Growth and development: hereditary and mechanical modulations

The application of zebrafish model in the study of cleft lip and palate development: A systematic review

Objective

Craniofacial growth and development are more than a scientific curiosity; it is of tremendous interest to clinicians. Insights into the genetic etiology of cleft lip and palate development are essential for improving diagnosis and treatment planning. The purpose of this systematic review was to utilize a zebrafish model to highlight the role of the IRF6 gene in cleft lip and palate development in humans.

Data

This review adhered to the guidelines outlined in the PRISMA statement. Nine studies were included in the analysis.

Sources

This study used major scientific databases such as MEDLINE, EMBASE, Web of Science, and the Zebrafish Information Network and yielded 1275 articles. Two reviewers performed the screening using COVIDENCE™ independently, and a third reviewer resolved any conflicts.

Study selection

After applying the inclusion and exclusion criteria and screening, nine studies were included in the analysis. The Systematic Review Center for Laboratory Animal Experimentation's (SYRCLE's) risk-of-bias tool was used to assess the quality of the included studies.

Results

The main outcome supports the role of the IRF6 gene in zebrafish periderm development and embryogenesis, and IRF6 variations result in cleft lip and palate development. The overall SYRCLE risk of bias was low-medium.

Conclusion

In conclusion, this review indicated the critical role of the IRF6 gene and its downstream genes (GRHL3, KLF17, and ESRP1/2) in the development of cleft lip and palate in zebrafish models. Genetic mutation zebrafish models provide a high level of insights into zebrafish craniofacial development.

Clinical relevance

this review provides a productive avenue for understanding the powerful and conserved zebrafish model for investigating the pathogenesis of human cleft lip and palate.

Determining the existence of the foramen of Huschke in patients with temporomandibular joint disorders using cone beam computed tomography: retrospective cohort study

Background

Foramen of Huschke has been presented as an unusual developmental defect in anteroinferior aspect of external auditory canal. It can be associated with significant otologic complications. The purpose of this study was to determine the association between existence of foramen of Huschke and temporomandibular joint disorders in Cone Beam Computed Tomography (CBCT) images.

Methods

Of an initial sample of 465 patients, we retrospectively evaluated the CBCT images of 118 individuals with clinical signs and symptoms of temporomandibular joint disorders as case group and 256 individuals as control group. The presence, size and localization of foramen of Huschke were assessed in the axial and corrected sagittal images. The sex and age distribution were determined. Fisher’s exact test, T-test and Pearson’s Chi-square were applied to assess the relationship between foramen of Huschke and temporomandibular joint disorders in the case and control groups considering age and sex.

Results

The foramen of Huschke prevalence was slightly higher in patients with temporomandibular joint disorders (3.4%) than patients without temporomandibular joint disorders (0.8%). However, the difference was not statistically significant (P = 0.082). foramen of Huschke was found in five females and one male. There was no significant difference between case and control groups considering the age of patients with foramen of Huschke (P = 0.683). There was no significant difference between the case and control groups, considering the right and left ears in distribution of foramen of Huschke (P = 0.099) (P = 0.183).

Conclusions

Higher prevalence of foramen of Huschke in patients with temporomandibular joint disorders may suggest possible mechanism for temporomandibular joint disorders development that can be affected by presence of foramen of Huschke.

Analysis of MYO1H Gene Polymorphism in Skeletal Class-III Malocclusion Due to Mandibular Prognathism

Background  Mandibular prognathism (MP) is a craniofacial deformity resulting from the combined effects of environmental and genetic factors. Although various linkage and genome-wide association studies for mandibular prognathism have identified multiple strongly associated regions and genes, the causal genes and variants responsible for the deformity remained ambiguous.

Aim  This research work was aimed to study the association between polymorphism rs10850110 of the MYO1H gene and skeletal class-III malocclusion in our local population.

Materials and Methods  Thirty patients with skeletal class III due to mandibular prognathism in the study group and 30 patients with skeletal class I in the control group were selected for this study. These patients were from both sexes and above age 10 years. Based on the cephalometric values, patients were categorized into study and control groups. SNB (angle between sella, nasion and point B at nasion) greater than 82 degrees with an ANB (angle between point A, nasion and point B at nasion) of less than 0 degrees in the study group and ANB (angle between point A, nasion and point B at nasion) of 2 to 4 degrees in the control group were categorized. The polymorphism (rs10850110) of the MYO1H gene was genotyped using polymerase chain reaction and restriction fragment length polymorphism. Associations were tested with SNP exact test using SNPstats software.

Results  The single-nucleotide polymorphism rs10850110 showed a statistically significant association with mandibular prognathism. The G allele of marker rs10850110 (5′ of myosin1H - MYO1H ) was overrepresented when compared with the “A” allele in mandibular prognathism cases ( p  < 0.0001), and this was very significant.

Conclusion  These results suggest that the rs10850110 polymorphism of the MYO1H gene is associated with an increased risk for mandibular prognathism.

Initial radiological signs of dentofacial deformity in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood and the temporomandibular joint (TMJ) is often involved. TMJ arthritis in growing individuals can cause deformation of facial skeleton (dentofacial deformity) and TMJ components (TMJ deformity). Treatment outcome hinges on early initiation of anti-inflammatory treatment and orthopaedic treatment with dental splints. The aim of the present study was to characterize the radiological signs of dentofacial deformity in patients with a JIA-induced need for orthopaedic treatment. We retrospectively studied 96 patients with JIA and 20 non-JIA controls to identify the initial radiological signs of JIA-induced dentofacial deformity leading to initiation of orthopaedic treatment. We found that initial radiological signs of dentofacial deformities were subtle and characterized by minor mandibular asymmetry and occlusal plane steepening. Radiological findings of TMJ deformity associated with initial dentofacial deformity were frequent and characterized by condylar articular surface flattening (OR 8.42), condylar subcortical cyst (OR 5.94), condylar surface erosion (OR 5.38) and condylar deviation in form (OR 25.39). Radiological signs of TMJ deformity were also documented in TMJs considered “healthy” during initial clinical and radiological examination. This study presents new knowledge of importance for early diagnosis of dentofacial deformity in JIA. Early diagnosis of dentofacial deformity is important as treatment outcome is greatly influenced by timely initiation.

