Analysis of the association of COL2A1 and IGF-1 with mandibular prognathism in a Chinese population.

OBJECTIVE: In this study, we performed a case-control association analysis to determine whether the candidate genes COL2A1 and IGF-1 are susceptibility genes for mandibular prognathism (MP). METHODS: Eleven and five single-nucleotide polymorphisms (SNPs) located in COL2A1 and IGF-1, respectively, were selected and genotyped in 211 cases and 224 controls. The individual SNPs and the relevant haplotypes were analyzed and tested for an association with MP, to identify genes potentially associated with MP. RESULTS: In the analysis of individual SNPs, the SNP rs1793953 in the COL2A1 gene showed a possible association with MP with regard to allelic frequency and genotypic distribution (p = 0.031; p = 0.025, respectively) in the 211 cases and 224 controls. The A allele of rs1793953 was associated with a significantly decreased risk of MP (OR: 0.74; 95% CI: 0.58-0.97). Linkage disequilibrium and haplotype analysis revealed that MP was not associated with haplotypes that included the rs1793953 alleles. IGF-1 gene did not show the association with MP. CONCLUSION: An association between polymorphism in the COL2A1 gene and MP was observed. The results suggested that the COL2A1 gene could be a new susceptibility gene for use in the study of genetic risk factors for MP.

A review of laser applications in orthodontics.

Laser technique now is widely applied in orthodontic treatment and proved to have many benefits. Soft tissue lasers can be used to perform gingivectomy, frenectomy and surgical exposure of tooth with less bleeding and swelling, improved precision, reduced pain and less wound contraction. Other laser applications include enamel etching and bonding and bracket debonding. Lower level lasers have the potential effects of pain control and accelerating tooth movement. Clinicians must be aware of the safety issues and risks associated with laser and receive proper training before the laser treatment is started.

Effect of different advancement positions on the maximum retrusive force of the mandible.

INTRODUCTION: Functional appliances lead, in different degrees, to loss of anchorage in the lower arch. By anchoring them to the mandibular bone, any dental side effects may be avoided and the skeletal effect enhanced. Stability of bone-borne fixation would be affected by forces created by the pull of the masticatory muscles. We aimed to identify mean maximum forces produced by mandibular retrusive muscles, at different degrees of advancement. SUBJECTS AND METHODS: Eighteen healthy adult volunteers participated in the study. Maximum retrusive force was measured using a splint/load cell system. Readings of the maximum forces of retrusion were taken from five mandibular positions: unstrained retruded position, and 4, 5, 6, and 7 mm anterior to the unstrained position. Data were presented as means ± SD and anova was performed to examine statistical significant differences between means of the maximum retrusion force. RESULTS: Mean maximum retrusion force ranged between 63.3 and 198.2 newtons at the unstrained and 7 mm positions, respectively. It increased as the distance of advancement increased, being statistically significantly (p < 0.05) less at unstrained position compared with all advancement distances, 4 mm of advancement than 6 and 7 mm advancement, 5 mm of advancement than at 7 mm advancement. CONCLUSION: Magnitude of the forces exerted by muscles during voluntary maximum retrusion movement from different advancement positions increased proportionately as the retrusion distance increased up to 7 mm. Such range of high forces might be important to consider when designing a bone-borne functional appliance.

Orthopedic protraction of the maxilla may affect cranial base synchondroses indicated by increased expressions of growth factors.

OBJECTIVES: To examine the biological adaptation of cranial base synchondroses (CBS) when the maxilla was forward positioned by orthopedic force. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at Shanghai Jiao Tong University. 50 Sprague-Dawley rats, 4 weeks of age, were divided into experimental (n=30) and control groups (n=20). MATERIAL AND METHODS: An orthopedic appliance was fitted to the cranio-maxillary complex to advance the maxilla forward. The animals in the experimental group, together with the counterparts in the control group, were sacrificed at days 1, 3, 5, 7, and 14, respectively. The whole cranial base housing both the spheno-ethmoid (SES) and spheno-occipital synchondroses (SOS) was removed for tissue processing and immunotest of Sox9, Core-binding factor α 1 (Cbfa1), and vascular endothelial growth factor (VEGF), three carefully selected growth factors that are markers of chondrogenesis in different stages and its transition to endochondral ossification. Semiquantitative analysis was also conducted by using a computerizing imaging system. RESULTS: The temporal tendency of the changes in the expressions of the three growth factors featured an increase from Day 3 and onwards for Cbfa1 and VEGF, and a following decline after Day 5 for Sox9. In both SES and SOS, the expressions of the three growth factors were significantly stronger in the experimental groups than that in groups (p<0.05). CONCLUSIONS: Protractive orthopedic force imposed on the maxilla provokes an enhancement of chondrogenic process in CBS.

