%; opening and closing translations were similar within sex, but their paths were longer in men than in women (P < 0.05); rotational angles around vertical and sagittal axes were negligible; the linear correlation between maximum mandibular opening and condylar translation was minor and not significant. In normal subjects, mouth opening and closing as modeled at the interincisor point was determined more by mandibular rotation than by translation, but in no occasion a pure rotation was found. The percentage rotation was not identical during mouth opening and closing; female and male paths were not totally coincident; no correlation between maximum mandibular opening and condylar translation was found.

Three-dimensional mandibular motion in skeletal Class III patients.

OBJECTIVE: The aim of the study was to analyze the characteristics and changes in mandibular condylar motion in patients with skeletal Class III malocclusion. METHODS: Using a 3D motion analyzer, mandibular movements were recorded in 9 patients with skeletal Class III malocclusion and 22 control subjects with Angle Class I jaw relationships. RESULTS: Class III patients had a similar interincisor point displacement but a significantly reduced displacement of both condyles on the sagittal and frontal planes, with smaller translation paths than control subjects (right -9.4 mm; left -4.8 mm). The overall condylar rotation component was larger in Class III patients (right +8.8%; left +7.3%). The largest inter-group significant differences were observed in the first 10% of mouth opening, in which Class III patients had a larger rotating component than control subjects (+20%, p < 0.01). CONCLUSIONS: Condylar motion was reduced in skeletal Class III patients, in particular in the translational path.

Kinematic analysis of mandibular motion before and after orthognathic surgery for skeletal Class III malocclusion: A pilot study.

OBJECTIVES: The aim of the study was to detect the changes in 3D mandibular motion after orthognathic surgery for skeletal Class III malocclusion. METHOD: Using a 3D motion analyzer, free mandibular border movements were recorded in nine patients successfully treated for skeletal Class III malocclusion and in nine patients scheduled for orthognathic surgery. Data were compared using Mann-Whitney non-parametric U-test. RESULTS: The results showed no differences between the groups in the total amount of mouth opening, protrusion, and in lateral excursions, but the percentage of mandibular movement explained by condylar translation was significantly increased after surgery (20% vs. 23.6%). During opening, the post-surgery patients showed a more symmetrical mandibular interincisal point and condylar path than pre-surgery patients (p < 0.01). DISCUSSION: Patients treated with orthognathic surgery for skeletal Class III malocclusion recover a good and symmetric temporomandibular joint function.

Assessment of electromyographic activity in patients with temporomandibular disorders and natural mediotrusive occlusal contact during chewing and tooth grinding.

OBJECTIVES: The aim of this study was to investigate whether the presence of a natural mediotrusive contact influences electromyographic (EMG) pattern activity in patients with temporomandibular disorders (TMDs). METHOD: Bilateral surface EMG activity of the anterior temporalis (AT), masseter (MM), and sternocleidomastoid (SCM) muscles was recorded in 43 subjects during unilateral chewing and tooth grinding. Thirteen patients had TMD and a natural mediotrusive contact (Group 1), 15 had TMD without a natural mediotrusive contact (Group 2), and 15 were healthy subjects without mediotrusive contacts (Group 3). All subjects were examined according to the Research Diagnostic Criteria for TMD (RDC/TMD). All EMG values were standardized as the percentage of EMG activity recorded during maximum isometric contraction on cotton rolls. RESULTS: EMG activity from all muscles measured showed no significant differences between groups during chewing and grinding. Overall, in all groups, the EMG activity during chewing was higher in the working side than the non-working side in AT and MM muscles. During grinding, these differences were only found in masseter muscles (mainly in eccentric grinding). SCM EMG activity did not show significant differences during chewing and grinding tasks. Symmetry, muscular balance, and absence of lateral jaw displacement were common findings in all groups. DISCUSSION: EMG results suggest that the contribution of a natural mediotrusive occlusal contact to EMG patterns in TMD patients is minor. Therefore, the elimination of this occlusal feature for therapeutic purposes could be not indicated.

