• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.21-30
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• 2001

The purpose of this study was to evaluate the skeletal relapse pattern of the mandibular prognathic patients after mandibular set back surgery by sagittal split ramus osteotomy. The horizontal and vertical position of the cephalometric points were measured before, after surgery and after one-year follow up period. The next, the positional change of the proximal and distal mandibular segment were evaluated respectively. The obtained results were as follows; 1. The horizontal and vertical position of Cd was not changed before and after surgery, and it was maintained its original position during the observation periods. 2. As the mandibular prognathism of the patients was severe before surgery, the more skeletal relapse tendency was observed during follow-up period(p<0.05). 3. As the horizontal positional change of the mandible which was obtained by mandibular set-back surgery was large, the more horizontal relapse tendency was observed during follow-up period(p<0.05). 4. The corpus axis angle decreased by sagittal split ramus osteotomy(p<0.01), but it was kept its reoriented position during follow-up period. 5. During the follow-up period after mandibular set-back by sagittal split ramus osteotomy, the forward relapse of mandible correlated with not only the forward rotation of the proximal segment but also the forward movement of the distal segment(p<0.05).

• Korean Journal of Cleft Lip And Palate
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• v.10 no.1
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• pp.57-65
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• 2007

It is well known that the main factor which contributes to the relapse of orthognathic surgery for Cleft Lip and Palate (CLP) patients is post-operative scar on hard and soft palate of maxilla. Therefore, to compensate the amount of relapse, though it cannot be the perfect way to prevent orthodontic, orthopedic relapse, the Le-fort I osteotomy of maxilla and set-back osteotomy of mandible are generally carried-out simultaneously. We are to review the factors contribute to the relapse of CLP patients after orthognathic surgery through this clinical case : The relapse of Skeletal Class III tendency immediately after orthognathic surgery for grown up CLP patients.

• The korean journal of orthodontics
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• v.50 no.6
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• pp.391-400
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• 2020

Objective: Increased gingival elasticity has been implicated as the cause of relapse following orthodontic rotational tooth movement and approaches to reduce relapse are limited. This study aimed to investigate the effects of sulforaphane (SFN), an inhibitor of osteoclastogenesis, on gene expression in gingival fibroblasts and relapse after rotational tooth movement in beagle dogs. Methods: The lower lateral incisors of five beagle dogs were rotated. SFN or dimethylsulfoxide (DMSO) were injected into the supra-alveolar gingiva of the experimental and control group, respectively, and the effect of SFN on relapse tendency was evaluated. Changes in mRNA expression of extracellular matrix components associated with gingival elasticity in beagles were investigated by real-time polymerase chain reaction. Morphology and arrangement of collagen fibers were observed on Masson's trichrome staining of buccal gingival tissues of experimental and control teeth. Results: SFN reduced the amount and percentage of relapse of orthodontic rotation. It also decreased the gene expression of lysyl oxidase and increased the gene expression of matrix metalloproteinase (MMP) 1 and MMP 12, compared with DMSO control subjects. Histologically, collagen fiber bundles were arranged irregularly and were not well connected in the SFN-treated group, whereas the fibers extended in parallel and perpendicular directions toward the gingiva and alveolar bone in a more regular and well-ordered arrangement in the DMSO-treated group. Conclusions: Our findings demonstrated that SFN treatment may be a promising pharmacologic approach to prevent orthodontic rotational relapse caused by increased gingival elasticity of rotated teeth in beagle dogs.

