Assessments of bilateral asymmetry with application in human skull analysis

As a common feature, bilateral symmetry of biological forms is ubiquitous, but in fact rarely exact. In a setting of analytic geometry, bilateral symmetry is defined with respect to a point, line or plane, and the well-known notions of fluctuating asymmetry, directional asymmetry and antisymmetry are recast. A meticulous scheme for asymmetry assessments is proposed and explicit solutions to them are derived. An investigation into observational errors of points representing the geometric structure of an object offers a baseline reference for asymmetry assessment of the object. The proposed assessments are applicable to individual, part or all point pairs at both individual and collective levels. The exact relationship between the developed treatments and the widely used Procrustes method in asymmetry assessment is examined. An application of the proposed assessments to a large collection of human skull data in the form of 3D landmark coordinates finds: (a) asymmetry of most skulls is not fluctuating, but directional if measured about a plane fitted to shared landmarks or side landmarks for balancing; (b) asymmetry becomes completely fluctuating if one side of a skull could be slightly rotated and translated with respect to the other side; (c) female skulls are more asymmetric than male skulls. The methodology developed in this study is rigorous and transparent, and lays an analytical base for investigation of structural symmetries and asymmetries in a wide range of biological and medical applications.

Facial Expressiveness in Infants With and Without Craniofacial Microsomia: Preliminary Findings

OBJECTIVE

To compare facial expressiveness (FE) of infants with and without craniofacial macrosomia (cases and controls, respectively) and to compare phenotypic variation among cases in relation to FE.

DESIGN

Positive and negative affect was elicited in response to standardized emotion inductions, video recorded, and manually coded from video using the Facial Action Coding System for Infants and Young Children.

SETTING

Five craniofacial centers: Children's Hospital of Los Angeles, Children's Hospital of Philadelphia, Seattle Children's Hospital, University of Illinois-Chicago, and University of North Carolina-Chapel Hill.

PARTICIPANTS

Eighty ethnically diverse 12- to 14-month-old infants.

MAIN OUTCOME MEASURES

FE was measured on a frame-by-frame basis as the sum of 9 observed facial action units (AUs) representative of positive and negative affect.

RESULTS

FE differed between conditions intended to elicit positive and negative affect (95% confidence interval = 0.09-0.66, P = .01). FE failed to differ between cases and controls (ES = -0.16 to -0.02, P = .47 to .92). Among cases, those with and without mandibular hypoplasia showed similar levels of FE (ES = -0.38 to 0.54, P = .10 to .66).

CONCLUSIONS

FE varied between positive and negative affect, and cases and controls responded similarly. Null findings for case/control differences may be attributable to a lower than anticipated prevalence of nerve palsy among cases, the selection of AUs, or the use of manual coding. In future research, we will reexamine group differences using an automated, computer vision approach that can cover a broader range of facial movements and their dynamics.

Maxillary and Mandibular Displacement in Hemifacial Microsomia: A Longitudinal Roentgen Stereometric Study of 21 Patients with the Aid of Metallic Implants

Objective

To record maxillary and mandibular displacement with articular growth and in response to bimaxillary surgical repositioning in patients with hemifacial microsomia (HFM) and to observe ipsilateral corpus/ramus growth in severely affected children.

Design

Prospective roentgen stereometric analysis (mean age 7 years 10 months to 18 years 0 months) and retrospective profile and panoramic roentgenograms. Mean total observation period was 9 years 1 month.

Setting

Department of Plastic and Reconstructive Surgery, Malmö University Hospital (Malmö, Sweden).

Patients

Twenty-one patients consecutively diagnosed from 1976 through 1988 with HMF, five of whom had bimaxillary surgery.

Interventions

Surgery was performed at the Department of Plastic and Reconstructive Surgery. Implants were inserted at the initial reconstructive surgical procedure under general anesthesia. Roentgen examinations were performed in connection with continued clinical evaluations and treatment.

Main Outcome Measures

Stereo roentgenograms were digitized at the Department of Orthopedic Surgery, Malmö University Hospital (Malmö, Sweden).

Results

Displacement of the jaws with articular growth and in response to bimaxillary surgical repositioning varied interindividually with no apparent common pattern. Relapse displacement occurred several years after bimaxillary surgery. Mandibular growth changes were found in the corpus/ramus area and alveolar process on the affected side.

Conclusions

A marked interindividual variability of maxillary and mandibular displacement indicates that the relevance of statistical analysis of HFM growth data may be questioned. We would suggest that precise and accurate longitudinal recordings of growth and response to surgery in individual HFM patients be more appropriate.

Three-dimensional surgical simulation improves the planning for correction of facial prognathism and asymmetry: A qualitative and quantitative study

Traditional planning method for orthognathic surgery has limitations of cephalometric analysis, especially for patients with asymmetry. The aim of this study was to assess surgical plan modification after 3-demensional (3D) simulation. The procedures were to perform traditional surgical planning, construction of 3D model for the initial surgical plan (P1), 3D model of altered surgical plan after simulation (P2), comparison between P1 and P2 models, surgical execution, and postoperative validation using superimposition and root-mean-square difference (RMSD) between postoperative 3D image and P2 simulation model. Surgical plan was modified after 3D simulation in 93% of the cases. Absolute linear changes of landmarks in mediolateral direction (x-axis) were significant and between 1.11 to 1.62 mm. The pitch, yaw, and roll rotation as well as ramus inclination correction also showed significant changes after the 3D planning. Yaw rotation of the maxillomandibular complex (1.88 ± 0.32°) and change of ramus inclination (3.37 ± 3.21°) were most frequently performed for correction of the facial asymmetry. Errors between the postsurgical image and 3D simulation were acceptable, with RMSD 0.63 ± 0.25 mm for the maxilla and 0.85 ± 0.41 mm for the mandible. The information from this study could be used to augment the clinical planning and surgical execution when a conventional approach is applied.

Reliability of the “Sydney,” “Sunnybrook,” and “House Brackmann” Facial Grading Systems to Assess Voluntary Movement and Synkinesis after Facial Nerve Paralysis

OBJECTIVE: To investigate the extent of within-system reliability and between-system correlation for the “Sydney” and “Sunnybrook” systems of grading facial nerve paralysis, and to examine the interobserver reliability and agreement of the “House Brackmann” grading system.

STUDY DESIGN: A fixed-effects reliability study in which 6 otolaryngologists viewed videotapes of patients with facial nerve paralysis.

SETTING: University and medical Centers.

PATIENTS: Patients with unilateral lower motor neurone facial nerve dysfunction greater than 1 year after onset, none of whom had undergone surgical reanimation procedures.

INTERVENTION: Twenty-one patients with facial nerve paralysis were videotaped while they performed a protocol of facial movements. Six otolaryngologists viewed the videotapes and scored them with the Sydney and Sunnybrook systems, and then gave a House Brackmann grade.

MAIN OUTCOME MEASURE: The 3 systems of grading facial nerve paralysis were evaluated and compared with the use of intraclass correlation coefficients, Pearson's weighted kappa, and percentage exact agreement values.

RESULTS: The Sydney and the Sunnybrook systems had good intrasystem reliability and high intersystem association for the assessment of voluntary movement. Grading of synkinesis was found to have low reliability both within and between systems. The House Brackmann system had substantial reliability as shown by weighted kappa but had a percentage exact agreement of 44%.

