• The korean journal of orthodontics
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• v.34 no.2 s.103
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• pp.197-203
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• 2004

Tweed-Merrifield directional force technology is a very useful concept, especially for the treatment of Glass II malocclusion. It has contributed to treating a favorable counter-clockwise skeletal change and balanced face, while head gear force using high pull J-hook (HPJH) in an appropriate direction is also essential to influence such results. Clinicians have encountered some problems concerning patients' compliance; however skeletal anchorage has been used widely of late because it does not necessitate patients' compliance, yet produces absolute anchorage. In this case, a good facial balance was obtained by Tweed-Merrifield directional force technology using HPJH together with skeletal anchorage, which provided anchorage control in the maxillary posterior area, torque control in the maxillary anterior area, and mandibular response. This indicates 4hat skeletal anchorage can be used to reinforce sagittal and vortical anchorage in the maxillary posterior area during the retraction of anterior teeth. The author used HPJH for torque control, Intrusion, and the bodily movement of maxillary anterior teeth during on masse movement. However, it is thought that such a result nay also be achieved by substituting mini- or microscrews for HPJH. Consequently, Tweed-Merrifield directional force technology using skeletal anchorage for the treatment of Class II malocclusion not only maximiaes the result of treatment but can also minimize patients' compliance.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.407-412
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• 2011

Purpose: The purpose of the present study was to evaluate the postoperative skeletal stability of two-jaw surgery (Le Fort I osteotomy and bilateral sagittal split ramus osteotomy) via surgery first orthodontic treatment (SFOT) in class III malocclusion. Methods: Thirty-two patients who had two-jaw surgery via SFOT were included in this study. Serial lateral cephalograms were obtained before (T0), immediately after (T1), and six months after (T2) surgery. Twelve variables were measured for horizontal and vertical skeletal stability as well as for dental change. All measurements were evaluated statistically by a paired t-test ($P$ <0.05). Results: The mean skeletal changes were $0.1{\pm}2.5$ mm at point A and $-12.0{\pm}7.4$ mm at the pogonion. The mean horizontal relapse was 11.6% at the pogonion, and the mean vertical surgical changes included an upward displacement of $2.1{\pm}7.1$ mm and a forward displacement of $1.4{\pm}4.6$ mm at the pogonion. Upper incisor inclination decreased after surgery and was maintained at T2, and lower incisors were proclined from T1 to T2 by postsurgical orthodontic treatment. Conclusion: Postoperative skeletal stability of two-jaw surgery via surgery first orthodontic treatment in class III malocclusion was clinically acceptable.

• The korean journal of orthodontics
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• v.50 no.2
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• pp.98-107
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• 2020

Objective: The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions. Methods: Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis. Results: In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups. Conclusions: Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.5
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• pp.316-324
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• 2013

This case report describes the treatment of a 23-year-old woman who had lip protrusion with gummy smile and mentalis muscle strain. Orthognathic surgery was performed in conjunction with orthodontics. Minimum dental decompensation was performed with presurgical orthodontics followed by an anterior segmental osteotomy for the majority of dental decompensation. Counterclockwise rotation of the maxillomandibular complex was applied by LeFort I osteotomy, and bilateral sagittal split ramus osteotomies with anterior segmental osteotomy to achieve overall facial balance. The active treatment period was 15 months. Stable occlusion and skeletal relationship were observed after a 10-month follow-up period.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.45-52
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• 2015

The purpose of this study was to compare and evaluate facemask effects when two types of intraoral appliances were used for maxillary protraction for patients with class III malocclusion. Eighteen patients with class III malocclusion were treated with a facemask for an average of 12 months. Two types of intraoral appliances were used: nine patients were treated with bonded expander (Group 1), and nine patients with Hyrax (Group 2). Cephalometric radiographs were taken before and after treatment. Cephalometric radiographs were traced, analyzed, and the results such as sagittal, vertical and soft-tissue changes were compared between two groups. The amount of anchorage loss was also measured to evaluate the difference between two groups. All patients showed significant sagittal skeletal changes after treatment, and there was no statistically significant difference between the two groups. When anchorage loss was evaluated, no differences were shown between the two. Facemask with Hyrax or bonded expander is similarly an effective method as a treatment in class III malocclusion patients.

• The korean journal of orthodontics
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• v.48 no.3
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• pp.143-152
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• 2018

Objective: This study examined cone-beam computed tomography (CBCT)-derived multiplanar-reconstructed (MPR) cross-sections to clarify the salient characteristics of patients with skeletal class III malocclusion with midface deficiency (MD). Methods: The horizontal and sagittal plane intersection points were identified for middle-third facial analysis in 40 patients in the MD or normal (N) groups. MPR images acquired parallel to each horizontal plane were used for length and angular measurements. Results: A comparison of the MD and N groups revealed significant differences in the zygoma prominence among female patients. The convex zygomatic area in the N group was larger than that in the MD group, and the inferior part of the midface in the N group was smaller than that in the MD group for both male and female patients. A significant difference was observed in the concave middle maxillary area among male patients. Conclusions: This study was conducted to demonstrate the difference between MD and normal face through MPR images derived from CBCT. Male patients in the MD group had a more flattened face than did those in the N group. Female patients in the MD group showed a concave-shaped lower section of the zygoma, which tended to have more severe MD. These findings indicate that orthognathic surgery to improve skeletal discrepancy requires different approaches in male and female patients.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.235-252
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• 1988