• Korean Journal of Cleft Lip And Palate
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• v.2 no.1_2
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• pp.15-22
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• 1999

It is well known that the postoperative skeletal instability after Le Fort I osteotomy for advancement of maxilla in the cleft patients is one of the major surgical problems. So we had tried to compare the amount of relapse after Le Fort I advancement surgery in the horizontal and vertical positional change, angular change of reference points between cleft patients and non-cleft patients. Longitudinal records of 10 consecutive cleft patients (test group) and 20 non-cleft patients (control group) were analyzed. Lateral cephalograms were taken preoperatively, immediately postoperatively, and 2, 6, 12 months postoperatively. We measured horizontal and vertical changes (ANS, PNS, AI) and angular change (SNA) of the reference points and lines. In the test group, horizontal relapse of ANS, PNS, AI point are 36.4%, 37.5%, 32.0% respectively at 12 months postoperatively. The vertical relapse of ANS, PNS, AI are 25.3%, 32.3%, 39.1% respectively at 12 months postoperatively. The angular change of SNA is 33.6% at 12 months postoperatively. In the control group, horizontal relapse of ANS, PNS, AI point are 23.8%, 30.2%, 21.7% respectively at 12 months postoperatively. The vertical relapse of ANS, PNS, AI are 22.7%, 27.3%, 25.1% respectively at 12 months postoperatively. The angular change of SNA is 22.2% at 12 months postoperatively. The cleft patients have a larger tendency of skeletal and dental relapse compared with non-cleft patients after Le Fort I surgery. So the oral and maxillofacial surgeons must keep in mind these facts in order to minimize the relapse phenomenon from the beginning of surgical planning to postoperative care.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.95-101
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• 2003

The purpose of this study was to evaluate the patterns of skeletal changes of proximal and distal segments after one jaw surgery and two jaw surgery with posterior impaction using SSRO on mandible in order to determine the skeletal origin of relapse and compare the stability of surgical methods in anterior open bite. The points and lines from lateral cephalometrics were measured before, after surgery, and at least 6-month follow up period. And then, the positional change of the proximal and distal segment were evaluated respectively. The results obtained were as follows; In cases of two jaw surgery, the results were stabler because they had less relapse factors. In cases of one jaw surgery, the value of APD were increased but it didn't relapse to the original value. Both of proximal and distal segments were responsible for the relapse tendency. But in one jaw surgery, the rotation of proximal segment was more responsible, and in two jaw surgery, the rotation of distal segment was.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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• pp.563-569
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• 1996

Skeletal and dental changes were examined in 38 patients of mandibular prognathism who been treated by a bilateral sagittal split osteotomy(SSRO) and internal fixation using titanium mini-screws. All patients were followed up for over 8 months after the surgeries, and postoperative cephalometric measurements were compared at 2 months and at 8 months. Linear measurements of the "Pog-most posterior screws" and angular measurementsts of "SN-Pog'were compared to figure out the change of bony fragments. The significancy of data were tested by unpaired T-test. The results were as follows : 1. The fixation screws were changed in cephalometric position as little as $0.32{\pm}2.51mm$ in SSRO and $0.15{\pm}1.00mm$ in SSRO & Le Fort I Osteotomy.(P<0.05) 2. Mandibular set-back over 5mm resulted in less stability of the fixation screws and higher relapse tendency. 3. The internal fixation using two screws along the inferior border and one on the superior ridge is considered to be very resistant to postoperative relapse of the repositioned bony segments.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.229-237
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• 1993

This study was intended to evaluate a post-operative relapse tendency in mandibular prognathism patients with open-bite. 18 patients with or without open-bite have undergone sagittal split ramus osteotomy and were investigated radiologically with cephalogram. The results were as following 1. The preoperative anterior facial height, mandibular plane angle and mandibular gonial angle were larger in open-bite patients than in nonopen-bite patients.(p>0.05) 2. There was significant correlation between surgical change of SNA, mandibular plane length and long-term relapse.(p<0.01). 3. There was relatively stable postoperative anterior facial height in open bite patients. 4. There was no significant correlation between the surgical change of mandibular plane angle, amount of mandibular setback and long-term relapse.(p>0.01) 5. This study showed that horizontal relapse was more significant than vertical relapse.