Rapid palatal expansion effects on mandibular transverse dimensions in unilateral posterior crossbite patients: a three-dimensional digital imaging study.

BACKGROUND: The purpose of this controlled study was to investigate indirect effects on mandibular arch dimensions, 1 year after rapid palatal expansion (RPE) therapy. METHODS: Thirty-three patients in mixed dentition (mean age 8.8 years) showing unilateral posterior crossbite and maxillary deficiency were treated with a RPE (Haas type) cemented on the first permanent molars. Treatment protocol consisted of two turns per day until slight overcorrection of the molar transverse relationship occurred. The Haas expander was kept on the teeth as a passive retainer for an average of 6 months. Study models were taken prior (T1) and 15 months on average (T2) after expansion. A control group of 15 untreated subjects with maxillary deficiency (mean age 8.3 years) was also recorded with a 12-month interval. Stone casts were digitized with a 3D scanner (3Shape, DK). RESULTS: In the treated group, both mandibular intermolar distance (+1.9 mm) and mandibular molar angulation (+9°) increased. Mandibular incisor angulation showed an increase of 1.9°. There was little effect on intercanine distance and canine angulation. Controls showed a reduction in transverse arch dimension and a decrease in molar and canine angulation values. CONCLUSIONS: RPE protocol has indirect widening effects on the mandibular incisors and first molars.

Normalizing surface electromyographic measures of the masticatory muscles: Comparison of two different methods for clinical purpose.

PURPOSE: To compare a new normalization technique (wax pad, WAX) with the currently utilized cotton roll (COT) method in surface electromyography (sEMG) of the masticatory muscles. METHODS: sEMG of the masseter and anterior temporalis muscles of 23 subjects was recorded while performing two repetitions of 5s maximum voluntary clenches (MVC) on COT and WAX. For each task, the mean value of sEMG amplitude and its coefficient of variation were calculated, and the differences between the two repetitions computed. The standard error of measurement (SEM) was calculated. For each subject and muscle, the COT-to-WAX maximum activity increment was computed. Participant preference between tasks was also recorded. RESULTS: WAX MVC tasks had larger maximum EMG amplitude than COT MVC tasks (P<0.001), with COT-to-WAX maximum amplitude increments of 61% (temporalis) and 94% (masseter) (P=0.006). WAX MVC had better test-retest repeatability than COT. For both MVC modalities, the mean amplitude (P>0.391) and its coefficient of variation were unchanged (P>0.180). The WAX task was the more comfortable for 18/23 subjects (P=0.007). CONCLUSION: WAX normalization ensures the same stability level of maximum EMG amplitude as COT normalization, but it is more repeatable, elicits larger maximum muscular contraction, and is felt to be more comfortable by subjects.

Reorganization of muscle activity in patients with chronic temporomandibular disorders.

OBJECTIVE: To investigate whether reorganization of muscle activity occurs in patients with chronic temporomandibular disorders (TMD) and, if so, how it is affected by symptomatology severity. METHODS: Surface electromyography (sEMG) of masticatory muscles was made in 30 chronic TMD patients, diagnosed with disc displacement with reduction (DDR) and pain. Two 15-patient subgroups, with moderate (TMDmo) and severe (TMDse) signs and symptoms, were compared with a control group of 15 healthy subjects matched by age. The experimental tasks were: a 5s inter-arch maximum voluntary clench (MVC); right and left 15s unilateral gum chewing tests. Standardized sEMG indices characterizing masseter and temporalis muscles activity were calculated, and a comprehensive functional index (FI) was introduced to quantitatively summarize subjects' overall performance. Mastication was also clinically evaluated. RESULTS: During MVC, TMDse patients had a significantly larger asymmetry of temporalis muscles contraction. Both TMD groups showed reduced coordination between masseter and temporalis muscles' maximal contraction, and their muscular activity distribution shifted significantly from masseter to temporalis muscles. During chewing, TMDse patients recruited the balancing side muscles proportionally more than controls, specifically the masseter muscle. When comparing right and left side chewing, the muscles' recruitment pattern resulted less symmetric in TMD patients, especially in TMDse. Overall, the functional index of both TMDmo and TMDse patients was significantly lower than that obtained by controls. CONCLUSIONS: Chronic TMD patients, specifically those with severe symptomatology, showed a reorganized activity, mainly resulting in worse functional performances.

