Lateral Excursion Research Articles

Evaluation of eccentric tooth contact on a semi-adjustable articulator by using an occlusal analysis system

Statement of problemDuplicating mandibular movement with a semi-adjustable articulator has been reported to lack accuracy. However, although previous studies have analyzed articulator movement, few have compared excursive tooth contact on the articulator with tooth contact during actual mandibular movement. PurposeThe purpose of this clinical study was to evaluate the concordance of semi-adjustable articulator contacts with intraoral contacts during eccentric movements by using a T-scan occlusal analysis system. Material and methodsForty-two participants with normal occlusion and without signs of temporomandibular disorder were analyzed for the reproducibility of eccentric tooth contact on a semi-adjustable articulator. Maxillary casts made from irreversible hydrocolloid impressions were mounted on a semi-adjustable articulator with the facebow. The condylar inclination of the articulator was set by using interocclusal records. Three recordings of right and left excursive mandibular movement and protrusive mandibular movement were made in the supine position by using the T-scan v9.1. The same procedure was then performed with the articulator. The results of complete mandibular movement from T-scan measurements were divided into 4 time points for analysis: T0, T1, T2, and T3. The concordance of intraoral and articulator occlusal contacts was evaluated at each point, and the occlusal force for each tooth was compared. Overall concordance and concordance of the working and nonworking sides were also calculated. Repeated measures analysis of variance was used to analyze differences between the concordance of intraoral and articulator contacts according to mandibular movement direction, time, and working and nonworking sides (α=.01). ResultsFor all teeth, concordance between the intraoral and articulator occlusal contacts during excursive mandibular movement was greatest at T0, decreasing at T1 and T2, and increasing at T3. No significant differences were found in the concordance among the right lateral, left lateral, and protrusive excursion (P>.01). The concordance of working side occlusal contacts during lateral excursion was significantly lower at T3 than that at T0 (P<.01). ConclusionsWhen comparing intraoral and articulator contacts during lateral eccentric mandibular movement, concordance was affected by time and working or nonworking side. Reproducibility of initial eccentric tooth contact on a semi-adjustable articulator appeared to be reliable. However, occlusal adjustment of the working side might be required after prosthesis delivery.

Effect of Nebulization on Laryngeal Parameters: Analysis Using High-Speed Digital Videolaryngoscopy

Superficial laryngeal hydration, obtained through nebulization, is related to the moisture level on the epithelial surfaces of the vocal folds, modifying their biomechanical and aerodynamic properties. Through high-speed videolaryngoscopy it is possible to obtain objective data for laryngeal analysis after nebulization and a better understanding of this phenomenon OBJECTIVE: To verify the effects of nebulization with saline solution on laryngeal parameters of digital videokymography obtained by high-speed videolaryngoscopy examination in women and men with and without laryngeal alterations METHOD: This is a clinical, comparative intra-subject study. Fifty-nine adults were selected, with and without laryngeal alterations, 30 females and 29 males. Digital videokymographs in the anterior, middle and posterior thirds of the vocal folds of the participants were analyzed before and after nebulization with 0.9% saline solution. Women without laryngeal alterations showed more parameters changes after nebulization, in which there was a decrease in maximum and medium opening, amplitude of opening of the left and right vocal fold in the anterior glottal third, and an increase of the percentage of closure of the vocal folds. These results indicate a minor extent of lateral excursion of the vocal folds during phonation. In women with laryngeal alterations, the parameters that changed after nebulization were the increased frequency of opening of the left and right vocal folds in the topography of the posterior third. In men, nebulization did not change the variables studied, except for the amplitude of the right vocal fold in men with laryngeal alterations, in the analysis of the posterior glottic third. The results suggest that surface hydration modifies laryngeal dynamics differently between genders. After nebulization with saline solution, women without laryngeal alterations showed a decrease in the lateralization of the vocal folds during phonation, suggesting a better phonatory efficiency.

Acute Effects of Soleus Stretching on Ankle Flexibility, Dynamic Balance and Speed Performances in Soccer Players.

