Search

Competing Interests: Competing interests: None declared.

Current approaches to facial reconstruction are based on the assumption of facial symmetry, though this has yet to be established in the literature. Through quantitative and qualitative analysis, symmetry of normal, male faces is examined here using the zygomatic complex as a bellwether for the rest of the facial skeleton. Three-dimensional models reconstructed from the computed tomography scans of 30 adult male patients displaying normal facial skeletal anatomy were analyzed. Seven zygomatic landmarks were identified on all craniofacial models, and asymmetry scores were calculated based on the average deviation distance upon reflection of 1 hemiface across the midfacial plane. Deviation maps were then generated for each zygomatic pair to enable visualization of the asymmetry. All landmarks displayed a slight (<3 mm) deviation from perfect symmetry, and analysis of zygomatic form asymmetry revealed an average of 0.4 mm of surface deviation between hemifaces. The presence of such slight asymmetries in the zygoma warrants further investigation as to the clinical relevance of such skeletal asymmetries from both an esthetic and biomechanical consideration to provide insight as to the proper approach to zygomatic restoration in cases of zygomatic fracture.

Purpose: This study evaluated the differences in the facial morphological characteristics of female patients exhibiting skeletal class II deformity with and without temporomandibular joint osteoarthrosis., Methods: Eighty-three female patients with skeletal class II deformity were included in this study; these patients were classified into three groups on the basis of the condylar features shown in cone-beam computed tomography scans: normal group, indeterminate for osteoarthrosis group, and osteoarthrosis group. The cephalometric differences among the three groups were evaluated through one-way ANOVA., Results: Of the 83 patients, 52.4% were diagnosed with osteoarthrosis, as indicated by the changes in the condylar osseous component. The cephalometric measurements that represented skeletal characteristics, including mandibular position relative to the cranial base, mandibular plane angle (MP-SN), posterior facial height (S-Go), and facial height ratio, were significantly different among the three groups (p < 0.05). The patients in the osteoarthrosis group yielded the smallest S-Go, the highest MP-SN, and the most retruded mandible., Conclusions: Temporomandibular joint osteoarthrosis is commonly observed in female patients with skeletal class II deformity. The morphological characteristics of the facial skeleton in patients with bilateral condylar osteoarthrosis may be altered.

Purpose: The purpose of this study was to assess gender differences in dentofacial characteristics of adult patients according to temporomandibular joint (TMJ) disc displacement (DD) status., Materials and Methods: The sample consisted of 293 adult patients (80 male and 213 female). Male and female patients were divided into 3 groups based on magnetic resonance images of bilateral TMJs: bilateral normal disc position (BN), bilateral DD with reduction (DDR), and bilateral DD without reduction (DDNR). Seventeen variables from lateral cephalograms were analyzed by 2-way analysis of variance to identify differences in dentofacial morphologies with respect to gender and TMJ DD status., Results: Patients with TMJ DD had short ramus height, short mandibular body length, and backward positioning of the ramus and mandible. These dentofacial characteristics became more severe as TMJ DD progressed to DDNR. In addition, dentofacial characteristics associated with TMJ DD were not significantly different between men and women except for effective mandibular length (Articulare to pogonion). Effective mandibular length even tended to decrease as TMJ DD progressed, but male patients showed a larger difference in effective mandibular length between BN and DDR than female patients., Conclusions: This study's findings suggest that dentofacial morphology is strongly associated with TMJ DD status and that skeletal Class II hyperdivergent pattern with a short ramus and mandible may be a potential indicator of TMJ DD regardless of gender., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Morphometric methods are used in biology to study object symmetry in living organisms and to determine the true plane of symmetry. The aim of this study was to determine if there are clinical differences between three-dimensional (3D) cephalometric midsagittal planes used to describe craniofacial asymmetry and a true symmetry plane derived from a morphometric method based on visible facial features. The sample consisted of 14 dry skulls (9 symmetric and 5 asymmetric) with metallic markers which were imaged with cone-beam computed tomography. An error study and statistical analysis were performed to validate the morphometric method. The morphometric and conventional cephalometric planes were constructed and compared. The 3D cephalometric planes constructed as perpendiculars to the Frankfort horizontal plane resembled the morphometric plane the most in both the symmetric and asymmetric groups with mean differences of less than 1.00 mm for most variables. However, the standard deviations were often large and clinically significant for these variables. There were clinically relevant differences (>1.00 mm) between the different 3D cephalometric midsagittal planes and the true plane of symmetry determined by the visible facial features. The difference between 3D cephalometric midsagittal planes and the true plane of symmetry determined by the visible facial features were clinically relevant. Care has to be taken using cephalometric midsagittal planes for diagnosis and treatment planning of craniofacial asymmetry as they might differ from the true plane of symmetry as determined by morphometrics.

