Rotation Of Complex Research Articles

Effects of condylar neck inclination and counterclockwise rotation on the stress distribution of the temporomandibular joint.

Three different kinds of condylar inclination were manually modelled anteriorly inclined condylar neck, vertical condylar neck, and posteriorly inclined condylar neck. Three different maxillary impactions were simulated to evaluate the effect of counterclockwise rotation. The von Misses stresses of the disc, compressive stresses of the glenoid fossa, and compressive stresses of the condyle were the highest in the models with posteriorly inclined neck and lowest in the models with vertical condylar neck design. Stresses of the temporomandibular joint increase with the counterclockwise rotation of the maxilla-mandibular complex. The posteriorly inclined neck should be considered a risk factor for condylar resorption with increased counterclockwise rotation.

Human in vivo midtarsal and subtalar joint kinematics during walking, running and hopping.

The interaction among joints of the midtarsal complex and subtalar joint is important for locomotor function; however, its complexity poses substantial challenges in quantifying the joints' motions. We determine the mobility of these joints across locomotion tasks and investigate the influence of individual talus morphology on their motion. Using highly accurate biplanar videoradiography, three-dimensional bone kinematics were captured during walking, running and hopping. We calculated the axis of rotation of the midtarsal complex and subtalar joint for the landing and push-off phases. A comparison was made between these rotation axes and the morphological subtalar axis. Measurement included total rotation about and the orientation of the rotation axes in the direction of the subtalar joint and its deviation via spatial angles for both phases. The rotation axes of all three bones relative to the talus closely align with the morphological subtalar axis. This suggests that the midtarsal and subtalar joints' motions might be described by one commonly oriented axis. Despite having such an axis, the location of the axes and ranges of motion differed among the bones. Our results provide a novel perspective of healthy foot function across different sagittal plane-dominant locomotion tasks underscoring the importance of quantifying midtarsal complex and subtalar motion while accounting for an individual's talus morphology.

Clockwise versus counterclockwise rotation in bimaxillary surgery: 3D analysis of facial soft tissue outcomes.

This study aimed to compare facial 3D soft tissue changes in subjects with Class III deformities who underwent bimaxillary clockwise (CW) and counterclockwise (CCW) rotational orthognathic surgery. Asian Class III subjects who completed bimaxillary surgical orthodontic treatments were enrolled and categorized into CW and CCW groups based on maxillary occlusal plane alterations. Preoperative and 9-month follow-up cone-beam computed tomography (CBCT) and 3D stereophotogrammetry were obtained, superimposed, and quantified for skeletal movements and soft tissue changes in six facial regions. Inverse probability of treatment weighting (IPTW) adjusted for potential confounding factors. Thirty-seven subjects were included (CW group, n = 20; CCW group, n = 17). Postsurgical chin volume significantly reduced in the CW group compared to the CCW group (mean difference 6362 mm3; p = 0.037), and intergonial width significantly decreased in the CW group (mean difference 6.2mm; p = 0.005). The postoperative alar width increased by 1.04mm and 1.22mm in the CW and CCW groups, respectively (p = 0.70). However, these changes were not significantly correlated to the direction of MMC pitch. Clockwise rotation of the bimaxillary complex demonstrated a significant advantage in reducing chin volume and intergonial width compared to counterclockwise rotation, leading to a reduced frontal lower face width among Asian Class III subjects.

Stress distribution and displacement with four different types of MARPE on craniofacial complex: A three-dimensional finite element analysis

