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Keitoku M, Yonemitsu I, Ikeda Y, Tang H, Ono T. Differential Recovery Patterns of the Maxilla and Mandible after Eliminating Nasal Obstruction in Growing Rats. J Clin Med 2022; 11:jcm11247359. [PMID: 36555975 PMCID: PMC9783669 DOI: 10.3390/jcm11247359] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/01/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Although nasal obstruction (NO) during growth causes maxillofacial growth suppression, it remains unclear whether eliminating the NO affects maxillary and mandibular growth differentially. We aimed to clarify whether eliminating NO can help regain normal maxillofacial growth and to determine the optimal intervention timing. Forty-two 4-week-old male Wistar rats were randomly divided into six groups. Their left nostril was sutured to simulate NO over different durations in the experimental groups; the sutures were later removed to resume nasal breathing. Maxillofacial morphology was assessed using microcomputed tomography. Immunohistochemical changes in hypoxia-inducible factor (HIF)-1α, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) of the condylar cartilage were evaluated to reveal the underlying mechanisms of these changes. Maxillary length was significantly lower in rats with NO for ≥5 weeks. In groups with NO for ≥7 weeks, the posterior mandibular length, ramus height, thickness of the hypertrophic cell layer in the condylar cartilage, HIF-1α levels, and RANKL levels were significantly lower and OPG levels and RANKL/OPG were significantly higher than those in the control group. Our findings suggest that eliminating NO is effective in regaining maxillofacial growth. Moreover, the optimal timing of intervention differed between the maxilla and mandible.
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Impact of the endocannabinoid system on murine cranial and alveolar bone phenotype. Ann Anat 2020; 230:151516. [PMID: 32240731 DOI: 10.1016/j.aanat.2020.151516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 03/10/2020] [Accepted: 03/14/2020] [Indexed: 11/23/2022]
Abstract
PURPOSE The endocannabionoid signaling system has been demonstrated to be present in the skeleton, with involvement in the regulation of skeletal homeostasis. However, investigations substantiating these findings in cranial and alveolar bones are missing to date. The aim of our study was to investigate a potential impact of the endocannabinoid system on cranial and alveolar bone structures and phenotypes. BASIC PROCEDURES CB1-/-, CB2-/- and WT mice (n = 5) were scanned via μCT. Reconstructed datasets were processed for analyses. Cranial cephalometric measurements were performed with OnyxCeph3TMsoftware. Alveolar bone densities were determined via mean grey value measurements with Mimics research 18.0. Alveolar bone heights around teeth in upper and lower jaws were morphometrically analyzed. Alveolar osteoclasts were quantified via TRAP staining of paraffin-embedded histologies. Bone-marrow derived macrophages isolated from murine hind legs were analyzed for CD40 and MMR expression via flow cytometry. MAIN FINDINGS CB2-/- mice exhibited significantly higher bone densities with mean grey values of 138.3 ± 22.6 compared to 121.9 ± 9.3 for WT for upper jaws, and 134.6 ± 22.9 compared to 116.1 ± 12.9 for WT 134.6 ± 22.9. Concurrently, CB2 receptor knockout entailed reduced alveolar bone heights of about 50% compared to WT mice. Antigen-presenting cell marker expression of MMR was significantly diminished in bone-marrow derived macrophages of CB2-/- mice. Cranium dimensions as much as alveolar osteoclasts were unaffected by receptor knockouts.CB1 receptor knockout did not involve statistically significant alterations in the parameters investigated compared to WT mice. PRINCIPAL CONCLUSIONS The endoncannabinoid system, and particularly CB2 receptor strongly affects murine alveolar bone phenotypes. These observations suggest CB2 as promising target in the modulation of oral bone phenotypes, probably by impact on bone dynamics via osteal immune cells.
