• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.152-161
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• 2007

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were $0.02{\pm}1.43mm$ at B point and $0.42{\pm}1.56mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.12{\pm}1.55mm$ at B point and $0.08{\pm}1.57mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were $1.22{\pm}2.21mm$ at B point and $0.74{\pm}2.25mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.92{\pm}1.81mm$ at B point and $0.83{\pm}2.11mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

• The korean journal of orthodontics
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• v.22 no.1
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• pp.67-88
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• 1992

The purpose of this study was to investigate the changes of mandibular movement and muscle activity following orthognathic surgery in patients with mandibular prognathism. Lateral cephalogram, M.K.G., E.M.G. recordings were obtained immediately before surgery, and 2 months and 8 months after surgery. Among the patients who received orthognathic surgery, 19(13 men, 6 women) were selected for this study. Statistical analysis for each time interval differences were performed with the SPSS package. The results were as follows: 1. Compared with the pre-operative group (opening 349.7mm/sec, closing 313.1mm/sec), the mean values of the maximum opening and closing velocity in the skeletal Class III surgery group were significantly decreased in the 2 months post-operative (opening 232.9mm/sec, closing 206.9mm/sec), but the values tended to increase in the 8 months post-operative group (opening 280.9 mm/sec, closing 319.1mm/sec). 2. Compared with the pre-operative group (61.7 mm/sec), the maximum velocity of the terminal tooth contact increased in the 2 months (72mm/sec) and 8 months (105.7mm/sec) postoperative groups. 3. In the mean value of vertical freeway space, there was significant difference between the normal group and the pre-operative group, but not between the normal group and the 8 months post-operative group. 4. In the mean values of the maximum opening, the maximum anterio-posterior movement from centric-occlusion, and the lateral deviation from centric occlusion, there was no significant difference between the normal group and the surgery group (the pre-operative and the 8 months post-operative groups). 5. The mature swallowing pattern was 58% in the pre-operative group, but 90% in the 2 months post-operative group, and 63% in the 8 months post-operative group. 6. In the comparison of muscle activity, there was no significant difference between the normal group and the surgery group during the rest position. However, during cotton roll clenching, there was significant difference between the normal group and the pre-operative group, but not between the normal group and the 8 months post-operative group.

• The korean journal of orthodontics
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• v.27 no.2
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• pp.283-296
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• 1997

Stomatognathic system is a complex one that is composed of TMJ, neuromuscular system, teeth and connective tissue, and all its components are doing their parts to maintain their physiological relationships. Mandible, in particular, performs various functions such as mastication, speech, and deglutition, the muscular activities that determine such functions are signalled by numerous types of proprioceptors that exist in periodontal membrane, TMJ, and muscles to be controlled by complicated pathways and mechanics of peripheral and central nervous system. Orthodontic treatment, especially when accompanied by orthognathic surgery, brings dramatic changes of stornatognat is system such as intraoral proprioceptors and muscle activities and thus, changes in patterns of mandibular function result The author tried to analyze changes in patterns of mandibular movement and physiologic activities of surrounding muscles in Skeletal Class III ortlrognathic surgery patients who presently show a great increase in numbers. The purpose of this study was to draw some objective guidelines in evaluating funclierual aspects of orthognathic surgery patients. Mandibular functional analysis using Biopak was performed for skeletal Class III prognathic patients who underwent IVRO(lntraoral Vertical Ramus Osteotmy), and the following results were obtained: 1. Resting EMG was greater in pre-surgical group than the control group, and it showed gradual decrease after the surgery. Clenching EMG of masseter and anterior temporalis of pre-surgical group was smaller than those of control group, they also increased post-surgically, and significant difference was found between pre-surgical and post-surgical(6 months) groups. 2. Resting EMG of anterior ternporalis was greater than that of all the other muscles, but there was no significant difference. Clenching EMG of anterior temporalis and masseter were greater than those of the other muscles with statistical difference. In swallowing, digastric muscle showed the highest EMG with statistical significance. 3. Limited range of mandibular movement was shown in pre-surgical group. Significant increase in maximum mouth opening was observed six months post-surgically, and significant increase in protrusive movement was observed three months post-surgically.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.216-226
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• 2005

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs (Quick Ceph Image $Pro^{TM}$ (ver 3.0) and $V-Ceph^{TM}$(ver 3.5)) for mandibular set-back surgery. The presurgical and postsurgical lateral cephalograms of 40 patients (20 males and 20 females) were traced on the same acetate paper with the reference taken as the cranial base outline. The presurgical skeletal outlines were digitized onto each computer program and the mandible was moved to mimic the expected surgical procedure with reverence to the mandibular anterior border and lower incisor position of the actual postsurgical skeletal outline. The soft tissue profile was generated and the amount and direction of skeletal movement was calculated with each software. The predicted soft tissue profile was compared to the actual postsurgical soft tissue profile. There were differences between the actual and the predicted surgical soft tissue profile charges in the magnitude and direction, especially the upper lip. lower lip and the soft tissue chin (P<0.05). Quick Ceph had more horizontal measurement errors and thickness errors for the upper lip and lower lip, but V-Ceph had more vertical measurement errors of the lower lip (P<0.05). There was a positive correlation between the prediction errors and the amount of mandibular movements in the vertical position of Sn, the horizontal position of Ls and the upper lip thickness for V-Ceph, and there was a negative correlation in the horizontal position and the thickness of the lower lip for Quick Ceph (P<0.05). However all of the Prediction errors of both imaging softwares were ranged within 3mm, and this was considered to be allowable clinically.

