Studies have been done to describe, compare, and present the shape of the face. In general, one of the ways of describing a face is based on the profile of the face. It measures the position, length, and angle of the upper, middle, and lower face. This may be based on surface anatomy (anthropometry) or on X-ray (cephalometry). Especially, cephalometry based on the lateral X-ray led to more accurate and objective measurements. And finally, many researches established the standard of a beautiful and ideal face type. For example, the ideal ratio of the upper, middle, and lower face is 1:1:1, and the position of the chin should be placed slightly behind the vertical perpendicular line from nasion. Another way of describing the facial shape is from the frontal view. The facial index is a ratio of length and width of the face in a frontal view. Frontal cephalometry is also used, but less frequently. Recently, studies are done on three-dimensionally by using 3-D CTs (Table 1.1).

Studies on the ideal face showed there is a huge difference between Asians and Caucasians [1]. Regarding the vertical proportion of the face, Asians prefer a short chin compared to Caucasians. However, this kind of aesthetic preferences also differs between nations. For example, as Japanese people usually prefer a round and short chin, Chinese people prefer a sharp long chin. It is quite natural that these aesthetic standards keep on changing for decades. You will easily find the beauties in old painting are not appealing to you anymore. Cultural trends also play an important role in the standards of beauty. For example, after a hit of a movie, the movie star becomes a trendy beauty icon. With the developments of communication and transportation, beauty standard tends to be globalized and synchronized. As SPA brands lead the fashion trends, beauty standards are also commercialized by mass media and global companies.