A 34-year-old patient with asymmetric hyperostosis of the craniofacial skeleton much more pronounced on the right side is presented. A long-term follow-up of 16 years showed progression of overgrowth even after skeletal maturity and despite repeated surgical corrections focusing on regional reduction of the hyperostoses. Clinical situation during infancy, adolescence, and adulthood is documented. Although the craniofacial hyperostosis in the patient was indicative of the Proteus syndrome, the applicable criteria were not met. Proportionate mild hemihypertrophia/hyperplasia of the patient's right extremities also exclude an oligosymptomatic variant of the Proteus syndrome limited to the skull. Both surgical strategies and difficulty of a diagnostic classification are discussed.

Purpose: In the present project, the virtual reconstruction of digital osteomized zygomatic bones was simulated using different methods., Materials and Methods: A total of 15 skulls were scanned using computed tomography, and a virtual osteotomy of the left zygomatic bone was performed. Next, virtual reconstructions of the missing part using mirror imaging (with and without best fit registration) and thin plate spline interpolation functions were compared with the original left zygomatic bone., Results: In general, reconstructions using thin plate spline warping showed better results than the mirroring approaches. Nevertheless, when dealing with skulls characterized by a low degree of asymmetry, mirror imaging and subsequent registration can be considered a valid and easy solution for zygomatic bone reconstruction., Conclusions: The mirroring tool is one of the possible alternatives in reconstruction, but it might not always be the optimal solution (ie, when the hemifaces are asymmetrical). In the present pilot study, we have verified that best fit registration of the mirrored unaffected hemiface and thin plate spline warping achieved better results in terms of fitting accuracy, overcoming the evident limits of the mirroring approach., (Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Introduction: The objective of this study was to compare the degrees of skeletal and dental asymmetry between subjects with Class II subdivision malocclusions and subjects with normal occlusions by using cone-beam computed tomography., Methods: Thirty subjects with Angle Class II subdivision malocclusions (mean age, 13.99 years) and 30 subjects with normal occlusions (mean age, 14.32 years) were assessed with 3-dimensional cone-beam computed tomography scans. Independent t tests were used to compare orthogonal, linear, and angular measurements between sides and between groups., Results: Total mandibular length and ramus height were shorter on the Class II side. Pogonion, menton, and the mandibular dental midline were deviated toward the Class II side. Gonion and the anterior condyle landmark were positioned more posteriorly on the Class II side. The mandibular dental landmarks were located more latero-postero-superiorly, and the maxillary dental landmarks more latero-antero-superiorly on the Class II side. There was loss of maxillary arch length, and the mandibular molar was closer to the ramus on the Class II side., Conclusions: The etiology of Class II subdivision malocclusions is primarily due to an asymmetric mandible that is shorter and positioned posteriorly on the Class II side. A mesially positioned maxillary molar and a distally positioned mandibular molar on the Class II side are also minor contributing factors., (Copyright © 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.)

Hemifacial hyperplasia is a developmental disorder characterized by marked unilateral facial asymmetry. It involves the hard and soft tissues of the face. The cause is unknown, although several predisposing factors have been described. A case report of an 8-year-old boy with hemifacial hyperplasia is presented to highlight the clinical and imaging findings.