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Aminabadi NA, Behroozian A, Talatahari E, Samiei M, Sadigh-Eteghad S, Shirazi S. Does prenatal restraint stress change the craniofacial growth pattern of rat offspring? Eur J Oral Sci 2015; 124:17-25. [PMID: 26620628 DOI: 10.1111/eos.12230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2015] [Indexed: 12/18/2022]
Abstract
A major and frequently encountered condition underlying the long-term programming effects of the intrauterine environment is exposure to stress. Gestational stress is an environmental factor that induces physical and behavioral alterations in offspring. Seventy female virgin Wistar rats were mated with one male rat for a maximum of four times, after which 52 pregnant rats were divided into two groups. In the experimental group the rats were exposed to restraint stress during pregnancy, whereas the control group did not receive the stress protocol. One male litter was randomly chosen from the offspring of each rat with 8-13 pups. A total of 40 male rat offspring were available for analysis. Thirty-one linear and angular measurements were analyzed in both study groups to investigate whether prenatal restraint stress changes the craniofacial growth pattern of rat offspring. In the prenatally stressed group, anterior cranial base length and viscerocranium measures were significantly increased compared with the control group, whereas cranial width, mandibular dimensions, and posterior cranial height and length remained unchanged. Furthermore, the prenatally stressed group showed backward rotation of the midface and decreased flattening of the cranial vault. It was concluded that prenatal chronic stress can induce alterations in the craniofacial growth pattern by promoting endochondral growth in the cranial base and nasal septum.
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Affiliation(s)
- Naser A Aminabadi
- Department of Pediatric Dentistry, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Ahmad Behroozian
- Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Elham Talatahari
- Department of Pediatric Dentistry, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Mohammad Samiei
- Department of Endodontic and Medical Nanotechnology, Faculty of Dentistry and Advanced Medical Sciences, Tabriz University of Medical Science, Tabriz, Iran
| | - Saeed Sadigh-Eteghad
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sajjad Shirazi
- Dental and Periodental Research Centre, Tabriz University of Medical Sciences, Tabriz, Iran
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Sholts SB, Esteban J, Herlin M, Viluksela M, Håkansson H. Craniofacial form is altered by chronic adult exposure to 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) in Han/Wistar and Long-Evans rats with different aryl hydrocarbon receptor (AhR) structures. Toxicol Rep 2014; 2:472-481. [PMID: 28962383 PMCID: PMC5598109 DOI: 10.1016/j.toxrep.2014.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 12/12/2014] [Indexed: 12/30/2022] Open
Abstract
Mammalian bone has shown a variety of responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure in experimental and wildlife studies. Although many responses have been well characterized in the postcranial skeleton, dioxin-induced effects on the cranium are largely unknown. In this study, we investigated the effects of chronic adult exposure to TCDD on cranial size and shape in dioxin-resistant Han/Wistar (H/W) and dioxin-sensitive Long–Evans (L–E) rat strains. Three-dimensional landmark configurations for the face, vault, and base of the cranium were recorded and analyzed using geometric morphometrics (GM) and dose–response modeling. The strongest effects were shown by L–E and H/W rats with daily exposures of 100 and 1000 ng TCDD/kg bw/day, respectively, resulting in significant reductions in centroid size (CS) in all three cranial modules for both strains except for the vault in H/W rats. Consistent with previous evidence of intraspecific variation in TCDD resistance, the benchmark doses (CEDs) for cranial size reduction in L–E rats were roughly 10-fold lower than those for H/W rats. For both strains, the face showed the greatest size reduction from the highest doses of TCDD (i.e., 3.6 and 6.3% decreases in H/W and L–E rats, respectively), most likely related to dose-dependent reductions in limb bone size and body weight gain. However, intrinsic morphological differences between strains were also observed: although the control groups of H/W and L–E rats had vaults and bases of comparable size, the face was 6.4% larger in L–E rats. Thus, although H/W rats possess an altered aryl hydrocarbon receptor (AhR) that appears to mediate and provides some resistance to TCDD exposure, their smaller reductions in facial size may also relate to strain-specific patterns of cranial development and growth. Future research will be aimed at understanding how ontogenetic factors may modulate toxic effects of prenatal and lactational exposure on the mammalian skeleton.