Various designs of mini-implants assisted rapid palatal expander (MARPE) appliances can impact treatment effectiveness through their biomechanical effects. The purpose of the study was to study the stress distribution and displacement with four different designs of the MARPE appliance on the craniofacial complex. A 3D finite element model of the craniofacial complex was created from CBCT DICOM data, comprising four distinct groups. Each group consisted of one 4-hole expansion screw positioned between the second premolar and first molar in all models. Group 1 used four single-cortical mini-implants (1.5×8mm) engaging only the palatal cortex. Group 2 employed four mini-implants (1.5×11mm) engaging both the palatal and nasal cortices. Group 3 had monocortical implants on the palatal slopes, while Group 4 was similar to group 3 with implants in the acrylic wings. Comparisons between groups were made for anchorage (groups 1 and 2), mini-implant position (groups 1 and 3) and surface effect (groups 3 and 4). Von Mises stresses and displacements at various skeletal and dental points were evaluated using ANSYS software. The highest stresses were observed in the maxillary, pterygoid and zygomatic bones, as well as in the mid- palatal suture in all four groups. Downward and forward rotation of the craniofacial complex was noted. Group 2 showed greater skeletal expansion than group 1. Among groups 1 and 3, group 3 showed a better stress distribution. Group 4 showed less dentoalveolar rotation than group 3. The MARPE appliances had an impact on the craniofacial complex with stresses on the mid-palatal suture, maxillary bone, pterygoid bones and anterior teeth. Clockwise rotation of the maxilla, zygomatic bones and dentition was noted, while the pterygoid bones and pterygoid suture were displaced backwards. MARPE with bicortical anchorage produces better skeletal expansion. Placing implants on the palatal slopes with acrylic wings results in better skeletal expansion with less clockwise rotation of the dentition.

Modeling Photoassociative Spectra of Ultracold NaK + K.

A model for photoassociation of ultracold atoms and molecules is presented and applied to the case of 39K and 23Na39K bosonic particles. The model relies on the assumption that photoassociation is dominated by long-range atom-molecule interactions well outside the chemical bond region. The frequency of the photoassociation laser is chosen close to a bound-bound rovibronic transition from the X1Σ+ ground state toward the metastable b3Π lowest excited state of 23Na39K, allowing us to neglect any other excitation, which could hinder the photoassociation detection. The energy level structure of the long-range 39K···23Na39K excited super-dimer is computed in the space-fixed frame by solving coupled-channel equations, involving the coupling between the 23Na39K internal rotation and the mechanical rotation of the super-dimer complex. A quite rich structure is obtained, and the corresponding photoassociation rates are presented. Other possible photoassociation transitions are discussed in the context of the proposed model.

Gearing Effect in Clockwise Rotational Orthognathic Surgery.

The standard procedure for managing skeletal class III malocclusion is maxillary advancement with mandibular setback. Occlusal plane-altering orthognathic surgery, such as jaw rotation, is useful as well. Although clockwise jaw rotation is a common procedure, its mechanism has not been well investigated. With this study, the authors aim to introduce the gearing effect to correct class III malocclusion in Asians by maxillary posterior impaction using clockwise rotation without advancing the maxilla. Patients with class III correction with clockwise rotation of the maxillomandibular complex without maxillary advancement were included; those who underwent genioplasty were excluded. Various facial skeletal cephalometric landmarks were measured using artificial intelligence-based cephalometric analysis software. The gearing effect was determined by dividing the lower anterior facial height (LAFH) in relatively short and long groups compared with those in the anterior nasal spine to posterior nasal spine length. In a total of 29 patients, the amount of menton setback between group 1 ( n = 15; short LAFH) and group 2 ( n = 14; long LAFH) was 1.67 ± 0.66 and 2.74 ± 0.99 mm per 1 mm of posterior nasal spine impaction, respectively ( P = 0.002), and 1.58 (interquartile range, 0.78) and 1.95 (interquartile range, 1.05) mm per 1 degree of clockwise rotation of the palatal angle, respectively ( P = 0.007). The convexity of the A point was improved without any significant change in the sella-nasion-A point angle before and after surgery. This article addresses the scientific evidence regarding the impact of clockwise rotational orthognathic surgery based on the gearing effect. The mandibular setback turned out to be more effective in patients with a long LAFH. Risk, II.

Does Clockwise Rotation of Maxillomandibular Complex Using Surgery-First Approach to Correct Mandibular Prognathism Improve Facial Appearance?