Resveratrol inhibits periodontal pathogens in vitro.

The gram-negative anaerobic bacteria A. actinomycetemcomitans (Aa) and P. gingivalis (Pg) are key components in the aetiology of periodontal disease, and associated hard-tissue destruction. Resveratrol is a phytoalexin, produced naturally by several plants when under attack by bacterial or fungal pathogens. It is found in many foods including mulberries, peanuts and the skin of labrusca and muscadine grapes. The objective of this study was to evaluate the effect of resveratrol on the in vitro growth of periodontal pathogens Aa and Pg. For comparison, resveratrol's effect on a variety of other oral microorganisms was also evaluated. Resveratrol demonstrates a poor solubility in water, thus different concentrations of resveratrol in the solvent dimethyl sulphoxide (DMSO) were added to calibrated suspensions of Aa and Pg. As a control, a parallel series of dilutions containing the vehicle DMSO alone was made to measure the effect of the solvent. Minimum inhibitory concentrations of the periodontal pathogens were calculated. All suspensions were incubated for 1, 3, 6 and 24 h in an anaerobic chamber at 37 °C. At each time interval, selected dilutions from each culture broth were plated on blood agar plates. Colonies appearing on blood agar plates were visually counted at 3 days for Aa, and at 5 days for Pg. The periodontal bacteria showed a significant decrease (p < 0.05) in viable counts after 1 h, whilst no colony forming units could be observed after 24 h. The results suggest that resveratrol possesses significant antimicrobial properties on periodontal pathogens in vitro.

Genes, genetics, and Class III malocclusion.

To present current views that are pertinent to the investigation of the genetic etiology of Class III malocclusion. Class III malocclusion is thought to be a polygenic disorder that results from an interaction between susceptibility genes and environmental factors. However, research on family pedigrees has indicated that Class III malocclusion might also be a monogenic dominant phenotype. Recent studies have reported that genes that encode specific growth factors or other signaling molecules are involved in condylar growth under mechanical strain. These genes, which include Indian hedgehog homolog (IHH), parathyroid-hormone like hormone (PTHLH), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF), and variations in their levels of expression play an important role in the etiology of Class III malocclusion. In addition, genome-wide scans have revealed chromosomal loci that are associated with Class III malocclusion. It is likely that chromosomal loci 1p36, 12q23, and 12q13 harbor genes that confer susceptibility to Class III malocclusion. In a case-control association study, we identified erythrocyte membrane protein band 4.1 (EPB41) to be a new positional candidate gene that might be involved in susceptibility to mandibular prognathism. Most of the earlier studies on the genetic etiology of Class III malocclusion have focused on the patterns of inheritance of this phenotype. Recent investigations have focused on understanding the genetic variables that affect Class III malocclusion and might provide new approaches to uncovering the genetic etiology of this phenotype.

Effects of vascular endothelial growth factor (VEGF) on MC3T3-E1.

UNLABELLED: Osteogenesis and angiogenesis are closely correlated. Vascular endothelial growth factor (VEGF) is believed to play a critical role in skeletal development. OBJECTIVE: To investigate whether VEGF has direct effects on bone cells activities and to better understand how VEGF promotes bone remodeling. MATERIALS AND METHODS: MC3T3-E1 cell line was cultured with and without VEGF in vitro. The cells in both control and test groups were collected at different culture time points of 24, 48 and 72 h. Real-time polymerase chain reaction (qPCR) was carried out to quantify the mRNA expression of VEGF receptor (VEGFR2), alkaline phosphatase (ALP) and osteocalcin (OCN), osteoprotegerin (OPG) and receptor activator of nuclear factor kappa ß ligand (RANKL). RESULTS: The expression of VEGFR2 significantly increased by 53% at 24 h and remained increased by 8% at 72 h compared to control (p < 0.05). ALP showed an early increase by 73% at 24 h (p < 0.001), but dropped by 14 and 41% at 48 and 72 h, respectively (p < 0.05). OCN was down-regulated by 41% at 24 h but then up-regulated by 149% at 72 h (p < 0.001). The expression of OPG significantly decreased by 7% at 24 h (p < 0.001) while dramatically increased by 133% at 72 h (p < 0.001). RANKL remained unchanged at all three time points (p > 0.05). CONCLUSION: VEGF promotes bone remodeling by direct effects on osteoblastic cells via regulating gene expression of ALP, OCN, and OPG through VEGFR2 signaling pathway.

