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PubMed1998

Childhood and adolescent changes of skeletal relationships.

This paper describes the development of anteroposterior (AP) and vertical (VER) skeletal relationships. A mixed-longitudinal sample of 49 females and 50 males was followed during childhood and adolescence. Childhood growth changes were assessed from 6 to 10 years for females and 8 to 12 years for males. Adolescent changes were evaluated from 9 to 13 years for females and 11 to 15 years for males. Anteroposterior relationships were described by the horizontal distance between ANS and Pg. Vertical relationships were described by the vertical distance between Pg and Go. Subsamples were defined based on overall changes (AP and VER) that were either greater than or less than average. The results showed that AP and VER relationships were not stable during growth. AP relationships changed over time due to differential growth movements of the mandible (as opposed to the maxilla). There was greater potential for horizontal discrepancies to decrease during childhood than during adolescence. The potential for AP discrepancies to increase was greater during adolescence. The VER relationships increased in the majority of subjects. The subsample whose vertical discrepancies increased most showed less inferior movement of gonion and more inferior movement of pogonion. Inferior movements of Pg and Go were greater during adolescence than childhood.

Adolescent↗
PubMed1993

Role of the mandibular first molar in the development of the supraorbital region in apes and humans.

Our previous studies in apes and humans have demonstrated that the development of the supraorbital ridge is a direct consequence of masticatory forces. The smaller the power arm/load arm ratio of the mandible, the greater the force exerted by the temporalis muscle and the larger the supraorbital ridge. The purpose of the present study is to further elucidate the role of the masticatory apparatus, in particular the role of the first mandibular molar. Measurements of the size of the supraorbital ridges in ape skulls and in human skulls from Tuscany, Italy and St. Lawrence Island, Alaska, were determined using parasagittal CAT scans as in our previous studies. For the purpose of this study, the mesio-distal and buccolingual dimensions of the first molar were measured from the actual tooth in all cases. Statistical analysis shows a positive correlation between the mesio-distal dimension of the mandibular first molar and the size of the ridge in humans (r = 0.61, p < 0.005) and in apes (r = 0.79, p < 0.01), which explains much of the variation in the size of the supraorbital ridge, 37% (0.61(2)) in humans and 62% (0.79(2)) in apes. The role of the mandibular first molar differs in humans versus apes because of differences in masticatory mechanics.

Adult↗
PubMed1996

Effects of reverse headgear treatment on sagittal correction in girls born with unilateral complete cleft lip and cleft palate--skeletal and dental changes.

Patients with cleft lip and cleft palate often develop maxillary retrognathism. This is due to the combined effects of the congenital deformity and surgical repairs. Early protraction of the maxilla with extraoral forces helps to achieve more balanced skeletal harmony and favorable occlusion for future growth to occur. The purpose of the present study is to investigate the proportion of the skeletal and dental changes contributing to the improvement in a group of Southern Chinese girls born with unilateral complete cleft lip and cleft palate treated by the reverse headgear. This study only focused on treating a homogenous sample group, i.e., only girls with unilateral complete cleft lip and cleft palate. This design was deliberate so as to avoid having boys and girls with various types of cleft all pooled together for analyses as seen in most of the previous reports. In addition, comparison was made with girls matched in having a similar deformity, presenting a similar skeletal structure and maturity status to reveal the genuine treatment effect. The 9.7 months of reverse headgear treatment improved the sagittal jaw relationship (p < 0.01) and overjet (p < 0.01), which was effected by about two-thirds skeletal and one-third dental changes.

Case-Control Studies↗
PubMed2005

Genesis of alcohol-induced craniofacial dysmorphism.

