Premature gray hair development in the interbrow region owing to the loss of maxillary first molars in young mice.

The exact sites of premature hair graying and whether tooth loss causes this condition remain unknown. In this study, we aimed to explore the effect of reduced mastication on premature hair graying. Maxillary first molars were extracted from young mice, and the mice were observed for 3 months, along with non-extraction control group mice. After 3 months, gray hair emerged in the interbrow region of mice in the tooth extraction group but not in the control group. The expression of tyrosinase-related protein-2 (TRP-2) mRNA was lower in the interbrow tissues of young mice without maxillary molars than in those with maxillary molars. Tooth loss leads to interbrow gray hair growth, possibly because of weakened trigeminal nerve input, suggesting that reduced mastication causes premature graying. Thus, prompt prosthetic treatment after molar loss is highly recommended.

Feasibility of spheno-occipital synchondrosis fusion stages as an indicator for the assessment of maxillomandibular growth: A mixed longitudinal study.

OBJECTIVES: This study aimed to assess the relative growth rates (RGRs) of the maxilla and mandible at varying fusion stages of the spheno-occipital synchondrosis (SOS), thereby elucidating the potential of SOS stages in predicting maxillomandibular growth. MATERIALS AND METHODS: A total of 320 subjects (171 boys and 149 girls), aged 6 to 18 years, were retrospectively included. Each subject had a minimum of two longitudinal cone-beam computed tomography (CBCT) images, with no more than one interval of SOS fusion stage change between the two scans. Subjects were categorized based on their SOS fusion stages and genders. The RGRs of the maxilla and mandible at various SOS fusion stages were measured and compared using longitudinal CBCT images. RESULTS: Significant statistical differences were observed in maxillomandibular RGRs across various SOS fusion stages. In girls, the sagittal growth of the maxilla remained stable and active until SOS 3, subsequently exhibited deceleration in SOS 4-5 (compared to SOS 3-4, P < .05) and continued to decrease in SOS 5-6. Whereas in boys, the sagittal growth of the maxilla remained stable until SOS 4, and a deceleration trend emerged starting from SOS 5 to 6 (P < .01 compared to SOS 4-5). Mandibular growth patterns in both genders exhibited a progression of increasing-accelerating-decelerating rates from SOS 2 to 6. The highest RGRs for total mandibular length were observed in SOS 3-4 and SOS 4-5. CONCLUSION: Spheno-occipital synchondrosis fusion stages can serve as a valid indicator of maxillomandibular growth maturation.

Variability of the maxillary suture maturation and density in the subjects with different sex and growth status.

INTRODUCTION: The objective of this study was to classify median palatine suture (MPS) maturation type in young and adult patients. Additionally, we compared MPS maturity type and density based on sex and growth status. MATERIALS AND METHODS: In this retrospective cone beam computed tomography study, we included a total of 221 subjects, grouped based on sex and growth status. Once scans were aligned and oriented in the sagittal view, we conducted our evaluations on the axial sections. Based on interdigitation and shape, the MPS were categorized into Maturation Types A through E. Additionally, MPS density was measured as Hounsfield unit equivalent pixel intensity value scale for anterior and posterior sutural regions. RESULTS: The majority of male (39%) and female (42%) subjects had MPS Maturation Type C. A maximum number of growing (42%) patients had Type C and nongrowing subjects (39%) had Type E sutures. The sex comparison showed significantly lower (p < .001) MPS density for both anterior and posterior regions in males when compared to females. Additionally, for the posterior region, nongrowing males had significantly lower (p < .001) MPS density when compared to nongrowing females. Subgroup comparisons of the MPS densities between growing and nongrowing males and growing and nongrowing females showed a significant difference (p < .001). CONCLUSION: Classification of the MPS based on the maturation types provides a reliable predictor for orthodontic treatment planning. MPS density is significantly higher in females as compared to males. Similarly, nongrowing individuals have significantly higher MPS density compared to growing individuals for both anterior and posterior locations.

A morphometric analysis of the immature human infraorbital canal.