Simple SummaryCalf muscles, including the gastrocnemius and soleus muscles, are very important for soccer players, but the benefits of soleus stretching are rarely reported. Both regular and soleus stretching conditions lead to better ankle range of motion, maximum plantarflexion strength, dynamic balance and speed performances compared to the no-stretching control. Adding soleus stretches into the regular stretching protocol would allow further improvement of ankle flexibility, maximum plantarflexion strength and curved running speed performances. The results from this study can provide insights for pre-exercise design and subsequent performances in soccer.Most dynamic stretching protocols include the gastrocnemius muscle, but soleus stretches are often neglected, which is the key powerful muscle for the push-off (concentric) of all speed movements. The purpose of this study was to examine whether the added soleus stretch in a regular stretching protocol would have greater benefits for ankle flexibility, dynamic balance and functional performance. Fourteen healthy male soccer players received each of the stretching conditions (regular stretching only (Regular), regular stretching with soleus stretching (Soleus) and no stretching (Control)) randomly on different training days, with two-day separation. The ankle flexibility, standing heel-lift balance and speed performances were assessed following each stretching intervention. The active dynamic stretches were performed for 30 s with three repetitions on each of the three (Regular) and four (Soleus) muscles. One-way ANOVA with repeated measures (or the Friedman non-parametric test) was performed to determine any significant effect with alpha = 0.05. Our findings revealed that both the Regular and Soleus stretching groups showed an increased active range of ankle motion compared to the no-stretching control (Ps < 0.05). In the heel raise balance test, both stretching groups experienced a significant increase in maximum plantarflexion strength as well as resultant anterior–posterior and medial–lateral CoP excursions compared to the no-stretching control (Ps < 0.05). In the sprinting tasks, both the Soleus and Regular stretching groups induced faster linear and curved running times (Ps < 0.05). When comparing the two stretching groups, Soleus stretching led to better ankle flexibility, maximum plantarflexion strength and curved running time (Ps < 0.05). Thus, added stretches on the soleus muscles can provide further benefits to speed performances in soccer.

Contribution of Longitudinal and Circumferential Shortening to Stroke Volume and Ejection Fraction in Severe Aortic Stenosis

Background: Left ventricular (LV) stroke volume (SV) is ejected by a combination of longitudinal shortening (LS), circumferential shortening (CS) and ventricular twist. Longitudinal shortening is caused by the motion of the mitral annulus towards the apex, causing wall thickening (circumferential and radial shortening), and left ventricular cavity and SV reduction. The role of LS in aortic stenosis (AS) is not defined. Objective: The aim of this study was to analyze the LS and CS contribution to SV and left ventricular ejection fraction (LVEF) in severe AS. Methods: The study included 152 patients (70±12 years, 64 women) with severe AS (valve area &lt;1 cm2 ) studied by cardiac Doppler echocardiography. The LS contribution to SV was evaluated by considering the base of the heart as a cylinder, with volume=base x height; the base was assumed as a circle with radius equal to (systolic septal thickness+systolic posterior wall thickness+end-systolic diameter)/2; and height, as an average of the mitral lateral, septal, anterior and inferior annulus systolic excursion. The CS contribution to SV was estimated as: SV - LS contribution to SV. Both contributions were expressed in absolute form and as SV percentages (% SV-LS and % SV-CS). Results: Longitudinal shortening contributed with approximately 2 thirds of SV (68±18 %) and CS with the rest. SV-LS correlated inversely with SV (r= - 0.45 p &lt;0.001) and SV-CS had direct correlation (r=0.45 p &lt;0.001). The % SV-LS contribution was greater in patients with LVEF &lt; 50%. Percent SV-LS correlated inversely with relative wall thickness (RWT) (r=0.32, p &lt; 0.01). Conclusion: The LS contribution to SV is greater than that of CS, and correlates inversely with SV. Percent SV-LS is higher in patients with LVEF &lt;50%. The aforementioned findings could have implications when considering cut-off points for longitudinal function indices (strain) without considering LVEF and/or ventricular geometry

Biomechanical measures of clinician-defined unsteadiness during a forward stepdown task in individuals post-arthroscopy for femoroacetabular impingement syndrome

