• The korean journal of orthodontics
• /
• v.26 no.1 s.54
• /
• pp.65-82
• /
• 1996

This study was carried out to study the changing patterns in muscle activities in Angle's II and Class III malocclusion patients following activator therapy, To study the activities of anterior temporal(T.A.), masseter(M.M.), posterior temporal(T.P.), and anterior belly of digastric(D.A.) muscles, surface electrodes were placed on 15 Angle's Class II and 17 Angle's Class III malocclusion patients and following conclusions were obtained after electromyographic recordings were taken at prior to the activator therapy and at some time between 6 -12 month after the start of activator therapy. 1. Class II and Class III malocclusion groups, when compared to normal occlusiongroup, showed no significant differences during resting and swallowing. But significant differences were observed in masseter and posterior temporal muscles during clenching. 2. Most of the muscles studied showed a certain pattern, that is those groups whose pre-treatment E.M.G. were lower than the normal value showed significant increase after activator therapy, whereas those groups whose pre-treatment E.M.G. were higher than the normal value showed significant decrease after activator therapy. This pattern was observed in all of the muscle groups studied except T.A.(swallowing), T.P.(clenching) and D.A.(swallowing, clenching) in Angle's Class III malocclusion group and in Angle's Class II malocclusion group, above tendency were observed only in T.A.(swallowing), M.M.(resting, swallowing) and T.P.(clenching). This pattern was less obvious during clenching. 3. When E.M.G. activity after activator therapy between Angle's Class II and Class III malocclusion group was compared, Class III malocclusion group showed more increase during resting, and Class II malocclusion group showed more increase during swallowing and clenching excepting M.M. and D.A. respectively.

• The korean journal of orthodontics
• /
• v.41 no.4
• /
• pp.297-306
• /
• 2011

Nonextraction camouflage treatment in mild Class III malocclusion is achieved by backward movement of the lower dentition and forward movement of the upper dentition. Many camouflage treatment modalities have been used for distal tipping and distal movement of mandibular posterior teeth. The amount of distal movement of mandibular dentition can be improved in cases of severe crowding, even without the patient's cooperation, by using miniscrews for anchorage. However, miniscrew insertion may be unsuccessful, and it may contact the adjacent root because of the distal movement of dentition. Distal tipping of mandibular dentition can be achieved using multiloop edgewise archwires and intermaxillary elastics. However, the complexity of this wire design causes discomfort to patients. Recently, a new treatment using improved superelastic NiTi wires (ISWs) and intermaxillary elastics has been introduced. ISWs can deliver orthodontic force more effectively, and their use with molar tip-back treatment has several advantages-this approach is effective, simple, and easy to use and reduces patient discomfort. The aim of this study was to report a case of camouflage treatment using ISW with tip-back and intermaxillary elastics for distal tipping of mandibular posterior dentition and to evaluate the effectiveness of this treatment in a clinical setting.

• The korean journal of orthodontics
• /
• v.36 no.1 s.114
• /
• pp.63-73
• /
• 2006

Numbers of postulations lie on the difference of integumental changes with two major surgical remedies of one jaw vs. two jaw surgery in skeletal Class III malocclusion. Accordingly it was the aim of the study to elucidate the skeletal profile changes with an accompanying disposition of soft tissues, consequently to yield the correlation and ratio of soft tissue changes with two types of surgical procedures, which in turn make it possible to predict the soft tissue outcomes by means of assembled regression equations. Cephalometric headfilms of fifty two adult skeletal Class III comprised of 26 maxillary advancement by Le Fort I osteotomy and mandibular setback by sagittal split ramus osteotomy simultaneously (double jaw surgery, group A), 26 mandibular setback alone (one jaw surgery, group B) were statistically analyzed. Group A manifested 72.4% soft tissue advancement to skeletal changes in the upper lip area, while group B appeared to have no statistically significant changes. The nasolabial angle showed more increment in group A than in group B, whereas the mentolabial angle illustrated more reduction in group B. The backward movement of soft tissue pogonion to skeletal change revealed 98% in group A, and 109% in group B. The double jaw surgery group characteristically revealed remarkable integ umental change in the upper lip area, while the one jaw surgery had major effects in the lower lip and soft tissue pogonion areas.