Craniosynostosis: current conceptions and misconceptions

Cranial bones articulate in areas called sutures that must remain patent until skull growth is complete. Craniosynostosis is the condition that results from premature closure of one or more of the cranial vault sutures, generating facial deformities and more importantly, skull growth restrictions with the ability to severely affect brain growth. Typically, craniosynostosis can be expressed as an isolated event, or as part of syndromic phenotypes. Multiple signaling mechanisms interact during developmental stages to ensure proper and timely suture fusion. Clinical outcome is often a product of craniosynostosis subtypes, number of affected sutures and timing of premature suture fusion. The present work aimed to review the different aspects involved in the establishment of craniosynostosis, providing a close view of the cellular, molecular and genetic background of these malformations.

Evaluation of the relationship between tympanic plate morphology and degenerative bone changes of condyle and articular eminence

INTRODUCTION

This study aimed to evaluate the relationship between tympanic plate morphology and degeneration of temporomandibular joint (TMJ) condyle and articular eminence (AE).

MATERIAL AND METHODS

Cone beam computed tomography images of 700 patients (345 males, 355 females) were evaluated. The prevalence and location of tympanic plate pneumatization (TPP) and foramen tympanicum (FT) were recorded. Sagittal scans of the TMJs were classified according to the degenerative bone changes of condyle and AE (flattening, osteophytes, erosion, sclerosis, and subcortical cysts).

RESULTS

TPP was found in 106 of 700 patients (15.2%) while FT was found in 165 (23.2%) of the patients. TPP and FT were bilateral in 52 (49.1%) patients and 46 (27.9%) patients, respectively. The mean axial diameter of FT was 2.53mm and the mean sagittal diameter was 2.52mm. The most common degenerative changes for condyle and AE were flattening.

CONCLUSION

To know these structures is important for surgical operations in the region of TMJ and ear to prevent complications. CBCT is useful to evaluate these anatomical landmarks and the relationship between them and the degenerative bone changes of condyle and AE.

The Special Developmental Biology of Craniofacial Tissues Enables the Understanding of Oral and Maxillofacial Physiology and Diseases

Maxillofacial hard tissues have several differences compared to bones of other localizations of the human body. These could be due to the different embryological development of the jaw bones compared to the extracranial skeleton. In particular, the immigration of neuroectodermally differentiated cells of the cranial neural crest (CNC) plays an important role. These cells differ from the mesenchymal structures of the extracranial skeleton. In the ontogenesis of the jaw bones, the development via the intermediate stage of the pharyngeal arches is another special developmental feature. The aim of this review was to illustrate how the development of maxillofacial hard tissues occurs via the cranial neural crest and pharyngeal arches, and what significance this could have for relevant pathologies in maxillofacial surgery, dentistry and orthodontic therapy. The pathogenesis of various growth anomalies and certain syndromes will also be discussed.

[Use of skeletal-related diagnostic methods in articles published from 2018 to 2020 in four major orthodontics journals]

Objective

To determine the skeletal-related diagnostic methods most commonly used according to the four most important orthodontics journals in the period from 2018 to 2020.

Methods

A review of the data available regarding the diagnostic procedures most frequently used to determine skeletal relationships in the four most important orthodontics journals from 2018 to 2020. Article review was performed using SCIMAGO 2018, which provides a series of parameters ranking the importance of the impact of publications and journals. We made a synopsis of the information analyzed to establish a correlation and compare sources, and critically examined the articles collected on the subject of interest. An online bibliographic search of databases including mainly Medline was carried out, followed by evaluation and selection of the bibliography, organized according to the significance and nature of the study.

Results

The four journals included in the bibliographic search were: AJODO, AO, EJO and KJO. The A point-Nasion-B point (ANB) method was used in 92.2% of the articles published in AJODO, and 7.8% did not describe the method used. Twenty-three articles in the AO journal were evaluated, all of which referred to the use of ANB as the method used. Finally, 16 and 11 articles from the EJO and KJO journals, respectively, were evaluated, with 93.8% and 95%, respectively of the articles using ANB as the method of choice for determining skeletal relationships.

Conclusion

The method of choice for skeletal-related diagnostics is ANB, although this widely known method presents a risk of geometric effect.

Comparing Clinical and Radiological Manifestations of Adolescent Idiopathic Condylar Resorption and Juvenile Idiopathic Arthritis in the Temporomandibular Joint

PURPOSE

This cross-sectional study compared orofacial manifestations at the time of diagnosis in 2 temporomandibular joint (TMJ) conditions: adolescent idiopathic condylar resorption (ICR) and TMJ involvement from juvenile idiopathic arthritis (JIA).

MATERIALS AND METHODS

This retrospective study included 19 JIAs, 19 ICRs, and 19 control patients, all treated at the Section of Orthodontics, Aarhus University Craniofacial Clinic, Denmark. From patient files, we retrieved radiological data from cone-beam computed tomographies along with information on symptoms and orofacial function at the time of diagnosis. Validated methodologies were used to evaluate TMJ and dentofacial morphology.

RESULTS

We found no statistically significant intergroup differences in severity of deformation of TMJ structures (TMJ deformity) between JIA and ICR patients. However, the ICR group showed significantly greater signs of dentofacial deformity on 4 outcome variables: mandibular inclination, posterior/anterior lower face height ratio, mandibular sagittal position, and mandibular occlusal plane inclination. Significant intergroup differences in clinical presentation were seen in 5 of 20 variables. Thus, the JIA group reported significantly more symptoms of TMJ pain, TMJ morning stiffness, and TMJ pain on palpation during the clinical examination, whereas the ICR group reported significantly more TMJ clicking during function and had a higher proportion of patients with anterior open bite.

CONCLUSIONS

Cone-beam computed tomography examination showed a similar degree of TMJ deformity in ICR and JIA patients at the time of diagnosis. ICR patients presented with a significantly higher degree of dentofacial deformity than JIA patients and healthy controls, which relates to the timing of the diagnosis. Arthralgia, TMJ morning stiffness, and TMJ palpitation pain were more common in JIA patients, whereas TMJ clicking during function and anterior open bites were more common in ICR patients.

Prevalence of foramen Huschke: evaluation of the association between mastoid pneumatization volume and the existence of foramen Huschke using cone beam computed tomography

PURPOSE

The study examined the association between mastoid pneumatization (MP) volume and the existence of foramen Huschke (FH).