BackgroundPatients with femoroacetabular impingement syndrome can present with aberrant movement patterns including unsteady balance. Balance training is included in rehabilitation after hip arthroscopy and may improve quality of movement; however, specific biomechanical measures associated with clinician-defined balance impairments are unknown. We aimed to understand these associations as they may inform targeted rehabilitative interventions. MethodsThe forward stepdown is a clinical test used to evaluate movement quality, including balance. 23 individuals at least one-year post-arthroscopy for femoroacetabular impingement syndrome and 15 healthy comparisons performed the forward stepdown, recorded by 3-dimensional motion capture and 2-dimensional video. Three physical therapists graded the 2-dimensional video for steadiness. Two-way analyses of variance were used to evaluate the interaction of group (post-arthroscopy/healthy comparison) by steadiness (steady/unsteady), for center of pressure medial-lateral excursion, center of pressure path length, and lateral trunk, pelvis, and lower extremity joint excursions. FindingsSix (26.1%) participants post-arthroscopy and five (33.3%) healthy comparisons were categorized as unsteady. The odds of being categorized as unsteady were not greater for participants post-arthroscopy (P = 0.72). There were no significant interactions; however, participants with clinician-defined unsteady balance, regardless of group, had significantly greater frontal plane trunk excursion, greater hip excursion, and greater center of pressure path length than those with steady balance (P ≤ 0.006). InterpretationThe odds of being categorized as unsteady were not greater for individuals post-arthroscopy for femoroacetabular impingement syndrome. Clinician-defined unsteadiness was associated with greater frontal plane trunk and hip motion which may be rehabilitation targets to improve balance during a dynamic single-leg task.

The effects of cannabis and alcohol on driving performance and driver behaviour: a systematic review and meta-analysis.

Cannabis and alcohol are frequently detected in fatal and injury motor vehicle crashes. While epidemiological meta-analyses of cannabis and alcohol have found associations with an increase in crash risk, convergent evidence from driving performance measures is insufficiently quantitatively characterized. Our objectives were to quantify the magnitude of the effect of cannabis and alcohol-alone and in combination-on driving performance and behaviour. Systematic review and meta-analysis. We systematically searched Academic Search Complete, CINAHL, Embase, Scopus, Google Scholar, MEDLINE, PsycINFO, SPORTDiscus and TRID. Of the 616 studies that underwent full-text review, this meta-analysis represents 57 studies and 1725 participants. We extracted data for hazard response time, lateral position variability, lane deviations or excursions, time out of lane, driving speed, driving speed variability, speed violations, time speeding, headway, headway variability and crashes from experimental driving studies (i.e. driving simulator, closed-course, on-road) involving cannabis and/or alcohol administration. We reported meta-analyses of effect sizes using Hedges' g and r. Cannabis alone was associated with impaired lateral control [e.g. g = 0.331, 95% confidence interval (CI) = 0.212-0.451 for lateral position variability; g = 0.198, 95% CI = 0.001-0.395 for lane excursions) and decreased driving speed (g = -0.176, 95% CI = -0.298 to -0.053]. The combination of cannabis and alcohol was associated with greater driving performance decrements than either drug in isolation [e.g. g = 0.480, 95% CI = 0.096-0.865 for lateral position variability (combination versus alcohol); g = 0.525, 95% CI = 0.049-1.002 for time out of lane (versus alcohol); g = 0.336, 95% CI = 0.036-0.636 for lateral position variability (combination versus cannabis; g = 0.475, 95% CI = 0.002-0.949 for time out of lane (combination versus cannabis)]. Subgroup analyses indicated that the effects of cannabis on driving performance measures were similar to low blood alcohol concentrations. A scarcity of data and study heterogeneity limited the interpretation of some measures. This meta-analysis indicates that cannabis, like alcohol, impairs driving, and the combination of the two drugs is more detrimental to driving performance than either in isolation.

A Computerized Simulation of the Occlusal Surface in Equine Cheek Teeth: A Simplified Model.

Equine mastication, as well as dental wear patterns, is highly important for the development of treatments in equine dentistry. During the last decades, the stress and strain distributions of equine teeth have been successfully simulated using finite element analysis. Yet, to date, there is no simulation available for dental tooth wear in equines. In this study, we developed a simplified two-dimensional computer simulation of dental wear. It provides a first tentative explanation for the development of the marked physiological inclination of the occlusal surface and for pathological conditions such as sharp enamel points in equine cheek teeth. The mechanical properties of the dental structures as well as the movement of the mandible during the equine chewing cycle were simulated according to previously published data. The simulation setup was optimized in preliminary test runs. Further simulations were conducted varying the lateral excursion of the mandible and the presence or absence of incisor contact during the chewing cycle. The results of simulations showed clear analogies to tooth wear patterns in living equids, including the formation of wear abnormalities. Our analysis indicates that small variations in the pattern of movement during the masticatory cycle, as well as incisor contacts, are leading to marked changes in the occlusal tooth wear patterns. This opens new research avenues to better understand the development of dental wear abnormalities in equines and might have serious implications on captive animal health, welfare, and longevity.