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Affiliation(s)
- Sabrina B Sholts
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, 10th and Constitution Avenue NW, Washington, DC 20560, USA
| | - Javier Esteban
- Instituto de Bioingeniería, Universidad Miguel Hernández, Av. de la Universidad s/n, 03202 Elche (Alicante), Spain
| | - Maria Herlin
- Clinical and Molecular Osteoporosis Research Unit, Department of Clinical Sciences, Lund University, Inga Marie Nilssons gata 22, SE-22100 Lund, Sweden.,Institute of Environmental Medicine, Karolinska Institutet, P.O. Box 210, SE-17177 Stockholm, Sweden
| | - Matti Viluksela
- Department of Environmental Health, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland.,Department of Environmental Science, University of Eastern Finland, Kuopio, Finland
| | - Helen Håkansson
- Institute of Environmental Medicine, Karolinska Institutet, P.O. Box 210, SE-17177 Stockholm, Sweden
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Gonzalez PN, Kristensen E, Morck DW, Boyd S, Hallgrímsson B. Effects of growth hormone on the ontogenetic allometry of craniofacial bones. Evol Dev 2014; 15:133-45. [PMID: 25098638 DOI: 10.1111/ede.12025] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Organism size is controlled by interactions between genetic and environmental factors mediated by hormones with systemic and local effects. As changes in size are usually not isometric, a considerable diversity in shape can be generated through modifications in the patterns of ontogenetic allometry. In this study we evaluated the role of timing and dose of growth hormone (GH) release on growth and correlated shape changes in craniofacial bones. Using a longitudinal study design, we analyzed GH deficient mice treated with GH supplementation commencing pre- and post-puberty. We obtained 3D in vivo micro-CT images of the skull between 21 and 60 days of age and used geometric morphometrics to analyze size and shape changes among control and GH deficient treated and non-treated mice. The variable levels of circulating GH altered the size and shape of the adult skull, and influenced the cranial base, vault, and face differently. While cranial base synchondroses and facial sutures were susceptible to either the direct or indirect effect of GH supplementation, its effect was negligible on the vault. Such different responses support the role of intrinsic growth trajectories of skeletal components in controlling the modifications induced by systemic factors. Contrary to the expected, the timing of GH treatment did not have an effect on catch-up growth. GH levels also altered the ontogenetic trajectories by inducing changes in their location and extension in the shape space, indicating that differences arose before 21 days and were further accentuated by a truncation of the ontogenetic trajectories in GHD groups.
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Affiliation(s)
- Paula N Gonzalez
- Departmentof Cell Biology and Anatomy, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, Canada T2N 4Z6; McCaig Institute for Bone and Joint Health, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute for Child and Maternal Health, Calgary, Alberta, Canada; Instituto de Genética Veterinaria, IGEVET-CONICET, La Plata, Argentina
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Litsas G. Growth hormone therapy and craniofacial bones: a comprehensive review. Oral Dis 2012; 19:559-67. [PMID: 23279133 DOI: 10.1111/odi.12041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 10/21/2012] [Accepted: 10/22/2012] [Indexed: 01/05/2023]
Abstract
Growth hormone (GH) has significant effects on linear bone growth, bone mass and bone metabolism. The primary role of GH supplementation in children with GH deficiency, those born small for gestational age or with other types of disorders in somatic development is to increase linear growth. However, GH therapy seems to elicit varying responses in the craniofacial region. Whereas the effects of GH administration on somatic development are well documented, comparatively little is known of its effects on the craniofacial region. The purpose of this review was to search the literature and compile results from both animal and human studies related to the impact of GH on craniofacial growth.
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Abstract
Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies.
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da Silva HCFP, Cecanho R. Using a specially designed cephalostat for longitudinal cephalometric studies in rats. Lab Anim (NY) 2010; 39:241-7. [PMID: 20664573 DOI: 10.1038/laban0810-241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 11/23/2009] [Indexed: 11/09/2022]
Abstract
To better understand and observe craniofacial growth, researchers carry out longitudinal cephalometric studies on animals. The authors constructed a cephalostat specially designed to study craniofacial growth in rats. They describe and validate a cephalometric technique using this cephalostat. They carried out cephalometric radiography and analysis of 62 Wistar rats. By using this method, the authors were able to take repeated, reproducible intracranial, intramandibular and craniomandibular measurements of the rats. The proposed method is a useful tool for studying the craniofacial growth process.