Background: This study was undertaken to investigate the facial skeletal features associated with chin deviation., Methods: Twenty-five patients (14 males and 11 females) diagnosed with chin deviations of more than 2 mm were recruited. Fifteen skeletal landmarks, including median and lateral points, were located on posteroanterior cephalograms. The CG-ANS (crista-galli of the ethmoid-anterior nasal spine) line and the perpendicular line through the CG were used as references. The differences between the distances from paired lateral points to reference lines were examined with intraclass correlation coefficients to analyze the symmetry of facial skeletal tissue. The factors associated with the amount or direction of chin deviation were analyzed by multiple regression analysis or by logistic regression analysis., Results: Seventeen subjects (68%) showed chin deviation to the left side and 8 subjects (32%) to the right side. Sixty-eight percent of subjects presented with Angle Class III malocclusion. Horizontal distances of all paired lateral points to the y-axis, in mandibular body length and effective length, showed a low grade of symmetry. Only vertical distances of paired zygomaticofrontal sutures and zygonion points to the x-axis were asymmetric. However, there were no significant asymmetries of the gonial angle, ramus height, and vertical distances from other paired lateral points to the x-axis. The amount of chin deviation was associated with the absolute differences of the left and right antegonion to the y-axis and zygomaticofrontal suture to the x-axis. The direction of chin deviation was significantly associated with the difference in the effective length of bilateral mandibular halves., Conclusion: Facial skeletal asymmetry exists in patients with chin deviation. This should be considered when planning treatment for both the nonsurgical and surgico-orthodontic cases with chin deviation.

OBJECTIVES - To understand how surgical interventions impact the organization and internal integration of the major components of the skull, we address the functional and developmental relationships during perinatal development. METHODS - A number of methods for quantifying modularity and integration of morphological data are available. Here, measures derived from three-dimensional computed tomographic (CT) images are used to investigate the statistical relationships among measures of the cranial vault, face and cranial base. First, we establish the pattern of associations among quantitative measures in a sample of children unaffected by a craniofacial anomaly. We statistically compare these normative patterns of cranial integration to those of a sample of children with a facial anomaly (complete unilateral complete cleft lip and palate), and to children with a neurocranial anomaly (isolated sagittal synostosis). Finally, we test whether surgery affects the strength and pattern of associations among measures within the cranial base in the affected children. RESULTS - Our analyses reveal strong internal integration of the cranial base in unaffected children and in our samples of unoperated cleft lip and palate, and sagittal synostosis. Post-operatively, the magnitude of integration of the cranial base is reduced relative to the pre-operative condition in both samples of children with craniofacial anomalies. CONCLUSION - Our results show how the cranial base adjusts to its broader structural context, and provides added support for the developmental and structural integration of cranial base with both cranial vault and face.

This investigation was aimed at the evaluation of the morphometric characteristics of the contralateral sides of the facial cranium in adult men and women, the evaluation of asymmetry manifestation degree and the detection of most frequent zones of its localization. The study was conducted on 180 crania (90--male, 90--female) of the adults of I and II mature age periods. To detect the asymmetry of the facial cranium, the original "fan" principle of morphometry was developed. This approach has shown the asymmetry in the area of localization of different "fans" ("superior", "inferior", "lateral"), i.e., in the different regions of the facial cranium. On the basis of the data obtained, it can be concluded that in order to identify the asymmetry of the facial 1 cranium and to estimate the asymmetry manifestation degree it is expedient to take into account the following parameters: the distance from a nasion point to a point on the lateral edge of apertura piriformis, from a nasion point to a frontomolare-temporale point, from a zygomaxillare point to a lateral point on naso-frontal suture, from a zygomaxillare point to a dacryon point, from a subspinale point to a nazomaxillare point and from a subspinale point to a lateral point on naso-frontal suture. As in the series of the male crania asymmetry of the facial cranium was significantly more expressed than in the series of female ones, it is assumed to be associated with the different tone of mimic muscles.