The initial diagnosis of fetal alcohol syndrome (FAS) in the United States was made because of the facial features common to the first cohort of patients. This article reviews the development of an FAS mouse model whose craniofacial features are remarkably similar to those of affected humans. The model is based on short-term maternal treatment with a high dosage of ethanol at stages of pregnancy that are equivalent to Weeks 3 and 4 of human gestation. At these early stages of development, alcohol's insult to the developing face is concurrent with that to the brain, eyes, and inner ear. That facial and central nervous system defects consistent with FAS can be induced by more "realistic" alcohol dosages as illustrated with data from an oral alcohol intake mouse model in which maternal blood alcohol levels do not exceed 200 mg/dl. The ethanol-induced pathogenesis involves apoptosis that occurs within 12 hrs of alcohol exposure in selected cell populations of Day 7, 8, and 9 mouse embryos. Experimental evidence from other species also shows that apoptosis underlies ethanol-induced malformations. With knowledge of sensitive and resistant cell populations at specific developmental stages, studies designed to identify the basis for these differing cellular responses and, therefore, to determine the primary mechanisms of ethanol's teratogenesis are possible. For example, microarray comparisons of sensitive and resistant embryonic cell populations have been made, as have in situ studies of gene expression patterns in the populations of interest. Studies that illustrate agents that are effective in diminishing or exacerbating ethanol's teratogenesis have also been helpful in determining mechanisms. Among these agents are antioxidants, sonic hedgehog protein, retinoids, and the peptides SAL and NAP.

Alcohol Drinking↗
PubMed1995

Juvenile chronic arthritis. Dentofacial morphology, growth, mandibular function and orthodontic treatment.

In children with Juvenile Chronic arthritis (JCA), temporomandibular joint involvement may lead to disturbances in dentofacial growth and mandibular function. The aim of this thesis was to study the dentofacial morphology, temporomandibular joint destruction and mandibular function in JCA children, and the relation between these factors. The intention was also to make a longitudinal study of the changes in facial morphology during growth and during treatment with functional appliances. Thirty-five JCA children, 12 boys and 23 girls, aged 7-16 years (mean 11.2 years), and the control groups, with either normal or distal occlusion, were studied by means of panoramic radiographs, lateral cephalograms, study casts, recordings of signs and symptoms of temporomandibular disorders (TMD), bite force and chewing characteristics. A method to evaluate the condylar height on panoramic radiographs was developed. Panoramic radiographs are found to be reliable for evaluation of the condylar height, provided the same panoramic machine is used. The dentofacial morphology in JCA children is characterized by a smaller, more retrognathic and steeper inclined mandible compared to that of healthy children with ideal occlusion. Compared to healthy children with distal occlusion, no difference in mandibular retrognathia could be demonstrated but the JCA children showed a smaller, more steeply inclined mandible. The presence and extent of condylar lesions play a significant role in the development of the facial morphology and also contribute to the facial heterogeneity among JCA children. During growth the JCA children without radiographically visible condylar lesions showed a growth pattern resembling that of healthy children with normal occlusion, while children with condylar lesions showed aggravation of the mandibular retrognathia and a tendency towards a backward-rotating growth pattern. The chewing movements in JCA children are restricted by the disease and by the presence of condylar lesions. In JCA children with distal occlusion, interaction between both factors (JCA and malocclusion) resulted in further alterations of the chewing movements and chewing velocity. Subjective signs and clinical symptoms of TMD are more frequently found in JCA children, some of which are significantly correlated to radiographic changes in the condyle. The bite force and the endurance time are about half of that of healthy children. A low molar bite force is significantly correlated to a low mouth-opening capacity. The orthodontic treatment with functional appliances resulted in improvement in the dental malocclusion, while the skeletal effects were of minor magnitude in both the JCA children and in healthy children with distal occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed2006

Expression pattern of the homeodomain transcription factor Pitx2 during muscle development.

Late-stage Pitx2(+/LacZ) mouse embryos stained with x-gal appeared to have blue muscles, suggesting that Pitx2 expression specifically marks some phase of the myogenic progression or muscle anlagen formation. Detailed temporal and spatial analyses were undertaken to determine the extent and onset of Pitx2 expression in muscle. Pitx2 was specifically expressed in the vast majority of muscles of the head and trunk in late embryos and adults. Early Pitx2 expression in the cephalic mesoderm, first branchial arch and somatopleure preceded specification of head muscle. In contrast, Pitx2 expression appeared to follow muscle specification events in the trunk. However, Pitx2 expression was rapidly upregulated in these myogenic structures by E10.5. Upregulation correlated tightly with the apposition of a non-myogenic, Pitx2-expressing, cell cluster lateral to the dermomyotome. This cluster first appeared at the forelimb level at E10.25, gradually elongated in the posterior direction, appeared to aggregate from delaminated cells emanating from the ventrally located somatopleure, and was named the dorsal somatopleure. Immunohistochemistry on appendicular sections after E10.5 demonstrated that Pitx2 neatly marked the areas of muscle anlagen, that Pax3, Lbx1, and the muscle regulatory factors (MRFs) stained only subsets of Pitx2(+) cells within these areas, and that virtually all Pitx2(+) cells in these areas express at least one of these known myogenic markers. Taken together, the results demonstrate that, within muscle anlagen, Pitx2 marks the muscle lineage more completely that any of the known markers, and are consistent with a role for Pitx2 in muscle anlagen formation or maintenance.