Correlation Between Prolonged Nasogastric Feeding and Temporomandibular Joint Dysfunction

Background: Nutrition is administered via enteral feeding in the form of fluid supplements to overcome malnutrition in hospitalized patients, or enteral tubes are intubated into the stomach and small bowel if the patient is unable to feed orally. The most common procedure performed by doctors across all medical specialties is nasogastric intubation. However, it has its own complications such as nasopharyngeal pain, aspiration, and trauma while insertion of the tube, but the impact of prolonged nasogastric tube feeding on temporomandibular joint (TMJ) is unknown. There is paucity of literature focusing on the TMJ; therefore, this study focuses on the correlation of prolonged nasogastric tube feeding and temporomandibular joint dysfunction. Materials and Methods: This was an observational study conducted among 59 participants. Patients undergoing nasogastric feeding for more than a week and having pain during mouth opening and left right lateral excursion were included in the study. Subjects with previous trauma to TMJ were excluded from study. Patients who were unconscious or uncooperative, had previous trauma to TMJ, and had facial surgery were excluded from the study. Result: Multivariate analysis revealed that there was no significant limitation of range of motions (ROMs; mouth opening [P = 0.232, t = 8.800], protrusion [P = 0.315, t = 17.130], right lateral excursion [P = 0.511, t = 16.768], and left lateral excursion [P = 0.5108, t = 18.143]) when compared to the ROMs at the time of insertion of nasogastric tube and 5–14 days after the removal of nasogastric tube. Also, there was significant TMJ pain. Conclusion: The study concludes that there was a significant correlation between duration of intubation and pain in masticatory muscles such as the temporalis and masseter, and medial and lateral pterygoid muscles and weak correlation between prolonged nasogastric intubation and TMJ movements.

The Effects of Ship’s Roll Motion on the Center of Mass and Margin of Stability During Walking: A Simulation Study

Walking strategies in an unstable environment like a ship differ from walking on stable ground. Extreme ship motions may endanger the safety of the crews. Notably, a loss of balance on board can lead to an injury or an accident of falling off a ship. Keeping one’s balance on board a ship is strongly influenced by the ship’s motion. Therefore, the objective of this study is to determine how walking on a ship differs from walking in a stable environment and explore the effects of the ship’s roll motion on balance control and stability while walking in sea environments. We hypothesized that step time variability, center of mass (COM), and margin of stability (MOS) would significantly differ between stable and unstable walking conditions. We also hypothesized that there would be an effect of rolling cycles and angles on increasing step time variability, COM excursion, and MOS variability. We recruited 30 healthy individuals between 21 and 39 years old for this study. Participants walked for two minutes at their self-selected speeds during the study with and without rolling on a computer-assisted rehabilitation environment (CAREN) system. The CAREN system was used to simulate the parametric roll motion of ships up to 20 degrees. This study quantified step time variability, peak COM excursion, and MOS variability in different rolling conditions. We found a significant difference in step time variability (p < 0.001), lateral peak COM excursion (p < 0.001), and MOS variability (p < 0.001) between waking on land and walking at sea.

Pattern of occlusal contacts in eccentric position of mandible in dental students

Introduction: Canine protection and group function are the two stand out occlusal schemes observed during laterotrusive movement of the mandible. The study aims to evaluate the frequency of these occlusal schemes in Nepalese dental students. Materials and methods: A cross-sectional study was conducted among dental students in People’s Dental College and Hospital, Kathmandu, Nepal after the ethical approval from PDCH-IRC. Sixty four undergraduate students aged 21-30 years, were examined for the occlusal contact patterns in lateral mandibular movements using 12μm shim stock. The data were analyzed using SPSS software (version 21) Result: On 1mm laterotrusive position on mandible, 43 subjects (67%) showed group function, 15 subjects (24%) canine guided and 6 subjects (9%) non specified occlusion. On 3mm laterotrusive movement, 31(48%) subjects showed group function and 27 subjects (42%) showed canine guided occlusal scheme. The most frequent mediotrusive contact was the second molar followed by the first molars during both 1mm and in 3mm excursion Conclusion: Majority of occlusal schemes of the study population were group function followed by canine protection and non specified occlusion. Canine protected occlusion scheme was increased on 3mm lateral excursion. Most of mediotrusive side contact seen on 2nd molar on 1mm.