CONCLUSIONS: For clinical grading of voluntary movement, there is good correlation between ratings given on the Sydney and Sunnybrook systems, and within each system there is good reliability. The assessment of synkinesis was far less reliable within, and less related between, systems. Although the reliability of the House Brackmann system was found to be high, examination of individual grades revealed some wide variation between trained observers.

Velopharyngeal insufficiency in hemifacial microsomia: Analysis of correlated factors

OBJECTIVE: To investigate the incidence of unilateral hypodynamic palate (UHP) and velopharyngeal insufficiency (VPI) in hemifacial microsomia (HFM), and to determine the dysmorphic manifestations having significant associations with UHP/VPI in HFM.

STUDY DESIGN: This was a nonrandomized study of 48 patients with unilateral HFM without cleft palate. The correlation between each anomaly and UHP/VPI was analyzed statistically. In addition, we observed 4 HFM patients with cleft palate to examine the influence on cleft palate speech.

RESULTS: The incidence of UHP in HFM was 50.0% and that of VPI was 14.6%. All the VPI patients had UHP. Severe micrognathia and soft tissue deficiency, macrostomia, and mental retardation were significant risk factors for developing VPI in HFM. Moreover, UHP exacerbated speech in HFM with cleft lip and palate.

CONCLUSIONS: Significant correlations were detected between VPI and HFM. This finding should be helpful in the overall management of HFM.

© 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Positive Affect Predicts Improved Lip Movement in Facial Movement Disorder

OBJECTIVES: Positive affect in individuals with a facial movement disorder may promote lip corner movement (zygomaticus major) during smiling. We investigated whether a positive affect marker (orbicularis oculi activity) observed in an initial clinic visit of individuals with facial movement disorder (N = 28) predicted increased lip corner movement at a subsequent visit.

STUDY DESIGN AND SETTING: In this clinical outcomes study, lip corner movement was assessed with the use of automated facial analysis. Asymmetry of movement was compared in individuals who smiled with or without the positive affect marker at an initial clinic visit.

RESULTS: The positive affect marker at the initial visit was associated with a reduction in the asymmetry of the lip corner movement at the second visit.

CONCLUSION: Positive affect predicts improved facial movement outcomes in patients with facial movement disorders.

SIGNIFICANCE: Positive emotion in facial movement patients may be an important factor in recovery of facial movement during therapy.

Features of facial asymmetry following incomplete recovery from facial paralysis

PURPOSE

The purpose of this study is to investigate peculiar patterns of facial asymmetry following incomplete recovery from facial paralysis that require optimal physical therapy for effective facial rehabilitation, and to decrease the incidence of avoidable facial sequelae.

MATERIALS AND METHODS

This study involved 41 patients who had facial sequelae following the treatment of various facial nerve diseases from March 2000 to March 2007. All patients with a followup of at least 1 year after the onset of facial paralysis or hyperactive function of the facial nerve were evaluated with the global and regional House-Brackmann (HB) grading systems. The mean global HB scores and regional HB scores with standard deviations were calculated. Other factors were also analyzed.

RESULTS

Four patterns of facial asymmetry can be observed in patients with incomplete facial recovery. The most frequently deteriorated facial movement is frontal wrinkling, followed by an open mouth, smile, or lip pucker in patients with sequelae following facial nerve injury. The most common type of synkinesis was unintended eye closure with an effort to smile.

CONCLUSION

We described common configurations of facial asymmetry seen in incomplete recovery following facial nerve injury in an attempt to develop an optimal strategy for physical therapy for complete and effective facial recovery, and to decrease the incidence of avoidable sequelae.

PC-based asymmetry analyzer for facial palsy study in uncontrolled environment: a preliminary study

We develop a PC-based quantitative asymmetry analyzing system for facial palsy patients. To collect frequent data, the system is designed to maximize the chance of measure and minimize the variation of measuring. The system is based on the DirectX technology adopting white balance correction, lip segmentation, point-tracking techniques. The degree and pattern of asymmetry is estimated by tracking the bi-lateral lip points. Tracking performance is tuned up by changing the configuration of tracking compared to previous study. All data are able to be sent via FTP and reviewed by clinician. DirectX technology makes it measure anywhere. White balance correction is effective in restoring color distortion and lip segmentation by region growing is effective in finding bi-lateral lip points but not in all environments. Point-tracking is a good method to provide the temporal movement of lip. A larger searching window of tracking points shows an improved performance in point of variation and robustness at fast movements. Transferring via Internet makes monitor the patient frequently. PC-based analyzing system is able to use not just in clinic but also at home. The system makes it possible to measure frequently and objectively and leads to diagnose exact conditions of patient.

[Diagnosis and therapy of adult patients with facial asymmetry]

The goal of orthodontic treatment is to improve the patient's life by enhancing dental and jaw functions and dentofacial esthetics [Graber TM, et al., Orthodontics current principles and techniques. 4(e) ed. St Louis: Elsevier, 2005.]. Harmonious occlusion is achieved following improvements of malocclusion via orthodontic treatment [Ehmer U and Broll P, Int J Adult Orthod Orthognath Surg 1992;7:153-159. Throckmorton GS, et al., J Prosthet Dent 1984;51:252-261.]. Perfect facial symmetry is extremely rare, and normal faces have a degree of asymmetry. Patients with dentofacial deformity more frequently have asymmetry of the face and jaws. There was a relationship between the type of malocclusion and the prevalence of asymmetry; 28% of the Class III group, but 40% to 42% of the Class I, Class II and long face groups respectively, were asymmetric [Severt TR and Proffit WR, Int J Adult Orthod Orthogn Surg 1997;12:171-176.]; therefore, facial asymmetry is a common complaint among orthodontic patients. Treatment of severe facial asymmetry in adults consists mainly of surgically repositioning the maxilla or the mandible [Bardinet E, et al., Orthod Fr 2002;73:243-315. Guyuron B, Clin Plast Surg 1989;16:795-801. Proffit WR, et al., Contemporary treatment of dentofacial deformity. 2003. St Louis: Mosby, 2003:574-644.], however, new methods, i.e. orthodontic tooth movement with implant anchorage, have recently been introduced [Costa A, et al., Int J Adult Orthod Orthognath Surg 1998;3:201-209. Creekmore TD and Eklund MK, J Clin Orthod 1983;17:266-269. Miyawaki S,et al., Am J Orthod Dentofacial Orthop 2003;124:373-378. Park HS, et al., J Clin Orthod 2001;35:417-422. Roberts WE, et al., Angle Orthod 1989;59:247-256.], and various treatment options can be chosen in patients with facial asymmetry. In this article, we describe the diagnosis and treatment of adult patients with facial asymmetry.

Moebius syndrome: clinical manifestations in a pediatric patient

Moebius syndrome is a congenital, nonprogressive disorder clinically characterized by loss of facial expression, impaired stomatognathic system functions, incapacity to close the eyelids, and several oral impairments. The purpose of this paper was to present the clinical manifestations and the dental treatment in a 5-year, 2-month-old male Moebius syndrome patient. The child presented with facial asymmetry, difficulty performing facial mimic movements and pronouncing some letters, and compromised suction, mastication, breathing, and deglutition. An intraoral examination revealed hypofunction of the perioral muscles, cheeks and tongue, ankyloglossia, anterior open bite, and absence of carious lesions and dental anomalies. The dental treatment consisted of frenectomy and further placement of a removable orthodontic appliance with a palatal crib for correction of the anterior open bite. After 12 months of follow-up, anterior open bite decreased and speech, deglutition, and mastication improved.