METHODS

Cone beam computed tomography (CBCT) images of 1117 patients (2234 mastoid regions) were analyzed. The prevalence of FH was calculated. The association of MP volume calculated in 83 patients (48 women, 35 men) with sex, side, and the existence of FH analyzed. T test and Pearson's Chi-square test were used for statistical analyses.

RESULTS

FH was observed in 223 (20%) patients. FH was unilateral in 141 (63.7%) patients (74 left-sided, 68 right-sided) and bilateral in 81 (36.3%) patients. Six patients with FH had herniation into the external auditory canal. MP volume was significantly greater in females (p = 0.016). Additionally, MP volume was significantly greater in patients having FH (p = 0.009).

CONCLUSION

It is possible to speculate that the volume of MP, which is in close neighborhood with the external auditory canal, somehow affects the existence of FH located in the tympanic segment.

ROCK-TAZ signaling axis regulates mechanical tension-induced osteogenic differentiation of rat cranial sagittal suture mesenchymal stem cells

Mechanical force across sutures is able to promote suture osteogenesis. Orthodontic clinics often use this biological characteristic of sutures to treat congenital cranio-maxillofacial malformations. However, the underlying mechanisms still remain poorly understood. Craniofacial sutures provide a special growth source and support primary sites of osteogenesis. Here, we isolated rat sagittal suture cells (rSAGs), which had mesenchymal stem cell characteristics and differentiating abilities. Cells were then subjected to mechanical tension (5% elongation, 0.5 Hz; sinusoidal waveforms) showing that mechanical tension could enhance osteogenic differentiation but hardly affect proliferation of rSAGs. Besides, mechanical tension could increase Rho-associated kinase (ROCK) expression and enhance transcriptional coactivator with PDZ-binding motif (TAZ) nuclear translocation. Inhibiting ROCK expression could suppress tension-induced osteogenesis and block tension-induced upregulation of nuclear TAZ. In addition, our results indicated that TAZ had direct combination sites with runt-related transcription factor 2 (Runx2) in rSAGs, and knock-downed TAZ simultaneously decreased the expression of Runx2 no matter with or without mechanical tension. In summary, our findings demonstrated that the multipotency of rSAGs in vitro could give rise to early osteogenic differentiation under mechanical tension, which was mediated by ROCK-TAZ signal axis.

Temporomandibular joint herniation into the middle ear: A rare cause of mastication-induced tinnitus

A 75-year-old patient complained of mastication-induced clicking tinnitus on the left side, and otoendoscopic examination revealed that the left tympanic membraneTM was outwardly bulged by clenching her teeth. Temporal bone computed tomography demonstrated that the posteromedial bony wall of the glenoid was partially dehiscent, allowing herniation of soft tissue contents of temporomandibular joint into the middle ear. Increased middle ear pressure due to soft tissue herniation can induce left tympanic membrane bulging and accompanying clicking tinnitus. Herniation of temporomandibular joint soft tissue into the middle ear should be considered as a differential diagnosis when clicking tinnitus is evoked by mastication.

Interdisciplinary Management of Dentofacial Deformity in Juvenile Idiopathic Arthritis

Temporomandibular joint (TMJ) arthritis impacts mandibular growth and development. This can result in skeletal deformity, such as facial asymmetry and/or malocclusion asymmetry. This article reviews the unique properties of TMJ and dentofacial growth and development in the setting of juvenile idiopathic arthritis (JIA). Specific orthopedic/orthodontic and surgical management of children with JIA and TMJ arthritis is discussed. The importance of interdisciplinary collaboration is highlighted.

Longitudinal evaluation of the association between Insulin-like growth factor-1, Bone specific alkaline phosphatase and changes in mandibular length

The aim of the current longitudinal study was to assess the levels of serum Bone-specific alkaline phosphatase (BALP) and serum Insulin like growth factor-1 (IGF-1) in different cervical vertebral maturation index (CVMI) stages and observe their association with the mandibular growth. Blood samples and lateral cephalograms of 63 subjects (age group of 11–17 years) were obtained at two time points, 12 months apart. On the basis of CVMI, all subjects were divided into six groups based on whether the subjects remained in same CVMI stage or transitioned to the next CVMI stage. Annual mandibular length was related with serum BALP and serum IGF-1 levels estimated using ELISA. Serum IGF-1 and BALP attained highest levels at CVMI stage 3 with peak BALP levels observed earlier than IGF-1. Although a positive correlation was determined between IGF-1 and BALP but BALP followed skeletal growth pattern more precisely. Overall IGF-1 and BALP were negatively correlated with mandibular length with notable growth in CVMI groups 3–3 (P < 0.01), 3-4 (P < 0.01), 4-4 (P < 0.001) and 5-5 (P < 0.001). In conclusion, BALP is a potential biomarker for skeletal growth assessment. However, the mandibular growth pattern was independent of changes in IGF-1 and BALP.

Effect of Long-Term Diving on the Morphology and Growth of the Distal Radial Epiphyseal Plate of Young Divers: A Magnetic Resonance Imaging Study

OBJECTIVE

To investigate the effects of long-term diving on the morphology and growth of the distal radial epiphyseal plate in young divers.

STUDY DESIGN

Cohort study.

SETTING

Guangzhou Sport University.

PARTICIPANTS

Thirty-eight professional divers, aged 10 to 17 years, and 25 age-matched volunteers.

INTERVENTIONS

Each subject received a physical examination at the beginning of the study and underwent bilateral magnetic resonance imaging of the wrist. The divers were divided into 2 groups depending on the status of the epiphyseal plate: group A (positive distal radial epiphyseal plate injury) and group B (no positive distal radial epiphyseal plate injury). A third group, group C, consisted of the 25 volunteers.

MAIN OUTCOME MEASURES

The frequency of distal radial epiphyseal plate injury and the thickness of the distal radial epiphyseal plate were analyzed across the 3 groups.

RESULTS

Twenty-nine cases (29/76, 38.15%) of distal radial epiphyseal plate injury were observed in 20 divers (20/38, 52.63%). The incidence of injury to the right hand was higher than that for the left (P = 0.009). There were statistically significant differences (P = 0.000) among the 3 groups in terms of epiphyseal plate thickness; group A > group B > group C.

