• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.261-272
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• 2000

Severe skeletal anteroposterior and vertical discrepancy is difficult to obtain satisfactory result by only orthodontic treatment, and much anteroposterior movement and treatment stability require orthodontic treatment with orthognathic surgery. The treatment goal of mandibular prognathic patients is to promote the function of stomatognathic system including mastication and phonetics, to improve the esthetics of facial profile and to maintain stability. Positional changes of hyoid bone, pharynx and tongue were seen with mandibular movement after orthognathic surgery. This study was performed to observe the changes of perimandibular tissues of orthodontic patients with skeletal mandibular prognathism who treated with orthodontic treatment, and the changes of hyoid bone, pharyx and tongue by relapse or recurrance after before and after orthognathic surgery and retention. The 22 patients who had mandibular prognathism were selected. They treated with orthodontic treatment with sagittal split ramus osteotomy as orthognathic surgery. And lateral cephalometric radiographs were taken 3 times : pre-surgery (T1), immediate post-surgery (T2) and 2 years alter retention (T3). The results were as follows : 1. The hyoid bone returned back after clockwise rotation to maxilla and occlusal plane during retention (P<0.01). 2. The hyoid bone moved posterior-inferiorly by mandibular surgery and returned back anterior-superior after retention. (P<0.01) 3. The changes of pharyngeal depth showed a little decrease at upper area in post- surgery, but it was not a significant difference generally through before, after and retention. 4. In relating to tongue base, the angle of tongue base was decreased and the dorsal area of tongue base moved to inferior-posterior direction and to superior direction again after retention (P<0.01). 5. Related to the thickness of upper and lower lip, the thickness of upper lip decreased after surgery, and the soft tissues below lower lip increased after surgery and decreased after retention.

• The korean journal of orthodontics
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• v.38 no.2
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• pp.104-120
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• 2008

Purpose: The purpose of this study was to assess the hard and soft tissue changes associated with mandibular bilateral sagittal split osteotomy and genioplasty. Methods: This is a retrospective study of 40 patients who underwent either bilateral sagittal split osteotomy for mandibular setback (BSSO group, n = 20) or in combination with advancement genioplasty (Genio group, n = 20). Lateral radiographs, were taken before and immediately after surgery, and at least 6 months after surgery. Results: Comparing hard and soft tissue changes between the BSSO group and Genio group, there were significant differences in the lower incisor, soft tissue B point (B'), and soft tissue Pogonion (Pg') (p < 0.5). The mean ratio of hard and soft tissue changes for B/B', Pg/Pg', and Menton/soft tissue Menton after surgery in the BSSO group was 0.997, 0.965, and 1.022 respectively, and 0.824, 0.602, and 0.887 respectively in the genio group. Significant differences were found between the two groups. There were significant differences in lip thickness (B-B', Pg-Pg') in the Genioplasty group between pre and postsurgery, but not in the BSSO group. Pogonion to Labrale inferior and B' had a correlation coefficient of 0.833, 0.922, respectively for the BSSO group, and 0.775, 0.799 for the Genio group. Conclusions: The results indicate that there is a significant difference between bilateral sagittal split osteotomy with or without genioplasty in the lower facial esthetics values. The combination of mandibular setback and genioplasty had a smaller change in soft tissue thickness of the symphysis area after surgery than that of mandibular setback only.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.118-126
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• 2019

Purpose: This research is to investigate factors that affect dental aesthetics and analyze whether individual perception affects and difference of genders affects the esthetic factors. Materials and methods: Seventy dental students of Chonnam University aged from 25 to 35 years old without periodontal problems were included. Maxillary dental cast for participants were made, and standardized photo was taken with a digital camera. Maximum visual width and the position of gingival zenith of maxillary anterior teeth and maximum height of the maxillary central incisors were measured by a measurement program and the shape of central incisor was categorized. Questionnaire was conducted to evaluate esthetic perception. SPSS program was used to perform statistical analysis. Results: The average visual width ratio of right maxillary anteriors was 1.38:1:0.78 and 1.41:1:0.81 for the left which differ from the golden ratio. The width to height ratio for right and left central incisor was 0.84 and 0.83 respectively. The gingival zenith position was determined to be: mostly, central incisors and canines were located in the distal side, lateral incisors were located in the center. The visual width ratio of right maxillary anterior teeth, ratio of width to height of central incisor, gingival zenith position, crown morphology and amounts of gingival exposure upon smiling were not significantly different between genders, and facial patterns and these dental esthetic factors were not related to aesthetic perception. Conclusion: Even though participants had the visual width ratio of maxillary anteriors or ideal width to ideal height of central incisors that did not agree with the golden ratio, they had high satisfaction for dental esthetics. Esthetic perception depends more on subjective judgements of participants than objective indices.