Objective: To analyze the aesthetic and functional outcomes in a large series of patients who underwent secondary correction of post-traumatic craniofacial deformities (PTCD) and to highlight the underlying principles and formulate treatment guidelines., Methods: A single surgeon's retrospective case series of 57 patients who underwent correction of PTCD., Outcome Measures: Evaluation by multiple surgeons who assessed aesthetic results and functional parameters after secondary correction of PTCD., Results: A good to excellent aesthetic outcome was achieved in the majority of patients. Traumatic telecanthus, enophthalmos, and occlusal deformity were the deformities most refractory to secondary correction. Aesthetic results were adversely affected by the severity and number of pre-existing abnormalities and by the presence of established deformities (beyond 6 to 12 months)., Conclusions: The basic principles of treatment include an initial major osseous reconstructive surgery to restore an anatomically correct craniofacial architecture followed by selective ancillary procedures to address soft tissue deficits and functional deformities. Soft tissue deformity is the major deterrent to achieving an ideal outcome.

Objective: To quantify comparative improvement between osseous and soft tissue asymmetry following primary lip repair., Design: Retrospective analysis of preoperative and postoperative computed tomography scans of infants with unilateral cleft lip and palate. Sixteen soft tissue landmarks were placed using an exploratory two-/three-dimensional image processing system and compared for asymmetry., Patients: Computed tomography scans were obtained on 26 patients (13 boys, 13 girls) of Chinese ethnicity (mean age = 0.25 years) prior to Millard lip repair. Nineteen of these contributed to follow-up comparative studies prior to palatoplasty at a mean age of 0.92 years. There were 18 left-sided and eight right-sided clefts., Main Outcome Measure: Euclidean distance matrix asymmetry analysis was used to determine the amount of soft tissue asymmetry pre- and postlip repair. Similar analyses of the same scans were performed for 41 osseous landmarks., Results: Soft tissue landmarks had 36/39 (92%) preoperative and 13/39 (33%) postoperative asymmetric pairs. Osseous distances demonstrated 77/125 (61%) asymmetric pairs preoperatively and 60/125 (48%) postoperatively. Soft tissue and osseous distances of the lip region demonstrated 32% and 39% postoperative asymmetry, respectively. Soft tissue and osseous distances of the nasal region demonstrated 52% and 72% postoperative asymmetry, respectively. Soft tissue and osseous distances of the facial landmarks demonstrated 24% and 34% postoperative asymmetry, respectively., Conclusions: Primary lip repair appears to effect gains in symmetry in soft tissue and provides sufficient molding forces to cause correlating symmetry changes in underlying osseous structures.

In this study, to clarify the influence of the maxillo-mandibular bones and cranium on airway morphology, maxillo-facial morphology in patients with jaw deformation was measured using cephalograms and X-ray CT imaging data. Subjects consisted of 25 adult women in whom cephalograms and X-ray CT were taken to diagnose jaw deformation. The data obtained were classified based on skeletal and facial patterns according to Ricketts analysis, and changes in internal diameter, height and volume of the middle pharyngeal airway were observed. The results showed that the internal diameter of the inferior airway expanded anteriorly when the mandibular bone was in the anterior position, and was slightly constricted and elongated vertically when the mandibular bone was posteriorly rotated. This suggests that airway volume is influenced by the anteroposterior position of the mandibular bone, in that it compensates for decreases in its volume by extending its height inferiorly to cope with posterior deviation of the mandibular bone.

The aim of this study was to investigate the relationship between mandibular outline asymmetry and skeletal discrepancy in a sample of orthodontic patients (33 females, 33 males) aged from 8 to 19 years. Skeletal discrepancy was assessed in both the anteroposterior and vertical planes, using standard cephalometric analyses. All were photographed under standardized conditions and the photographs were then digitized for analysis using a computerized system to assess differences in four variables (area, perimeter, compactness and moment-ratio) between the right and left sides of the mandibular outline. The results showed good repeatability of the photographic, cephalometric and digitization methods. A statistically significant relationship was found between mandibular outline asymmetry and both anteroposterior and vertical skeletal discrepancy in this sample, when compared with patients with an average skeletal pattern. There appeared to be a statistically significant relationship between a reduced ANB angle (< 3 degrees) and mandibular outline asymmetry (P = 0.051), as well as between an increase in lower face height and mandibular asymmetry (P = 0.023).