Animals↗
PubMed1998

Assessment of biological changes in a nonorthodontic sample using the PAR index.

The aim of the present study was to assess the effect of normal growth and development on the Peer Assessment Rating index between 12 and 22 years of age. The sample consisted of 49 nonorthodontic subjects (24 male and 25 females) from the Nijmegen Growth Study. The mean age at the first observation was 12.2 +/- 0.7 years and at the second observation 22.1 +/- 0.6 years. The dental casts at these ages were scored with the Peer Assessment Rating index. The influence of the Angle classification and the treatment need on changes over time in the Peer Assessment Rating score were evaluated. The mean changes in the PAR scores over time between cases that have more than 30% improvement to those that have less than 30% improvement were calculated. The results indicate that there were no significant differences between the mean Peer Assessment Rating score at 12 years of age (12.20 +/- 0.91) and at 22 years of age (12.45 +/- 1.28), but there were relevant differences in individual cases. The changes were irrespective of the Angle classification or the treatment need. Changes over time in the weighted Peer Assessment Rating score were mainly correlated to changes in the anterior crossbite and the overjet. This correlation may be influenced, however, by the applied weighting factor for those occlusal traits.

Adolescent↗
PubMed2002

Role of cranial base flexure in developing sagittal jaw discrepancies.

The aim of this longitudinal cephalometric study was to investigate skeletal features in patients with small and large cranial base angles. Two groups of untreated subjects were formed on the basis of a small and large cranial base angle N-S-Ar at the age of 5 years: the large cranial base angle group (n = 22) consisted of subjects with an N-S-Ar angle larger than 125 degrees (mean, 128.1 degrees ), and the small cranial base angle group (n = 20) included subjects with an N-S-Ar angle of less than 120 degrees (mean, 117.6 degrees ). Cephalometric data of the 2 groups were analyzed at subject ages 5 and 12 years. At both ages, the groups showed significant differences of the variables SNA, SNB, individualized ANB, and Y axis. The unadjusted ANB angle and the angle of convexity N-A-Pg were not significantly different between the 2 groups. According to the individualized norm of the ANB angle, subjects with a large cranial base angle in the primary dentition demonstrated a skeletal Class II tendency both at the initial observation and at the longitudinal follow-up. On the basis of cephalometric variables at 12 years of age, it was possible to classify 88.1% of the initial large and small cranial base angle individuals, indicating a constancy of the skeletal pattern during the longitudinal follow-up. The relationship between cranial base flexure and skeletal pattern of the jaws seems to be established before the age of 5 years.

Cephalometry↗
PubMed2005

Craniofacial development in obese adolescents.

The purpose of this study was to investigate craniofacial morphology in obese adolescents and to compare the morphological data with those of normal adolescents. The study was based on measurements of lateral cephalometric roentgenograms of adolescents who had been diagnosed as obese. Linear and angular measurements were obtained from cephalometric tracings of 27 females (mean age 15.6 +/- 0.83 years) and 23 males (mean age 13.9 +/- 0.98 years). The data were compared with corresponding measurements of gender and age matched controls. The results showed that both males and females in the obesity group exhibited significantly larger mandibular and maxillary dimensions than the controls. On average, mandibular length (Cd-Pgn) was 10 mm greater in males and 8 mm greater in females. Maxillary length (Pm-A) was 3.5 mm greater in males and 3 mm greater in females. When considering vertical dimensions, lower anterior (Ans-Gn) and posterior (S-Go) face height were 4 and 5 mm greater in the obese males, respectively, while in the obese females both these distances were 4 mm greater compared with the controls. Both maxillary (SNA) and mandibular (SNB, SNPg) prognathism were more pronounced in the obesity group than in the control group. This also influenced the average soft tissue profile, which was less convex in the obesity groups. The mandibular plane angle (ML/SN) was smaller in the obesity group than in the control group. Craniofacial morphology differs between obese and normal adolescents. In general, obesity was associated with bimaxillary prognathism and relatively greater facial measurements.

