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    Lateral Cephalometric Standards for Mongolian 6-15 Year Old Children with Normal Occlusion
    (Mongolian National University of Medical Sciences, 2018-09-25) ; ; ;
    Keiji Moriyama
    ;
    Objectives: The aim of this study was to establish the age and gender-specific lateral cephalometric standards for Mongolian children with normal occlusion. Methods: A total of 541 children between 6 and 15 years of age were selected based on the normal occlusion criteria. Lateral cephalograms of each subject were scanned and analyzed with the use of WinCeph version 11.0 software package. Descriptive statistics (mean and standard deviation) were calculated for all measured variables. Independent t-tests were performed to assess the intergender differences. Results: Cephalometric angular measurements remain largely constant, whereas most cephalometric linear measurements change with advancing age, such as anterior facial height (N-Ans, Ans-Me), hard palatal length (Ans-Pns) mandibular ramus height (Cd-Go), mandibular body length (Cd-Gn) were increasing significantly by dental age in both gender. Gender differences were not statistically significant for any of the angular measurement at ages studied, but linear measurements of male subjects had larger average values than female subjects. Conclusion: Our results showed that linear cephalometric dimension of the hard tissue was gender-dependent. Therefore, gender-specific differences of craniofacial distances should be taken into account during diagnosis and treatment planning. The results from this study can be used as reference values for 6-15 years old children of Mongolia.
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    Lateral Cephalometric Linear Measurement Standards of Mongolian Children with Normal Occlusion from 6-7 Years of Age
    (Mongolian National University of Medical Sciences, 2017-06-25) ; ; ; ;
    Moriyama, Keiji
    Objectives: The aim of this study was to analyze craniofacial linear dimensions in subjects with normal occlusions to establish age and gender-specific lateral cephalometric linear measurement norms for Mongolian children. Methods: 161 six year old children and 122 seven year old children were recruited for this study. Digital cephalograms of 75 six year old children (34 male and 41female), 49 seven year old children (22 male and 27 female) were selected to establish lateral cephalometric linear measurement norms. Anatomic landmarks were identified directly on the digital images. The means and standard deviations of linear measurements were calculated using 18 variables. Student’s t-test was employed to test for gender differences in each age. Results: Anterior cranial base length and midfacial length were significantly larger in six year old male subjects. Mo-Ms and A-Ptm were significantly larger in seven year old male subjects. Conclusion: Our results showed that linear craniofacial dimension of the hard tissue was gender-dependent. Therefore, gender-specific differences of craniofacial distances should be taken into account during diagnosis and treatment planning. The results from this study can be used as reference values for 6-7 years old children of Mongolia.
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    Facial Soft Tissue Profile Analysis in Mongolian Children
    (Mongolian National University of Medical Sciences, 2020-12-29) ; ; ; ;
    Objectives: The present study aimed to evaluate the specific variables of facial soft tissue changes in Mongolian children using angular and linear measurements. Methods: We studied the lateral cephalograms of 541 subjects (228 male and 313 females) having normal occlusion between the ages of 6 and 15 years. Two orthodontists read all radiographs to determine their cerebral vertebral maturation index (CVMI). The radiographs were digitized and cephalometric measurements were made. Results: The Gl'-Sn-Pg' angle for all participants was 170.2 ± 5.4°. The Nasofrontal Gl’-N’-Tn’ angle was 147.2 ± 7.6° for all participants. It decreased with CVMI stage for girls (p = 0.000). The Nasofacial angle Tn- N'- Pog' angle averaged 20.4 ± 7.7° for all participants. The Nasomental angle N'- Tn-Pog' angle on averaged 144.9 ± 4.3° for all participants. It decreased with the CVMI stage for girls (p = 0.000). The Mentocervical Tn-Pog Me-NTP angle was significantly larger in boys than girls (107.8 ± 8.6° vs. 105.3 ± 7.8°, p = 0.001). The Nasolabial angle Ls-Sn-Col angle averaged 100.8 ± 10.6° for all subjects. It decreased with the CVMI stage for both boys (p = 0.043) and girls (p = 0.021). The distance between the E line and TUL was significantly larger in boys than girls (1.7 ± 2.1 vs. 1.2 ± 2.0 mm, p = 0.004). It also significantly decreased with the CVMI stage for both boys (p = 0.033) and girls (p = 0.000). The space between the E line and TLL averaged 1.9 ± 2.0 mm for all subjects. It did not differ by gender. However, it decreased with the CVMI in both boys (p = 0.022) and girls (p = 0.006). Conclusions: We have provided important results for comparing cephalometric soft-tissue values in Mongolian children in this study. These results provide a valuable guide for orthodontic diagnosis and treatment in our country.