• The korean journal of orthodontics
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• v.40 no.6
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• pp.421-431
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• 2010

Objective: This study aimed to verify the intra-individual reproducibility of the natural head position (NHP) in adult Korean patients in the centric relation (CR) position and to prove the inter-individual variability of the Frankfurt horizontal (FH) plane and sella-nasion (SN) line compared to the true horizontal line (THL). In addition, the study aimed to investigate the correlations between linear measurements from A-point and B-point to the nasion true vertical line (NTVL) and angular measurements from A-point and B-point to the SN line. Methods: Two lateral cephalograms were taken of 116 subjects (23 males, 93 females) with CR wax bites in a NHP at a one-week interval. Results: Method errors of three variables and intraclass correlation coefficients of six parameters proved the intra-individual reproducibility of NHP (p < 0.001). The angle of the FH to the THL was not significantly different from $0^{\circ}$ (p > 0.05), but it was clinically variable (SD $3.89^{\circ}$) on the inter-individual level. Conversely, the angle of the SN line to the THL was significantly different from $7^{\circ}$ (p < 0.05). Very low correlation was found between the linear measurements and angular measurements of A-point and B-point (p < 0.01). Conclusions: The NTVL could be a useful reference line for assessing the antero-posterior position of the maxilla and mandible of Korean adult patients in NHP and CR.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.33-41
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• 2000

Although it is well known that the chincup, used to correct a skeletal class III malocclusion in growing children, reduce the mandibular prognathism by arresting the growth of the mandibular length and rotating the mandible posteroinferiorly, the majority of the studies about chincup is focused on condylar head that plays an Important role in mandibular growth. The aim of this study was to evaluate the morphologic change of the mandibular symphysis where extraoral force is applied directly during chincup treatment. The data lot this study were obtained from lateral cephalometric radiographs of 62 growing children(chincup group:32, control group:30) with mixed dentition who had been accepted lot the orthodontic treatment at Chonbuk National University Dental Hospital. The results were as follows : 1. Symphysis height was increased both in chincup therapy group and control group during treatment. Symphysis depth was decreased or maintained the initial values in chin cup therapy group, whereas increased in control group. Posterior symphysis depth was decreased both in chin cup therapy group and control group, but anterior svmphysis detph was increased in control group, whereas decreased in chincup therapy group. 2. Chin depth and chin curvature were increased in control group, whereas maintained or decreased in chincup therapy group during treatment. Chin angle, menton ang1e and symphysis angle were decreased in control group, whereas increased in chincup therapy group. It suggested that bone deposition in pogonion area that occur normally with mandibular growth was supressed by direct contact of chincup. 3. When growing children wear chincup, symphysis morphology was maintained due to inhibition of forward growth at mandibular symphysis. It may be due to the suppression of bone deposition in anterior part of symphysis.

• The korean journal of orthodontics
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• v.26 no.4
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• pp.414-420
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• 1996

Cephalometric measureements have disadvantage of representing cranio-facial structures in two dimension only and therefore they pose limitations in describing three-dimentional structures of cranio-facial region. More interests have been put on the correlation between the two planes. This study evaluated correlations between facial type score, which allows effects on malocclusion, growth change prediction and establishment of treatment method and prognosis, and measurements from submentovertex view. Cephalometric view and submentovertex view were taken of skeletal Class I adults with optimal profile and correlations between them have been observed. Following results were obtained: 1. To learn about factors that influence average condylar angulation, FACE, INT-CO-ANG, MN-CORPUS, CON-RATIO, GON-RATIO, MN-RATIO were used as variables and underwent multiple regression analysis. As a result, the following equation was obtained : CON-AVE=.l73(FACE)-.322(INT-CO-ANG)+36.34(GON-RATIO) +.420(MN-CORPUS) (($R^2=.85451$) 2. The following equation was obtained concerning facial type score. FACE= .050(CON-ANG)+.023(INT-CO-ANG)-.075(MN-CORPUS)($R^2=.31547$) 3. Among the submentovertex measurements, MN-CORPUS, CON-RATIO, GON-RATIO, MN-RATIO showed close correlations. (P<0.05) 4. Average condylar angualtions were $23.37^{\circ}$ on the right and $20.71^{\circ}$ on left. There was a difference between the two. FACE : facial type soore. CON-ANG: mean value of condylar angulation. CON-AVE: mean value of Rt. Lt condylar angulation. INT-CO-ANG : angle between Rt. Lt condylar axis. MN-CORPUS : angle formed between RT. Lt gonion & pogonion. CON-RATIO: lntercondylar distance/mandibular body length. GON-RATIO : intergonion distanoe/mandibular body length. MN-RATIO: lntermylohyoid distance/mandibular body length. MX-RATIO: intermaxillary tuberosity distance/ANS-PNS distance.