CONCLUSIONS

Distal radial epiphyseal plate injury is common in divers, and more injuries are seen in the right hand. Moreover, growth of the radius was impaired in divers relative to controls. We consider that loading during diving may influence growth of the epiphyseal plate in either a transient or permanent manner.

Relationship between the degree of mastoid pneumatization and the presence of persistent foramen of Huschke

The aim of this study was to determine the relationship between the degree of mastoid pneumatization and the presence of persistent foramen of Huschke (FH). Temporal computed tomography images of 714 patients (1428 ears) who applied to the Otorhinolaryngology Department of Karabuk University Training and Research Hospital between January 2016 and June 2018 were retrospectively analysed. We compared the mastoid pnomatization levels of 95 patients (74 females, 21 males, mean age 53.18±15.09years) who had persistent FH and 135 patients (103 females, 32 males, mean age 54.29±15.82years) with no FH who had similar age and gender. FH was found to be unilateral (right: 23, left: 45) in 68 (71.5%) out of 95 patients with FH, and FH was bilateral in 27 (28.4%) patients. The degree of mastoid pnomatization of the patients with FH was significantly higher than the patients without FH (p=0.015). The degree of pneumatization of the mastoid bone may lead to persistent FH by affecting the ossification process of the tympanic segment, which has a close anatomical relationship with it.

Incidence of Foramen Tympanicum (of Huschke): Comparing Cadaveric and Radiologic Studies

PURPOSE

The foramen tympanicum (FT) represents a developmental anomaly that forms due to incomplete fusion of processes of the tympanic ring. Its presence in the population is controversial and it has been associated with a number of otologic complications. The aim of this study was to systematically analyze the prevalence, anatomical characteristics, and ethnic variations of the FT and compare these parameters in cadaveric and radiologic studies.

METHODS

An extensive search was conducted through the major electronic databases, and identified articles were separated into 2 groups based on their methodology: cadaveric and radiologic studies. Data extracted included study modality, prevalence data, ethnicity, gender, side, laterality, and diameter.

RESULTS

A total of 8 studies (n = 2671 patients) were included into our meta-analysis. The main findings revealed that the prevalence of the FT in the population is 14.9%, it is more often unilateral (62.5%) than bilateral (37.5%), it is most often reported in Asia (21.4%), and it is more prevalent in cadavers (21.2%) than in radiologic studies (8.8%) (not statistically significant).

CONCLUSION

As the FT is present in more than one-tenth of the population, it is important to consider the possibilities of its presence when undertaking surgical procedures in the temporomandibular joint and ear region and plan accordingly to avoid injuries. Clinicians should keep it as one of the possible diagnoses while confronted with patients presenting with otologic complications. The use of newer imaging techniques was recommended, such as cone-beam computer tomography to detect the FT prior to surgery.

Relationship between matrilin-1 gene polymorphisms and mandibular retrognathism

INTRODUCTION

Mandibular retrognathism is a type of malocclusion that refers to an abnormal posterior position of the mandible as a result of a developmental abnormality. From the literature, it is evident that the mandibular growth pattern is determined by the intramembranous ossification of the mandibular body and endochondral ossification of the condyle. Matrilin-1 is a cartilage extracellular matrix protein, and matrilin-1 gene (MATN1) polymorphisms have been found to be involved in dental malocclusions of humans. In this study, we aimed to examine the association between MATN1 polymorphisms and the risk of mandibular retrognathism, in a case-control study with a South Indian population.

METHODS

Eighty-one patients with mandibular retrognathism (SNB, <78°) and 71 controls having an orthognathic mandible (SNB, 80° ± 2°) were recruited. In both the patient and control groups, subjects with an orthognathic maxilla (SNA, 82° ± 2°) were included. Three single nucleotide polymorphisms of the MATN1 gene (rs1149048, rs1149042, and rs1065755) were genotyped using polymerase chain reaction-restriction fragment length polymorphism. The statistical association analysis was performed using the chi-square test. Pair-wise linkage disequilibrium was computed, and haplotypes were compared between subjects and controls. Nonparametric tests were used to compare cephalometric measurements between groups.

RESULTS

No polymorphic site deviated from Hardy-Weinberg equilibrium in the controls. The rs1149042 genotypes and alleles were found to be associated with reduced risk of mandibular retrognathism. Furthermore, rs1149042 genotypes were associated with mandibular measurements (SNB and ANB). There was no strong and consistent linkage disequilibrium linkage disequilibrium across two different single nucleotide polymorphisms and haplotypes were not associated with mandibular retrognathism.

CONCLUSIONS

The results of our study suggest an association between the MATN1 gene polymorphisms and mandibular retrognathism.

Inhibition of bone resorption by bisphosphonates interferes with orthodontically induced midpalatal suture expansion in mice

OBJECTIVES

Craniofacial sutures are important growth sites for skull development and are sensitive to mechanical stress. In order to determine the role of bone resorption in stress-mediated sutural bone growth, midpalatal suture expansion was performed in mice receiving alendronate, an anti-resorptive bisphosphonate.

MATERIALS AND METHODS

The midpalatal sutures of 8-week-old C57BL/6 mice were expanded by orthodontic wires over the period of 2 weeks. Mice with maxillary expansion without drug treatment as well as untreated animals served as controls. Skulls were analyzed with micro-computed tomography (micro-CT), immunohistochemistry and histology.

RESULTS

Maxillary expansion in mice without drug treatment resulted in an increase of TRAP-positive osteoclasts. In contrast, no increase in osteoclasts was observed in expanded sutures of mice with bisphosphonate treatment. Double calcein labeling demonstrated rapid bone formation on the oral edges of the expanded sutures in mice without bisphosphonate treatment. Less bone formation was observed in bisphosphonate-treated mice after expansion. Histology revealed that the sutural architecture was reestablished in expanded sutures of mice without bisphosphonate treatment. In contrast, the sutural architecture was disorganized and the cartilage had an irregular form, following expansion in bisphosphonate-treated mice. Finally, micro-CT imaging demonstrated that the total amount of maxillary expansion was significantly lower in mice with bisphosphonate treatment as compared to those of mice without drug treatment.

CONCLUSIONS

In conclusion, our results indicate that osteoclast-mediated bone resorption is needed for maxillary suture expansion and reorganization of sutural architecture.