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The significance of RUNX2 in postnatal development of the mandibular condyle. J Orofac Orthop 2010; 71:17-31. [PMID: 20135247 DOI: 10.1007/s00056-010-9929-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 12/02/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE RUNX2, in the Runt gene family, is one of the most important transcription factors in the development of the skeletal system. Research in recent decades has shown that this factor plays a major role in the development, growth and maturation of bone and cartilage. It is also important in tooth development, mechanotransduction and angiogenesis, and plays a significant role in various pathological processes, i.e. tumor metastasization. Mutations in the RUNX2 gene correlate with the cleidocranial dysplasia (CCD) syndrome, important to dentistry, particularly orthodontics because of its dental and orofacial symptoms. Current research on experimentally-induced mouse mutants enables us to study the etiology and pathogenesis of these malformations at the cellular and molecular biological level. This study's aim is to provide an overview of the RUNX2 gene's function especially in skeletal development, and to summarize our research efforts to date, which has focused on investigating the influence of RUNX2 on mandibular growth, which is slightly or not at all altered in many CCD patients. MATERIALS AND METHODS Immunohistochemical analyses were conducted to reveal RUNX2 in the condylar cartilage of normal mice and of heterozygous RUNX2 knockout mice in early and late growth phases; we also performed radiographic and cephalometric analyses. RESULTS We observed that RUNX2 is involved in normal condylar growth in the mouse and probably plays a significant role in osteogenesis and angiogenesis. The RUNX2 also has a biomechanical correlation in relation to cartilage compartmentalization. At the protein level, we noted no differences in the occurrence and distribution of RUNX2 in the condyle, except for a short phase during the 4th and 6th postnatal weeks, so that one allele might suffice for largely normal growth; other biological factors may have compensatory effects. However, we did observe small changes in a few cephalometric parameters concerning the mandibles of heterozygous knockout animals. We discuss potential correlations to our findings by relating them to the most current knowledge about the RUNX2 biology.
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Saleh HA, El-Aziz GA, El-Fark MM, El-Gohary M. Effect of Maternal Lead Exposure on Craniofacial Ossification in Rat Fetuses and the Role of Antioxidant Therapy. Anat Histol Embryol 2009; 38:392-9. [DOI: 10.1111/j.1439-0264.2009.00960.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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da Silva HCFP, Cecanho R. Cephalometric changes produced by locally applied anabolic steroid in Wistar rats. Arch Oral Biol 2009; 54:389-95. [PMID: 19233344 DOI: 10.1016/j.archoralbio.2009.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 01/10/2009] [Accepted: 01/17/2009] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND OBJECTIVE There is a strong relationship between neuromuscular activity and facial skeletal morphogenesis. The systemic use of anabolic steroid accelerates craniofacial growth and induces high functional activity of rats' masticatory muscles. The present study examines the effect of an anabolic steroid locally applied in the masseter muscle of growing rats with the purpose of verifying possible craniofacial changes with minimum drug side effects, using cephalometric analysis. MATERIALS AND METHODS Forty-three 3-week-old Wistar rats were evaluated and divided into two groups: (1) NAN group (local bilateral masseter injection of nandrolone decanoate - 0.05 microg/3 microl/bi-weekly) and (2) CON group (local bilateral masseter injection of sterile oil - 3 microl). Tukey and Wilcoxon tests were used. RESULTS In NAN group the cephalometric measures showed horizontalized facial growth (reduce of FMA angle -p<0.01), increase of posterior facial height, decrease of anterior facial height, reduction of gonial angle (p<0.05), increase of mandibular height (p<0.01). There was no variation in the length of the mandible, in the skull and animals' weight gain, thus demonstrating that no important systemic effect occurred. CONCLUSION The local injection of nandrolone in the masseter muscle of rats was capable to alter the growth direction and the morphology of the craniofacial complex in Wistar rats.