Facial aesthetics may be optimized based on a deeper understanding of soft tissue changes after orthognathic surgery. The purpose of the study was to delineate facial soft tissue changes after clockwise rotation (CWR) of the maxillomandibular complex (MMC) to correct mandibular prognathism using the surgery-first approach. This prospective cohort study enrolled patients over 18years of age with skeletal Class III malocclusion in the craniofacial center. The patients were excluded with previous history of craniofacial syndrome, orthognathic surgery trauma, infection at surgical sites, chin deviation (menton deviation ≥4mm), 2 or more missing data points after surgery, or without informed consent. This study compared significant facial changes before (T0) and after orthodontic debonding (T1) in the CWR and control groups. The patients were divided in accordance with maxillary occlusal plane change (OPC) after surgery into CWR (OPC >4°) and control (OPC ≤4°) groups. The primary outcome variable was frontal lip curvature (FLC: Right Cheilion-Stomion-Left Cheilion, degree) with or without upper lip curving upward at T1, where upper lip curving upward was considered more favorable. The covariates included age, sex, and various cephalometric measurements. The Mann-Whitney U test, paired, and independent t-test were implemented to compare the intragroup and intergroup differences. Statistical significance was indicated by P value <.05. The study comprised 34 patients (21 women) in the control group and 37 (29 women) in the CWR group; their mean ages were 23.64±4.38 and 24.21±3.84years, respectively (P value=.562). At T1, the CWR group had significant increased FLC (P value=.001), alar width (P value=.034), and lower vermilion height (P value=.018), and decreased lower lip length (P value=.004). The high FLC group had significant decreased upper lip projection (P value=.002) and increased nasolabial angle (P value=.013). The significant relationship between CWR and high FLC was supported by the χ2 test (P value=.018) and multiple logistic regression (P value=.017). Greater CWR of the MMC increased FLC and lower vermilion height and reduced lower lip length. High FLC resulting from the CWR of the MMC improved facial appearance by moving the upper lip curve upward.

Case report impact on orthognathic surgery for counterclockwise rotation and effect on airway, with or without temporomandibular joint total joint prostheses

PurposePresent case reports that have generated new treatment protocols improving treatment of patient outcomes with jaw deformities and airway compromises requiring counterclockwise rotation (CCWR) of the maxillo-mandibular complex (MMC) with or without a requirement for temporomandibular joint (TMJ) total joint prostheses (TJP). Presented are studies that verify the efficacy of these procedures. MethodsInitial case presentations were identified in reference to CCWR of the MMC without and with TMJ total joint prostheses in cases of co-existing end-stage TMJ pathology. A non-systematic literature search was conducted to identify studies pertinent to subject matter. ResultsTwo case reports are presented that have significantly affected our specialty: 1) CCWR of the MMC and effect on airway, and 2) TMJ TJP with concomitant maxillary osteotomies for CCWR of the MMC. Forty papers were identified meeting the filtered criteria. Twenty-nine papers were excluded as case reports, philosophy, technique, or small case series. Eleven studies met the inclusion criteria and are summarized according to the data included. These studies validate the efficacy and stability of CCWR of the MMC in the presence of healthy joints as well as patients with end-stage TMJ pathology using custom TMJ TJP in conjunction with orthognathic surgery. ConclusionsPatients with healthy TMJs can be treated with CCWR of the MMC with predictable outcomes and stability. Patients with end-stage TMJ pathology can benefit from TMJ TJP and orthognathic surgery for CCWR of the MMC with good stability, improved function, decreased pain, improved airway, and quality of life.

Management of Class III malocclusion by orthodontic clockwise rotation of maxillo-mandibular complex – A case report

Severe Skeletal Class III malocclusions in adult patients are managed by surgical orthodontic correction and orthodontic camouflage especially in borderline cases. An orthodontic camouflage is best opted in situations where the patient is either reluctant to have an invasive procedure or mitigate other ways to obtain an ideal interincisal relation, best esthetic outcome and function. There are many ways suggested to treat Class III malocclusions non-surgically like fixed appliance with class III intermaxillary elastics, extraction of mandibular first bicuspids, extraction of mandibular first and maxillary second bicuspids and enmasse distalization of mandibular arch using temporary anchorage devices. Clockwise rotation of maxillo-mandibular occlusal complex gives promising treatment outcome in selected cases with extrusion of upper arch and possible clockwise rotation of the mandible for improving mandibular prognathism. This case report aims to illustrate a Class III non-growing patient treated by clockwise rotation of maxillo-mandibular occlusal complex for achieving optimum facial esthetics and function.

Assessment of three-dimensional rotation of the shoulder complex and scapulohumeral rhythm during sagittal movement.