Influence of unilateral masseter muscle atrophy on craniofacial morphology in growing rabbits

PURPOSE

The purpose of the study was to evaluate whether the induction of unilateral masticatory muscle dysfunction can alter the skeletal growth patterns.

MATERIALS AND METHODS

Twenty-one white male New Zealand rabbits (4 weeks old) were divided into 3 groups of 7 subjects: group 1 served as the control to study normal craniofacial growth. In groups 2 and 3, rabbits were injected with 5 units and 15 units of Botulinum toxin A (BTXA) into the right masseter muscle, respectively. The effect of a neuromuscular blockade of masseteric activity on craniofacial growth was evaluated with 3 samples of serial computed tomography (CT) scans with a slice thickness of 0.625 mm, taken at 4 weeks (base line), 8 weeks (endpoint of prepubertal craniofacial growth), and 24 weeks (after pubertal growth).

RESULTS

The ipsilateral mandibular ramus height, zygomatic arch length, and masseteric length did not develop as much as those of the contralateral side after pubertal growth. At age 24 weeks, the masseter muscle volume asymmetry index reached -13.8% (group 2), -18.4% (group 3), and -1.6% for the control group. The ipsilateral side of the hemimandible showed less bone volume after 8 weeks but it showed partially recovered symmetry at 24 weeks. The maxillomandibular incisor midline and transverse molar discrepancies were not evident in any of the groups.

CONCLUSIONS

The BTXA injection can be an effective method in inducing site-specific muscular hypofunctions so that masticatory muscle-craniofacial bone interaction can be investigated efficiently. The result showed that the unilateral atrophy of the masseter muscle in the growing subjects influenced the morphology of the local skeletal sites. This did not, however, result ultimately in mandibular midline asymmetry or right-left asymmetry in hemimandibular volume after growth. The results imply that alterations in specific masticatory muscle function can be compensated by the growth of other structural components.

Correlations of frontal lip-line canting with craniofacial morphology and muscular activity

INTRODUCTION

The purpose of this study was to investigate factors affecting lip-line canting by using musculoskeletal analyses.

METHODS

Fifty-six adults with lip-line canting were selected as subjects. They were divided into 3 groups according to the changes of lip line during smiling: increasing (group I), decreasing (group D), and minimal (group M). Lip-line canting at rest was correlated to craniofacial morphology and muscular activity: Regarding craniofacial morphology, various craniofacial measurements in lateral and frontal cephalograms were used, including inclination of the tongue blade placed across both first molars. The zygomaticus major was the focus of the measurement of muscular activity affecting lip-line canting, and its activity during smiling was evaluated by using a needle electrode.

RESULTS

In group I, lip-line canting at rest showed a significant correlation with the right-left (R/L) difference of muscular activity, but no significant correlation with the measurements of craniofacial morphology. In group D, lip-line canting showed a positive correlation with the measurements of craniofacial morphology, such as the inclination of the tongue blade, and a negative correlation with the R/L difference of muscular activity. In group M, lip-line canting showed no significant correlation with the R/L difference of muscular activity, but a significant correlation with inclination of the tongue blade.

CONCLUSIONS

The results indicate that lip-line canting is caused by craniofacial morphology when the change of lip-line canting during smiling is minimal, whereas lip-line canting is affected by the R/L difference of muscular activity in addition to craniofacial morphology when the cant of lip line markedly changes during smiling. The findings suggest that the cause of lip-line canting can be identified easily by the change of canting during smiling, without complicated musculoskeletal analyses.

Relationship Between the Morphologies of the Masseter Muscle and the Ramus and Occlusal Force in Patients With Mandibular Prognathism

PURPOSE

The purpose of this study was to examine the relationship between the morphologies of the masseter muscle and the ramus and occlusal force in patients with mandibular prognathism.

PATIENTS AND METHODS

The study group consisted of 71 patients with mandibular prognathism. They were divided into 2 groups, consisting of prognathism with or without symmetry, determined by frontal cephalogram analysis. All patients underwent 3-dimensional (3D) computed tomography (CT) and occlusal force was recorded with pressure-sensitive sheets.

RESULTS

In the cross-sectional area of masseter muscle, there were no significant differences between the right and left sides in the symmetry and asymmetry groups. In occlusal force, there was no significant difference between the symmetry and asymmetry groups. Occlusal force was not significantly correlated to the cross-sectional area of the ramus, but it was significantly positively correlated to the cross-sectional area of the masseter muscle (P < .05).

CONCLUSION

Occlusal force was associated with the ipsilateral cross-sectional area of masseter muscle in patients with prognathism; however, it was not associated significantly with the degree of mandibular deviation.

Ocular correction effects on EMG activity of stomatognathic muscles in children with functional mandibular lateral- deviation: a case control study

AIM

This study was conducted in order to determine the ocular correction effects on electromyography activity of anterior temporal, masseter, sternocleidomastoid and anterior digastric muscles in children with functional mandibular lateral-deviation.

METHODS

This study was performed on 32 subjects, aged between 8 and 12 years with functional lateral deviation of mandible and oculo-extrinsic muscular tone disorders. After complete ophthalmologic evaluation and ocular correction prescription, the children were randomly divided into two groups: study and control. In the study group (16 subjects) EMG activity at rest was recorded in the following conditions: with eyes closed; with eyes open; with ocular correction modified through electromyographic control. In the control group (16 subjects) EMG activity at rest was recorded in the following conditions: with eyes closed; with eyes open; with conventional ocular correction. Data were acquired in 15-seconds trial using a SEMG K7, while the subjects maintained rest dental position.

RESULTS/STATISTICS

Both groups presented a significative correlation between value of lateral-deviation and the degree of ocular-extrinsic muscular tone disorders (r=0.69). In addition, a significant statistical increase of EMG activity at rest with eyes open in both groups was observed in the anterior temporal left and right. A significant decrease of EMG activity with open eyes was observed only with ocular correction upon electromyographic control (study group). The findings, expressed as Symmetry Index, showed a significant increase of muscles imbalance right/left with conventional methods of ocular correction (p < 0.0001).

CONCLUSION

The significant worsening in EMG activity, mainly observed with conventional corrective lenses, could have an important consequence in clinical diagnostic and therapeutic behaviour because anterior temporal muscles are important in postural position of the mandible. Instead EMG corrective lenses could improve tonus and balance of stomatognathic muscles and, therefore, support the functionality of orthodontic treatment. Moreover, the data suggest an interesting new tool in order to reach an interdisciplinary approach to complex growth disorders represented by functional lateral deviation of mandible and ocular-extrinsic muscular tone disorders.

Facial shape and asymmetry by three-dimensional laser surface scanning covary with cognition in a sexually dimorphic manner

The embryological unity over early fetal life of the anterior brain, neuroepithelium, neural crest, and facial ectoderm is responsible for facial dysmorphogenesis in disorders of early brain development, including schizophrenia. This study examined covariance of facial shape and asymmetry with cognition in a normal sample of 36 men and 51 women using geometric morphometrics. Facial shape and asymmetry covaried with verbal and visual spatial cognitive functions in a sexually dimorphic manner. Events over early fetal life may be an important determinant of sexually dimorphic covariance of anterior facial shape and asymmetry with aspects of cognition that involve the anterior brain.