PURPOSE: The importance of the infraorbital canal in the growth of the maxilla and associated mid-facial region has significance for innervation of this region as well as the associated dentition, yet little is known about the development of the canal. An analysis of its dimensions and morphology during the late prenatal and early postnatal periods was thus undertaken. The aim of this study was to describe changes in the morphology, size and branching pattern of the infraorbital canal during the late prenatal and early postnatal stages of human growth. METHODS: Fifty human fetal and neonatal maxillae were analyzed. The sample included 27 late prenatal individuals (30 gestational weeks and birth) and 23 early postnatal individuals (birth and 1 year). Maxillae were scanned using a Nikon XTH 225 L micro-CT unit and analyzed using VG studiomax v3.2. Measurements included the maximum width, height and surface area of each foramen associated with the infraorbital canal and the total length of the canal, bilaterally. RESULTS: All the measurements of the canal were greater in the early postnatal group than in the late prenatal group, while the walls and branching pattern of the canal were better developed in the postnatal group. Bone development occurred within the walls as development proceeded. Variations in the branching pattern of the canal were found. CONCLUSION: The morphology of the infraorbital canal reflected the developmental stage of associated structures such as the dentition, maxillary sinus and orbit.

Metameric variation of upper molars in hominoids and its implications for the diversification of molar morphogenesis.

Metameric variation of molar size is in part associated with the dietary adaptations of mammals and results from slight alterations of developmental processes. Humans and great apes exhibit conspicuous variation in tooth morphology both between taxa and across tooth types. However, the manner in which metameric variation in molars emerged among apes and humans via evolutionary alterations in developmental processes remains largely unknown. In this study, we compare the enamel-dentine junction of the upper molars of humans-which closely correlates with morphology of the outer enamel surface and is less affected by wear-with that of the other extant hominoids: chimpanzees, bonobos, gorillas, orangutans, and gibbons. We used the morphometric mapping method to quantify and visualize three-dimensional morphological variation, and applied multivariate statistical analyses. Results revealed the following: 1) extant hominoids other than humans share a common pattern of metameric variation characterized by a largely linear change in morphospace; this indicates a relatively simple graded change in metameric molar shape; 2) intertaxon morphological differences become less distinct from the mesial to distal molars; and 3) humans diverge from the extant ape pattern in exhibiting a distinct metameric shape change trajectory in the morphospace. The graded shape change and lower intertaxon resolution from the mesial to distal molars are consistent with the concept of a 'key' tooth. The common metameric pattern observed among the extant nonhuman hominoids indicates that developmental patterns underlying metameric variation were largely conserved during ape evolution. Furthermore, the human-specific metameric pattern suggests considerable developmental modifications in the human lineage.

Intraspecific variability in human maxillary bone modeling patterns during ontogeny.

OBJECTIVES: This study compares the ontogenetic bone modeling patterns of the maxilla to the related morphological changes in three human populations to better understand how morphological variability within a species is established during ontogeny at both micro- and macroscopic levels. MATERIALS AND METHODS: The maxillary bones of an ontogenetic sample of 145 subadult and adult individuals from Greenland (Inuit), Western Europe (France, Germany, and Portugal), and South Africa (Khoekhoe and San) were analyzed. Bone formation and resorption were quantified using histological methods to visualize the bone modeling patterns. In parallel, semilandmark geometric morphometric techniques were used on 3D models of the same individuals to capture the morphological changes. Multivariate statistics were applied and shape differences between age groups were visualized through heat maps. RESULTS: The three populations show differences in the degree of shape change acquired during ontogeny, leading to divergences in the developmental trajectories. Only subtle population differences in the bone modeling patterns were found, which were maintained throughout ontogeny. Bone resorption in adults mirrors the pattern found in subadults, but is expressed at lower intensities. DISCUSSION: Our data demonstrate that maxillary morphological differences observed in three geographically distinct human populations are also reflected at the microscopic scale. However, we suggest that these differences are mostly driven by changes in rates and timings of the cellular activities, as only slight discrepancies in the location of bone resorption could be observed. The shared general bone modeling pattern is likely characteristic of all Homo sapiens, and can be observed throughout ontogeny.

Do Patients With Cleft Lip and Palate Differ From Normal Individuals in Skeletal Maturity?