Due to the influence of spinal and respiratory movements, it is difficult to accurately measure the range of motion of each joint. To conduct a three-dimensional (3D) measurement of each joint in the shoulder complex in different postures in the sagittal plane of the upper extremity. Thirteen healthy adults with no history of shoulder surgery for trauma or chronic pain were enrolled in the present study. The computed tomography (CT) imaging data of the shoulder complex were acquired in four postures via the reconstruction and alignment of 3D images. The angles of the postural changes were measured, and rotation vectors were used for descriptions and statistical analyses. There was a statistical difference in the rotation angles between the dominant and non-dominant sides of the sternoclavicular joint when the posture changed from a resting position to a posterior inferior position. During the postural change from a resting position to a horizontal position, the regression coefficient (β) of the humerothoracic joint to the sternoclavicular joint was 0.191, and the β of the humerothoracic joint to the glenohumeral joint was 0.621. During the postural change from the horizontal position to the rear upper position, the β of the humerothoracic joint to the sternoclavicular joint was 0.316, and the β of the humerothoracic joint to the glenohumeral joint was 0.845. During the postural change from the resting position to the rear lower position, the β of the humerothoracic joint to the glenohumeral joint was 0.991. The application of the image alignment technique enabled the direct and accurate measurement of the bony structures of the shoulder joint. The helical approach accurately described the scapulohumeral rhythm during 3D motion. There was a scapulohumeral rhythm of the shoulder complex during 3D composite sagittal movement, with different ratios for different joints and postures.

Does Clockwise Rotation of Maxillomandibular Complex Using Surgery-First Approach to Correct Mandibular Prognathism Affect Surgical Movement and Stability?

Orthognathic surgery (OGS) using the surgery-first approach (SFA) can decrease treatment time and increase patient satisfaction. Clockwise rotation (CWR) of the maxillomandibular complex to correct mandibular prognathism leads to optimized functional, aesthetic, and stable outcomes. This study examined the combined effect of SFA and CWR of the maxillomandibular complex to correct mandibular prognathism by comparing the surgical movement before (T0) and immediately after OGS (T1) and the stability between T1 and 12 months after OGS (T2). This prospective cohort study enrolled patients with skeletal Class III malocclusion who underwent SFA involving Le Fort I osteotomy and bilateral sagittal split osteotomy, with or without genioplasty. Based on the occlusal plane (OP) change at T0-T1, the patients were divided into CWR (OP>4°) and control (C) groups (OP≤4°). The predictor variable was OP change at T0-T1. The primary outcome variable was the stability of pogonion (Pog) at T1-T2. The covariates included demographic factors, cephalometric measurements (anterior facial height, posterior facial height, OP, mandibular plane angle, incisor mandibular plane angle, overjet, and overbite), and 3-dimensional landmark displacement (anterior nasal spine, A-point, upper central incisor, upper first molar, lower central incisor, lower first molar, Pog, gonion, and condylion). An independent t-test was used to compare between these 2 groups when appropriate. The level of significance was set at P<.05. The sample included 28 patients (17 females) in the C group and 36 (24 females) in the CWR group; the mean ages were 23.89±3.35 and 24.08±4.02years, respectively. For the surgical movement at T0-T1, the CWR group showed an association with vertical movement of the maxilla at posterior nasal spine (P=.005), anterior nasal spine (P<.001), and A-point (P<.001) and horizontal backward movement of the mandible at B-point (P<.001), Pog (P<.001), and gonion (P=.042). At T1-T2, all landmarks remained stable without clinically significant difference between the 2 groups. Surgical movement in the CWR group could vertically displace the maxilla and setback mandible more than that in the C group. Postoperative skeletal stability remained the same between the 2 groups at 1year after OGS.

TMJ disc repositioning associated with orthognathic surgery for the treatment of severe retrognathism

Introduction: Orthognathic surgery associated with temporomandibular disc reposition is a modality of surgical treatment for dentofacial deformities associated with temporomandibular disorders that has been shown to be a stable and predictable alternative for such situations. However, there is still no consensus in the literature regarding the treatment modality in these cases. Several studies have been developed looking for more stable and predictable results in favor of the best patient treatment. Case Report: Patient with a class II facial pattern and temporomandibular dysfunction, submitted to bilateral repositioning of the articular disc and orthognathic surgery with counterclockwise rotation of the maxillomandibular complex, with improvement of the symptoms and of the functionality of the stomatognathic system, and satisfaction with facial aesthetics. Conclusion: Although there are controversies about the surgical repositioning of chronic articular disc displacements in retrognathism, this treatment modality has demonstrated long-term stability and reduction or resolution of joint symptoms.