CLINICAL SIGNIFICANCE

Orthodontic palatal expansion can be complicated in patients with inherited or drug-induced diseases of osteoclast dysfunction.

Three-dimensional analysis of cranial base morphology in patients with hemifacial microsomia

BACKGROUND

Many researchers have studied the relationship between facial asymmetry and cranial base morphology, but they have failed to reach a consensus. In this study, we aimed to verify whether the cranial base is involved in hemifacial microsomia (HFM).

METHODS

We included 66 patients with HFM who were treated at the Plastic and Reconstructive Surgery Department of Shanghai Ninth People's Hospital from January 2013 to October 2016. The patients were divided into three groups according to Pruzansky and OMENS classifications, separately. The controls were 20 patients diagnosed with mandibular angle hypertrophy but with no facial asymmetry. Angular and linear measurements of the cranial base were obtained for all patients.

RESULTS

The two classification methods yielded similar results. The intersection angle between two planes showed differences in the severe group. In the moderate and severe groups, the middle and posterior cranial angles were significantly different and the CIP and SP lengths were shorter in the affected side. Landmarks such as the carotid canal and internal acoustic canal could be considered as references.

CONCLUSIONS

The cranial base is involved in hemifacial microsomia. This relationship supports the hypothesis of HFM pathogenesis and opens new avenues to classification methods.

Osteocalcin and serum insulin-like growth factor-1 as biochemical skeletal maturity indicators

Background

With change in concepts of growth determination methods, there is a surge in the measurement of biomarkers for appraisal of growth status. Osteocalcin is a bone-specific protein and was observed to parallel the normal growth curve. Hence, the present study was intended to assess the levels of serum osteocalcin and serum insulin-like growth factor-1 (IGF-1) and compare them with cervical vertebral maturation index (CVMI) stages.

Methods

The cross-sectional study was performed on 150 subjects (75 males and 75 females) in the age group of 8–20 years and segregated into six CVMI stages. Serum osteocalcin and IGF-1 were estimated by ELISA. Mann-Whitney U test was used to compare the mean ranks of serum osteocalcin and serum IGF-1 with different CVMI stages. Spearman correlation was performed to find association between serum osteocalcin and serum IGF-1 across six CVMI stages.

Results

Peak serum IGF-1 levels were obtained at CVMI stages 4 and 3 for males and females, respectively, with insignificant difference between stages 3 and 4 in females. Peak serum osteocalcin levels were found at stage 5 and 3 for males and females with insignificant difference from other stages except stages 5 and 6 in males. A statistically significant correlation was seen between serum IGF-1 and serum osteocalcin across six CVMI stages (P < 0.01).

Conclusions

Osteocalcin followed IGF-1 across all CVMI stages but showed insignificant interstage differences.

Cellular scale model of growth plate: An in silico model of chondrocyte hypertrophy

The growth plate is the responsible for longitudinal bone growth. It is a cartilaginous structure formed by chondrocytes that are continuously undergoing a differentiation process that starts with a highly proliferative state, followed by cellular hypertrophy, and finally tissue ossification. Within the growth plate chondrocytes display a characteristic columnar organization that potentiates longitudinal growth. Both chondrocyte organization and hypertrophy are highly regulated processes influenced by biochemical and mechanical stimuli. These processes have been studied mainly using in vivo models, although there are few computational approaches focused on the rate of ossification rather than events at cellular level. Here, we developed a model of cellular behavior integrating biochemical and structural factors in a single column of cells in the growth plate. In our model proliferation and hypertrophy were controlled by biochemical regulatory loop formed between Ihh and PTHrP (modeled as a set of reaction-diffusion equations), while cell growth was controlled by mechanical loading. We also examined the effects of static loading. The model reproduced the proliferation and hypertrophy of chondrocytes in organized columns. This model constitutes a first step towards the development of mechanobiological models that can be used to study biochemical interactions during endochondral ossification.

Dental Age in Orthodontic Patients with Different Skeletal Patterns

Objective. To evaluate the difference between chronological and dental age, calculated by Willems and Cameriere methods, in various skeletal patterns according to Steiner's ANB Classification. Methods. This retrospective cross-sectional study comprised the sample of 776 participants aged between 7 and 15 years (368 males and 408 females). For each participant, panoramic images (OPT) and laterolateral cephalograms (LC) were collected from the medical database. On LC ANB angle was measured; on OPT dental age (DA) was calculated while chronological age (CA) and sex were recorded. The sample was divided into three subgroups (Class I, Class II, and Class III) with similar distribution based on the chronological age and ANB angle. CA was calculated as the difference between the date of OPT imaging and the date of birth, while DA was evaluated using Willems and Cameriere methods. ANB angle was measured on LC by two independent investigators using the cephalometric software. Differences between sexes and the difference between dental and chronological age were tested by independent and paired samples t-test, respectively; one-way ANOVA was used to test differences among ANB classes with Tukey post hoc test to compare specific pairs of ANB classes. Results. The significant difference was found between Class III and other two skeletal classes in males using both dental age estimation methods. In Class III males dental age was ahead averagely by 0.41 years when using Willems method, while Cameriere method overestimated CA for 0.22 years. Conclusion. In males with Class III skeletal pattern, dental development is faster than in Classes I and II skeletal pattern. This faster development is not present in females.

The Cranial Base in Craniofacial Development: a Gene Therapy Study

The etiology of midface retrusion remains largely unclear. We hypothesized that the cranial base synchondroses play a key role in the development of the craniofacial skeleton in the Sandhoff mouse model. We observed that developmental abnormalities of the cranial base synchondroses involving proliferative chondrocytes are important in craniofacial growth and development. Neonatal restitution of β-hexosaminidase in mutant mice by gene therapy successfully ameliorated the attendant skeletal defects and restored craniofacial morphology in vivo, suggesting this as a critical temporal window in craniofacial development. Analysis of our data implicates parathyroid-related peptide (PTHrP) and cyclo-oxygenase-2 (COX-2) as possible factors underlying the development of the aforementioned skeletal defects. Hence, timely restitution of a genetic deficiency or, alternatively, the restoration of PTHrP or cyclo-oxygenase activity by the administration of PTH and/or non-steroidal anti-inflammatory drugs or COX-2 selective inhibitors to affected individuals may prove beneficial in the management of midface retrusion.