Orthopedic treatment to improve deficient maxillary growth of cleft lip and palate patients is an important part of treatment. The success of this treatment is strongly dependent on the time of initiation of therapy. There has been a large controversy in the available literature regarding the skeletal age of these patients. The aim of the present study was to compare the skeletal age of cleft lip and palate patients with normal individuals.37 unilateral and 14 bilateral cleft lip and palate patients and 47 healthy individuals participated in this cross-sectional study. The patients were classified into 8 to 10 and 11 to 14-year-old individuals. Cervical vertebral maturational stage of participants was evaluated in the lateral cephalometry. The skeletal age of cleft lip and palate patients was compared with normal controls. Chi-square was used for statistical analysis. There was not a significant difference in the skeletal developmental stage of unilateral and bilateral cleft compared to their normal peers according to their age and sex. Also, significant difference in skeletal maturational stage of cleft lip and palate patients was not found between boys and girls (P = 0.8). Similarly, no significant difference was found in the skeletal age of the 3 studied groups without considering the age and sex of participants (P = 0.5). Regarding the similar skeletal maturational stage of cleft lip and palate patients with normal controls in our study, their maxillofacial orthopedic treatment can be initiated at similar time to normal peers.

The Influence of Lip Repair on the Growth of Craniofacial Structures in Bilateral Cleft Lip and Palate Patients With Unoperated Palate From Childhood to Adulthood.

PURPOSE: Surgical treatment of complete bilateral cleft lip and palate (BCLP) is the most difficult procedure among common cleft lip and palate. This study was to research the long-term effect of lip surgery by localizing the craniofacial growth pattern of BCLP patients in the Han people in western China compared with normal healthy people from childhood to adulthood. PATIENTS AND METHODS: A cross-sectional study included a sample of 43 BCLP patients who have received lip repair and a control group of 55 normal healthy people with Angle Class I occlusion at the similar age, gender and ethnicity, and all participants were obtained from the Department of Oral and Maxillofacial Surgery, Sichuan University. Sixteen linear and 14 angular bony landmarks were identified on lateral cephalometric radiographs at the average age of 5.6-year-old, 10.7-year-old, and 24.2-year-old. The measurements were used to represent the growth changes of cranial base, bony nasopharynx, maxillary, mandibular and maxilla-mandibular relationship. Between-group differences were assessed by using the Independent-Sample t test. RESULT: Lip repair has a slow and long-term effect on the craniofacial morphology. The tension from repaired orbicularis oris muscle would cause a decrease in maxillary sagittal length and the retroposition of maxilla combined with the mandibular functional displacement, which would cause a positive change in the postoperative facial morphology of BCLP patients in the long run. CONCLUSION: BCLP patients who have undergone lip repair at an early age have the potential to develop better facial convexity.

Incidence and morphology of the incisive suture in CT scanning of young children and human fetuses.

PURPOSE: Incisive suture is a suture classically described on the oral face of the palate in fetuses and young children. The aim of our study was to describe the evolution of the incisive suture in human fetuses and to evaluate the incidence of this suture in a population of young children under 4 years, to determine if there is a possibility of improving the anterior growth of the maxilla, by stimulation of this suture. METHODS: One hundred and thirty CT scan images of patients aged from birth to 48 months have been studied and nine fetal palates aged from 18 to 26 weeks of development, have been scanned using high-resolution X-ray micro-computed tomography RESULTS: The CT scan images of patients showed that an incisive suture was present in 33/130 cases (25,4%). All the patients with a suture were under 2 years old. The fetal palate study showed that the suture was present in the inferior aspect of the palate (oral cavity) in all cases. The incisive suture increased from 18 to 24 weeks. At 26 weeks it stopped growing although the intercanine length increased. Considering the closure of the suture in a vertical plane, our study on fetuses has shown that the incisive suture is closing from its superior side (nasal side) to its inferior side. CONCLUSIONS: Considering all these results it appears to us that the incisive suture is partially ossified after birth, it cannot be stimulated by orthodontic appliances.

Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: maxillary growth at eight years of age.