Reliability of a Trapezium Miniplate with Endoscope-Assisted Internal Fixation in Mandibular Subcondylar Fractures: A Three-Dimensional Analysis.

This study aimed to evaluate the reliability of a trapezium plate for open reduction and internal fixation (ORIF) of mandibular subcondylar fractures with the simultaneous use of an endoscope. We selected and retrospectively studied 18 patients (12 males and 6 females) with unilateral mandibular subcondylar fractures who visited the Wonju Severance Christian Hospital. The mean age of the patients was 43.43 ± 15.76 years. Patients underwent ORIF with trapezium miniplate application through an intraoral incision under general anesthesia. The clinical and radiographic findings of the fractured side were compared with those of the non-operated side at 6 months follow-up. All occlusions became stable, and transient functional disturbances disappeared within 6 months of periodic follow-up. Functional mandibular movement recovered within the normal range, with an average mouth opening of 41.5 mm, protrusion of 7.5 mm, and lateral excursion of 7 mm at 6 months. Radiographic controls and statistical analysis confirmed a decent anatomical reduction in all 18 cases. In conclusion, the use of a trapezium miniplate with endoscope-assisted ORIF in mandibular subcondylar fractures can be useful for fixation and functional recovery.

Outcomes of total joint alloplastic reconstruction in TMJ ankylosis

The purpose of this study was to evaluate subjective and objective outcomes in patients with temporomandibular joint (TMJ) ankylosis treated with TMJ alloplastic reconstruction (TMJR). All patients diagnosed with TMJ ankylosis that underwent TMJR at our institution between 2010 and 2019 were retrospectively reviewed. Patients were divided into 2 cohorts: bony and fibrous ankylosis. Subjective variables assessed were facial pain and headaches, TMJ pain, jaw function, diet, and disability. Objective variables assessed were maximum interincisal opening and lateral excursions. The Mann-Whitney test was employed to analyze subjective variables and an unpaired t-test was used to analyze the objective variables. P < .05 was considered statistically significant. Twenty-eight patients met the inclusion criteria (21 female, 7 male). The mean age at the time of surgery was 42 years, and the mean number of prior TMJ surgeries was 3. A total of 52 TMJRs were performed in the 28 patients, and the mean follow-up time was 46 months. All subjective variables were significantly improved, and the mean maximum interincisal opening increased from 16.9 mm to 37.25 mm. The results of the study demonstrate that TMJR is an effective and reliable method for the management of both fibrous and bony TMJ ankylosis.

Foot Mechanics Define Directional Changes in Curved-Path Walking: New Methods to Assess the Motor Skill of Walking

Although it is essential to navigating the world, curved path walking is a challenge to mediolateral balance control. The focus of previous curved-path walking research was in spatiotemporal characteristics. We quantified the foot-ground interaction, center of pressure (COP) characteristics during non-linear (eg curved-path) walking important to understand the functional mechanics of directional changes for curved paths. We hypothesized the foot mechanics differ between older adults with better versus poorer curved-path walking (Figure of 8 Walk Test, F8W). Twenty-five older adults (mean age 71.8 ± 8.9 years) completed the F8W on an instrumented walkway (Protokinetics, LLC.) The derived metrics of the foot mechanics included medial/lateral movement of the COP for inside and outside steps, maximum medial and lateral COP excursions, and total medial/lateral COP range. Pearson correlations were used to examine relations F8W (time and steps) and COP metrics; ANOVAs were used to examine differences in COP metrics between older adults grouped by median-split of F8W time. Longer F8W time and more steps were related to lesser total COP range and outside foot lateral maximum excursion (r range -0.415 to -0.706, p<0.04). Older adults with stronger F8W performance compared to poorer F8W performance had larger outside foot total COP ranges (3.61cm vs 4.39cm, p=0.016) and greater lateral excursion (1.60cm vs 2.12cm, p=0,003). Foot-ground interactions offer new insights into control of curved path walking and methods for evaluating efficacy of interventions focused on improving walking skill in older adults.