• The korean journal of orthodontics
• /
• v.31 no.4 s.87
• /
• pp.393-401
• /
• 2001

The purposes of this study were to assess the treatment results in orthodontic department, Kyung Hee University, to evaluate the occlusion at 2 year follow-up control, in relation to the original malocclusion, and changes occurring in the follow-up period, and to determine whether treatment and posttreatment changes of the PAR index were related to the original Angle classification Dental study casts of 25 patients in permanent dentition were evaluated using Peer Assessment Rating (PAR) index. The PAR index was measured at the pretreatment stage, immediately after treatment, and at 2 yews posttreatment. The following results were obtained : 1. The treatment reduced the PAR index by 85.05% and it indicates that KHDC clinic has a high standard of treatment 2. The follow-up result of 75.40% PAR score reduction implies a gain of 9.55% of posttreatment PAR score during follow-up period. 3. There is no relationship between the treatment changes of the PAR index and the orignal Angle classification.

• The Journal of Korean Academy of Prosthodontics
• /
• v.62 no.1
• /
• pp.28-37
• /
• 2024

Severe cases of mandibular prognathism can be treated with orthodontic therapy or surgical correction, but there are situations where only prosthetic improvement is possible. An understanding of class III patients is needed, including a vertical chewing pattern and the absence of anterior guidance. Additionally, it is relatively easy to increase occlusal vertical dimension to correct the anterior crossbite, but this approach can sometimes lead to unfavorable results, necessitating careful diagnosis and treatment planning. In this case report, oral rehabilitation was conducted in a patient with mandibular prognathism and asymmetry, utilizing implants and fixed dental prosthesis. Through a step-by-step treatment approach, the existing occlusal vertical dimension was maintained, and the final fixed dental prosthesis restoration was completed. Accordingly, it shows functional and aesthetically appropriate results, and reports on the patient's diagnosis and treatment process.

• The korean journal of orthodontics
• /
• v.29 no.3 s.74
• /
• pp.303-315
• /
• 1999

The aim of this study was to evaluate the morphology of the mandibular symphysis and anterior alveolar and skeletal relationship under the influence of the rotational growth pattern of mandible in skeletal Class III malocclusion. A total of U untreated adult subjects were divided into two groups-forward rotational growth pattern group, backward rotational growth pattern group-according to the suggestion of Skieller et al.. The antero-posterior position, vertical relationship, mandibular symphysis and anterior alveolar and skeletal relationship were assessed on lateral cephalometric radiographs. Mandibular symphysis and anterior alveolar and skeletal relationship in each subject were studied and the following conclusions were drawn : 1. Concerning the antero-posterior position, forward rotational growth pattern group showed significantly larger SNA, SNB. Conceming the vertical relationship, all measurements showed statistically significant differences. 2. Forward rotatioal growth pattern group showed significantly larger IMPA, MnAD, backward rotational growth pattern group showed significantly larger MxABH. 3. There was no statistically significant difference in symphysis ratio to mandibular plane between forward and backward rotational growth pattern group. 4. In the correlative analysis of rotational growth pattern of mandible and mandibular symphysis, anterior alveolar and skeletal relationship, statistically significant correlations in overbite, IMPA, MnAD, symphysis width were showed.

• The korean journal of orthodontics
• /
• v.30 no.5 s.82
• /
• pp.643-655
• /
• 2000

In Patients with severe skeletal discrepancy, surgical orthodontic treatment must be accompanied, and recently two jaw surgery has become a common procedure, resulting in improved esthetics and function. Choosing the position of the occlusal plane in this two jaw surgery is an important factor in postoperative stability Therefore this must be taken into consideration during the diagnosis and treatment plan. In this study, among patients with skeletal Class III occlusion, 25 patients(8 male, 17 female, average age $23.2{\pm}3.17$) who have undergone two jaw surgery, setting the ideal occlusal plane according to Delaire's architectural and structural cranial analysis. In comparing preoperative($T_1$). postoperative($T_2$, average of 15.4 days), and long-term postoperative($T_3$, average of 32.6 months) lateral cephalometric radiography, the following conclusions have been made. 1. There were no significant changes of the occlusal plane angle after the two jaw surgery, and there were no significant differences between the surgical technique(SSRO and IVRO). 2. The postoperative changes of the occlusal Plane had no relationship with the amount of jaw movement, amount of posterior impaction, nor the time relapse after surgery. 3. After two jaw surgery, in the SSRO group there was significant forward movement of the mandible, and in the IVRO group the lower incisors extruded as the mandible moved backward and downward which makes the genial angle and the mandibular plane angle significantly increased

• The korean journal of orthodontics
• /
• v.33 no.1 s.96
• /
• pp.63-72
• /
• 2003