Ribosomal protein eL39 is important for maturation of the nascent polypeptide exit tunnel and proper protein folding during translation.

During translation, nascent polypeptide chains travel from the peptidyl transferase center through the nascent polypeptide exit tunnel (NPET) to emerge from 60S subunits. The NPET includes portions of five of the six 25S/5.8S rRNA domains and ribosomal proteins uL4, uL22, and eL39. Internal loops of uL4 and uL22 form the constriction sites of the NPET and are important for both assembly and function of ribosomes. Here, we investigated the roles of eL39 in tunnel construction, 60S biogenesis, and protein synthesis. We show that eL39 is important for proper protein folding during translation. Consistent with a delay in processing of 27S and 7S pre-rRNAs, eL39 functions in pre-60S assembly during middle nucleolar stages. Our biochemical assays suggest the presence of eL39 in particles at these stages, although it is not visualized in them by cryo-electron microscopy. This indicates that eL39 takes part in assembly even when it is not fully accommodated into the body of pre-60S particles. eL39 is also important for later steps of assembly, rotation of the 5S ribonucleoprotein complex, likely through long range rRNA interactions. Finally, our data strongly suggest the presence of alternative pathways of ribosome assembly, previously observed in the biogenesis of bacterial ribosomal subunits.

Surgical-Orthodontic Treatment of Skeletal Class II Malocclusion with Obstructive Sleep Apnea and Multiple Missing Teeth

In the treatment of skeletal Class II retrognathic mandible, the airway should be considered for the progress and outcome of the treatment. The case report demonstrates combined orthodontic and orthognathic surgery in a 39-year-old woman with chief complaint of maxillary protrusion. The clinical examination and X-ray revealed skeletal Class II with a retrognathic mandible, high mandibular plane, vertical maxillary excess (VME), bilateral deformed condyles, and narrow posterior airway space. Moreover, the patient had several missing teeth with a posterior lingual crossbite. Polysomnography revealed obstructive sleep apnea (OSA), with a high apnea–hypopnea index (AHI) of 12.1/h. Her body mass index was low at 17.2. The preoperative orthodontic treatment included leveling, alignment, and molar uprighting. Maxillary segmental LeFort I was designed to expand her maxillary intermolar width and impact the anterior part of her maxilla. Also, bilateral sagittal split osteotomies were performed to advance her mandible position with a counterclockwise rotation of the maxillomandibular complex. The postoperative orthodontic treatment included settling the bite, monitoring the relapse, and managing the dental space for future prosthodontic rehabilitation. After a total treatment time of 1 year and 10 months, her profile was improved, her airway volume was enlarged, and her OSA was resolved, with the AHI changed to 4.3/h at 11 months after surgery then further decreased to 0/h when debonded.

Delayed Soft Tissue Changes after Clockwise Rotation of the Maxillo-Mandibular Complex.

The purpose of this study was to evaluate delayed soft tissue changes of the maxilla-mandibular complex MMC using three-dimensional (3D) cone-beam computed tomography after clockwise repositioning orthognathic surgery. This study included 21 patients that underwent maxilla-mandibular complex clockwise rotational orthognathic surgery by 1 doctor from January 2015 to June 2019. Radiographic images (panorama, lateral cephalogram, posteroanterior view, and conebeam computed tomography) were taken and 3D analysis was performed using the Invivo 5 (Anatomage Inc, Santa Clara, CA) to acquire 3D images before surgery, immediately after surgery, at 6 months after surgery and 21 months after surgery. The 9 soft tissue landmarks were measured and compared in terms of postoperative changes in transverse, vertical, and anteroposterior directions. The points were at the outer commissure of the eye fissure (Exocathion; Exc_r, Exc_l), at the midline of both the nasal root and the nasofrontal suture, analogous to bony N (soft tissue nasion; N), the most prominent point on the nasal tip (Pronasale; Prn), the most lateral point in the curved baseline of each ala, indicating the facial insertion of the nasal wing base (Alare curvature; Ac_r, Ac_l), the most lateral point on the soft tissue contour of each mandibular angle (Soft tissue Gonion; Go_r, Go_l), and the most inferior midpoint on the soft tissue contour of the chin (soft tissue menton; Me). The most prominent point of the nasal tip (Prn) moved 1.36 mm upward and 1.55 mm forward in the vertical and anteroposterior planes immediately after surgery. However, there were no significant changes in Ac_r and Ac_l even immediately after surgery. Both soft tissue gonions shifted downward and forward between immediately after surgery and 6 months after surgery. However, no significant change was observed in the value of any of the 9 soft tissue points between 6 months and 21 months after surgery ( P value < 0.05). No significant changes were observed between 6 and 21 months after surgery, which suggests no delayed soft tissue changes occur in surgically treated patients after the resolution of surgically-related facial edema and swelling and postsurgical remodeling of hard tissue in overlying soft tissue.

