Main Instructor Ganjargal Ganburged
Department / Institution Department of Orthodontics, Mongolian National University of
Classification Research report
Harmonious facial aesthetics and optimal functional occlusion have long been recognized as the two most important goals of orthodontic treatment. To accomplish some of these goals, a knowledge of the normal craniofacial growth as well as the effects of orthodontic treatment on the soft tissue profile is essential. Facial features have been commonly studied in full- face and profile views. Several methods have been used to evaluate these facial changes including anthropometry, photogrammetry, computer imaging, and cephalometry. Some researchers have studied the thickness of the soft tissues to determine the relationship between the hard and soft tissues, and to determine the effect of hard tissues on facial aesthetics. Others have highlighted the necessity for the hard and soft tissues to be evaluated together, and that peri-oral function, facial aesthetics, and stability are important factors in orthodontic treatment.
Materials and Methods:
The present study was conducted on lateral cephalograms of 541 subjects (228 male and 313 females) having normal occlusion in the age group of 6 to 15 years. All radiographs were digitized on a computer using a cephalometric software program (Winceph 11.0; Rise, Sendai, Japan) Total of 6 angular 38 linear measurements were measured for skeletal hard tissue analysis using 31 landmarks (Figure 1), and 3 reference planes. The landmarks and measurements were taken according to the soft tissue cephalometric analysis, and true vertical line (TVL) was established. Structures to the right of TVL were given a positive sign and those to the left of TVL were given a negative sign. The soft tissue cephalometric parameters were divided into 5 groups: Dentoskeletal structures (Figure 2), Soft tissue structures (Figure 3), Facial lengths (Figure 4), Projections to TVL (Figure 5), and Harmony values (Figure 6). All statistical analysis was calculated using SPSS version 25.0 statistical analysis software. The result was presented as mean for quantitive variables and compared using the student t-test and Mann-Whitney U test. Statistical significance was determined at a p-value of P<0.05.
Comparison analysis of some measurement results with age groups shows that Mx-occlusal plane angle, Md1 to Md occlusal plane angle, Nasolabial angle has been decreased with age, Mx1, Mx occlusal plane angle, and Overbite was stable with age, whereas the other measurement results show increase in tendency with age groups. No statistically significant gender differences were observed in age groups Distinct ethnic difference was found between Caucasians and Mongolian kids. The facial angle in Mongolian kids was more than north American kids, whereas the Nasolabial angle in Mongolian kids less than North American kids. It shows that facial features in Mongolian kids less pronounced convexity facial profile than Caucasians. The nasal projection feature was observed more in Caucasian kids than Mongolian kids. The other features including upper and lower lip thickness were thicker in Caucasian kids, whereas the upper and lower lip length feature was shorter in Mongolian kids.
The results of the present study suggested that the differences exist in the facial structures of two ethnic groups (Mongolian and Caucasian). Therefore, separate norms for distinctive populations are necessary and that one set of norms cannot be applied to patients of different races and ethnic origin. Thus, the results of the present study suggest that racial differences should be considered during diagnosis and orthodontic and orthognathic treatment planning.
The Result of Facial Soft Tissue Cephalometric Analysis Between The Ages of 6 and 15 Years in Mongolian Children: A Cephalometric Study