Journal List > Korean J Orthod > v.38(4) > 1043555

Hwang, Lee, Hwang, Choi, and Lim: Prediction of frontal soft tissue changes after mandibular surgery in facial asymmetry individuals



To aid the development of a frontal image simulating program, we evaluated the soft tissue frontal changes in relationship to movement of hard tissue with orthognathic surgery of facial asymmetry patients.


Preoperative and postoperative frontal cephalograms and frontal view photographs of 45 mandibular surgery patients with facial asymmetry were obtained in a standardized manner. Vertical and horizontal changes of hard tissue and soft tissue were measured from cephalograms and photographs, respectively. Soft tissue change in result to hard tissue change was then analyzed.


Both vertical and horizontal correlation analysis showed a weak relationship between the changes. Hard tissue points that were picked for 1:1 mean ratio with soft tissue points did not show any significant relevance. For each soft tissue change, regressive equation was formulated by stepwise multiple regression analysis, and the equation for soft tissue Menton was most reliable in predicting changes. Both vertical and horizontal hard tissue changes were used together in prediction of vertical or horizontal soft tissue change.


The results suggest that computerized image simulation using regression analysis may be of help for prediction of soft tissue change, while 1:1 mean ratio method is not useful.

Figures and Tables

Fig 1
Cephalometric landmarks to represent hard tissue change. Detailed description of landmarks is in Table 2.
Fig 2
Photometric landmarks to represent soft tissue change. Detailed description of landmarks is in Table 3.
Table 1
Description of the subjects used in this study and summary of orthognathic surgery performed

*The number in the surgery column indicates the amount of operation (unit; mm); The degree of chin deviation before and after surgery is expressed as the angle formed by Cg-ANS and ANS-Me lines (unit: °). Mn, mandible; Genio, genioplasty; Vt, vertical; AP, anteroposterior; Rt, right; Lt, left.

Table 2
Description of frontal cephalometric landmarks used in this study
Table 3
Description of photometric landmarks used in this study
Table 4
Correlation coefficient between hard tissue change and soft tissue change in the horizontal direction

*p < 0.05; p < 0.01.

Table 5
Correlation coefficient between hard tissue change and soft tissue change in the vertical direction

*p < 0.05; p < 0.01.

Table 6
Mean ratio between soft tissue and hard tissue change in the horizontal direction

*p < 0.05; p < 0.01.

Table 7
Mean ratio between soft tissue and hard tissue change in the vertical direction

*p < 0.05; p < 0.01.

Table 8
Results of stepwise multiple regression analysis for the horizontal change of soft tissue points
Table 9
Results of stepwise multiple regression analysis for the vertical change of soft tissue points


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