OBJECTIVES: To assess differences in craniofacial growth at 8 years of age according to the different protocols for primary cleft surgery in the Scandcleft project. DESIGN AND SETTING: Prospective, randomized, controlled clinical trial (RCT) involving 10 centres, including non-syndromic Caucasians with unilateral cleft lip and palate (UCLP). In Trial 1, a common surgical method (1a) with soft palate closure at 3-4 months of age and hard palate closure at 12 months of age was tested against similar surgery but with hard palate repair at 36 months (delayed hard palate closure) (1b). In Trial 2, the common method (2a) was tested against simultaneous closure of both hard and soft palate at 1 year (2c). In Trial 3, the common method (3a) was tested against hard palate closure together with lip closure at 3 months of age and soft palate closure at 1 year of age (3d). Participants were randomly allocated by use of a dice. Operator blinding was not possible but all raters of all outcomes were blinded. SUBJECTS AND METHODS: The total number of participating patients at 8 years of age was 429. Lateral cephalograms (n = 408) were analysed. The cephalometric angles SNA and ANB were chosen for assessing maxillary growth for this part of the presentation. RESULTS: Within each trial (Trial 1a/1b, Trial 2a/2c, and Trial 3a/3d), there was no difference in cephalometric values between the common and the local arm. There were no statistically significant differences in the SNA and ANB angles between the common arm in Trial 1a (mean SNA 77.8, mean ANB 2.6) and Trial 2a (mean SNA 79.8, mean ANB 3.6) and no difference between Trial 1a and Trial 3a, but a statistical difference could be seen between Trial 2a and Trial 3a (mean SNA 76.9, mean ANB 1.7). However, the confidence interval was rather large. Intra- and inter-rater reliability were within acceptable range. CONCLUSIONS: The timing and the surgical method is not of major importance as far as growth outcomes (SNA and ANB) in UCLP are concerned. REGISTRATION: ISRCTN29932826. PROTOCOL: The protocol was not published before trial commencement.

Ontogeny of the human maxilla: a study of intra-population variability combining surface bone histology and geometric morphometrics.

Bone modeling is the process by which bone grows in size and models its shape via the cellular activities of the osteoblasts and osteoclasts that respectively form and remove bone. The patterns of expression of these two activities, visible on bone surfaces, are poorly understood during facial ontogeny in Homo sapiens; this is due mainly to small sample sizes and a lack of quantitative data. Furthermore, how microscopic activities are related to the development of morphological features, like the uniquely human-canine fossa, has been rarely explored. We developed novel techniques for quantifying and visualizing variability in bone modeling patterns and applied these methods to the human maxilla to better understand its development at the micro- and macroscopic levels. We used a cross-sectional ontogenetic series of 47 skulls of known calendar age, ranging from birth to 12 years, from a population of European ancestry. Surface histology was employed to record and quantify formation and resorption on the maxilla, and digital maps representing each individual's bone modeling patterns were created. Semilandmark geometric morphometric (GM) methods and multivariate statistics were used to analyze facial growth. Our results demonstrate that surface histology and GM methods give complementary results, and can be used as an integrative approach in ontogenetic studies. The bone modeling patterns specific to our sample are expressed early in ontogeny, and fairly constant through time. Bone resorption varies in the size of its fields, but not in location. Consequently, absence of bone resorption in extinct species with small sample sizes should be interpreted with caution. At the macroscopic level, maxillary growth is predominant in the top half of the bone where bone formation is mostly present. Our results suggest that maxillary growth in humans is highly constrained from early stages in ontogeny, and morphological changes are likely driven by changes in osteoblastic and osteoclastic rates of expression rather than differences in the bone modeling patterns (i.e. changes in location of formation and resorption). Finally, the results of the micro- and macroscopic analyses suggest that the development of the canine fossa results from a combination of bone resorption and bone growth in the surrounding region.

Dental development in children with supernumerary teeth in the anterior region of maxilla.