Adolescent↗
PubMed2004

Titanium screw implants in optimization of radiographic evaluation of facial growth in longitudinal animal studies.

The aim of this study was to develop a method that optimizes the reliability of longitudinal radiographic evaluation of small and fast-growing animals, such as the rabbit. Because the use of conventional cephalometric methods, including superimposition of serial radiographs, is more problematic in small animals than in humans, two titanium-alloy screws were placed 10 mm apart in the sagittal crest of the parietal bone in 10 growing New Zealand white rabbits. The anterior screw served as holder for a steel pin that, in turn, secured the fixation of the rabbit's head to a specially designed cephalostat. A lateral cephalogram of each animal was exposed on four occasions at one-month intervals. Computer-aided superimpositions were made of all four cephalograms from each animal using the screws in the calvarium as reference structures. To evaluate the method, the superimpositions were repeated after three to eight weeks, and the superimposition reproducibility was calculated. From the results, it can be concluded that the method allows congruent positioning of the animal skull relative to the film-focus assembly at repeated radiographic examinations. Furthermore, it introduces readily identified reference structures in the animal skull that can be used at high-precision superimposition of serial radiographs.

Animals↗
PubMed2001

Magnetic resonance spectroscopy of the masseter muscle in different facial morphological patterns.

The aims of this study were (1) to develop a reliable noninvasive method to evaluate the masseter muscle metabolism, by using (31)P-magnetic resonance spectroscopy, and (2) to evaluate the metabolic profile of the masseter muscle in subjects with various facial patterns. The maxillary-mandibular relationship, which varied from hypodivergent to hyperdivergent, was measured on lateral cephalograms of 20 adults, 22 to 35 years of age. (31)P-spectra were acquired from the masseter muscle at rest with a custom-made, single-turn, double-tuned, 3 x 5-cm oblong surface coil. The inorganic phosphate to phosphocreatine (Pi/PCr) ratios were measured and compared in relation to vertical and sagittal cephalometric measurements. A statistically significant (R(2) = 0.65, r = 0.81, P = .001) relationship was found between Pi/PCr ratio and the palatal-to-mandibular plane angle. As the maxillary-to-mandibular divergence increased, the Pi/PCr ratio decreased. This correlation suggests that muscles with a higher Pi/PCr ratio have a higher resting metabolic activity than those with a lower Pi/PCr ratio. Consequently, these muscles may keep bone under more tension and influence its growth in a more horizontal direction. Another possible explanation of the results is that the fiber type composition of the masseter muscle varies with facial morphology.

Adult↗
PubMed1989

Changes in the maxillary and mandibular tooth size-arch length relationship from early adolescence to early adulthood. A longitudinal study.

The purpose of this study was to determine the association between the changes in maxillary and mandibular tooth size-arch length discrepancies (TSALD) and various dentofacial variables for 18 male and 14 female subjects with normal occlusion. All subjects were participants in the Iowa Longitudinal Growth Study and records were evaluated at two stages of dental development: stage I, when the permanent second molars initially erupted into occlusion (X age = 13.3 years); and stage II, at early adulthood (X age = 26.0 years). The following sets of variables were evaluated: mesiodistal crown diameters of single and groups of permanent teeth, dental arch widths and lengths, curve of Spee, maxillary and mandibular anterior and total crowding or spacing, anterior tooth rotations, and various cephalometric dentofacial parameters. Student's t test were used to compare subjects with the most and least changes. Regression analyses also were used to assess the relationships between these parameters and the changes in the maxillary and mandibular tooth size-arch length relationship. The most consistent finding from the t test comparisons is the significantly greater reduction in the available arch length in the group with the most TSALD at early adulthood. No other variables were found to be consistently different in the comparisons between the two groups. The results of the regression analysis indicated that a number of dentofacial variables are associated with the changes in the maxillary and mandibular TSALD--for example, the mesiodistal diameter of different teeth and the changes in anterior and posterior facial heights. The clinical implications of the present findings are discussed.

Adolescent↗
PubMedDate not supplied

Dietary consistency and craniofacial development related to masticatory function in minipigs.