The purpose of this study was to evaluate the occurrence of craniofacial asymmetries in four areas of human skulls of various age groups to test the hypothesis that there is craniofacial symmetry before the chewing habit is established. The data were obtained from 95 skulls of fetuses, infants, children, and adults, from the collection of Federal University of São Paulo. The following measurements were taken on each skull with a digital caliper: from the infraorbital foramen to the anterior nasal spine (IOF); from the greater palatine foramen to the posterior nasal spine (GPF); from the spinous foramen to the basion (SF); and from the spinous foramen to the zygomatic arch (ZA). On different occasions, each measurement was taken three times on both sides of the skull in random order. The mean of the right-side measurements were subtracted from the mean of the left-side measurements, and the differences were transformed into percentages. Comparisons were made by analysis of variance. The presence of cranial asymmetry was statistically significant throughout the whole sample. The minimum value found was 2.8% and the maximum 6.5%. All age groups presented the same degree of asymmetry of distances IOF, GPF, and SF. The group of infants presented a higher degree of asymmetry on distance ZA, followed by the groups of fetuses, children, and adults. This study confirmed statistically significant craniofacial asymmetry in fetuses and infants (before dentition). Therefore, the hypothesis that craniofacial asymmetry only appears after establishment of the chewing habit was not supported.

The purpose of this study was to evaluate the effect of unilateral disk displacement without reduction (UDDN) on the skeletal and dental pattern of affected individuals. There were 12 symptomatic female patients and 46 asymptomatic normal female volunteers. All study participants had bilateral high-resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes to evaluate the temporomandibular joints. Linear and angular cephalometric measurements were taken to evaluate the skeletal, denture base, and dental characteristics of the two groups. ANOVA was used to compare the symptomatic subjects with the control subjects. A few skeletal differences were found. There was an overall reduction in length of the anterior (S-Na) and total (S-Ba) cranial base measurements in the UDDN group. The mandibular plane angle was steeper and the posterior ramal height (Ar-Go) was shorter in the symptomatic group. The only dental difference found was a relative infraeruption of the lower first molar. This study suggests that subjects with UDDN may manifest altered craniofacial morphology. Although the cephalometric measurements used did not account for any asymmetry, previous studies have shown that UDD may cause mandibular asymmetry. Presence of asymmetry and altered craniofacial morphology should alert the clinician especially while orthodontically treating children and surgical patients.

Objectives: This investigation is a part of a multidisciplinary descriptive evaluation of the Silver-Russell syndrome (SRS). The aim of this study was to describe the craniofacial morphology, occlusion and dental age in children with the SRS., Design: A descriptive literature-controlled study., Setting and Sample Population: Sixteen children diagnosed as having SRS, 10 boys and six girls, aged 4.4-14.5 years, were referred from different parts of Sweden to the Queen Silvia Children's Hospital, Göteborg University., Experimental Variable: Facial morphology was measured on lateral and postero-anterior radiographs. Occlusion, tooth eruption and palatal height were measured on casts, and dental maturity was evaluated on orthopantomograms., Outcome Measure: Linear and angular measurements were obtained from lateral radiographs and the ratios of the linear measurements from the postero-anterior radiographs. The degree of tooth calcification shown on orthopantomograms was taken as a measure of dental maturity. Biometric measurements were taken and the degree of tooth eruption was recorded from the dental casts. The SRS children were compared with reference groups with t-test and z-scores., Results: Overall, SRS children were found to have smaller linear facial dimensions and deviations in the facial proportions, such as a small retropositioned, and steeply inclined maxilla and mandible, and a proportionally larger anterior facial height in relation to the posterior facial height. In 40% of them a smaller facial height or length on one side (facial asymmetry) was correlated to the smaller side of the body. The frequency of malocclusions was higher, and the palatal height showed a tendency towards an increase. Dental maturity was within normal limits, while the time of tooth eruption was slightly delayed., Conclusions: The deviating facial morphology described above is a part of the syndrome, which is characterized by short stature, growth hormone deficiency and asymmetries of the body. The higher percentage of malocclusions in the SRS children might lead to a greater need of orthodontic treatment.