OBJECTIVE: Development of human dentition has been used as a predictor for evaluating the growth and maturity of an individual. It is fairly identical in a specific population, but the effect of development on subjects with dental anomalies had not been fully explored, particularly on subjects with supernumerary teeth (ST). This study hence aims to evaluate the dental development of children with and without ST. MATERIALS AND METHODS: Sample size calculation was conducted and 320 radiographs of subjects with and without supernumerary teeth (ST) were obtained from the archives of a teaching hospital. The subjects in both groups were age and sex matched. All the subjects belong to southern Chinese ethnicity aged 2 to 14 years. The left-side dentition was scored, and dental age (DA) was estimated by obtaining scores from the southern Chinese dental reference dataset. Paired t test was used to calculate the difference between chronological age and dental age (CA-DA) for boys and girls with and without ST and further based on the number and position of ST. RESULTS: The difference between chronological age and dental age (CA-DA) was 0.10 years for boys and 0.19 years for girls with ST whilst 0.01 and 0.05 years for boys and girls without ST (p > 0.05). The boys with bilateral ST showed significant delay in dental development of 0.23 years (p < 0.05). Position of the ST did not have any influence on dental age. CONCLUSIONS: No significant difference was observed in the dental development of children with and without supernumerary teeth. CLINICAL RELEVANCE: Understanding dental development of children with supernumerary teeth may be useful in appropriate treatment planning of such conditions.

Three dimensional maxillary growth modeling in newborns.

OBJECTIVES: The aim of this study was to develop an accurate and intuitive semi-automatic segmentation technique to calculate an average maxillary arch and palatal growth profile for healthy newborns in their first year of life. MATERIALS AND METHODS: Seventy babies born between 1985 and 1988 were included in this study. Each child had five impressions made in the first year after birth that were digitalized. A semi-automatic segmentation tool was developed and used to assess the maxillary dimensions. Finally, random effect models were built to describe the growth and build a simulation population of 10,000 newborns. The segmentation was tested for inter- and intra-observer variability. RESULTS: The Pearson correlation coefficient for each of the variables was between 0.94 and 1.00, indicating high inter-observer agreement. The paired sample t test showed that, except for the tuberosity distance, there were small, but significant differences in the landmark placements between observers. Intra-observer repeatability was high, with Pearson correlation coefficients ranging from 0.87 to 1.00 for all measurements, and the mean differences were not significant. A third or second degree growth curve could be successfully made for each parameter. CONCLUSIONS: These findings indicated this method could be used for objective clinical evaluation of maxillary growth. CLINICAL RELEVANCE: The resulting growth models can be used for growth studies in healthy newborns and for growth and treatment outcome studies in children with cleft lip and palate or other craniofacial anomalies.

The Influence of the First-Stage DO Treatment of Palate Defect on Growth of Maxilla.

To study the influence of distraction osteogenesis (DO) on the maxillary growth as first-stage treatment of palatal defect. The uniform palate defect experimental animal models (21 miniature pigs) were established surgically. Then animals were randomly divided into negative control group (A, n = 6), conventional surgery group (B, n = 6), and distraction osteogenesis group (C, n = 9) respectively. The group A underwent none treatment as control group, the group B were undergoing a conventional defect repair surgery, and the group C were undergoing a distraction osteogenesis treatment. Cone beam computed tomography examination was performed monthly to analyze the growth of maxilla for 6 months. One pig of group C was randomly sacrificed at 2, 4, and 8 weeks after the completion of DO and the tissue of distraction gap was stained with hematoxylin-eosin and Masson staining. At the end of 6th months, all pigs were sacrificed and tissues of the surgical area were stained as previous described. The palate defect was repaired by the distraction osteogenesis with the successful bone formation on the distraction gap. Group A and group C kept a similar growth rate, but that of group B was relatively slow. Distraction osteogenesis is efficient and successful for closing the defect of palate and there is no significant disturbance on the subsequent growth of the maxilla.

Analysis of Dental Arch in Children With Oral Cleft Before and After the Primary Surgeries.