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Abbassy MA, Watari I, Soma K. Effect of experimental diabetes on craniofacial growth in rats. Arch Oral Biol 2008; 53:819-25. [DOI: 10.1016/j.archoralbio.2008.02.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 01/11/2008] [Accepted: 02/02/2008] [Indexed: 11/25/2022]
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Watanabe K, Imamura H, Uchikanbori S, Fujita Y, Maki K. Effects of Restricted Calcium Intake on Bone and Maxillofacial Growth. Angle Orthod 2008; 78:445-52. [DOI: 10.2319/101106-417.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Accepted: 02/01/2007] [Indexed: 11/23/2022] Open
Abstract
Abstract
Objective: To investigate the effects of a low calcium diet on maxillofacial development by evaluating Bone Mineral Content (BMC) in the lower alveolar bones, femurs, and tibias and by performing cephalometry on growing rats.
Materials and Methods: Thirty 5-week-old male Wistar rats were randomly divided into 3 groups; the control group (n = 10) was given standard diet for 6 weeks, the low calcium/standard diet group (n = 10) was given a calcium-restricted diet for the first 4 weeks, and then a standard diet for the following 2 weeks, and the low calcium diet group (n = 10) was given the calcium-restricted diet for 6 weeks. After the rats were euthanized, heads and legs were fixed and cephalometry was performed. Next, mandibles, femurs and tibias were digitally photographed and the BMC was evaluated using our newly developed software.
Results: The BMC was decreased in all of the bone samples from the two groups that received restricted calcium. In the low calcium/standard diet group, the BMC recovered the most in the tibias and least in the lower alveolar bones. Development of the mandibles in the anterior-posterior direction was accelerated, while that in the superior-inferior direction was inhibited in those rats.
Conclusion: The BMC reduction following calcium deficiency in the lower alveolar bone hardly recovers, so prevention is important. Development of the mandible in a superior-inferior direction is inhibited while that in an anterior-posterior direction is accelerated due to a calcium-restricted diet.
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Affiliation(s)
- Koji Watanabe
- a Graduate PhD student, Department of Developmental Stomatognathic Function Science, Kyushu Dental College, Fukuoka, Japan
| | - Hitoshi Imamura
- b Research Fellow, Department of Developmental Stomatognathic Function Science, Kyushu Dental College, Fukuoka, Japan
| | - Shinsaku Uchikanbori
- a Graduate PhD student, Department of Developmental Stomatognathic Function Science, Kyushu Dental College, Fukuoka, Japan
| | - Yuko Fujita
- a Graduate PhD student, Department of Developmental Stomatognathic Function Science, Kyushu Dental College, Fukuoka, Japan
| | - Kenshi Maki
- c Chief Professor, Department of Developmental Stomatognathic Function Science, Kyushu Dental College, Fukuoka, Japan
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Abed GS, Buschang PH, Taylor R, Hinton RJ. Maturational and functional related differences in rat craniofacial growth. Arch Oral Biol 2007; 52:1018-25. [PMID: 17643386 DOI: 10.1016/j.archoralbio.2007.05.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 05/16/2007] [Accepted: 05/24/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND Whilst decreases in masticatory muscle function have been linked with increased prevalences of craniofacial dysmorphology and malocclusion in humans, the relative susceptibility of the different craniofacial components remains poorly understood. METHODS Thirty-two wild-type male Sprague-Dawley rats were randomly assigned to two groups (n=16 each), one raised on a soft diet (SD) and the other on a hard diet (HD). Body weights and three radiographs (lateral, dorso-ventral, and tibial X-rays) were taken at baseline (T1=23 days old) and every 2 weeks thereafter for 8 weeks (T5=79 days old). The X-ray images were scanned, standardised points were digitised, and linear measurements were calculated. Multilevel statistical models were used to describe longitudinal absolute growth changes and statistically evaluate group differences. Relative maturity curves were generated for each measurement based on the animals' T5 status. The experimental effect was calculated as the absolute and relative growth differences between the HD and SD groups. RESULTS The HD group was significantly heavier than the SD group at T5, but no differences in tibial length were observed. Eight of the 20 craniofacial measurements (40%) showed significant size differences at the end of the experiment, with the SD group showing deficiencies in each instance. All of the vertical measurements, as well as most of the mandibular (67%) and transverse (67%) measures, showed absolute growth deficits in the SD group. Relative maturity curves demonstrated considerable variation among craniofacial structures (ranging from 42 to 98%). The neurocranial measures were the most mature; the mandibular measures were the least mature; the viscerocranial measures, which were most variable, tended to be intermediate. Whilst unrelated to the absolute experimental effect, the structures' relative maturity explained almost 70% (r=-0.82) of the relative experimental effect. CONCLUSION The results of this study support the notion that masticatory function is a key determinant of the craniofacial growth pattern and that its effects are modulated by the relative growth potential of the different craniofacial components.