Effect of Buguzhi (Psoralea corylifolia fruit) extract on bone formation.

The objective of the study is to compare the amount of new bone produced by Buguzhi (Psoralea corylifolia fruit) extract in collagen matrix to that produced and collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm, were created in the parietal bone of 9 New Zealand white rabbits. Six defects were grafted with Buguzhi extract mixed with collagen matrix. Six defects were grafted with collagen matrix alone (positive control) and 6 were left empty (negative control). Animals were sacrificed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells was made on 100 sections (50 sections for each group) using image analysis. A total of 275% more new bone was present in defects grafted with Buguzhi extract in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control group. The amount of bone cells was also significantly greater in the Buguzhi group than in the positive control group. To conclude, Buguzhi extract in collagen matrix has the effect of increasing new bone formation locally in vivo. Buguzhi extract in collagen matrix can be used as a bone graft material.

Inhibitory effect of quercetin on periodontal pathogens in vitro.

Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) are bacteria strongly associated with early onset, progressive and refractory periodontal disease and associated alveolar bone loss. Quercetin is a flavonoid found in many foods including apples, onions and tea. The aim of this study was to evaluate the effect of quercetin on in vitro growth of periodontal pathogens Aa and Pg. For comparison, quercetin's effect on several oral microbes was also evaluated. Different concentrations of quercetin solution were added to calibrated suspensions of Aa and Pg. All suspensions were incubated for 1, 3, 6, and 24 h in an anaerobic chamber at 37 degrees C. At each time point, selected dilutions from each culture broth were plated on blood agar plates. Colonies appearing on blood agar plates were visually counted on 3 days for Aa and 5 days for Pg. Minimum inhibitory concentrations of both periodontal pathogens were also determined. Both periodontal bacteria showed a significant decrease (p < 0.05) in viable counts after 1 h. No colony forming units of Pg could be observed after 24 h. The results suggest that quercetin possesses significant antimicrobial properties on periodontal pathogens in vitro.

Does orthodontic tooth movement cause an elevation in systemic inflammatory markers?

SUMMARY: The aim of this study was to evaluate the effects of orthodontic treatment on systemic levels of the inflammatory markers, C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6). The study group comprised 11 girls and 6 boys (mean age 13.1 years) treated with fixed appliances and distalizing headgear. Venous blood samples were taken from the cubital vein of each subject before treatment (T0) and then at three further time points during treatment (T1-T3), 2 months apart. The sera from these blood samples were analysed using enzyme-linked immunosorbent assay (ELISA) assay technology for CRP, TNF-alpha, and IL-6 concentration levels. Data were compared between baseline and subsequent sequential time points using a Mann-Whitney test for non-normally distributed variables. The results showed that there was no significant elevation of any of the three inflammatory markers at any of the time points. This research provides evidence that conventional orthodontic treatment is not associated with a systemic immune response in the factors investigated.

Functional analysis of core binding factor a1 and its relationship with related genes expressed by human periodontal ligament cells exposed to mechanical stress.

Mechanical stress induces human periodontal ligament (PDL) cells to express an osteoblastic phenotype in vitro. Core binding factor a1 (CBFA1) is a key regulator of osteoblast differentiation. This study was designed to investigate the role of CBFA1 in alveolar bone remodelling, specifically the expression of CBFA1 messenger RNA (mRNA) in human PDL cells under mechanical stress and its up- and downstream relationships with other bone remodelling markers. Cultured human PDL cells were exposed to mechanical stress. The expressions of CBFA1 and alkaline phosphatase (ALP), osteopontin (OPN), osteoprotegrin (OPG), and receptor activator nuclear factor kappa B ligand (RANKL) were detected before and after RNA interference (RNAi) of CBFA1. The data were analysed using a t-test and one-way analysis of variance. After mechanical stress loading, CBFA1 mRNA expression was raised initially, followed by an increased expression of ALP and RANKL, decreased expression of OPG, and a change in OPN expression. After CBFA1 knock-down in human PDL cells by small hairpin (sh) RNA, the expression of ALP, OPN, OPG, and RANKL also changed. These findings suggest that in the present model system CBFA1 may play an important role in PDL-mediated bone remodelling in response to mechanical stimulation. Mechanical stress: CBFA1-ALP and OPG-PDL homeostasis may be one of the signal transduction pathways of human PDL cell differentiation under mechanical stress without exclusion of the involvement of other pathways.