The Influence of Craniofacial Growth in a Case of Transverse Facial Cleft

This report presents the case of a female patient bearing a right-side transverse facial cleft. She has received interdisciplinary treatment since birth. At regular intervals, dental casts were made, and profile and full-face photographs, lateral and postero-anterior cephalograms were taken during the course of orthodontic treatment and maxillofacial surgery. We evaluated her diagnostic records with the intent of documenting the effects of growth and therapy on the skeletal structures of the facial cranium and on occlusion, and to show the influence on facial esthetics. Her facial morphology and occlusion were manifest at birth and in the primary dentition. The maxilla and mandible deviated from the midsagittal plane toward the cleft side, with the mandible considerably more affected, revealing a markedly posterior position. The lateral skeletal deviation of both jaws increased slightly during growth, yet the midline deviation of the dental arches and malocclusion clearly worsened. The increasing deviation was not obvious in full-face photographs. Especially in the primary and mixed dentition, the mandible shifted to the anterior, which was visible in both the lateral cephalograms and profile photographs. On the whole, however, no noteworthy alteration in the character of the craniofacial morphology occurred by the time growth was complete, despite functional jaw-orthopedic and maxillofacial surgical treatment consisting of two distraction osteogenesis procedures.

Correlation of mandibular deviation with temporomandibular joint MR dimensions, MR disk position, and clinical symptoms

OBJECTIVE

The objective of this study was to investigate the difference of the temporomandibular joint (TMJ) between deviated and nondeviated sides of the mandible in adult patients with mandibular deviation.

STUDY DESIGN

TMJ size, disk displacement, and clinical symptoms of 28 patients were examined clinically and by magnetic resonance imaging (MRI). Twelve age- and sex-matched control subjects were also used to evaluate which side of the mandible in patients was similar to the control.

RESULTS

The TMJ on the deviated side showed a smaller condyle and a higher incidence of disk displacement than the nondeviated side and those in the controls. However, the clinical symptoms showed no differences between the deviated and nondeviated sides, and no association with disk displacement.

CONCLUSIONS

Our results suggest that the deviated side was the abnormal side and may have some association with mandibular deviation. However, the clinical symptoms could not indicate those differences.

A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction

Clinical reports and research studies have documented the behavior of chronic low back and neck pain patients. A few hypotheses have attempted to explain these varied clinical and research findings. A new hypothesis, based upon the concept that subfailure injuries of ligaments (spinal ligaments, disc annulus and facet capsules) may cause chronic back pain due to muscle control dysfunction, is presented. The hypothesis has the following sequential steps. Single trauma or cumulative microtrauma causes subfailure injuries of the ligaments and embedded mechanoreceptors. The injured mechanoreceptors generate corrupted transducer signals, which lead to corrupted muscle response pattern produced by the neuromuscular control unit. Muscle coordination and individual muscle force characteristics, i.e. onset, magnitude, and shut-off, are disrupted. This results in abnormal stresses and strains in the ligaments, mechanoreceptors and muscles, and excessive loading of the facet joints. Due to inherently poor healing of spinal ligaments, accelerated degeneration of disc and facet joints may occur. The abnormal conditions may persist, and, over time, may lead to chronic back pain via inflammation of neural tissues. The hypothesis explains many of the clinical observations and research findings about the back pain patients. The hypothesis may help in a better understanding of chronic low back and neck pain patients, and in improved clinical management.

The relationship between temporomandibular joint disc morphology and stress angulation in skeletal Class III patients

The aim of this study was to examine the relationship between disc position and stress direction on the condyle by means of stress analysis using the rigid body spring model (RBSM) theory. The material consisted of 88 joints of 44 Class III dentofacial deformity patients, divided into symmetry and asymmetry groups on the basis of the Mx-Md midline position. The asymmetry group was identified by comparison with a reference midline vertical plane passing through a plane from ANS to Me. Asymmetry was diagnosed when the angle between these two planes was greater than 3 degrees. The geometry of the stress analysis model was based on sagittal tomography of the subject. The first molar, gonial angle, and the most anterior, superior, and posterior points on the condyle were plotted on a computer display, and stress angulation on the condyles was calculated with the RBSM program. In addition to anterior displacement with or without reduction, three types of disc position could be identified using magnetic resonance imaging (MRI): anterior, fully covered and posterior. In the asymmetric group, stress angulation was significantly higher (P < 0.05) at the deviation side compared with the non-deviation side. There was also a significant correlation between disc position and stress angulation (P < 0.05). In the asymmetry group, regression analysis indicated a significant correlation (P < 0.001) between the difference in stress angulation (between the deviation side and the non-deviation side) and the degree of asymmetry (measured by the angle of asymmetry). This study demonstrated that temporomandibular joint (TMJ) stress was associated with TMJ morphology in Class III patients whether or not they were asymmetric.

Three-Dimensional Finite Element Analysis of the Mandible and Temporomandibular Joint During Vertical Ramus Elongation by Distraction Osteogenesis

Distraction osteogenesis has been accepted as an alternative treatment modality for hypoplastic mandibles. Knowledge about the changes occurring in the temporomandibular joint region during mandibular distraction osteogenesis is, however, limited and controversial. Stress distribution in the temporomandibular joint region during unilateral vertical mandibular ramus distraction was studied using a finite element model. The finite element model was based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the temporomandibular joint and mandible was analyzed quantitatively at different intervals of the vertical mandibular ramus elongation. During the distraction phase, the condyles, articular disks, and glenoid fossa regions were loaded with a differentiated stress pattern. The affected right condyle, disk, and fossa were submitted to increasing loads with increasing elongation compared with the contralateral temporomandibular joint. Loading on the unaffected left side shifted posteriorly and slightly laterally, because the left condyle was the center of rotation. The loading of the temporomandibular joint regions was low during the active distraction phase, although local areas were subjected to elevated peak stresses.

Three-Dimensional Finite Element Analysis of the Mandible and Temporomandibular Joint on Simulated Occlusal Forces before and after Vertical Ramus Elongation by Distraction Osteogenesis

Distraction osteogenesis has recently become a mainstay for treatment of mandibular hypoplasia. Thorough knowledge about changes in the temporomandibular joint (TMJ) and the surrounding parts of the mandible and the skull after mandibular distraction is still lacking. The purpose of the current study was to investigate the stress distribution in the mandible and the TMJ before and after skeletal correction by intraoral unilateral vertical mandibular ramus distraction, using a finite element (FE) model. The FE models were based on computed tomography scans and magnetic resonance imaging scans of a patient with unilateral hypoplasia of the right mandibular ramus caused by juvenile idiopathic arthritis. The character of stress distribution in the mandible and TMJ before and after skeletal correction by 15 mm of vertical distraction of the mandibular ramus was analyzed quantitatively and compared during centric occlusion. Before the distraction osteogenesis treatment, the condyles, articular discs, and glenoid fossa regions are loaded with a different stress pattern. The affected right condyle, disc, and fossa are loaded diffusely and externally in comparison with the anterior and with centralized loading on the normal left side. After unilateral mandibular distraction osteogenesis, the load became more centric and symmetrical. The results suggest that correction of the mandibular deformity by distraction osteogenesis tends to normalize the stress patterns in the TMJ.