The deformities of craniofacial bones in brachycephaly (n = 2) and plagiocephaly (n = 2) were compared using three-dimensional skull replicas. In brachycephaly the bilateral deformities of the cranial base were similar to the unilateral deformities on the affected side in plagiocephaly. Shortening of the anterior-middle cranial fossas and expansion of the middle cranial fossas suggest downward and anterior displacement of both temporomandibular (TM) joints resulting in the underdevelopment of the middle-inferior facial bones, though this is less conspicuous in brachycephaly for three reasons. The most important one is that the patients have an imposing facial morphology characterised by high, protruding facial bones, as found on the affected side in plagiocephaly. Secondly, the frontal bones are flattened and positioned posteriorly in the anteroposterior direction, which also helps to mask the underdevelopment of the middle-inferior facial bones. Finally, as bony deformities are symmetrical in brachycephaly, they are not as obvious as they would be if they were unilateral.

Objective: Individuals with unilateral cleft lip and palate (UCLP) manifest a plethora of phenotypic characteristics, including asymmetric development of the middle and lower facial skeleton. The purpose of this study was to retrospectively investigate the development of cranial base asymmetries in patients with UCLP noted on posteroanterior cephalometric radiographs., Methods: Thirty individuals with UCLP and 64 controls participated in this study. Medial and lateral cranial base asymmetries were analyzed on frontal cephalometric radiographs relative to three developmental stages. Furthermore, the development of horizontal and vertical lower facial asymmetry in these patients with UCLP was assessed in relation to cranial base, nasomaxillary, and dentoalveolar structures., Results: Individuals with UCLP demonstrated cranial base asymmetries that did not significantly differ from individuals without cleft. In addition, lower facial asymmetry in patients with UCLP correlated with horizontal lower facial and dentoalveolar asymmetries but not with cranial base or nasomaxillary structures., Conclusions: No significant vertical cranial base asymmetries were detected in patients with UCLP. Horizontal lower facial asymmetry appeared to develop in close relation to the vertical asymmetries of mandibular fossae and dentoalveolus.

Measurements of 18 bilateral signs were carried out in 94 Negroid skulls. All parts of the facial skull are clearly asymmetrical, if regarded separately, while the summary sizes of the left and right halves of the facial skull are equal. In the upper part of the face the most asymmetrical parameters are the width of the bridge of the nose, width of the nose, and width of the palate, while the least asymmetrical are the height of the orbit and palate and length of the palate. In the mandibular part the greatest asymmetry was observed in the thickness and height of the mandibular corpus and height of the mandibular branches. The resultant combination of symmetry of the total sizes of both sides of the facial skull and asymmetry of individual parts is interpreted as an indication of the compensatory changeability of bilateral signs of the facial skull. The results are similar to data on the asymmetry of the facial skull of Mongoloid, Europeoid, and the intermediate skulls.

Normal asymmetry in the area of the craniofacial skeleton can be directional or fluctuating in nature. Directionality can in principle be found in three dimensions: anteroposterior, cranio-caudal, and asymmetries in the left-right dimension. When it comes to directional left right differences, an explanation has been difficult to find, although expressions of this type are obvious. Recent findings made in molecular genetics strongly support the genetic inheritance pattern of laterality. When functionally increased asymmetries of facial structures are concerned, it is often difficult to determine the exact contribution of each factor involved. In the light of recent experimental data, however, it seems that the influence of occlusion on the development of balanced facial structures is highly important during the early periods of life. A review of these factors is given in this article.