DEVELOPMENTAL SCENARIOS OF THE EPIPHYSIS AND GROWTH PLATE UPON MECHANICAL LOADING: A COMPUTATIONAL MODEL

Long bone growth relies on the continuous bone formation from cartilaginous tissue (endochondral ossification). This process starts in the central region (diaphysis) of the forming bone and short before birth, ossification starts in bone extremes (epiphysis). A cartilaginous region known as the growth plate is maintained until adolescence between epiphysis and diaphysis to further contribute to longitudinal growth. Even though there are several biochemical factors controlling this process, there is evidence revealing an important regulatory role of mechanical stimuli. Up to now approaches to understand mechanical effects on ossification have been limited to epiphysis. In this work, based on Carter's mathematical model for epiphyseal ossification, we explored human growth plate response to mechanical loads. We analyzed growth plate stress distribution using finite element method for a generic bone considering different stages of bone development in order to shed light on mechanical contribution to growth plate function. Results obtained revealed that mechanical environment within the growth plate change as epiphyseal ossification progresses. Furthermore, results were compared with physiological behavior, as reported in literature, to analyze the role of mechanical stimulus over development. Our results suggest that mechanical stimuli may play different regulation roles on growth plate behavior through normal long bone development. However, as this approach only took into account mechanical aspects, failed to accurately predict biological behavior in some stages. In order to derive biologically relevant information from computational models it is necessary to consider biological contribution and possible mechanical–biochemical interactions affecting human growth plate physiology. Along these lines, we propose the dilatatorial parameter k used by Carter et al. should assume different values corresponding to the developmental stage in question. Thus, reflecting biochemical contribution changes over time.

Incidence of Foramen of Huschke in South Andhra Population of India

INTRODUCTION

Foramen of Huschke (FH) is an opening present in anteroinferior wall of External Acoustic Meatus (EAM) on the tympanic plate of temporal bone. The developing tympanic ring normally gets closed by the age of 5 years, if not, leads to the persistence of FH, shows a communication between the EAM and mandibular fossa of temporal bone.

AIM

The aim of the present study was to report on the incidence of FH in adult skulls and individual temporal bones, belonging to South Coastal Andhra population.

MATERIALS AND METHODS

Ninety three skulls and 34 temporal bones (18 right and 16 left) obtained from the Department of Anatomy and ENT respectively, irrespective of their sex were utilized. This Tympanic Plates (TP) was observed for the occurrence of FH.

RESULTS

Incidence of FH was found in 18 (16.22%) on right and 24 (22.02%) on left side. Bilateral FH was seen in 13 (13.98%) and multiple FH was 13 (5.91%). Mostly it was situated on left than the right side.

CONCLUSION

This study revealed that about 38% of South Coastal Andhra crania have FH. The presence of FH may render external and middle ear structures vulnerable to injury during arthroscopy of the Temporomandibular Joint (TMJ). Since FH can result in TMJ herniation and salivary gland fistulisation through the anterior wall of the bony EAM, surgeons working in this area must be cautious during surgical procedures. Also, data obtained from different populations, as observed from our study can be useful in racial and anthropological studies.

Signaling mechanisms implicated in cranial sutures pathophysiology: Craniosynostosis

Normal extension and skull expansion is a synchronized process that prevails along the osteogenic intersections of the cranial sutures. Cranial sutures operate as bone growth sites allowing swift bone generation at the edges of the bone fronts while they remain patent. Premature fusion of one or more cranial sutures can trigger craniosynostosis, a birth defect characterized by dramatic manifestations in appearance and functional impairment. Up until today, surgical correction is the only restorative measure for craniosynostosis associated with considerable mortality. Clinical studies have identified several genes implicated in the pathogenesis of craniosynostosis syndromes with useful insights into the underlying molecular signaling events that determine suture fate. In this review, we exploit the intracellular signal transduction pathways implicated in suture pathobiology, in an attempt to identify key signaling molecules for therapeutic targeting.

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Cranial sutures operate as bone growth sites.

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Premature fusion of one or more cranial sutures can trigger craniosynostosis.

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Several genes are involved in the pathogenesis of craniosynostosis syndromes.

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An array of molecular signaling events determine suture fate.

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Herein, the signal transduction pathways implicated in suture pathobiology are discussed.

Evolving concepts of heredity and genetics in orthodontics

The field of genetics emerged from the study of heredity early in the 20th century. Since that time, genetics has progressed through a series of defined eras based on a number of major conceptual and technical advances. Orthodontics also progressed through a series of conceptual stages over the past 100 years based in part on the ongoing and often circular debate about the relative importance of heredity (nature) and the local environment (nurture) in the etiology and treatment of malocclusion and dentofacial deformities. During the past 20 years, significant advancements in understanding the genomic basis of craniofacial development and the gene variants associated with dentofacial deformities have resulted in a convergence of the principles and concepts in genetics and in orthodontics that will lead to significant advancement of orthodontic treatments. Fundamental concepts from genetics and applied translational research in orthodontics provide a foundation for a new emphasis on precision orthodontics, which will establish a modern genomic basis for major improvements in the treatment of malocclusion and dentofacial deformities as well as many other areas of concern to orthodontists through the assessment of gene variants on a patient-by-patient basis.

Pain control in orthodontics using a micropulse vibration device: A randomized clinical trial

OBJECTIVE

To investigate the relationship between a micropulse vibration device and pain perception during orthodontic treatment.

MATERIALS AND METHODS

This study was a parallel group, randomized clinical trial. A total of 58 patients meeting eligibility criteria were assigned using block allocation to one of two groups: an experimental group using the vibration device or a control group (n  =  29 for each group). Patients used the device for 20 minutes daily. Patients rated pain intensity on a visual analog scale at appropriate intervals during the weeks after the separator or archwire appointment. Data were analyzed using repeated measures analysis of variance at α  =  .05.

RESULTS

During the 4-month test period, significant differences between the micropulse vibration device group and the control group for overall pain (P  =  .002) and biting pain (P  =  .003) were identified. The authors observed that perceived pain was highest at the beginning of the month, following archwire adjustment.

CONCLUSION

The micropulse vibration device significantly lowered the pain scores for overall pain and biting pain during the 4-month study period.