Factors regulating endochondral ossification in the spheno-occipital synchondrosis.

OBJECTIVES: To identify the temporal pattern of core-binding factor alpha1 (Cbfa1) and vascular endothelial growth factor (VEGF) expressions in the spheno-occipital synchondrosis in vitro with and without tensile stress. MATERIALS AND METHODS: Sixty male BALB/c mice were randomly divided into an experimental group (with tensile stress) and a control group (without tensile stress) at each of five time points. Animals were sacrificed and the cranial base synchondroses were aseptically removed. In the experimental groups, mechanical stress was applied on the surgical explants with helical springs and incubated as organ culture for 6, 24, 48, 72, and 168 hours. In the control group, the springs were kept at zero stress. Tissue sections were subjected to immunohistochemical staining for quantitative analysis of Cbfa1 and VEGF expression. RESULTS: Quantitative analysis revealed that Cbfa1 and VEGF expressions reached a peak increase at 24 and 48 hours, respectively. Compared with the control groups, both Cbfa1 and VEGF were expressed consistently higher in the experimental groups at all time points. CONCLUSION: Mechanical stress applied to the spheno-occipital synchondrosis elicits Cbfa1 expression and subsequently up-regulates the expression of VEGF. Increased levels of expression of both factors could play a role in the growth of the spheno-occipital synchondrosis.

VEGF: an essential mediator of both angiogenesis and endochondral ossification.

During bone growth, development, and remodeling, angiogenesis as well as osteogenesis are closely associated processes, sharing some essential mediators. Vascular endothelial growth factor (VEGF) was initially recognized as the best-characterized endothelial-specific growth factor, which increased vascular permeability and angiogenesis, and it is now apparent that this cytokine regulates multiple biological functions in the endochondral ossification of mandibular condylar growth, as well as long bone formation. The complexity of VEGF biology is paralleled by the emerging complexity of interactions between VEGF ligands and their receptors. This narrative review summarizes the family of VEGF-related molecules, including 7 mammalian members, namely, VEGF, placenta growth factor (PLGF), and VEGF-B, -C, -D, -E, and -F. The biological functions of VEGF are mediated by at least 3 corresponding receptors: VEGFR-1/Flt-1, VEGFR-2/Flk-1, VEGFR-3/Flt-4 and 2 co-receptors of neuropilin (NRP) and heparan sulfate proteoglycans (HSPGs). Current findings on endochondral ossification are also discussed, with emphasis on VEGF-A action in osteoblasts, chondroblasts, and chondroclasts/osteoclasts and regulatory mechanisms involving oxygen tension, and some growth factors and hormones. Furthermore, the therapeutic implications of recombinant VEGF-A protein therapy and VEGF-A gene therapy are evaluated. Abbreviations used: VEGF, Vascular endothelial growth factor; PLGF, placenta growth factor; NRP, neuropilin; HSPGs, heparan sulfate proteoglycans; FGF, fibroblast growth factor; TGF, transforming growth factor; HGF, hepatocyte growth factor; TNF, tumor necrosis factor; ECM, extracellular matrix; RTKs, receptor tyrosine kinases; ERK, extracellular signal kinases; HIF, hypoxia-inducible factor.

A new approach to control condylar growth by regulating angiogenesis.