Analysis of the clinical manifestations of 3 425 patients with orofacial pain of temporomandibular disorders

Objective: To describe and analyze the clinical manifestations of patients with orofacial pain of temporomandibular disorders (TMD). Methods: A retrospective study on orofacial pain was conducted for 3 425 patients diagnosed as TMD based on clinical symptoms and signs in the Department of Temporomandibular Disorders and Orofacial Pain, School of Stomatology, The Fourth Military Medical University. The patients included 1 158 males and 2 267 females with a median age of 32 years. The gender, age, course of disorders, pattern and site of pain, CT imaging diagnosis of temporomandibular joint (TMJ) were analyzed. The distribution of gender, age and disorder course interval were described. The differences in frequency of the pattern and site of pain, imaging diagnosis in different gender, age and disease course interval were compared. Chi-square test and non-parametric rank sum test were performed using software SPSS 23.0. Results: Of the 3 425 patients, 29.1% (997/3 245) had signs of joint popping, and 40.1% (1 373/3 425) had restricted opening. The pain frequency was higher in males who had disorder course less than 1 month (P<0.01) and also in males who had open-and-close and/or lateral excursion and/or protrusion pain without tenderness or other pain without tenderness (P<0.05). However, the pain frequency was higher in females who had tenderness (P<0.01). The pain frequencies in those over 56 years old with tenderness combined with open-and-close and/or lateral excursion and/or protrusion pain were higher than in patients of other ages (P<0.01). In patients with unilateral TMJ pain, the frequency in males was higher than females(P<0.01), while the frequency in females was higher in patients with unilateral TMJ pain combined with unilateral or bilateral myalgia and the frequency was higher in patients under 15 years old having bilateral TMJ pain and/or unilateral or bilateral myalgia (P<0.05). In patients with unilateral TMJ pain, the frequency in those with disorder course≤1 month was higher than in those with other disease duration intervals (P<0.01), while in patients with bilateral myalgia or TMJ pain plus unilateral or bilateral myalgia, the frequency in those with disorder course>3 years was higher than in those with other disease duration intervals(P<0.01). In patients with unilateral TMJ pain, the frequency was higher in those having open-and-close and/or lateral excursion and/or protrusion pain (P<0.01). In patients with unilateral myalgia and bilateral myalgia, the frequency was higher in those having tenderness (P<0.01). The frequency of TMJ space changes in male patients was higher than females and the frequency of hyperosteogeny and resorption in females were higher than males (P<0.05). The frequency of TMJ space changes and developmental problems were higher in patients aged 16 to 35 years, while the frequencies of hyperosteogeny, bone resorption and cystis in those over 56 years were higher than other ages (P<0.01). The frequency of TMJ space changes in patients with disorder course≤1 month was higher than in those with other disease duration intervals (P<0.01), while the frequency of hyperosteogeny was higher in patients with disorder course>3 years (P<0.01). Conclusions: The male to female ratio in the present patients with orofacial pain of TMD was about 1 to 2. Most of the patients visited hospital within half a year after the disorders occurred. The pattern and site of the orofacial pain, signs on TMJ CT images showed some distribution regularities in views of gender, age and disorder course.

Potential effect of pre-activated muscles under a far-side lateral impact

Objective The goal of this study is to evaluate the potential effect of muscle pre-activation under a lateral impact scenario, in this case focusing on a far-side impact, using an Active Human Body Model. Methods In total fourteen simulations were run, out of these, twelve were computed with an Active Human Body Model and two with a passive one. The models were subjected to a far-side impact scenario reaching up to 14 g’s. Two different pre-crash scenarios were analyzed with the Active Human Body Model: (1) constant velocity, and (2) braking deceleration. During the pre-crash phase a lambda control based on the muscle length computed the muscle activation. Since there is no available data concerning the neuromuscular strategy of the occupants subjected to high accelerations, six different control strategies were analyzed during the in-crash phase. Besides, rib fracture and brain injury risk were analyzed, since they are the two most relevant body regions in this simplified far-side crash scenario. Results The pre-activation of the muscles showed an effect on both the occupant kinematics and estimated injury risks. Depending on the considered muscle strategy, the head lateral excursion varied up to 75 mm, specifically for the scenario with constant velocity. Moreover, the rib fracture probability and the brain injury indicator revealed higher injury risks for the passive Human Body Model. When applying the constant velocity during pre-crash, the fracture probability for two or more ribs ranged from 9.91 to 46.06% for the Active Human Body Model, whereas it reached 84.3% for the passive model. The brain injury indicator was reduced by about 10% when using the active model compared to the passive one. Conclusions The numerical results show that the pre-activation of the muscles affects the kinematic and injury outcomes in car crashes. In this study, six muscular control strategies have been proposed. The two muscular controls that may be most realistic are: constant activation after the in-crash phase starts, by trying to hold the position prior to the crash, or no stimulation, by not responding to the upcoming in-crash event.