Since the 1890s oral biological researchers have been interested in the idea that strenuous mastication of unprocessed food will stimulate proper oral-facial growth and occlusal relationships. Conversely, lack of such function due to consumption of refined food is one hypothesis among many for the etiology of malocclusion in industrialized humans. Adequately controlled experimental testing of the idea has been limited to rats. To investigate the "disuse" theory in a larger-bodied and more occlusally relevant animal model, we raised four Yucatan minipigs from weaning on hard diet (HD) and another four on softened but equivalent diet (SD). The animals were monitored for eight months, sacrificed, and then occlusal and osteometric data collected. Variations due to dietary regime are pervasive and not due to caries, periodontitis, or attrition differences. Whereas HD body weight is 10% greater than SD, the deep masseter is 25% greater, with similar disproportion in superficial masseter and temporalis weight. Facial prognathism, arch narrowness, tooth crowding/maleruption and posterior cranial tapering are markedly different in the two groups. A curious posterior torsional difference in the mandibular rami, as well as broadness and flatness of the mandibular symphysis, also occur in SD. We performed a Q-mode principal coordinates analysis of the 19 logged variables for the specimens, bootstrapping the variable list, to demonstrate a statistically significant (P < .01) overall pattern of dramatic differences. Having controlled other celebrated orthodontic etiologies (genetic background, respiratory mode, infectious degeneration and interproximal attrition), these results support the proposition that dietary consistency relates directly to human craniofacial growth.

Animals↗
PubMed1994

Does nasal septal deviation influence adult posterior choanal size?

Despite the development of modern imaging techniques, no study has been carried out to establish the normal size (particularly the area) of the adult posterior choanae. In this study we present our findings of the normal anatomical sizes of the adult posterior choanae and its relationship to septal deviation, by analysing MRI images of 70 patients. Coronal sections through the sphenoid rostrum and axial sections through the nasal septum were used. There were 32 males and 38 female patients. The age ranged between 18 and 73 years (mean 35.6). Our results show that the posterior choanal dimensions were as follows: right area: 1.35-6.1 cm2 (mean 2.7 cm2); left area: 1.4-5.9 cm2 (mean 2.7 cm2); right width: 0.9-2.1 cm (mean 1.5 cm); left width: 0.9-2.2 cm (mean 1.5 cm); right height: 2.5-4.0 cm (mean 2.6 cm); and left height: 1.5-4.0 cm (mean 2.5 cm). Chi-square analysis showed no statistically significant differences between left- and right-sided measurements. Twenty-three patients had a deviated septum towards the left side, 22 patients towards the right side, and 25 patients had no septal deviation. Chi-square analysis showed no statistical correlation between deviation of the nasal septum and any of the three dimensions of the posterior choanae studied.

Adult↗
PubMed1999

[3-D model analysis of the maxilla of infants with lip-jaw-palate clefts].

For the investigation of three-dimensional morphological changes in the maxilla of children with cleft lip and palate, the use of two-dimensional test analysis is inadequate. Since no standardised three-dimensional method has so far been available, a three-dimensional digital, computer-aided procedure was developed to visualize and metrically analyse the growth of the edentulous maxilla of infants with cleft lip and palate. Chronologically consecutive casts of the maxillas (obtained at the ages of one week, and three, six and twelve months) of five children with complete unilateral CLP were measured optically with the instrument Micromeasure 70. Following digitation, the casts were reconstructed in the computer, aligned and superimposed using the Orthosurf program. The distances between the surfaces were then measured; in addition, the surfaces were segmented perpendicular to the alveolar crest at reference points C1, C1', C2, C2' and I. The volumes of the resulting segments were determined and compare with one another. Specially designed software automated the following steps: 1. identification of reference points; 2. alignment of the cloud of points in a system of coordinates, and 3. identification of the alveolar crest. Our initial results show that (1) the new method enables visualization of the extent and direction of morphological changes of the mucosal surface, and (2) reproducible quantification of these changes via the determination of changes in the volume of defined alveolar segments. The three-dimensional analysis presented here permits a comprehensive three-dimensional measurement of the models of the edentulous maxilla of infants with cleft lip and palate.

Cephalometry↗
PubMed2003

[Genetic and experimental approach to bony craniofacial growth: the role of the divergent homeobox gene Msx1].