This study aimed to evaluate longitudinally the alteration of the dental arch dimensions of children with different oral cleft types, before and after the primary surgeries. Three-dimensional images of the maxillary dental casts of children with unilateral complete cleft lip (G1), unilateral complete cleft lip and palate (G2), and cleft palate (G3). The children were evaluated at pre-cheiloplasty (T1), pre-palatoplasty (T2), and 1 year after palatoplasty (T3). The measurements obtained: intercanine (C-C') and intertuberosity (T-T') distances, anterior (I-CC') and total (I-TT') arch lengths. To analyze the intraexaminer error, paired t-test was applied and Dahlbergh formula. The intragroups comparisons were applied: paired t-test, ANOVA followed by Tukey, Wilcoxon test, and Kruskal-Wallis test followed by Dunn test. The intergroup comparisons were performed by independent t-test and Mann-Whitney test. In G1, the C-C', T-T', and the I-TT' distances revealed a significant increase of the maxilla. In G2, the C-C' distance statistically decreased from T1 to T3, T-T' distance showed statistical increase from T1 to T3. The I-TT' length increased with statistically significant differences between T1 and T3, T2 and T3. In G3, the C-C', T-T', and I-TT' distance increased was statistically significant. The longitudinal evaluation of the changes occurred in the dental arches with different oral cleft types showed that cheiloplasty and palatoplasty caused the most alterations in the development of the maxillary dimensions of children with complete cleft lip and palate.

Critical Growth Processes for the Midfacial Morphogenesis in the Early Prenatal Period.

BACKGROUND: Congenital midfacial hypoplasia often requires intensive treatments and is a typical condition for the Binder phenotype and syndromic craniosynostosis. The growth trait of the midfacial skeleton during the early fetal period has been assumed to be critical for such an anomaly. However, previous embryological studies using 2-dimensional analyses and specimens during the late fetal period have not been sufficient to reveal it. OBJECTIVE: To understand the morphogenesis of the midfacial skeleton in the early fetal period via 3-dimensional quantification of the growth trait and investigation of the developmental association between the growth centers and midface. METHODS: Magnetic resonance images were obtained from 60 human fetuses during the early fetal period. Three-dimensional shape changes in the craniofacial skeleton along growth were quantified and visualized using geometric morphometrics. Subsequently, the degree of development was computed. Furthermore, the developmental association between the growth centers and the midfacial skeleton was statistically investigated and visualized. RESULTS: The zygoma expanded drastically in the anterolateral dimension, and the lateral part of the maxilla developed forward until approximately 13 weeks of gestation. The growth centers such as the nasal septum and anterior portion of the sphenoid were highly associated with the forward growth of the midfacial skeleton (RV = 0.589; P < .001). CONCLUSIONS: The development of the midface, especially of the zygoma, before 13 weeks of gestation played an essential role in the midfacial development. Moreover, the growth centers had a strong association with midfacial forward growth before birth.

Craniofacial growth spurt in Class I subjects.

INTRODUCTION: The objective was to study the growth spurt of Class I subjects, focusing on the ability to predict the peak of the growth spurt of the maxillary (Co-A) and mandibular (Co-Pog) lengths from the maturational changes of the cervical vertebrae. METHODS: The longitudinal lateral cephalographs of 14 males (ages, 10-15 years) and 12 females (ages, 9-14 years) were selected from the Craniofacial Growth Studies Legacy Collection of the American Association of Orthodontists Foundation. The cephalographs were taken at regular 1-year intervals. A cervical vertebral maturation (CVM) method that divided skeletal maturation into 6 stages was used for growth prediction. Growth increments calculated for the annual age intervals were used to examine the diagnostic performance of the CVM method. RESULTS: In males, the most peaks for Co-Pog were detected in the CVM3-CVM4 interval in 7 males (50%); for Co-A, the most peaks were found in the CVM2-CVM3 interval in 7 males (50%). In females, the most peaks for both Co-Pog and Co-A were seen in the CVM2-CVM3 interval in 7 females (58%) and in 6 females (50%), respectively. The fewest peaks were detected in CVM4-CVM5 for both males and females. CONCLUSIONS: In Class I subjects with balanced anteroposterior jaw relationships, presence of CVM3 would indicate the peak of the growth spurt, and CVM2 would mean that the peak has not yet arrived. During CVM2, the shapes of cervical vertebrae 3 and 4, whether trapezoid or horizontal rectangular, would indicate whether the subject is in the early CVM2 or is about to be in CVM3.

Evaluation of three-dimensional superimposition technique on parietal bone of the puberty beagle dogs.