Why do the craniofacial bones grow asymmetrically in patients with plagiocephaly (unilateral coronal synostosis)? We obtained three-dimensional skeletal replicas of two patients with the condition and analysed the deformities of the facial bones. From this analysis we deduced that the asymmetric deformation of the facial bones in these patients was caused by a combination of three rotations: rotation of the calvaria toward the affected side because of premature synostosis of the coronal and sphenofrontal sutures; rotation of the facial bones on the horizontal plane toward the unaffected side caused by anterior displacement of the TM (temporomandibular)-joint on the affected side; and downward rotation of the facial bones toward the unaffected side caused by inferior displacement of the TM-joint on the affected side.

The relationship between the bone and muscles of mastication in hemifacial microsomia was studied using three-dimensional volumetric computed tomography scans and image processing techniques. High resolution head computed tomography scans were obtained from 31 patients with unilateral hemifacial microsomia and eight normal patients. Using three-dimensional volume renderings of bone, mandibular deformities in patients with hemifacial microsomia were classified using the Pruzansky system. For each patient, specific craniofacial bones (temporal bone, maxilla mandible) and the muscles of mastication (masseter, temporalis and lateral and medial pterygoid) were segmented bilaterally from the image volume for independent display and volume measurement. Volumes were expressed as the ratio of the affected: unaffected sides. For the masseter and temporalis, the relationship between muscular hypoplasia and osseous hypoplasia in its origin and insertion was studied by plotting affected:unaffected bone volume as a function of affected:unaffected muscle volume for each muscle, bone of origin, bone of insertion triplet. The volumes of the pterygoid muscles were compared with hemimandibular volumes. The precision of object segmentations was examined by repetitive definition tasks, whereas the accuracy of volume measurement was tested by scanning custom-made phantom objects and comparing digital to physical object volume measurements. Volume measurements performed using these techniques were both accurate and precise. In hemifacial microsomia, the extent of hypoplasia of specific muscles of mastication predicted the extent of dysplasia in their osseous origin and insertion. However, the reverse was not true. The extent of hypoplasia of the facial bones did not necessarily predict the extent of hypoplasia in the attached muscles of mastication. Pruzansky grade of the mandible described the degree of mandibular hypoplasia on the affected side, but was inconsistent in its prediction of volume decrease of the other facial bones.

A clinical study of the craniofacial features in Apert syndrome is based on our experience with 136 cases. Characteristics included hyperacrobrachycephaly, steep wide forehead, flat occiput, common craniofacial asymmetry, ocular hypertelorism and proptosis, downslanting palpebral fissures, divergent upgaze and esotropic downgaze, a tendency towards large ears, and marked depression of the nasal bridge. The nose is short and wide with a bulbous tip, and the anterior facial height is reduced. Common features during infancy included horizontal grooves above the supraorbital ridges that disappear with age, a break in the continuity of the eyebrows, and a trapezoidal-shaped mouth at rest. Radiographic aspects of Apert syndrome were also assessed. Tables are provided which compare the craniofacial features of Apert and Crouzon syndromes.

Diffuse skeletal cystic angiomatosis is an extremely rare disorder that has not previously been reported in detail in the dental literature. This case report deals with the oral manifestations in a 10-year-old boy. Clinical, radiographic, and computed tomographic examinations showed hyperplasia of the right side of the face. The computed tomographic imaging studies revealed the extent of the jawbone lesions and the adjacent hyperplastic soft tissues. The histologic appearance of the lesions, the course of the disease, and the differential diagnosis are discussed.

A new disorder describing multiple hamartomas distinct from neurofibromatosis and Klippel-Trenaunay-Weber syndrome was first reported in 1979. It was named Proteus syndrome after the Greek god Proteus, the polymorphous, who could change his shape at will to avoid capture. The clinical manifestations are extensive, including cranial exostoses; progressive enlargement, asymmetry and disfigurement of the skull; macrocephaly; exostoses of the ear canals, nasal bridge, and alveolar ridge; partial gigantism of the hands or feet, asymmetry of the limbs, plantar hyperplasia, hemangiomas, lipomas, lymphangiomas, varicosities, verrucous epidermal nevi, and long bone overgrowth. A case report of Proteus syndrome is presented and discussed along with a review of the pertinent literature.