Contralateral botulinum injections improve drinking ability and facial symmetry in patients with facial paralysis

PURPOSE

To report two patients who experienced improved drinking ability as well as facial appearance with contralateral injection of botulinum toxin.

DESIGN

Retrospective case reports.

METHODS

Two patients were treated with botulinum toxin contralateral to the VIIth nerve palsy to improve drinking ability as well as facial asymmetry.

RESULTS

Botulinum toxin injections improved facial asymmetry as well as drinking ability in two patients with facial nerve palsies.

CONCLUSIONS

Contralateral botulinum toxin injections improved drinking ability in two patients with facial nerve palsy.

Late Results After Unicoronal Craniosynostosis Correction

The authors report nine patients with unicoronal synostosis who were treated with the same surgical protocol and who now have reached skeletal maturity. These patients all underwent surgery at the Australian Craniofacial Unit during a 2-year period by one of two craniofacial surgeons and one of two neurosurgeons. The operative procedure in all of these cases was the same technique, in which there was unilateral advancement of the affected side. No cases required reoperation; however, one case subsequently required revision of the coronal scar, and two cases required strabismus correction. All cases were reviewed to evaluate patient results by the clinical staff; recent photographs at skeletal maturity also were reviewed. Two patients had adult computed tomography scans available for skeletal assessment, and one additional patient had undergone serial computed tomography scans during childhood. The patients also completed an anonymous questionnaire to ascertain their assessment of their appearance. The results of the clinical and radiologic assessments and questionnaire suggest that the operative procedure undertaken in these cases has produced satisfactory results in the long term, with few individuals requiring (or even considering) additional surgery, despite some persistent asymmetry.

Three-dimensional changes in the condyle during development of an asymmetrical mandible in a rat: A microcomputed tomography study

A rapidly growing postnatal animal model was used to study changes in the calcified tissue of the mandibular condyle during altered muscle function. A maxillary occlusal splint was designed to shift the mandible laterally (left) during closure. Groups of 5 Wistar rats were killed at 5, 9, 15, 21, 30, and 40 weeks (n = 30), with an equal number of controls. The experimental animals developed shorter, asymmetrical mandibles compared with the control animals. The left condyle became larger and thicker than the right condyle. Microcomputed tomography assessment of the left and right condylar trabecular bone indicated that both had less bone volume than the control condyle. The right masseter muscle significantly lost fiber size and type IIA oxidative fibers, suggesting that the right masseter muscle was used with less tension development. In contrast, the left masseter maintained its fiber size and was similar to the control masseter fiber diameters. Comparison in the sequence of changes indicated that the morphologic changes occurred first in the ramus (age, 5 weeks), before the corpus (age, 15 weeks), and before changes in masseter fiber size and composition (age, 9 weeks). This study showed that both the mandible and the condyle modified their shape and size, as well as the trabecular bone of the condyle, during shifting of the mandible to one side as it closed.

Open reduction of pediatric atlantoaxial rotatory fixation: long-term outcome study with functional measurements

OBJECT

Atlantoaxial rotatory fixation (AARF) is an uncommon disorder of childhood in which resolution usually occurs spontaneously or after traction therapy. In a minority of children irreducible or chronic fixation develop, and the natural history then usually involves restriction of head on neck movement, abnormal head position, and progressive facial asymmetry. The conventional management in these cases has been a posterior fusion.

METHODS

The authors performed an open reduction via the extreme-lateral approach without adjunctive fixation surgery in 13 children who ranged in age from 4 to 11 years. Postoperatively, halo jacket therapy was undertaken for 8 to 12 weeks. There were no neurological complications despite damage to one vertebral artery and one wound infection. Functional outcome was assessed after a minimum of 24 months (range 29-72 months). Facial asymmetry markedly improved. Sagittal movements were similar to those observed in control individuals. Axial rotation, although reduced compared with that in controls, was present but usually asymmetrical.

CONCLUSIONS

In the authors' opinion, open reduction provides the best possibility of normal facial development and return of axial movement in cases of AARF.

Biology and mechanics of facial asymmetries in children and youths

There is a need for further knowledge about the normal and abnormal growth patterns of bones and teeth. Genetic make-up, as well as various types of diseases and injuries such as trauma, inflammation, radiation and chemicals may affect skeletal and dental growth sites, thereby causing faulty growth. The degree of the subsequent deformity depends not only on the type, intensity, extent and chronology of the noxious agent, but also on the site and its particular involvement in growth activity. The knowledge of what happens to the stomatognathic system when some of its parts are altered is very important. Dentists are challenged to visualize the entire system in all its relationships: they must visualize the dynamics of how the system works. The relationship of the maxilla to the mandible and the mechanics of the stomatognathic system must be considered as a whole when considering the occlusion. The aim of this paper is to focus attention on the biologic basis of facial asymmetries and the functional reasons for their stabilization.

Three-dimensional video-analysis of facial movements in healthy volunteers

The aim of this study was to determine the mean distances of facial movements in 24 healthy individuals aged between 22 and 70 years, using the digitised three-dimensional video-analysis system developed by Frey et al. The subjects were divided into three groups of eight. The first group consisted of individuals aged between 20 and 30 years (mean+/-s.d.=25.0+/-2.33 years). Subjects in the second group were aged between 40 and 50 years (mean+/-s.d.=46.8+/-2.53 years), and the third group consisted of subjects aged between 60 and 70 years (mean+/-s.d.=63.6+/-3.07 years). In all groups the sexes were equally represented. No subject had had treatment to the face, nor did they have paralysis, scars or diseases of the skin. Males showed larger movements of the face than females, on average by 1.40+/-0.73 mm (15.08%). Subjects aged between 60 and 70 years demonstrated the largest movements of the face. The evaluation of facial movements in 24 healthy volunteers showed that sex and age affect facial dynamics. Thus study generated three-dimensional standard values for healthy facial movements.

Hemifacial microsomia

Hemifacial microsomia is the second most common congenital facial anomaly, second only to cleft lip and palate. While its precise etiology is not yet known, it is likely caused by a disruption in the development of the first two branchial arches early in embryologic development. The resulting phenotype is one of varying degrees of unilateral hypoplasia of the mandible, ear deformity, and macrostomia. Early diagnosis of hemifacial microsomia is important not only to plan for surgical reconstruction of affected features, but also to lead the physician in further evaluation for associated abnormalities or disabilities. This article will introduce the reader to the most common variants seen in hemifacial microsomia, discuss the possible etiologies of the anomalies, and will highlight the importance of evaluating these patients early in life for such potentially disabling but correctable problems such as hearing loss, feeding disabilities, and neurological deformities.

[Effect of unilateral mastication on the remodeling of the glenoid fossae in Wistar rats]

OBJECTIVE

To investigate the effect of unilateral mastication on glenoid fossae by means of animal experiment.

METHODS

An animal model of unilateral mastication was established by extracting right mandibular molars of Wistar rats. The rats were sacrificed in different period to examine the location changes of glenoid fossae through sagittal and horizontal plane.