OBJECTIVE: To provide a comprehensive review of the mechanisms of growth of mandibular condyle, the roles of angiogenesis enhancers and inhibitors during endochondral ossification in mandibular condyle and newly developed delivery methods for local gene delivery that may represent strategies to regulate condylar growth. DESIGN: Narrative review. RESULTS: Angiogenesis is the crucial step in mandibular condylar growth for it regulates the transformation from cartilage to bone. Angiognesis enhancers, especially VEGF and FGF, play important roles in the process of new blood lumen formation and invasion. On the other hand, angiostatin and endostatin inhibit angiogenesis by targeting endothelial cells and several signal cascades. Delivery methods such as liposomes, stem cells and virus vectors have been studied. Recombinant AAV-mediated gene therapy is considered as one of the most promising strategies of condylar growth management. CONCLUSION: AAV-mediated gene therapy using VEGF or angiogenesis inhibitor will be a promising way to regulate condylar growth at an early stage.

Human periodontal ligament cells express osteoblastic phenotypes under intermittent force loading in vitro.

UNLABELLED: Mechanical strain applied to bone leads to bone remodeling. In the oral cavity, it is unclear how such mechanical force applied to move teeth orthodontically induces alveolar bone remodeling. It is known that osteoclasts are the only cells that are responsible for bone resorption, while the formation and activity of osteoclasts are regulated by osteoblasts. So it is believed that osteoblasts play an important role not only in bone formation but in bone remodeling as well. Therefore, the purpose of this study was to examine the effect of mechanical force on human periodontal ligament (PDL) cells and whether they express osteoblastic characters in vitro. METHODS: Human PDL cells cultured in vitro were loaded with intermittently stretching force for 24 hours. The expression of alkaline phosphatase (ALP), osteocalcin (OCN) and osteoprotegerin (OPG) were detected at mRNA and protein levels at 0, 2nd, 4th, 6th, 12th, 24th hours after intermittent force loading. RESULTS: Without any stimulation, ALP and OPG mRNA expressions were detected in human PDL cells by in-situ hybridization, but not that of OCN mRNA. ALP mRNA signal was up-regulated and that of OPG was down-regulated by mechanical force within 24 hours. OCN mRNA expression was induced by mechanical force in the late phase of the 24-hours loading cycle. The changes in secreted proteins showed similar results with those seen at the mRNA level. CONCLUSION: Human PDL cells express osteoblastic phenotypes under intermittent force loading and play a role in alveolar bone remodeling.

Repeated mechanical loading enhances the expression of Indian hedgehog in condylar cartilage.

Indian hedgehog (Ihh) acts as a mechanotransduction mediator that converts mechanical strain into cellular proliferation and cartilage formation in mandibular condylar cartilage. The aim of this study was to examine the effect of repeated mechanical strain on the level of expression of Ihh and type II collagen mRNA in condylar growth. Two hundred and eighty 35 days old Sprague-Dawley rats were divided into 10 experimental and 10 control groups. Repeated mechanical loading was applied by advancing the mandible in a stepwise manner by fitting a stepwise bite jumping appliance. Animals were sacrificed together with their matched controls on 10 different time points. Total RNA was extracted from condylar cartilage immediately after dissection. Ihh and type II collagen mRNA was quantified using real-time PCR. In the experimental group, Ihh mRNA increased significantly on experimental day 7. Upon the second advancement, another peak was elicited 7 days later. Type II collagen showed a significant increase on days 21 and 44 of advancement. This indicated that mechanical loading in a repeated manner, triggers the expression of Ihh which in turn increases the number of replicating mesenchymal cells as well as the amount of the cartilage formed. Taken together these events increase condylar growth.

Factors regulating condylar cartilage growth under repeated load application.

Mechanical loading can influence the biological behavior of the bone-associated cells leading to adaptive changes in skeletal mass and architecture. SOX9 and PTHrP genes are known to regulate chondrocyte differentiation and delay maturation, ultimately control the endochondral bone formation. To investigate the effects of repeated mechanical loading on bone, 280 Sprague-Dawley rats were used in this experiment. The animals were randomly allocated into experimental and control groups. Repeated mechanical loading was applied through a bite-jumping device in the experimental group. The experimental animals were sacrificed on 10 different time points together with the matched control. Total RNA was extracted from the mandibular condylar cartilage for PTHrP and SOX9 genes quantification using real-time RTPCR. Results showed that PTHrP expression was increased and reached a peak level on the seventh day after mechanical loading was given. Repeated mechanical loading triggered a significant increase of PTHrP expression leading to another peak increment. The expression of SOX9 was highly correlated with the PTHrP expression, and its pattern of expression was similar to that of PTHrP after repeated mechanical loading. In conclusions, repeated mechanical loading on the condyle triggers the expression of PTHrP and SOX9, which in turn promotes condylar cartilage growth.

