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Tanikawa Plast Aesthet Res 2020;7:48 I http://dx.doi.org/10.20517/2347-9264.2020.136 Page 3 of 16

structure (e.g., the corner of the mouth); Type II landmarks are more ambiguous and usually describe the
maxima of curvature (e.g., nasal tip); Type III landmarks are geometric constructions generated from lines
or Type I and/or II landmarks (e.g., midpoint of the right and left eyes); and semi-landmarks represent
[18]
surfaces or curves between landmarks . A key concept of GMM is based on the fact that morphology can
be mapped systematically, often within a “morphospace”, with the use of these landmarks. Morphospaces
are maps that show how shapes are defined by quantitative traits. GMMs rely on the superimposition of
landmark coordinate data r to place individuals in a common morphospace.

Recently, the clinical application of a GMM-a novel 3D quantitative analysis method-in the quantification
[19]
and visualization of the 3D configuration of the facial soft tissues was reported . 3D faces were fitted with
mathematical wire meshes based on 26 landmarks, and the nodes of the fitted meshes were used as semi-
landmarks. All faces were superimposed based on the landmarks and were statistically analyzed in the
facial morphospace. The analysis included the average range of faces with regard to sex, age, and race, and
the method compared a patient’s face with this normal range. This enabled us to understand the patient’s
static facial form characteristics quantitatively and instantaneously. In their report, the applicability of
the system to three cases, namely one case each of Class II malocclusion, Class III malocclusion, and jaw
deviation, was reported; however, the applicability of this system to the cleft facial shape remains unclear.

Thus, the objectives of this study were as follows: (1) to examine whether the previously published soft-
[19]
tissue evaluation methods developed based on GMMs could be applied to patients with a cleft lip
before or after treatment; (2) to determine soft-tissue morphological characteristics that distinguish non-
cleft participants from patients with a cleft lip; and (3) to examine the variations of cleft facial shapes.
Furthermore, we discuss the clinical application of the GMM based on the results of Objectives (1)-(3).

METHODS
The study was approved by the ethics committee for medical research at Osaka University Dental Hospital
(ID: H25-E37-1). An informed consent to participate in the study was obtained from all participants.

Systems
[19]
A system for evaluating facial morphology that was developed in a previous study was employed in the
present study. The overview of the system is shown in Figure 1. The system was divided into three parts: (1)
mesh fitting on the 3D facial picture; (2) development of the normative ranges of faces; and (3) evaluation
of the new face with the normative face. In the present study, the normative range of the face was defined
as the average and ±1 standard deviation ( ±1 SD), and the patient data were compared to the normative
range of faces. To develop the normative ranges, 200 participants (female, n = 100; male, n = 100) between
18 and 35 years of age were recruited from the students and faculty of Osaka University in Japan. For the
[19]
detailed inclusion criteria, please see the previous study . Then, the normative faces, including the mean
coordinate values and the standard deviation for each sex group, were used to evaluate new patients. The
equations were as follows:

Z-score = | p - m |/s (x)
(x)
(x)
(x)
Z-score = - ( p - m )/s (y)
(y)
(y)
(y)
Z-score = (p - m )/s (z)
(z)
(z)
(z)
where p , p , and p indicate the coordinate values of each image of the sample patients; m , m , and
(z)
(y)
(y)
(x)
(x)
m indicate the average coordinate values of the control group; and s , s , and s indicate the standard
(y)
(x)
(z)
(z)
deviation of the coordinate values of the control group in the x-, y-, and z-directions, respectively. To
visualize the results, the Z-scores were visualized as color values. For a detailed description, please see the
previous study .
[19]