Tooth agenesis and clef palate are associated to the mutation of the Msx1 homeobox genes, highlighting the pivotal role of homeobox genes during the initial development of the craniofacial skeleton. Msx1 also controls the terminal differentiation of mineralised tissues forming cells. Recently, a Msx1 antisense RNA has been identified which inhibits Msx1 protein expression in odontoblastic cells. In order to investigate the role of Msx1 gene and its antisense RNAs during the late developmental stages of the craniofacial bone formation, the expression pattern of Msx1 protein, sense and antisense transcripts and the aspects of bone growth have been studied in post-natal normal and Msx1 knock-in mutant mice. Msx1 protein was strongly expressed in preosteoblasts of specific bone sites such as the basal mandible. At the same bone sites, bone growth was impaired or markedly decreased in knock-in mice. The comparison between the various expression patterns of Msx1 protein, sense and antisense RNAs suggests that the site-specific action of Msx1 protein on bone growth and craniofacial morphogenesis and that Msx1 protein level could be controlled by the local ratio of Msx1 sense and antisense RNAs. Regarding our experimental data and hypothesis, a clinical study of patients with MSX1 mutation will be performed in order to better characterize the abnormalities of the craniofacial skeleton growth.

Animals↗
PubMed2001

Orthodontic aspects of the use of oral implants in adolescents: a 10-year follow-up study.

The aim of the present study was to evaluate the long-term effect of implants installed in different dental areas in adolescents. The sample consisted of 18 subjects with missing teeth (congenital absence or trauma). The patients were of different chronological ages (between 13 and 17 years) and of different skeletal maturation. In all subjects, the existing permanent teeth were fully erupted. In 15 patients, 29 single implants (using the Brånemark technique) were installed to replace premolars, canines, and upper incisors. In three patients with extensive aplasia, 18 implants were placed in various regions. The patients were followed during a 10-year period, the first four years annually and then every second year. Photographs, study casts, peri-apical radiographs, lateral cephalograms, and body height measurements were recorded at each control. The results show that dental implants are a good treatment option for replacing missing teeth in adolescents, provided that the subject's dental and skeletal development is complete. However, different problems are related to the premolar and the incisor regions, which have to be considered in the total treatment planning. Disadvantages may be related to the upper incisor region, especially for lateral incisors, due to slight continuous eruption of adjacent teeth and craniofacial changes post-adolescence. Periodontal problems may arise, with marginal bone loss around the adjacent teeth and bone loss buccally to the implants. The shorter the distance between the implant and the adjacent teeth, the larger the reduction of marginal bone level. Before placement of the implant sufficient space must be gained in the implant area, and the adjacent teeth uprighted and paralleled, even in the apical area, using non-intrusive movements. In the premolar area, excess space is needed, not only in the mesio-distal, but above all in the bucco-lingual direction. Thus, an infraoccluded lower deciduous molar should be extracted shortly before placement of the implant to avoid reduction of the bucco-lingual bone volume. Oral rehabilitation with implant-supported prosthetic constructions seems to be a good alternative in adolescents with extensive aplasia, provided that craniofacial growth has ceased or is almost complete.

Adolescent↗
PubMed1994

Development of a strain of rabbits with congenital simple nonsyndromic coronal suture synostosis. Part II: Somatic and craniofacial growth patterns.

In the March 1993 issue of The Cleft Palate-Craniofacial Journal we reported a female rabbit born in our laboratory with complete bilateral coronal suture (CS) synostosis. This follow-up study presents our attempts to breed the animal and establish a strain of craniosynostotic rabbits. The second part of this study presents longitudinal somatic and craniofacial growth data in offspring with coronal suture synostosis. Serial growth data from 72 animals were collected for the present study. The sample consisted of 11 animals (10 offspring and the original female) with complete nonsyndromic unilateral (plagiocephalic) or bilateral (brachycephalic) CS synostosis, 19 animals with partial CS synostosis, and 42 unaffected control litter mates. At 10 days of age, all animals had radiopaque amalgam markers placed on either side of the frontonasal, coronal, anterior lambdoidal, and sagittal sutures. Body weights and serial lateral and dorsoventral head radiographs were taken at 1.5 (10 days), 6, 12, and 18 weeks of age. All animals showed similar body weights at 1.5 weeks of age, while completely synostosed animals exhibited a slight (about 12%), but significantly (p < .001) lowered body weight by 18 weeks of age. Results revealed that by 1.5 weeks of age the completely synostosed animals already exhibited brachycephalic cranial vaults, midfacial hypoplasia, and increased flattening of the cranial base compared to unaffected siblings. This pattern continued through 18 weeks of age, with the partially synostosed animals exhibiting intermediate morphologies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