Temporomandibular Joint Herniation Into the External Auditory Canal: Two Cases Involving a Persistent Foramen Tympanicum

A congenital bony defect of the external auditory canal (EAC) may cause temporomandibular joint (TMJ) herniation into the EAC. This rare condition is known as persistent foramen tympanicum. We report 2 cases of symptomatic TMJ herniation through a patent foramen tympanicum. The patients complained of mastication-induced tinnitus. Otoscopic examination revealed that a whitish protruding mass at the anterior wall of the EAC bulged when the patients closed their mouths. After conservative managements such as avoidance of chewing foods on the affected side for 2 months, mastication-induced tinnitus disappeared and the size of protruding mass was decreased in one of the patients. Surgical repair of the bony defect has been the treatment of choice. In cases when symptoms are trivial and patients do not want surgical treatment, however, conservative management would be a sound alternative.

Regional variations in growth plate chondrocyte deformation as predicted by three-dimensional multi-scale simulations

The physis, or growth plate, is a complex disc-shaped cartilage structure that is responsible for longitudinal bone growth. In this study, a multi-scale computational approach was undertaken to better understand how physiological loads are experienced by chondrocytes embedded inside chondrons when subjected to moderate strain under instantaneous compressive loading of the growth plate. Models of representative samples of compressed bone/growth-plate/bone from a 0.67 mm thick 4-month old bovine proximal tibial physis were subjected to a prescribed displacement equal to 20% of the growth plate thickness. At the macroscale level, the applied compressive deformation resulted in an overall compressive strain across the proliferative-hypertrophic zone of 17%. The microscale model predicted that chondrocytes sustained compressive height strains of 12% and 6% in the proliferative and hypertrophic zones, respectively, in the interior regions of the plate. This pattern was reversed within the outer 300 μm region at the free surface where cells were compressed by 10% in the proliferative and 26% in the hypertrophic zones, in agreement with experimental observations. This work provides a new approach to study growth plate behavior under compression and illustrates the need for combining computational and experimental methods to better understand the chondrocyte mechanics in the growth plate cartilage. While the current model is relevant to fast dynamic events, such as heel strike in walking, we believe this approach provides new insight into the mechanical factors that regulate bone growth at the cell level and provides a basis for developing models to help interpret experimental results at varying time scales.

Skeletal development of the glenoid and glenoid-coracoid interface in the pediatric population: MRI features

OBJECTIVE

To assess the MRI appearance of normal skeletal development of the glenoid and glenoid-coracoid interface in the pediatric population. To the best of our knowledge, this has not yet been studied in detail in the literature.

MATERIALS AND METHODS

An IRB-approved, HIPAA-compliant retrospective review of 105 consecutive shoulder MRI studies in children, ages 2 months to 18 years was performed. The morphology, MR signal, and development of the following were assessed: (1) scapular-coracoid bipolar growth plate, (2) glenoid and glenoid-coracoid interface secondary ossification centers, (3) glenoid advancing osseous surface.

RESULTS

The glenoid and glenoid-coracoid interface were identified in infancy as a contiguous, cartilaginous mass. A subcoracoid secondary ossification center in the superior glenoid was identified and fused in all by age 12 and 16, respectively. In ten studies, additional secondary ossification centers were identified in the inferior two-thirds of the glenoid. The initial concavity of the glenoid osseous surface gradually transformed to convexity, matching the convex glenoid articular surface. The glenoid growth plate fused by 16 years of age. Our study, based on MRI, demonstrated a similar pattern of development of the glenoid and glenoid coracoid interface to previously reported anatomic and radiographic studies, except for an earlier development and fusion of the secondary ossification centers of the inferior glenoid.

CONCLUSIONS

The pattern of skeletal development of the glenoid and glenoid-coracoid interface follows a chronological order, which can serve as a guideline when interpreting MRI studies in children.

Evaluation of foramen tympanicum using cone-beam computed tomography in orthodontic malocclusions

The foramen tympanicum is a persistent anatomic formation of the temporal bone due to a defect in ossification normal bone physiology in neonatal or postnatal period. This study determined the occurrence and location of the foramen tympanicum in a Turkish sample using cone-beam computed tomography. Scans of 370 sites in 185 patients were retrospectively analyzed to determine foramen tympanicum occurrence, sizes, and locations according to their orthodontic malocclusions. Measurements were done on axial and sagittal sections to identify the dimensions. Differences in foramen tympanicum incidence by measurements, sex, side, malocclusions, and location were statistically evaluated. Foramen tympanicum was determined in 42 (22.7%) of 185 patients. No statistical difference was found considering location and sex (P > 0.05), but it was found more bilaterally in female patients within significance level at P = 0.024. Mean sizes did not differ significantly by sex but were found to be greater in females. In axial diameter, the average measurement was found wider on the right side of all patients (P = 0.017). The findings showed a greater foramen tympanicum dimension among class II than among class I and III subjects (P < 0.05). Knowledge about these structures is helpful for the interpretation of imaging (especially cone-beam computed tomography) and provides valuable information especially before orthognathic surgery to avoid intraoperative reconstruction and complications.

Comparison of closure times for cranial base synchondroses in mesaticephalic, brachycephalic, and Cavalier King Charles Spaniel dogs

Premature closure of cranial base synchondroses has been proposed as the mechanism for brachycephaly in dogs and caudal occipital malformation syndrome (COMS) in Cavalier King Charles Spaniels. The purpose of this retrospective study was to compare times of closure for cranial base synchondroses in mesaticephalic, brachycephalic, and Cavalier King Charles Spaniel dogs. Cranial magnetic resonance imaging studies were retrieved for client-owned dogs less than 18 months of age. Breed, age, skull conformation, and the open or closed state of cranial base synchondroses were independently recorded by two observers. For dogs with a unanimous observer agreement, regression analysis was used to test effects of age and gender on the open or closed status of synchondroses and differences between groups. A total of 174 dogs were included in MRI interpretations and 165 dogs were included in the regression analysis. Statistically significant differences in closure time of the spheno-occipital synchondrosis were identified between brachycephalic and mesaticephalic dogs (P = 0.016), Cavalier King Charles Spaniels and mesaticephalic dogs (P < 0.0001), and Cavalier King Charles Spaniels and brachycephalic dogs (P = 0.014). Findings from the current study supported the theory that morphological changes leading to the skull phenotype of the Cavalier King Charles Spaniels could be due to an earlier closure of the spheno-occipital synchondrosis.