RESULTS

The anterior points of glenoid fossae in non-masticatory side of experimental groups were more anterior than those in masticatory sides. The anterior points of the glenoid fossae of non-masticatory sides in experimental groups were more anterior than those of the same sides in the control groups after inducing unilateral mastication for two and four months. After inducing unilateral mastication for two and four months, the anterior and the posterior points of the glenoid fossae of non-masticatory sides in experimental groups became closer to the midline by comparison with masticatory sides as well as the same sides in control groups. Locations of glenoid fossae in masticatory sides showed no changes in comparison with the same side of the control groups.

CONCLUSION

The forward and inward remodeling of the glenoid fossae can be observed after unilateral mastication was induce to the non-masticatory sides of experimental rats. It is concluded that unilateral mastication might be one of the etiologic factor of temporomandibular joint disorders.

Relationship between facial asymmetry and masseter reflex activity

PURPOSE

In this study, we evaluated the tonic vibration reflex (TVR) of the masseter muscles in patients with facial asymmetry.

SUBJECTS AND METHODS

The study was conducted with 10 volunteers without facial asymmetry and 12 orthognathic patients with facial asymmetry. Subjects were seated in a chair and held a stimulator composed of an electric motor and an acrylic bite block between the upper and lower dentitions at facial midline, to elicit TVR. Electromyographic activity was recorded using a pair of silver electrodes affixed bilaterally with adhesive tape to the skin over the superficial masseter. The amount of mandibular deviation was measured on the frontal cephalogram. The reflex response was evaluated with the following: TVR index (%) = integral TVR x 100/ integral maximum voluntary contraction (MVC), and with the TVR ratio: integral TVR on the high MVC side/ integral TVR on the low MVC side.

RESULTS

In the patient group, the average TVR index on the deviated side was significantly higher than that on the nondeviated side. In all subjects, including the control and patient groups, a negative correlation between the amount of mandibular deviation and the side-to-side difference in TVR index was seen (r = -0.536, P <.05, n = 22). In addition, patients with a lower MVC on the deviated side than on the nondeviated side showed a significantly higher TVR ratio than did the control group.

CONCLUSIONS

These results suggest that the difference between the right and left reflex responses elicited by TVR might be related to frontal craniofacial morphology.

Preoperative facial muscle imaging predicts final facial function after facial nerve grafting

BACKGROUND AND PURPOSE

Our goal was to determine whether preoperative MR imaging of facial muscles predicts facial function after facial nerve grafting.

METHODS

A retrospective review of all patients undergoing facial nerve grafting between 1997 and 2001 revealed 26 patients. Twelve of the patients had adequate preoperative MR images available for review and had undergone clinical follow-up for at least 12 months. Eight had malignant parotid tumors, and four had benign skull base or parotid tumors. Preoperative facial muscle MR imaging appearance was categorized as symmetrical or asymmetrical. The asymmetrical images were further classified into mild or pronounced asymmetry. Preoperative facial function was classified by using the House-Brackmann scale. Postoperative function was graded with the May scale.

RESULTS

Four patients had symmetrical facial muscles shown by preoperative MR imaging, three had mild asymmetry, and five had pronounced asymmetry. No or mild asymmetry had an 86% positive predictive value for good to excellent functional outcome. Eighty percent of patients with pronounced asymmetry experienced poor functional outcomes. Six of eight patients with malignant and perineural tumors at surgery had asymmetrical facial muscles revealed by preoperative MR imaging studies.

CONCLUSION

Symmetrical or mildly asymmetrical facial muscles are predictive of good facial function after nerve grafting. Pronounced asymmetry of facial muscles on MR images is predictive of poor facial function after grafting. Asymmetric facial muscles on preoperative MR images are associated with perineural tumor spread in patients with malignant disease.

Relationship between transverse dental anomalies and skeletal asymmetry

The recognition and elimination of dental compensation is essential in presurgical orthodontic treatment to achieve successful stabilization of the occlusion after surgery. However, the relationship between a transverse dental anomaly and skeletal asymmetry is not fully understood. To evaluate this relationship, frontal cephalometric and 3-dimensional dental model analyses were carried out on 44 adult Japanese Class III patients (mean age 21 years 11 months) who required surgical orthodontic treatment. The patients were divided into 2 groups: a facial asymmetry group in which the mandibular transverse deviation exceeded +/- 1 SD from the norm, and a control group in which the mandibular transverse deviation was within +/- 1 SD of the norm. Statistical comparison with a control group showed characteristic dental anomalies in the facial asymmetry group, including asymmetry of the curve of Spee, molar inclination, dental arch form, lateral overjet, and slanting of the occlusal plane. Stepwise linear regression analysis showed that transverse and vertical skeletal asymmetry variables including the mandible and the maxilla were effective parameters for characteristic dental anomaly variables, and a significant high correlation between dental anomalies and skeletal asymmetry was found.

Lateral functional shift of the mandible: Part I. Effects on condylar cartilage thickness and proliferation

Lateral functional shift of the mandible is characterized by transverse rotation of the entire mandible about a vertical axis toward 1 side of the head. The effect of this shift is that the condyle on the side opposite the direction of the shift is displaced anteriorly, or protruded, while the condyle on the side toward the shift is more stable positionally and is likely to be slightly retruded. According to the view that growth of the mandibular condylar cartilage (MCC) adapts to its local functional-biomechanical environment, differential changes in metabolic activity of the MCC would be expected on the nonprotruded and the protruded sides. To evaluate this hypothesis, 21 rats (28 days old) were fitted with intraoral positioners designed to shift the mandibular postural position asymmetrically. Cartilage thickness and BrdU labeling index in the MCC 3, 7, and 14 days after placement of the positioners were compared with those in age-matched controls that received no positioners. Cartilage thickness in the MCC on the protruded side was significantly greater than that in the controls at each time interval, with the difference increasing slightly with time. The labeling index for the protruded MCC was significantly greater than the controls at both 7 and 14 days after positioner placement. Trends on the nonprotruded side were generally opposite, culminating in reduced thickness and proliferation after 14 days. Thickness and labeling index were greater on the protruded side at every time interval except 3 days (labeling index). These trends in cartilage thickness and proliferation are consistent with previous studies of MCC changes after bilateral functional protrusion or retrusion. These data suggest that changes in MCC thickness and proliferative activity might accompany a lateral functional shift of the mandible in growing persons.

Facial motion analysis with a video and computer system after treatment of acoustic neuroma

OBJECTIVE

To objectively evaluate facial function with a computer and video system in a group of normal adults and a group of adults who have been treated for acoustic neuroma.

STUDY DESIGN

A prospective descriptive study was performed in which the experimenter performing the objective facial motion analysis was blinded to the subjective rating of facial function.

PATIENTS

The normal subjects comprised 18 women and 16 men. The subjects who had been treated for acoustic neuroma included 12 patients (seven women and five men) who underwent treatment for acoustic neuroma.

METHODS

Light-reflective markers were placed at selected facial sites. A video and computer-assisted system was used to measure displacement that was unconfounded by head motion at these sites during two expressions. Proximal and remote displacement were measured for the x and y coordinates. Percentage of asymmetry relative to the total displacement was determined.