The lack of an animal model of congenital coronal suture (CS) synostosis has prompted the widespread use of an experimental rabbit model using adhesive immobilization of the CS. Such postnatal models have helped make significant scientific contributions but may still not fully represent all aspects of the human congenital condition. In the March 1993 issue of The Cleft Palate-Craniofacial Journal we reported a female rabbit born in our laboratory with complete bilateral CS synostosis. This follow-up study presents our attempts to breed this animal and establish a strain of craniosynostotic rabbits. To date, we have accomplished 10 back- and intercrosses with these animals and have produced a total of 71 live offspring; 10 animals exhibited complete nonsyndromic unilateral (plagiocephalic) or bilateral (brachycephalic) CS synostotic deformities at birth, and 19 animals exhibited partial CS synostosis that showed more than 75% growth retardation across the CS (well below the 95% confidence interval for normals). Results revealed that gestational time and litter size averages were consistent with those reported for the strain, although the average litter size decreased with increased inbreeding. By 1.5 weeks of age the completely synostosed animals already exhibited brachycephalic cranial vaults and midfacial hypoplasia compared to unaffected siblings. Initial pedigree analysis suggested an autosomal dominant inheritance pattern with incomplete penetrance and variable expressivity. The development of such a congenital rabbit model may prove useful in helping to understand the etiopathogenesis of this condition in human populations.

All bilateral sizes of the facial skeleton of Tajik, Khakass and Kazakh skulls have demonstrated an asymmetry. In the three series the greatest values of the asymmetry were obtained for the sizes of the orbital, zygomatic and mandibular areas, the least ones--for the sizes of the upper jaw. Greater sizes were less asymmetrical. The indices of asymmetry of the least sizes of the facial skeleton are characterized by the greatest variability at the intra-group level. The Tajik skulls were considerably different in the degree of asymmetry from both the Khakass and kazakh skulls mainly in the sizes of the upper part of the facial skull. Values of asymmetry of Kazakh and Khakass skulls were similar as a whole.

The pre- and intraoperative determination of the midface symmetry during the management of trauma or reconstructive surgery cases may be difficult due to swelling of the covering tissue. To handle these problems, a new apparatus, called "Zygometer", is introduced. This instrument is able to measure the position of the midface bones and enables a comparison with the controlateral side. The results of a study with 250 persons to get standard measurements for symmetry and asymmetry are presented and discussed. Indications and clinical application of the zygometer are demonstrated.

The dysmorphic growth patterns of the craniofacial skeleton are summarized in five patients with the Proteus syndrome. Two different modes of abnormal growth are present. One mode involves focal overgrowth of membrane bones, producing multiple hyperostoses which result in progressive craniofacial disfigurement and asymmetry. The second mode involves overgrowth of cartilage in the condyle, resulting in dentofacial asymmetry. The phenotype of the craniofacial skeleton results from both processes. In terms of appearance, the mode involving hyperostosis seems more dramatic in most cases than the mode involving cartilage.

One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.

Three cases of gross craniofacial polyostotic fibrous dysplasia are presented, together with a brief review of the condition, and pertinent points regarding the cases are discussed. As complete excision of the lesion and immediate reconstruction is rarely feasible or possible, and partial excision may result in accelerated growth of the lesion during the patient's active growth phase, resection only to protect, maintain or restore certain important functions (e.g. vision) during this period are advocated, after which close follow-up is mandatory until the lesion becomes quiescent, when further surgical procedures may be undertaken.

Craniofacial fibrous dysplasia occurring in a mother and two of her three daughters is reported. In all three patients, the condition was characterized by extensive bilateral and bimaxillary involvement. All patients exhibited radiographic evidence of abnormal maxillary and mandibular bone and tooth displacement. Morphologic examination of deciduous teeth from the daughters showed replacement of normal pulp tissue by fibro-osseous lesion. Because of the familial occurrence of the cases, it is proposed that they comprise an example of inherited craniofacial fibrous dysplasia.