Over the Past decades, the number of Patients seeking orthodontic treatment has increased markedly with socioeconomic development and change of recognition on appearance. The purpose of this study was to provide an epidemiologic data base related to the orthodontic treatment need. We could take an adequate information regarding the characteristics of orthodontic patients, and the changing trends about treatment mordality. Distrubution and treands were Investigated in 676 patients who had been examined and diagnosed at Department of orthodontics, Dental Hospital, Seoul National University from January to June in 1992 and 2002. 1. Sex distribution of patients changed from 1:2.1 to 1:1.5 (male female). 2. In 2002, are distribution had shown $7\~12$ year-old group being the largest$(32.0\%)$ and percentage of $19\~24,\;13\~18,\;over\;25,\;4\~6,\;0\~3$ year-old group were $24.0\%,\;21.6\%,\;14.2\%,\;5.8\%,\;2.4\%$ respctively. Compared with data in 1992, the number of adult patients highly increased. 3. With regard to Angle classification, each percentage of Class I, Class II div 1, Class II div 2, and Class III malocclusion were $25.0\%,\;20.9\%,\;3.4\%,\;and\;48.1\%$ respectively in 2002. 4. Geographic distribution showed that most of the patients visited $(37.0\%)$ lived in northeast of Seoul in 2002. 5. Mandibular prognathism showed the highest percentage in chief complaints. The percentages of crowding and facial asymmetry were $14.2\%\;and\;11.8\%$ in 2002. Patients with facial asymmetry increased significantly. 6. Percentages of patients treated with fixed appliance and orthognathic surgery were $38.0\%\;and\;25.0\%$ in 2002. Patients needed to observe the growth pattern comprised $13.0\%$ with increasing trends. The use of chin cap reduced and the percentage of ortognathic surgery and growth observation increased significantly.

• The korean journal of orthodontics
• /
• v.29 no.1 s.72
• /
• pp.113-127
• /
• 1999

The purpose of this study is to investigate the stability of counterclockwise rotation of mandible by sagittal split ramus osteotomy to correct the skeletal Class III malocclusion with anterior open bite. Twenty five skeletal Class III open bite patients(mean age 20.6 years) who were treated by the sagittal split ramus osteotonues with rigid fixation were examined in this study. Cephalometric radiographs were taken for each Patients Preoperative(T1), ewly Postoperative(T2), and late postoperative Period(T3). Mean postoperative period was 8.0 months. Cephalometric analysis was done and data from T1, T2, and T3 were analyzed statistically by Paired t-test and Pearson correlation analysis. The following results were obtained. 1. Mandibular plane angle decreased $2.9^{\circ}$ and mandibular occlusal plane angle related to SN Plane decreased $2.7^{\circ}$ after orthognathic surgery(T2). At 6 months after orthognathic surgery(T3), mandibular plane angle increased $1.0^{\circ}$, but mandibular occlusal plane angle did not changed. 2. The amount of horizontal relapse long time after orthognathic surgery(T3) was 1.6 mm at B point and it was $22\%$ of the total posterior movements. There was no vertical relapse in the anterior facial height. 3. The related factor with horizontal relapse at late postoperative period was mandibular plane angle(p<0.01). The related factors with decreasing posterior facial height were amount of mandibular setback(p<0.01), increasing of mandibular ramus height(p<0.01), and decrease of the mandibular plane angle during operation(p<0.01). 4. There was no relationship between the amount of changes in mandibular occlusal plan angle during operation and the amount of relapse after surgery.

• The korean journal of orthodontics
• /
• v.40 no.6
• /
• pp.383-397
• /
• 2010

Objective: The objective of this study was to compare maxillary soft tissue changes and their relative ratios to hard tissue changes after anterior segmental osteotomy (ASO)/bilateral sagittal split ramus osteotomy (BSSRO) and Le Fort I/BSSRO in skeletal Class III malocclusion with upper lip protrusion. Methods: The study sample comprised the ASO/BSSRO group (n = 14) and the Le Fort I/BSSRO group (n = 15). The Le Fort I/BSSRO group included cases of maxillary posterior impaction only. Lateral cephalograms were taken 2 months before and 6 months after surgery. Linear and angular measurements were performed. Results: The anterior maxilla moved backward in both groups after surgery, however the amount of change was significantly larger in the ASO/BSSRO group (p < 0.01). The ratios of hard to soft tissue change were 79% (SLS to A point), 80% (LS to A point) in the ASO/BSSRO group, and 15% (SLS to A point), 68% (LS to A point) in the Le fort I/BSSRO group. In addition, there was a $3.23^{\circ}$ increase of the occlusal plane in the Le Fort I/BSSRO group. Conclusions: When two-jaw surgery is indicated in skeletal Class III patients with protrusive lips, ASO may be a treatment of choice for cases with more severe upper lip protrusion, while Le Fort I with posterior impaction may be considered if an increase of occlusal plane angle is required.