RESULTS

Significant asymmetry in displacement for the y coordinate during the eyes-closed expression occurred in 100% of the subjects who had been treated for acoustic neuroma with apparent facial dysfunction and 0% of the subjects who had been treated for acoustic neuroma with no apparent facial dysfunction. Synkinesis was severe (>0.2 cm) in 17%, moderate (0.1-0.2 cm) in 25%, mild (>95th percentile for normal subjects but <0.1 cm) in 42%, and absent in 16% of the subjects who had been treated for acoustic neuroma.

CONCLUSION

This method of objective assessment of facial function is useful in the evaluation of the asymmetry in facial motion and in the detection and quantification of synkinesis. The findings suggest that those subjective rating systems of facial function that compare the abnormal to the normal side may be confounded by compensatory motion on the presumed normal side.

Relationship between functional disc position and mandibular displacement in adolescent females: posteroanterior cephalograms and magnetic resonance imaging retrospective study

The purpose of this study was to investigate the relationship between the disc positions of temporomandibular joints (TMJ), the vertical and lateral mandibular displacement (VMD and LMD, respectively) and age in female adolescents with signs and symptoms of the temporomandibular disorders (TMD). The VMD and LMD were assessed, using posteroanterior (PA) cephalograms. The disc positions were assessed by magnetic resonance imaging (MRI) and categorized as follows: normal disc position, functional disc displacement and functional disc dislocation. Excluding patients with osteoarthritis, the total number of subjects was 54 female adolescents who were grouped into three: the bilateral normal disc position group, the unilateral or bilateral functional disc displacement group, and the unilateral or bilateral functional disc dislocation group. We compared the extent of VMD and LMD between the three groups, and investigated their correlation with age. Results indicate that functional disc displacement and dislocation are related to mandibular displacement, and VMD did not correlate with age but LMD did correlate with age. This study suggests that the onset of disc displacement is related to the mandibular displacement and disturbs normal growth of the mandible three-dimensionally.

Mandibular asymmetry and antigonial notching in individuals with unilateral cleft lip and palate

OBJECTIVE

To determine whether asymmetric antigonial notching is associated with the development of mandibular and lower facial asymmetry in individuals with unilateral cleft lip and palate (UCLP).

DESIGN

Retrospective mixed-longitudinal investigation including UCLP and nonaffected orthodontic patients.

PARTICIPANTS

All (24) available patients with UCLP treated in our clinic with complete longitudinal records, and 72 skeletal maturation matched noncleft orthodontic patients that served as controls. Subject records included hand-wrist, panoramic, frontal, and 45 degrees oblique cephalometric radiographs.

MAIN OUTCOME MEASURES

The development of mandibular asymmetry, measured on oblique cephalometric radiographs, as well as lower facial asymmetry, measured on frontal cephalometric radiographs, was monitored in individuals with UCLP in relation to antigonial notching asymmetry, assessed on panoramic and oblique cephalometric radiographs.

RESULTS

First, no statistical differences were found in antigonial notching asymmetry between patients with UCLP and noncleft controls. Second, antigonial notching asymmetry, observed on panoramic and oblique cephalometric radiographs, significantly correlated with the attendant development of mandibular and lower facial asymmetry in individuals with UCLP. Third, the development of mandibular and lower facial asymmetry at pubertal and postpubertal growth spurt stages significantly correlated with antigonial notching asymmetry, measured on panoramic radiographs, at prepubertal and pubertal growth spurt stages, respectively.

CONCLUSIONS

The degree of antigonial notching noted on panoramic radiographs can be used as an early indicator of developing mandibular and lower facial asymmetry in individuals with UCLP.

Changes in the masticatory cycle following treatment of posterior unilateral crossbite in children

In a previous study, we established that young children with unilateral posterior crossbite have a longer mandibular ramus and more superiorly and posteriorly positioned condyles on the crossbite side. In this study, we evaluated chewing cycle shape and duration in 14 of the patients before treatment, and we looked for changes in cycle shape and duration 6 months after treatment with rapid palatal expansion. Mandibular kinematics was recorded while chewing gum using an optoelectric recording system at 100 Hz. Subjects were asked to chew normally for 20 cycles, chew on the crossbite side only for 20 cycles, and chew on the noncrossbite side only for 20 cycles. A special computer program selected the 10 most representative cycles from each series and computed an average duration and an average maximum excursion along 3 orthogonal axes. Multilevel linear models were used to generate an 8th-order polynomial describing average cycle shape and to test for statistically significant differences in shape between the patients and the controls and between the patients before and after treatment. Before treatment, the patients chewed more slowly than did the controls. Treatment shortened their cycle duration to equal control values. Before treatment, the patients also had larger maximum excursions than did the controls and exhibited a reverse-sequence cycle shape when chewing on the crossbite side. Treatment did not alter the patients' abnormal cycle shape. These results suggest that some features of the masticatory kinematics respond to orthodontic treatment alone, but others do not.

Townes-Brocks syndrome versus expanded spectrum hemifacial microsomia: review of eight patients and further evidence of a "hot spot" for mutation in the SALL1 gene

PURPOSE

It can be difficult to differentiate clinically between hemifacial microsomia (HFM) and Townes-Brocks syndrome (TBS). The distinction is important because TBS is inherited as an autosomal dominant trait, whereas HFM is sporadic.

METHODS

We performed a retrospective analysis of eight patients with HFM-expanded spectrum and anal anomalies to determine whether this subset has TBS.

RESULTS

Two patients had major phenotypic findings of TBS. Sequencing of SALL1, the gene mutated in TBS, in four of the eight patients revealed one with a C --> T transition (resulting in a nonsense mutation R276X) at a previously identified mutational "hot spot."

CONCLUSION

Patients with overlapping features of both syndromes should be screened for SALL1 mutations.

Changes in speech following unilateral mandibular distraction osteogenesis in patients with hemifacial microsomia

OBJECTIVE

The purpose of this study was to describe changes in articulation, resonance, and velopharyngeal function following mandibular distraction osteogenesis.

DESIGN

This is a descriptive, post hoc study comparing the performance of patients on measures of articulation, resonance, and velopharyngeal function before and after mandibular distraction.

SETTING

The data were collected at a tertiary health care center located in Chicago.

PATIENTS

The clinical data from preoperative and postoperative evaluations of seven mandibular distraction patients were used.

OUTCOME MEASURES

The outcome measures were number of articulation errors, severity of hypernasality and audible nasal emission, and velopharyngeal orifice size as estimated using the pressure-flow technique.

RESULTS

Immediately after distraction, 28% (2/7) experienced a temporary deterioration in articulation and 42% (3/7) experienced a deterioration in nasal resonance. But by the long-term follow-up evaluation, all had returned to their preoperative levels. Pressure-flow test results generally support the perceptual findings.

CONCLUSIONS

Patients being considered for mandibular distraction surgery should receive preoperative and postoperative speech evaluations and be counseled about risks for changes in their speech following surgery.