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Affiliation(s)
- George S Abed
- Department of Orthodontics, Baylor College of Dentistry, 3302 Gaston Ave., Dallas, TX 75246, USA
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Abstract
UNLABELLED Complete anthropometrical data on a sample of 111 Russian males aged 20.0+/-2.3 years were obtained to investigate craniofacial morphology according to individual orthodontic status (OS). Subsample analyses were performed, using a variety of grouping factors. a) 1-spacing on both dental arches; 2-absence of crowding, spacing, rotation, or displacement of teeth on both dental arches; 3-crowding on both dental arches; b) 1-spacing on mandible; 2-absence of crowding, spacing, rotation, or displacement of teeth on mandible; 3-crowding on mandible; c) 1-spacing on maxilla; 2-absence of crowding, spacing, rotation, or displacement of teeth on maxilla; 3-crowding on maxilla. Wilks' Lambdas were found to be 0.29 to 0.59; all were significant. CONCLUSIONS 1. Significant positive and negative correlations were found between craniofacial measurements and an individual's OS. 2. Measurements exhibited statistically significant differences between the groups with different OS at the p<0.05 level and some at p<0.01. 3. Using forward stepwise discriminant analysis, a high difference in craniofacial architecture between the groups with different OS was found. Canonical discriminant analysis indicates the face pattern connected to crowding: relatively high medial vertical mandible height in combination with a vertically long and narrow face; to spacing: a wide face with wide nose and high upper lip is combined with shortened medial vertical mandible height. 4. Depending upon the grouping factor, 10 to 12 variables were chosen in the canonical discriminant model. Classification functions and means of canonical roots were calculated; morphological interpretations of canonical roots were performed. 5. Definitive OS is a complicated product of interaction during the ontogenesis of jaws between the time of teeth eruption and the growth of two growth fields (alveolar and corpus) under the simultaneous influence of hormonal status and the chronological age of the individual.
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Affiliation(s)
- Nadezda V Lupacheva
- Institute and Museum of Anthropology, Moscow State University, Moscow, Russian Federation.