Segmental Maxillomandibular Rotational Advancement (SMMRA) in the Treatment of Adult Patients with Severe Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) occurs as an increased collapsibility of the upper airway during sleep, which threatens health and quality of life. Asian men with greater severity of OSA presents less obese and are connected with craniofacial abnormalities. Although the traditional maxillomandibular advancement (MMA) had the comparable effectiveness to the continuous positive airway pressure therapy, the midfacial esthetics might be compromised in Asian individuals. The modified MMA procedure was proposed to balance the esthetic demands and improvement of OSA symptoms. The case report showed a 25-year-old man presented with a diagnosis of severe OSA. The pretreatment Apnea Hypopnea Index (AHI) score was 100 events/h. He exhibited skeletal Class II hyperdivergent facial pattern with mandibular retrognathism. To correct dentofacial deformities and improve sleep function, the modified surgical-orthodontic procedure was undertaken. The surgery-first approach was adopted for early improvement of OSA. The surgical procedures of SMMRA comprise the maxillary LeFort I segmental osteotomy, bilateral sagittal split osteotomy and genioglossus-genioplasty osteotomy. The counterclockwise rotation of maxillomandibular complex was further done to maximize mandibular advancement. The total treatment duration was 13 months. The well-aligned dentitions and solid dental occlusion were achieved. The subjective perception of sleep quality was improved. The patient was satisfied with the post-treatment facial appearance. Following the skeletal movement, the dimension of pharyngeal airway space was increased. The post-treatment AHI score was reduced to 12.1 events/h; the nadir oxygen saturation increased from 74% to 86%. The case report demonstrated the SMMRA procedure effectively improved adult Asian patients with severe OSA without deterioration of facial attractiveness and dental occlusion.

Does Combined Temporomandibular Joint Reconstruction With Patient-Fitted Total Joint Prosthesis and Orthognathic Surgery Provide Stable Skeletal and Occlusal Outcomes in Juvenile Idiopathic Arthritis Patients?

To determine skeletal and occlusal surgical changes and long-term stability outcomes for patients diagnosed with juvenile idiopathic arthritis (JIA) after TMJ reconstruction with TMJ Concepts patient-fitted total joint prostheses (TJP) and concomitant maxillary orthognathic surgery. A retrospective cohort study was conducted of all patients diagnosed with JIA, receiving TJP, and concomitant maxillary orthognathic surgery between 1991 and 2019, at Baylor University Medical Center treated by 1 surgeon. Patient evaluations presurgery (T1), immediate postsurgery (T2), and at longest follow-up (LFU) (T3) were analyzed using 20 cephalometric landmarks to compute 29 linear and angular measurements to determine surgical changes, long-term skeletal and occlusal stability, as well as oropharyngeal airway changes. Comparative data were tested for significance (α=0.05) using paired and unpaired t tests. Forty-two patients met the JIA inclusion criteria, with a median age of 17.5 years and median postsurgical follow-up of 26 months. There were significant surgical changes (T1-T2) (P ≤ .05) for all parameters associated with mandibular linear and angular surgical changes, except for the horizontal position of posterior nasal spine and the vertical/horizontal position of gonion, indicating highly stable surgical outcomes. There were significant improvements in the oropharyngeal airway dimensions. This study suggests that TMJ Concepts patient-fitted TJP for TMJ reconstruction in conjunction with maxillary orthognathic surgery for counterclockwise rotation of the maxillo-mandibular complex for the JIA patients provides long-term skeletal and occlusal stability as well as dimensional improvement in the oropharyngeal airway.