The quadrilateral analysis is a proportional analysis which evaluates the skeletal configuration of lower face on the relations between both jaws in the horizontal as we]1 as vortical dimensions. This study was undertaken to analyse the harmony and disharmony of quadrilateral patterns in normal occlusion and malocclusion. The present study was carried out on lateral cephalograms of 530 Korean children; the subjects consisted of 135 normal occlusions (63 male and 72 female), 105 Class II division 1 malocclusions (52 male and 53 female), 109 Class III malocclusions (50 male and 59 female), 91 hypodivergent facial types (44 male and 47 female) and 90 hyperdivergent facial types (45 male and 45 female). The following conclusions were reached: 1. Means and standard deviation in each group and sex were obtained from normal occlusion and malocclusion. 2. Quadrilateral mean diagram in normal occlusion was constructed for male and female, respectively. 3. In normal occlusion, 1:1 ratio exists between the maxillary base length (A' to Ptm') and mandibular base length (B' to J'), but lower facial height is targer than above. 4. Difference is effective to estimate the degrees of Class II and Class III malocclusion, and lower facial height (LFH) and sagittal angle is effective to recognize the hypodivergent and hyperdivergent facial type. 5. Quadrilateral analysis is able to visualize the anteroposterior and vertical dysplasia of lower face, and it is helpful to recognize certain problems in malocclusion.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.2
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• pp.184-190
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• 2000

Objective : To compare two different methods of rigid fixation in postoperative stability after mandibular setback. Material and Methods : 28 patients with Class III malocclusion were treated by bilateral sagittal split ramus osteotomy(BSSRO) and mandibular setback were selected for this study. Group A(n=14) had the bone segments fixed with monocortical miniplate on the lateral side of the mandibular body and Group B(n=14) had three noncompressive bicortical screw inserted at the genial area through a transcutaneous approach. Cephalograms were taken preoperatively, postoperatively within 1 weeks and at a follow-up period (mean 8.9 months after surgery) and the amount of setback and postoperative change were measured. Results : Postoperative relapse between two groups was minimal in setback of the mandible. Statistical analysis showed no significant difference in postoperative relapse. Conclusion : This study suggests that both methods of skeletal fixation investigated give comparable postoperative stability and their use in mandibular setback appears to be a fairly stable clinical procedure .

• The korean journal of orthodontics
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• v.22 no.4 s.39
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• pp.837-853
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• 1992

The purpose of this study was to investigate the positional changes of the mandibular condyles after orthognathic surgery In patients with severe skeletal Class III malocclusion. This study was based on 21 patients who had received bilateral sagittal split osteotomy for mandibular setback. Among them 14 were fixated non - rigidly (W group), and 7 were fixated rigidly (R group). After submental vertex view analysis, each subject was given the T.M.J. Tomogram in both centric occlusion and centric relation immediate before, $4\~6$ weeks after and more than 6 months after surgery. The anteroposterior and vertical changes between each time interval were measured and analyzed statistically. Following results were obtained. 1. There was no significant difference between right and left condyles in their anteroposterior and vertical changes of the condylar position. 2. In anteroposterior changes of condylar position of the wire fixation group, the condyles were moved anteriorly 4-6 weeks after surgery, and then the pattern of reestablishment to their preoperative position was observed more than 6 months after surgery. In the rigid fixation group, there was no significant difference in any observation periods of centric occlusion and centric relation. 3. In vertical changes of condylar position of the wire fixation group. the condyles were moved inferiorly 4-6 weeks after surgery, and then the pattern of reestablishment to their preoperative position was observed more than 6 months after surgery. In the rigid fixation group, the condyles were moved inferiorly 4-6 weeks after surgery, and then the pattern of reestablishment to their preoperative position was observed more than 6 months after surgery in centric occlusion only.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.1
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• pp.51-55
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• 2000

Purpose : The purpose of this study is to setup a standard treatment protocol in surgical correction of skeletal malocclusion with Angle Class III patients. We asessed the soft tissue changes according to skeletal changes of patients who have undergone orthognathic surgery with bilateral split sagittal ramus osteotomy (BSSRO) and advancing genioplasty. Materials & Methods : The soft tissue change of 9 skeletal Class III patients was assessed after BSSRO and advancing genioplasty. The patient group was skeletal Class III who was surgically treated by BSSRO & advancing genioplasty. The average follow up period is 13 months with the range of 6 and 30 months. All patients have undergone preoperative and postoperative orthodontic treatment. The assessment was devided into two groups. One was antero-posterior relationship and the other was vertical relationship of dimensional changes of soft tissue after orthognathic surgery. Results : In antero-posterior dimensional changes after surgery, the percentage of soft tissue change in comparison to hard tissue was 89%. Vertical ratio after surgery, 86% soft tissue changes were assessed.