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Sardi ML, Rozzi FR. Developmental connections between cranial components and the emergence of the first permanent molar in humans. J Anat 2007; 210:406-17. [PMID: 17428202 PMCID: PMC2100294 DOI: 10.1111/j.1469-7580.2007.00701.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The age of emergence of the first molar (M1) is a developmental event correlated with many variables of primate life history, such as adult brain size. The evolution of human life history is characterized by the inclusion of childhood, which takes place between weaning and M1 emergence. Children still depend on adults for nutrition due to their small digestive system and their immature brains. By contrast, juveniles are not dependent because of M1 emergence, which enables shifting to adult type diet, and attainment of nearly adult brain size. In this study, developmental connections between M1 emergence and growth of cranial components were explored in two ways in order to understand the developmental basis of their evolutionary connections: (1) differences in growth trajectories of cranial components with respect to M1 emergence and (2) differences between individuals with and without fully emerged M1. Growth of anteroneural, midneural, posteroneural, otic, optic, respiratory, masticatory and alveolar cranial components was analysed in human skulls of individuals aged 0-20 years and in an adult reference skull. Volumetric indices were calculated to estimate size. Two subsamples were selected in order to focus on the transition between deciduous and permanent dentition: those with full deciduous dentition and before M1 reaches the occlusal plane; and those who present M1 in full emergence and no other cheek-tooth at the occlusal plane. The principal results were as follows. (1) Trajectories fitted using the whole sample are characterized by an inflection point that takes place before M1 emergence for neural components and around M1 emergence for facial components. (2) Associations between growth and age tend to be strong in those with full deciduous dentition, and weak in those who present M1 in full emergence. (3) Individuals who present M1 in full emergence are larger than those with full deciduous dentition. (4) Growth of components linked to the central nervous system is not linear until M1 emergence. Individuals who present M1 in full emergence are only larger than individuals with full deciduous dentition by 4-5% of adult size. (5) The alveolar component does not show increments between full deciduous dentition and M1 emergence. (6) When volumetric indices were standardized by age, the growth trajectories of individuals with full deciduous dentition and of those with M1 were not decoupled. In general terms, M1 emergence does not show a strong association with growth of the components that may explain differences in life histories. However, the main changes in neural and alveolar components occur in the first 3 years of life, which may be developmentally connected with M1 crown formation.
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Affiliation(s)
- Marina L Sardi
- UPR 2147 Dynamique de l'Evolution Humaine, CNRS, Paris, France.
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Influence of prednisolone on craniofacial and long bones in growing rats: A cephalometric and peripheral quantitative computed tomographic analysis. PEDIATRIC DENTAL JOURNAL 2007. [DOI: 10.1016/s0917-2394(07)70103-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Singleton DA, Buschang PH, Behrents RG, Hinton RJ. Craniofacial growth in growth hormone-deficient rats after growth hormone supplementation. Am J Orthod Dentofacial Orthop 2006; 130:69-82. [PMID: 16849075 DOI: 10.1016/j.ajodo.2005.02.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 01/26/2005] [Accepted: 02/23/2005] [Indexed: 11/18/2022]
Abstract
INTRODUCTION Growth hormone (GH) supplementation is an established therapy to increase stature in GH-deficient or short-for-age children, but comparatively little is known of its effects on the craniofacial skeleton. METHODS Using a mutant strain of Lewis rats (dw/dw) in which GH levels were 6% to 10% of normal, but other trophic hormones were unaffected, we investigated the differential susceptibility of craniofacial measures to GH supplementation, characterized their potential for partial or complete catch-up growth, and compared their growth changes with those in long bones. At 24 days of age and for 3 subsequent weeks, radiographs of the lateral head, upper limb, and lower limb were obtained from 3 groups of growing rats (n = 8-9 in each group): dwarf (experimental) with GH injection, dwarf (sham) with vehicle injection, and wild type (control) with vehicle injection. The x-ray images were scanned, standardized points digitized, and linear distances measured. Absolute growth curves were generated for each group by using multilevel modeling procedures and iterative generalized least-squares curve fitting. RESULTS For every measure, growth differences were evident between the experimental and the sham groups, but the treatment effect varied inversely with relative maturity of the measure. Although all craniofacial measures showed some catch-up growth, only 31% of craniofacial measures had complete catch-up compared with all limb measures. The percentage of catch-up varied inversely with relative maturity of the measure. Our results suggest that the effects of GH supplementation vary considerably, so that measures with the lowest relative maturity (greatest baseline potential) show the greatest treatment effect and catch-up, whereas more mature measures show less growth response to GH replacement. CONCLUSIONS These results suggest that, depending on the timing of GH supplementation, there is potential for change in proportions or shape of the craniofacial complex.
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Affiliation(s)
- Douglas A Singleton
- Department of Orthodontics, Baylor College of Dentistry, Texas A&M University System Health Sciences Center, Dallas, Tex, USA
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