TMJ morphology and function in a patient with Klippel-Trenaunay syndrome. Case report

Klippel-Trenaunay syndrome is a rare congenital mesodermal disturbance of uncertain etiology in variable expression. The classic manifestation is the triad of congenital mesodermal abnormalities. Clinically a diversity of phenotypes with subjacent malformations may be encountered. The deviations of the mesioblastic germ layer affecting angioblastic, lymphoblastic and osteoblastic structures, may give rise to malformations either alone or in an unlimited diversity of associations. While this syndrome may be diagnosed by chance in the course of ultrasonic scanning during pregnancy, it is normally diagnosed during infancy or early childhood. Evaluation and carefully coordinated medical treatment are important in minimizing morbidity and relieving multiple complaints. The aim of our investigation was to evaluate and correlate the clinical, functional, radiographic and MRI findings in a patient suffering from this syndrome. We present a 13-year-old male patient suffering from extreme facial asymmetry in association with hypertrophy of the complete right side of the body. In spite of pronounced functional and morphologic asymmetry, no signs of degenerative joint disease were identified by radiography or MRI. Since temporomandibular joint dysfunction and facial asymmetry can result in irreversible degenerative joint disease, close follow-up monitoring is indispensable if joint damage is to be prevented.

The relationship between frontal facial morphology and occlusal force in orthodontic patients with temporomandibular disorder

The aim of this study was to investigate the relation between frontal craniofacial morphology and the distribution of occlusal force in orthodontic patients with and without TMD. Experimental data were obtained from 45 female orthodontic patients (TMD-free group: 22 subjects; TMD group: 23 subjects) using the pressure-sensitive sheet. The following results were obtained: (1) There were significant differences in the gonial angle width and the mandibular deviation of the postero-anterior cephalogram between the two groups. (2) There were significant differences in occlusal force, occlusal contact area and average occlusal pressure between the two groups. (3) On the relation between the frontal craniofacial morphology and the occlusal data, the asymmetry indices of occlusal force and occlusal contact area showed significant positive correlations to the mandibular deviation and the ratios of maxillary and gonial angle widths in the TMD group. The TMD-free group showed the smaller mandibular deviation and the smaller asymmetry indices of occlusal force and occlusal contact area than those in the TMD group. It could be concluded that orthodontic patients with TMD may have not only the morphological disharmony but also the imbalance of occlusal force.

Three-dimensional nasolabial displacement during movement in repaired cleft lip and palate patients

The objective of this study was two-fold: (1) to explore the suitability of a novel modified Procrustes fit method to adjust data for head motion during instructed facial movements, and (2) to compare the adjusted data among repaired unilateral (n = 4) and bilateral (n = 5) cleft lip and palate patients and noncleft control subjects (n = 50). Using a video-based tracking system, three-dimensional displacement of 14 well-defined nasolabial landmarks was measured during four set facial animations without controlling for head motion. The modified Procrustes fit method eliminated the contributions of head motion by matching the most stable landmarks of each video-recorded frame of the face during function to frames at rest. Its effectiveness was found to approximate that of a previous method (i.e., use of a maxillary occlusal splint to which stable dentition-based markers were attached). Data from both the unilateral and bilateral cleft lip and palate patients fell outside the normal range of maximum displacements and of asymmetry, and individual patients demonstrated greater right-versus-left asymmetry in maximum displacement than did individual noncleft subjects. It is concluded that the modified Procrustes fit method is fast, is easy to apply, and allows subjects to move the head naturally without the inconvenience of a splint while facial movement data are being collected. Results obtained using this method support the view that facial movements in cleft patients may be severely hampered and that assessment of facial animation should be strongly considered when contemplating surgical lip revisions.

Location of the glenoid fossa after a period of unilateral masticatory function in young rabbits

Changes in glenoid fossa position and skull morphology after a period of unilateral masticatory function were studied. The right-side maxillary and mandibular molars in twenty-seven 10-day-old rabbits were ground down under general anaesthesia. The procedure was repeated twice a week, until the rabbits were 50 days old. Fourteen rabbits were then killed and 13 left to grow to age 100 days. Nine 50-day-old and sixteen 100-day-old rabbits with unmodified occlusions served as controls. Three-dimensional measurements were made using a machine-vision technique and a video-imaging camera. The glenoid fossa position become more anterior in both groups of animals subjected to molar grinding as compared with controls (P < 0.01 in the 50-day-old group and P < 0.05 in 100-day-old group). In the 100-day-old group the right-side fossa was also in a more inferior position (P < 0.01). The glenoid fossa was more anteriorly located on the right than on the left side of individual animals in the group in which the right-side molars had been ground down (P < 0.001).

SPECT bone scintigraphy in the diagnosis and management of mandibular condylar hyperplasia

Isotope bone scans have been used for a number of years to assess growth activity in the mandibular condyle in patients who present with facial asymmetry. The aim is to distinguish normal bone growth within the condyle from increased activity that may be the cause of the asymmetry. Previous studies have, however, relied only on planar images. SPECT (single photon emission computed tomography) has been used with quantitative assessments of one mandibular condyle to clivus or lumbar spine, but we have compared one condyle with the other, which is more sensitive and accurate in detecting abnormal activity. A relative percentage uptake of 55% or more in the affected mandibular condyle is considered to be abnormal, and this has been validated by comparison with an age-matched control group. We have used SPECT as an aid to diagnosis and treatment in 18 patients with asymmetrical growth and have constructed a therapeutic algorithm to aid the treatment of these patients.

A longitudinal three-dimensional evaluation of the growth pattern in hemifacial microsomia treated by mandibular distraction osteogenesis: a preliminary report

This study analyzed in three dimensions the longitudinal growth pattern of young patients with hemifacial microsomia (HFM) before and after mandibular distraction osteogenesis (DO). Six individuals with HFM (five boys and one girl; age at distraction, 12.5 +/- 2.4 years) were treated with similar procedures (surgery, type and direction of distraction, no functional orthodontic treatment before and after DO). Two individuals who did not undergo DO until late in their growth were used to compare growth patterns. In addition, one individual besides the six previously chosen sample in whom no DO was performed was also used to compare longitudinal growth patterns. Lateral and posteroanterior (PA) cephalograms were utilized preoperatively, spanning a period of 9 years. Computerized three-dimensional models were constructed from the lateral and PA cephalograms using a vector intercept algorithm. In the comparison group, for a period of 8 years on the affected side, the ramus height, body length, and total mandibular length increased at an average rate of 1.3, 1.9, and 3.0 mm per year respectively. On the unaffected side, the ramus height increased by 2.1 mm per year, 1.9 mm in the body, and 2.9 mm per year in total mandibular length. On average, the gonial angle on the affected side was increased by 1 deg per year, yet decreased by 1 deg per year on the unaffected side. The proportions between the affected to the unaffected side were maintained. In the six individuals 18 months after DO, it was found that the ramus height was reduced by 1.0 mm, whereas the body was found to resume its growth with a faster rate on the distracted side, maintaining its proportion. Angular changes demonstrated closing of the gonial angle on both the unaffected (0.5 deg) and distracted (3.5 deg) sides. Observed in three dimensions were the following: (1) On average, unoperated patients with isolated HFM tend to maintain their asymmetrical facial proportions and do not worsen substantially with time. (2) Different treatment effects were seen on the ramus, body, and total length of the mandible: changes in body length > ramus height > total length. (3) Eighteen months after DO, the correction was stable but with some degree of settling back from the initial overcorrection (< 5%). (4) Eighteen months after DO the mandibular body was found to have greater growth than the ramus. (5) Evaluating changes in three dimensions provides an improved understanding of the growth pattern and distraction effects on the mandible and its structural components. (6) Additional studies on the effect of mandibular distraction on other conditions involving mandibular deformities are required. In addition, the effect of various distractor devices should also be evaluated. Three-dimensional evaluation is recommended for improved accuracy.