Does the Cannula Diameter Affect Outcomes of Temporomandibular Joint (TMJ) Arthrocentesis?

Since its implementation, temporomandibular joint (TMJ) arthrocentesis can be performed with cannulas of different diameters. The aim of this study was to determine the differences in cannula diameter for TMJ arthrocentesis on intraoperative and postoperative parameters. A prospective randomized clinical study was conducted using the documentation of Wilkes stage 3 patients with TMJ disorders. Patients were assigned to 2 groups using a system of computer-assisted randomization. Double puncture arthrocentesis (DPA) was performed with 21-gauge cannulas (group 1) and 18-gauge cannulas (group 2). The primary predictor variable was cannula diameter. Pain values assessed using a Likert-type (0 to10) visual analog scale (VAS) were selected as primary outcome variable. Mandibular movements including maximum mouth opening (MMO), lateral excursions (LE) and protrusion (P), were selected as secondary outcomes. Mandibular movements and pain values were recorded before treatment and at 1st day and 3rd months intervals. Descriptive, comparative, and bivariate analyses were conducted. Intraoperative complications were also recorded. DPA was applied to 33 patients (29 females, 4 males). Although group 1 was found to be significantly more advantageous than group 2 in terms of pain levels (P < .05), no statistically significant difference was discovered in terms of total complication numbers and mandibular movements at the follow-up periods (P >.05). Despite the limited sample size cannula thickness affects postoperative pain level significantly in conventional TMJ arthrocentesis.

Open Treatment with Ultrasound Activated Resorbable Pins Versus Closed Treatment of Adult Mandible Condylar Head Fractures.

The purpose of the study was to investigate whether open reduction and internal fixation (ORIF) with ultrasound activated resorbable pins (UARPs) is superior to closed treatment of condylar head (CH) fractures. The investigators hypothesized that fixation with UARPs is superior to closed treatment of CH fracture. It was a prospective pilot study on CH fracture patients. Patients in closed group were managed conservatively with arch bar fixation and elastic guidance. Fixation in open group was done with UARPs. Assessment was done for primary objective of stability of fixation by UARPs and secondary objectives of functional outcome and complications. The study sample included 20 patients (10 in each group). 10 patients (11 joints) in closed group and 9 patients (10 joints) in open group were available for final follow-up. 5 joints showed re-dislocation of fractured segment, 1 joint showed slightly imperfect but adequate fixation and 4 joints showed adequate fixation in open group. In the closed group, displaced fragment was fused with mandible at displaced position in all the joints. All the joints showed resorption of medial condylar head at 3months follow-up in open group. There was minimal resorption of condyle in closed group. Occlusion was deranged in 3 patients in open group and 1 patient in closed group. MIO, pain scores and lateral excursions were equal in both the groups. The results of the present study rejected the hypothesis that fixation of CH with UARPs was superior than closed treatment. There was resorption of medial CH fragment in open group as compared to closed group.

Study on the reconstruction of a four-dimensional movement model and the envelope surface of the condyle in normal adults

The objective of this study was to reconstruct the envelope surface of the condyle and the four-dimensional trajectory model in mandibular border movement in normal adults. Eleven healthy subjects were selected as volunteers. Cone-beam computed tomographic (CBCT) scanning was performed on the volunteers. The three-dimensional (3D) movement path of the mandible was recorded using a virtual articulator (PN-300), which was based on a 3D model of the mandible. We used Proplan CMF 3.0 (Materialise) software to perform this from the DICOM data generated by CBCT scans. The distance of condylar movement was measured in this model during volunteers’ mouth opening, protrusion, and lateral excursions. The envelope surface of the condyle was reconstructed by merging a functional condylar surface at each recording moment during the movement of the whole border. In the mandibular digital models, the condyle moved downward firstly, and moved upward to the position of maximum mouth opening. The condyle moved forward and downward during protrusion. The working condyle rotated slightly and the non-working condyle moved forward, downward, and inward during lateral excursions. The mean (SD) movement distance of 11 subjects was 19.04 (4.37) mm during mouth opening (including downward and upward) and 9.75 (2.38) mm during protrusion. During lateral excursions the mean (SD) movement distance of the working condyle was 2.87 (1.13) mm, the mean (SD) movement distance of the non-working condyle was 10.85 (3.25) mm. The envelope surface of healthy volunteers showed a double-peak pattern. The envelope surface of the condyle and four-dimensional movement model can be reconstructed by merging the trajectory of the mandible recorded from the novel virtual articulator PN300 and a 3D image of the mandible.