Hand in glove: brain and skull in development and dysmorphogenesis

The brain originates relatively early in development from differentiated ectoderm that forms a hollow tube and takes on an exceedingly complex shape with development. The skull is made up of individual bony elements that form from neural crest- and mesoderm-derived mesenchyme that unite to provide support and protection for soft tissues and spaces of the head. The meninges provide a protective and permeable membrane between brain and skull. Across evolutionary and developmental time, dynamic changes in brain and skull shape track one another so that their integration is evidenced in two structures that fit soundly regardless of changes in biomechanical and physiologic functions. Evidence for this tight correspondence is also seen in diseases of the craniofacial complex that are often classified as diseases of the skull (e.g., craniosynostosis) or diseases of the brain (e.g., holoprosencephaly) even when both tissues are affected. Our review suggests a model that links brain and skull morphogenesis through coordinated integration of signaling pathways (e.g., FGF, TGFβ, Wnt) via processes that are not currently understood, perhaps involving the meninges. Differences in the earliest signaling of biological structure establish divergent designs that will be enhanced during morphogenesis. Signaling systems that pattern the developing brain are also active in patterning required for growth and assembly of the skull and some members of these signaling families have been indicated as causal for craniofacial diseases. Because cells of early brain and skull are sensitive to similar signaling families, variation in the strength or timing of signals or shifts in patterning boundaries that affect one system (neural or skull) could also affect the other system and appropriate co-adjustments in development would be made. Interactions of these signaling systems and of the tissues that they pattern are fundamental to the consistent but labile functional and structural association of brain and skull conserved over evolutionary time obvious in the study of development and disease.

Simultaneous and differential fronto-orbital and midface distraction osteogenesis for syndromic craniosynostosis using rigid external distractor II

In syndromic craniosynostosis, the relation between the supraorbital area and the frontal bone is not good, and it is not possible to reform this area with 1-block advancement. To avoid this problem, the frontal bone is separated from the fronto-orbital bandeau, each is reshaped and remodeled separately, and then both are reattached. The retrusion of the midface, especially in syndromic craniosynostosis, is usually greater than that of cranial bones, so the technique usually separating the midface from the cranium is Le Fort III osteotomy, which allows differential distraction of each part. In this procedure, the cranial and midfacial bones are advanced simultaneously and differentially, both to the planned extent, in a single-stage operation, using rigid external distractor II, correcting exorbitism, respiratory embarrassment, and cranial structures and avoiding eye complications in the future. This procedure was used, with a follow-up, in 10 patients with syndromic craniosynostosis from 2 to 5 years.

Pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement with counterclockwise rotation for Class II anterior open bite malocclusions

OBJECTIVES

The purpose of this study was to cephalometrically evaluate the pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion.

METHODS

The study included 49 patients (98 lateral teleradiographs; 36 females and 13 males) who were analysed in the pre-operative (1 week before surgery) and post-operative (6 months after surgery) periods. In each lateral teleradiography, the dimensions of the inferior and superior pharyngeal airway space, TB-PhW1 [the point between the posterior aspect of the tongue to the dorsal pharyngeal wall (oropharynx) (TB) and the point on the dorsal pharyngeal wall closest to TB (PhW1)] and UP-PhW2 [and the point between the posterior aspect of the soft palate to the dorsal pharyngeal wall (nasopharynx) (UP) (PhW2)] measurements were evaluated, as well as the dimensions of the frontal and sphenoid sinuses. The differences between the two operative times were evaluated by Student's t-test.

RESULTS

All measurements showed excellent reproducibility for the intraclass correlation coefficient (ICC > 0.9; p < 0.0001). There was an increase in the measurements TB-PhW1 and UP-PhW2 and a decrease in the dimensions of the frontal and sphenoid sinuses after orthognathic surgery.

CONCLUSIONS

The morphology of the superior and inferior pharyngeal airway space and frontal and sphenoid sinuses changes after 6 months of maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion.

A radiographic analysis of tooth morphology following the use of a novel cyclical force device in orthodontics

Background

The purpose was to determine whether or not a novel device used in conjunction with orthodontic treatment produced root resorption shown on 3D images generated from a new cone beam computerized tomography.

Methods

Subjects were actively recruited and those who received braces for the first time were invited to participate. Patients were assigned to receive a functioning device and used the devices for 20 min daily for a six month study period. CBCT images were taken of the dentition at the start of treatment and at the end of the study period.

Results

14 subjects out of a possible 17 subjects completed using the device during the study period. The mean age of the subjects was 20.3 years. Measurements of all teeth present were made from the mesial buccal roots of the first molar on one side of the dental arch to the mesial buccal roots of the first molar on the opposing side of the same arch. These measurements were recorded as linear lengths in mm. A paired t-test was used to determine if significant differences occurred for root lengths at the end of treatment compared to the start of treatment for each of the individual tooth groups. No statistical differences were noted for root length changes above 0.5 mm and 1 mm.

Conclusions

No statistically significant findings were noted for root length change at the end of treatment compared to the start of treatment when using this novel robotic device. No significant differences were noted between roots of anterior and posterior teeth. No clinically significant changes between root lengths were noted above 0.5 mm.

Modularity of the oral jaws is linked to repeated changes in the craniofacial shape of african cichlids

The African cichlids of the East-African rift-lakes provide one of the most dramatic examples of adaptive radiation known. It has long been thought that functional decoupling of the oral and pharyngeal jaws in cichlids has facilitated their explosive evolution. Recent research has also shown that craniofacial evolution from radiations in lakes Victoria, Malawi, and Tanganyika has occurred along a shared primary axis of shape divergence, whereby the preorbital region of the skull changes in a manner that is, relatively independent from other head regions. We predicted that the preorbital region would comprise a variational module and used an extensive dataset from each lake that allowed us to test this prediction using a model selection approach. Our findings supported the presence of a preorbital module across all lakes, within each lake, and for Malawi, within sand and rock-dwelling clades. However, while a preorbital module was consistently present, notable differences were also observed among groups. Of particular interest, a negative association between patterns of variational modularity was observed between the sand and rock-dwelling clades, a patter consistent with character displacement. These findings provide the basis for further experimental research involving the determination of the developmental and genetic bases of these patterns of modularity.