Effect of naringin on bone cells.

Statin, a HMG-CoA reductase inhibitor, was shown to increase BMP-2 gene expression for bone formation, by blocking the mevalonate pathway in cholesterol production. We investigated the effect of naringin, a flavonoid available commonly in citrus fruits, which was also a HMG-CoA reductase inhibitor, in UMR 106 osteoblastic cell line in vitro. The control group consisted of cells cultured without any intervention for different time intervals (24 h, 48 h, and 72 h), whereas the experimental (naringin) group consisted of cells cultured with naringin of different concentrations (0.001 micromol/L, 0.01 micromol/L, and 0.1 micromol/L) for the same time intervals of the control. Colorimetric Tetrazolium (MTT) assay, total protein content assay, and alkaline phosphatase activity were used to measure the cellular activities. Results for the naringin group showed an increase in MTT assay compared with the control and the effect was dose dependent. At high concentration (0.1 micromol), the increases ranged from 60% to 80%. In the total protein content assay, naringin also showed an increase compared with control and the effect was also dose dependent. At high concentration (0.1 micromol), the increases ranged from 9% to 20%. In the alkaline phosphatase activity assay, naringin at high concentration (0.1 micromol) significantly increased the activity up to 20%. In conclusion, naringin significantly increased bone cell activities in vitro. This is the first study specifically attempted to investigate the effect of naringin on bone cell activities. Besides statin, this provided another example of mevalonate pathway blockage in the cholesterol production pathway by HMG-CoA reductase inhibition will increase the bone cell activities.

Matrix metalloproteinase-9 regulates graft bone resorption.

OBJECTIVE: To explore the relationship between bone resorption and matrix metalloproteinase-9 (MMP-9) expression in autogenous and allogenic bone grafts. MATERIALS AND METHODS: A total of 18 critical-size (10 x 15 mm) defects were created in rabbit mandibles bilaterally. Three groups of six defects each were grafted with autogenous endochondral (EC) bone, autogenous intramembranous (IM) bone, and allogenic IM bone. Three months later, the defects were retrieved for quantitative analysis on the basis of histology, immunohistochemistry, and in situ hybridization. RESULTS: A close relationship existed between MMP-9 expression and graft bone resorption. The parallel between MMP-9 expression and graft bone resorption suggested that bone resorption was accomplished in part by increased MMP-9 production evident in preosteoclasts and osteoclasts. CONCLUSIONS: MMP-9 plays an important role in graft bone resorption. Autogenous EC bone grafts express higher levels of MMP-9 leading to more resorption than autogenous or allogenic IM bone grafts.

Dentofacial characteristics of Chinese obstructive sleep apnea patients in relation to obesity and severity.

OBJECTIVE: To evaluate dentofacial characteristics in relation to obesity and degree of severity of obstructive sleep apnea (OSA) in male Chinese patients and to elucidate the relationship between demographic parameters (age, body weight, height, and body mass index [BMI]) cephalometric parameters and OSA in these subjects. MATERIALS AND METHODS: Lateral cephalograms of 121 Chinese male patients in natural head posture were obtained. Based on BMI value, the patients were divided into three groups. Based on apnea-hypopnea index (AHI) value, the patients were divided into a mild-to-moderate and a severe group. RESULTS: The hyoid position and soft palate length were significantly different among the three obesity groups. Soft palate length was significantly longer (P < .01) in the severe OSA group than in the mild-to-moderate OSA group. Tongue base was significantly more inferiorly placed (P < .05) in the severe OSA group than in the mild-to-moderate OSA group. Craniocervical extension was significantly increased (P < .05) in the severe OSA group. Statistically significant differences were found among the three obesity groups in mandibular length, mandibular body length, maxillary length, anterior cranial base length, and overbite. The multiple stepwise linear regression analysis identified body weight, lower posterior facial height, mandibular body length, craniocervical extension, and sella-hyoid distance as the significant predictive variables for AHI. CONCLUSIONS: This study revealed the existence of craniofacial and upper airway soft tissue differences in relation to obesity and severity of OSA among male Chinese OSA patients. Body weight and certain cephalometric parameters were significant predictors of OSA in Chinese male subjects.