• The korean journal of orthodontics
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• v.41 no.3
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• pp.154-163
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• 2011

Objective: The purpose of this study was to quantitatively evaluate relapse tendency after orthodontic treatment and determine the contributing factors by using the American Board of Orthodontics objective grading system (ABO-OGS). Methods: The subjects were 80 patients with more than 2 years of retention period after completing orthodontic treatment at the dental hospitals of Busan University, Kyunghee University, and Dankook University. The posttreatment (T2) and post-retention (T3) ABO-OGS measurements were analyzed in relation to age, gender, Angle's classification, extraction, retention period, and pretreatment condition (initial peer assessment rating (PAR) index, T1) by multiple regression analysis. Results: Among the 7 ABO-OGS criteria, alignment worsened but occlusal contact and interproximal contact improved in T3, but not in T2 ($p$ < 0.01). The 4 other criteria showed no significant differences. Multiple regression analysis showed that alignment, occlusal relationship, overjet, and interproximal contact were significant linear models, but with a low explanation power. Age, gender, Angle's classification, extraction, retention period, and pretreatment condition (initial PAR index, T1) had little influence on the ABO-OGS changes between T3 and T2. Conclusions: An orthodontist's understanding of posttreatment relapse tendency can be useful in diagnosis and during patient consultation.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.4
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• pp.319-322
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• 2011

Purpose: The purpose of this study was to examine the appropriate degree of set-back of the mandible by evaluating the rate of relapse after surgery. Methods: Among the patients who visited our hospital from January 2002 to January 2007 and who underwent orthognathic surgery, of the patients available for follow-up observation, the rate of relapse after surgery was investigated according to the set-back degree. The patients were divided into groups by the degree of set-back, and relapse was evaluated by the radiographs performed the day after surgery, 6 months after surgery, 1 year after surgery, 2 years after surgery and 3 years after surgery. Results: In cases that exceeded the limit of posterior movement of the mandible (13 mm) or that had the wrong position of the condyle, a greater tendency toward relapse was shown. Conclusion: Based on the results of this study, among the cases that required a large amount of posterior movement of the mandible, two jaw surgeries accompanied by bilateral sagittal split ramus osteotomy (BSSRO) and LeFort I osteotomy are recommended.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.2
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• pp.9-20
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• 1990

A series of 19 cases with maxillary hyperplasia and mandibular retrognathia were operated on by simultaneous superior repositioning of the maxilla after Le Fort I osteotomy and anterior repositioning of the mandible after bilateral sagittal split ramus osteotomies with or without osteotomy of the inferior border of the mandible. These were evaluated by retrospective cephalometric and computer analysis for the longitudinal skeletal and dental changes for an average of 17.1 months after surgery. For stabilization of the osteotomized segments, the authors used wire osteosynthesis by means of bilateral infraorbital and zygomatic buttress suspension wire at the maxilla, and direct interosseous wire at the split segments of the mandibular rami. Results show generally good stability after simultaneous maxillary and mandibular surgery with wire osteosynthesis, and a minimal to moderate tendency toward skeletal and dental relapse. This article is a preliminary study to defy the efficiency of the wire osteosynthesis (wo)compared with rigid internal fixation (RIF) for simultaneous maxillary and mandibular surgery. 1. The vertical relapse rate of the A point after superior repositioning of the maxilla is 2.2%. 2. The horizontal relapse rate of the B point after advancement of the mandible is 18.3%. 3. The condyle is distracted inferiorly and slightly posteriorly at the immediate postoperative period. 4. At the long term follow up examination, the condyle presents tendency of return to the preoperative position. 5. Condylar segment angle is decreased at the immediate postoperative period, and at the long term follow up evaluation, the angle is increased. 6. Gonial angle is increased at the immediate postoperative period, and then is decreased at the long term follow up evaluation. 7. The dentition is satisfactory with acceptable movement at the long term follow up evaluation. 8. At the mandibular free body analysis, genioplasty shows good stability. 9. Wire osteosynthesis provides excellent stabilization for the simultaneous maxillary and mandibular surgery.