Dynamic balance in elite karateka.

In karate, balance control represents a key performance determinant. With the hypothesis that high-level athletes display advanced balance abilities, the purpose of the current study was to quantitatively investigate the motor strategies adopted by elite and non-elite karateka to maintain balance control in competition. The execution of traditional karate techniques (kihon) in two groups of elite Masters (n = 6, 31 ± 19 years) and non-elite Practitioners (n = 4, 25 ± 9 years) was compared assessing body center of mass (CoM) kinematics and other relevant parameters like step width and angular joint behavior. In the considered kihon sequence, normalized average CoM height was 8% lower (p < 0.05), while CoM displacement in the horizontal direction was significantly higher in Masters than in Practitioners (2.5 vs. 1.9 m, p < 0.05), as well as CoM average velocity and rms acceleration (p < 0.05). Step width was higher in Masters in more than half of the sequence steps (p < 0.05). Results suggest that elite karateka showed a refined dynamic balance control, obtained through the increase of the base of support and different maneuvers of lower limbs. The proposed method could be used to objectively detect talented karateka, to measure proficiency level and to assess training effectiveness.

Double-powered free gracilis muscle transfer for smile reanimation: A longitudinal optoelectronic study.

The choice of the motor donor nerve is a crucial point in free flap transfer algorithms. In the case of unilateral facial paralysis, the contralateral healthy facial nerve can provide coordinated smile animation and spontaneous emotional expression, but with unpredictable axonal ingrowth into the recipient muscle. Otherwise, the masseteric nerve ipsilateral to the paralysis can provide a powerful neural input, without a spontaneous trigger of the smile. Harvesting a bulky muscular free flap may enhance the quantity of contraction but esthetic results are unpleasant. Therefore, the logical solution for obtaining high amplitude of smiling combined with spontaneity of movement is to couple the neural input: the contralateral facial nerve plus the ipsilateral masseteric nerve. Thirteen patients with unilateral dense facial paralysis underwent a one-stage facial reanimation with a gracilis flap powered by a double donor neural input, provided by both the ipsilateral masseteric nerve (coaptation by an end-to-end neurorrhaphy with the obturator nerve) and the contralateral facial nerve (coaptation through a cross-face nerve graft: end-to-end neurorrhaphy on the healthy side and end-to-side neurorrhaphy on the obturator nerve, distal to the masseteric/obturator neurorrhaphy). Their facial movements were evaluated with an optoelectronic motion analyzer. Before surgery, on average, the paretic side exhibited a smaller total three-dimensional mobility than the healthy side, with a 52% activation ratio and >30% of asymmetry. After surgery, the differences significantly decreased (analysis of variance (ANOVA), p < 0.05), with an activation ratio between 75% (maximum smile) and 91% (maximum smile with teeth clenching), and <20% of asymmetry. Similar modifications were seen for the performance of spontaneous smiles. The significant presurgical asymmetry of labial movements reduced after surgery. The use of a double donor neural input permitted both movements that were similar in force to that of the healthy side, and spontaneous movements elicited by emotional triggering.

Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players.

Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2), who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM), which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001), normalized CoM height was 1.3% lower (p<0.001) and CoM velocity 10% higher (p<0.01); foot and shank velocities were about 5% higher (p<0.01); arms were more abducted (p<0.01); shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference). We concluded that differences in motor control between preferred and non-preferred leg kicks exist, particularly in the movement velocity and upper body kinematics. Coaches can use these results to provide effective instructions to players in the learning process, moving their focus on kicking speed and upper body behavior.

Validation of a protocol for the estimation of three-dimensional body center of mass kinematics in sport.