Utilizing virtual surgical planning and orthognathic surgery to correct severe facial asymmetry without orthodontic treatment

Combining double-jaw surgery and orthodontic treatment to correct dentofacial asymmetry is a standard procedure but time consuming and costly. In order to provide alternative solutions, previewing the possible results with precise virtual surgical planning (VSP) system can help clinicians select patients suited for correcting facial asymmetry surgically without orthodontic treatment. In our experiences, after rigid or semirigid fixation of the maxilla, using intermaxillary fixation (IMF) without mandibular bony fixation is another key. This kind of fixation can minimize the chances of changing the condylar position and occlusion after the rotation of the maxillomandibular complex. If the original occlusion can be maintained, then orthodontic treatment can be avoided. Here we presented two facial asymmetry cases who requested surgical correction and refused orthodontic treatment. With careful preoperative planning using VSP, double-jaw surgery with maxillary bony fixation and IMF was conducted and both patients were satisfied by their aesthetic outcomes. With minimal dental compensation, the long-term results were relatively stable.

In vivo primary and coupled segmental motions of the healthy female head-neck complex during dynamic head axial rotation

While previous studies have greatly improved our knowledge on the motion capability of the cervical spine, few reported on the kinematics of the entire head-neck complex (C0-T1) during dynamic activities of the head in the upright posture. This study investigated in vivo kinematics of the entire head-neck complex (C0-T1) of eight female asymptomatic subjects during dynamic left–right head axial rotation using a dual fluoroscopic imaging system and 3D-to-2D registration techniques. During one-sided head rotation (i.e., left or right head rotation), the primary rotation of the overall head-neck complex (C0-T1) reached 55.5 ± 10.8°, the upper cervical spine region (C0-2) had a primary axial rotation of 39.7 ± 9.6° (71.3 ± 8.5% of the overall C0-T1 axial rotation), and the lower cervical spine region (C2-T1) had a primary rotation of 10.0 ± 3.7° (18.6 ± 7.2% of the overall C0-T1 axial rotation). Coupled bending rotations occurred in the upper and lower cervical spine regions in similar magnitude but opposite directions (upper: contralateral bending of 18.2 ± 5.9° versus lower: ipsilateral bending of 21.4 ± 5.1°), resulting in a compensatory cervical lateral curvature that balances the head to rotate horizontally. Furthermore, upper cervical segments (C0-1 or C1-2) provided main mobility in different rotational degrees of freedom needed for head axial rotations. Additionally, we quantitatively described both coupled segmental motions (flexion–extension and lateral bending) by correlation with the overall primary axial rotation of the head-neck complex. This investigation offers comprehensive baseline data regarding primary and coupled motions of craniocervical segments during head axial rotation.

Pseudomonas Flagella: Generalities and Specificities.

Flagella-driven motility is an important trait for bacterial colonization and virulence. Flagella rotate and propel bacteria in liquid or semi-liquid media to ensure such bacterial fitness. Bacterial flagella are composed of three parts: a membrane complex, a flexible-hook, and a flagellin filament. The most widely studied models in terms of the flagellar apparatus are E. coli and Salmonella. However, there are many differences between these enteric bacteria and the bacteria of the Pseudomonas genus. Enteric bacteria possess peritrichous flagella, in contrast to Pseudomonads, which possess polar flagella. In addition, flagellar gene expression in Pseudomonas is under a four-tiered regulatory circuit, whereas enteric bacteria express flagellar genes in a three-step manner. Here, we use knowledge of E. coli and Salmonella flagella to describe the general properties of flagella and then focus on the specificities of Pseudomonas flagella. After a description of flagellar structure, which is highly conserved among Gram-negative bacteria, we focus on the steps of flagellar assembly that differ between enteric and polar-flagellated bacteria. In addition, we summarize generalities concerning the fuel used for the production and rotation of the flagellar macromolecular complex. The last part summarizes known regulatory pathways and potential links with the type-six secretion system (T6SS).