Arthrocentesis Versus Level 1 Arthroscopy in Internal Derangement of Temporomandibular Joint.

Internal derangement of the temporomandibular joint is defined as an abnormal position of the articular disc in relation with mandibular condyle and articular eminence presenting as disc displacement with or without reduction. This study was conducted on thirty patients diagnosed with Internal derangement of TMJ consisting of 8 males and 22 females averaging 34.6years. Two groups Conventional Arthrocentesis (Group A) and Level 1 Arthroscopy (Group B) consisted of 15 cases each divided alternately. Clinical evaluation parameters included VAS for pain, maximal interincisal opening, deviation on mouth opening, range of motion including lateral excursion & protrusion movements recorded at 1week, 1month & 6months postoperatively. Wilke's Staging according to MRI findings was recorded preoperatively and 6months postoperatively. At 6month follow-up, average reduction in VAS for pain & deviation on mouth opening was 72.43% & 24.73% in Group A and 77.66% & 65.41% in Group B, respectively. Average increase in MIO, right & left excursion & protrusion movements was 29.55%, 31.33%, 20.12% & 32.45% in Group A and 34.94%, 41.37%, 39.29% and 36.51% in Group B, respectively. Improved results were obtained clinically for all Wilke's stages in both groups with more number of patients improving in Group B. On comparing results, improvement was observed in various clinical evaluation parameters of both the groups at 6months follow-up. However, statistically significant & better results were obtained for the Arthroscopy group.

Functional Outcomes with Facial Artery Musculo-Mucosal (FAMM) Flap and Dental Implants for Reconstruction of Floor of the Mouth and Tongue Defects in Oncologic Patients.

Optimal functional outcomes in oncologic patients with squamous cell carcinoma (SCCA) of the tongue and floor of the mouth require good lingual mobility, adequate facial competence, the cheek suction effect and dental rehabilitation with osseointegrated implants. In this study, twenty-two oncologic patients who had been diagnosed with intraoral SCCA affecting the tongue and the floor of the mouth and who had undergone wide resection of the tumor and immediate reconstruction with an inferiorly pedicled FAMM flap and immediate osseointegrated implants were assessed. Lingual mobility, speech articulation, deglutition, implant success rate, mouth opening, and aesthetic results were evaluated. All patients were staged as T2 and the defect size ranged from 3.7 × 2.1 cm to 6.3 × 4.2 cm. A selective neck dissection was performed in all patients as part of their oncologic treatment, either electively or for node positive disease. Thirteen patients (59%) were diagnosed with node positive disease and underwent adjuvant radiotherapy. A total of 101 osseointegrated implants were placed for prosthetic rehabilitation and 8 implants were lost (7.9%), of which 7 received radiotherapy (87.5%). The implant success rate was 92.1%. Mouth opening was reported as normal in 19 patients (86.3%). Tongue tip elevation was reported as excellent in 19 patients (86.3%) and good in 3 patients (13.6%). Lingual protrusion was referred to as excellent in 15 patients (68.2%) and good in 6 patients (27.2%). Lateral excursion was reported as excellent in 14 patients (63.6%) and good in 7 patients (31.8%). In terms of speech articulation, 20 patients reported normal speech (90.9%). Regarding deglutition, 19 patients (86.3%) reported a regular diet while a soft diet was reported by 3 patients (13.7%). Aesthetic results were referred to as excellent in 17 patients (77.3%). FAMM flaps, immediate implants and fixed prostheses enable the functional rehabilitation of oncologic patients, optimizing aesthetics and functional outcomes even in patients undergoing irradiation, thus returning oncologic patients to an excellent quality of life.