Since strictly related to balance and stability control, body center of mass (CoM) kinematics is a relevant quantity in sport surveys. Many methods have been proposed to estimate CoM displacement. Among them, segmental method appears to be suitable to investigate CoM kinematics in sport: human body is assumed as a system of rigid bodies, hence the whole-body CoM is calculated as the weighted average of the CoM of each segment. The number of landmarks represents a crucial choice in the protocol design process: one have to find the proper compromise between accuracy and invasivity. In this study, using a motion analysis system, a protocol based upon the segmental method is validated, adopting an anatomical model comprising 14 landmarks. Two sets of experiments were conducted. Firstly, our protocol was compared to the ground reaction force method (GRF), accounted as a standard in CoM estimation. In the second experiment, we investigated the aerial phase typical of many disciplines, comparing our protocol with: (1) an absolute reference, the parabolic regression of the vertical CoM trajectory during the time of flight; (2) two common approaches to estimate CoM kinematics in gait, known as sacrum and reconstructed pelvis methods. Recognized accuracy indexes proved that the results obtained were comparable to the GRF; what is more, during the aerial phases our protocol showed to be significantly more accurate than the two other methods. The protocol assessed can therefore be adopted as a reliable tool for CoM kinematics estimation in further sport researches.

Facial reanimation with masseteric to facial nerve transfer: a three-dimensional longitudinal quantitative evaluation.

Facial paralysis is a severe pathological condition, negatively affecting patients' quality of life. The altered tone and mobility of the mimetic musculature provoke both functional and morphological deficits. In the present study, we longitudinally measured facial movements in 14 patients (21-69 years) affected by unilateral facial paralysis not lasting longer than 23 months. The patients were analyzed before and after surgical masseteric to facial nerve neurorrhaphy. Examinations were performed at least 3 months after they had clinically started to regain facial mimicry. The displacement of selected facial landmarks was measured using an optoelectronic three-dimensional motion analyzer during: maximum smile without clenching (pre- and postsurgery), maximum smile by clenching on their posterior teeth (only postsurgery), and spontaneous smile (recorded during the vision of a funny video in both examinations). Before facial surgery, in all smiles facial landmarks moved more in the healthy than in the paretic side; after surgery, the differences decreased for both reduction of the healthy-side motion, and increment of the paretic-side motion (motion ratio before 52%, after 87%, p < 0.05, Students' t-test). The ratio between the paretic and healthy-side total motion (asymmetry) did not modify for maximum and spontaneous smiles, but significantly increased for the maximum smiles made with teeth clenching (asymmetry before 32%, after 11%, p < 0.001). Spontaneous smiles were recorded only in a subset of patients, but their execution was modified by surgery, with more symmetrical movements of the rehabilitated-side landmarks (asymmetry before 33%, after 10%), and reduced motion of the healthy-side ones (motion ratio before 51%, after 83%). In conclusion, the significant asymmetry in the magnitude of facial movements that characterized the analyzed patients before surgery reduced after surgery, at least in those facial areas interested by the masseteric to facial nerve reanimation.

Mandibular kinematics and masticatory muscles EMG in patients with short lasting TMD of mild-moderate severity.

Mandibular kinematic and standardized surface electromyography (sEMG) characteristics of masticatory muscles of subjects with short lasting TMD of mild-moderate severity were examined. Volunteers were submitted to clinical examination and questionnaire of severity. Ten subjects with TMD (age 27.3years, SD 7.8) and 10 control subjects without TMD, matched by age, were selected. Mandibular movements were recorded during free maximum mouth opening and closing (O-C) and unilateral, left and right, gum chewing. sEMG of the masseter and temporal muscles was performed during maximum teeth clenching either on cotton rolls or in intercuspal position, and during gum chewing. sEMG indices were obtained. Subjects with TMD, relative to control subjects, had lower relative mandibular rotation at the end of mouth opening, larger mean number of intersection between interincisal O-C paths during mastication and smaller asymmetry between working and balancing side, with participation beyond the expected of the contralateral muscles (P<0.05, t-test). Overall, TMD subjects showed similarities with the control subjects in several kinematic parameters and the EMG indices of the static test, although some changes in the mastication were observed.