OBJECTIVES: This study aimed to (a) evaluate the stability of the parietal bone of 6-9 months old beagles and (b) examine whether parietal regional superimposition can provide an atraumatic and effective solution for further maxillary expansion study. MATERIALS AND METHODS: Six prepubertal 6-month-old male beagles were included. Six miniscrew markers were inserted into the left and right sides of the parietal bone, and two of them were placed bilaterally near the palatal suture. The subjects were scanned with cone beam computed tomography (CBCT) at three time points of T0 (6 months old), T1 (7.5 months old) and T2 (9 months old), respectively. All skull models were analyzed by both the miniscrew superimposition and the parietal regional superimposition. RESULTS: The two superimposition methods had no significant difference (p > 0.05) in displacements of miniscrew markers between left and right first premolars (PM1). The maxillary superimposition between T0 and T2 indicated that the length and width of the maxillary as well as the width of the zygoma root increased significantly (p < 0.05), while the height of maxillary had no significant difference (p > 0.05) over the 3 months. CONCLUSIONS: The parietal bone is relatively stable for beagles from 6 months old to 9 months old and thus can be used as a reference region for 3D skull model superimposition of the beagle dog.

Growth and Development of Craniofacial Structures in Patients at Different Ages With Unrepaired Submucous Cleft Palate.

PURPOSE: Submucous cleft palate (SMCP) is a particular subtype of cleft palate deformity; research related to the craniofacial features of patients with SMCP is comparatively rare. The study objective was to perform a cephalometric comparison of the craniofacial features of patients with SMCP and non-cleft controls at different ages. MATERIALS AND METHODS: The sample in this cross-sectional study was composed of 2 groups: SMCP patients and non-cleft controls. The primary predictor variables were study group (cleft and non-cleft) and age. Age was divided into 3 groups. The outcome variables of interest were craniofacial measurements. The measurements used reflect cranial length, cranial angle, maxillary sagittal length and protrusion, maxillary vertical height, pharyngeal depth, facial height, mandibular length and protrusion, mandibular plane angle, and intermaxillary relation. Adjusted cephalometric craniofacial measurements between the groups were compared in 3 age groups using generalized linear models after being adjusted for age and gender. RESULTS: The study included 60 SMCP patients and 60 non-cleft controls. SMCP patients and non-cleft controls were divided into 3 subgroups: those aged 5 to 7 years, those aged 9 to 11 years, and those aged 18 to 30 years. Patients with SMCP at age 5 to 7 years showed a shortened cranial base length, maxillary sagittal length and height, and bony pharynx depth. Patients with SMCP at age 9 to 11 years showed a smaller maxillary sagittal length and bony pharynx depth and an inharmonious jaw relationship. Patients with SMCP at age 18 to 30 years showed a smaller maxillary sagittal length and height and an inharmonious jaw relationship. CONCLUSIONS: SMCP is associated with progressive maxillary retrognathism and reduced profile convexity from childhood to adulthood.

Characteristics of the Development of the Maxillae and Vomer in Patients With Bilateral Cleft Lip and Palate.

The aim of this study was to investigate the anatomical features of the maxillae and vomer in patients with bilateral cleft lip and palate (BCLP). Craniofacial measurements of 24 adult BCLP patients (GB) and 32 normal adult controls (GN) were carried out. We measured the width and length of the maxillae, their relative positions with respect to the coronal plane passing through the basion, and the volume, length, cross-sectional area, and mean width of the vomer. Between-group differences were assessed using independent-sample t tests. Finite element models (FEMs) were used to explore the bite forces acting on the bone by evaluating the distribution of stress and bone displacement. The mean vomer volume and width were significantly larger in the GB group than in the GN group (P = 0.000), whereas the length was significantly shorter (P = 0.000). The anterior maxillary length (A1-P3M⊥CP) was significantly larger in the GB group (P = 0.013), whereas the posterior maxillary length (P3M-P6M⊥CP) and overall maxillary length (A1-P6M⊥CP) at the dental level were significantly reduced (P < 0.01). In the BCLP FEM analysis, the maximum displacement was on the left premaxillary edge (0.2 mm), and high Mises stresses were found in the superior region of the vomer (22.4 Mpa), high tensile stresses in the inferior region (14.3 Mpa), and significant compressive stresses in the superior region (-24.7 Mpa). In summary, for BCLP patients, forward growth of the maxillae and vomer was inhibited during maxillary development, and the vomer was thicker and its volume was increased compared with the vomer in normal subjects.