• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.19 no.1
• /
• pp.25-34
• /
• 1997

This study was made with lateral cephalometric radiography of 28 skeletal class III malocclusion patients that were performed to setback surgery of mandible. The 28 patients were selected by four standards as follows. 1) Set-back amount of mandible is below 10 mm 2) No extrusion and intrusion of posterior tooth or alteration of interincisial angle at period of postoperative orthodontic treatment. 3) Change of mesial segment location of mandible on lateral cephalometrics 4) No genioplasty And 28 patients were divided to three group(1,2,3 group) by degree of preoperative occlusal plane angle to Burstone's horizontal plane. The preoperative occlusal plane angle, which of 1 group was smaller than $7^{\circ}$ and 2 group was between $7^{\circ}$ to $15^{\circ}$ and 3 group was larger than $15^{\circ}$. The results were as follows : 1. As the preoperative occlusal plane angle was larger, the degree of mandibular prognathism was not severe. 2. On comparsion of preoperative and immediate postoperative cephalometric analysis, specific relationship of occlusal plane angle and set-back amount of mandible was not present. 3. As the preoperative occlusal plane angle was smaller, the alteration of postoperative occlusal plane angle was increased tendency. As the preoperative occlusal plane angle was larger, the alteration of postoperative occlusal plane angle was decreased tendency. 4. The relapsed degree of B point distance to Vertical plane was not relationship to the degree of preoperative occlusal plane angle.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.29 no.2
• /
• pp.141-147
• /
• 2007

The purpose of this study was to evaluate the effects of maxillary occlusal plane angle to postoperative skeletal stability by comparative analysis after two-jaw surgery of patients with skeletal CIII malocclusion. This study was made with lateral cephalometric radiography of 52 patients with skeletal class III malocclusion that were performed to Le Fort I osteotomy and BSSRO. And 52 patients were divided to Group A(n=30) and B(n=22). Maxillary posterior impaction was not conducted in Group A, which the pre-operative maxillary occlusal plane angle was in a normal range, and for Group B, which the pre-operative maxillary occlusal plane was low, the maxillary posterior impaction was conducted. The results were obtained as follows : 1. The relapse rate of Group A, which the pre-operative maxillary occlusal plane angle was in a normal range, was relatively stable compared to Group B, which the pre-operative maxillary occlusal plane was low. 2. The relapse rate of each measurement of Group B, which had the maxillary occlusal plane altered during the operation, was somewhat high, and of those, the post-operative relapse rate of overjet, overbite, mandibular plane angle appeared to be significantly high in the statistics. The analyzed results above, was thought to be indicating that the pre-operative maxillary occlusal plane angle was closely related to the post-operative skeletal stability, and that obtaining post-operative skeletal stability only through operative normalization of occlusal plane angle may meet limitations.

• The korean journal of orthodontics
• /
• v.28 no.2 s.67
• /
• pp.175-187
• /
• 1998

The purpose of this study was to predict the prognosis of class III malocclusion treatments. 25 patients selected for this study were devided into two groups by the stability of dentitional, skeletal and soft tissue profile improvement. One was stable group which consisted of 12 children and the other was relapse group with 13 children. Various measurements in initial lateral cephalogram were calculated and analyzed by t-test, correlation coefficient and discriminant analysis. The results of this study were summarized as follows 1. In both stable and relapse groups, there was not distinct difference in the antero-posterior skeletal relationship (P<0.05). 2. As the result of wits, hn to occlusal plane angle and occlusal plane to mandubular plane angle, the occlusal plane of relapse group was stepper than that of the stable group. 3. In correlation coefficient analysis, the overjet and the occlusal plane to mandibular plane angle showed significant correlations (p<0.001, p<0.01). 4. The discriminant function was obtained from three major influential measurements; overjet, AB to occlusal plane angle and articular angle, and this function could discriminate correctly in 88% of these samples.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.41 no.4
• /
• pp.298-305
• /
• 2014

The purpose of this study is to evaluate the effects of facemask therapy in patients with Class III malocclusion with two types of bonded expanders covering different numbers of anchored teeth and to compare the anchorage value of two types of bonded expander. Eighteen subjects with Class III malocclusion in early mixed dentition were included in this study, and subjects were divided into two groups based on the number of teeth covered by bonded expander: group 1 (splinting four teeth on each side, 9 subjects) and group 2 (splinting three teeth on each side, 9 subjects). Lateral cephalograms were obtained and assessed before (T1) and after (T2) the treatment. The facemask therapy showed skeletal effects including anterior movement of maxilla and backward rotation of mandible in both groups, with no significant differences between groups. Mesial movement of maxillary molars which indicates anchorage loss of the bonded expander was found in both groups, but significantly larger mesial movement was found in group 2 than in group 1. In conclusion, the value of anchorage was different according to the number of teeth covered by bonded expander as an intraoral anchorage of facemask, but there were no significant differences in skeletal effects.

• The korean journal of orthodontics
• /
• v.28 no.3 s.68
• /
• pp.353-370
• /
• 1998

This study was conducted to investigate the changes in the structural parts of the craniofacial skeleton subsequent to chincap therapy in the juvenile skeletal Class III patients. The subject consisted of 29 Korean children(14 males, 15 females) who had skeletal Class III malocclusion and were undergone chincap therapy from the beginning of the treatment (and an auxilliary upper removable appliance, if necessary). The control group was composed of 21 children(10 males, 11 females) with skeletal Class III malocclusion who had no orthodontic treatment. Cephalometric data at the mean age of 7 and 2 years later were analyized by finite element method, and compared between groups by independent group t-test(p<0.05). The results of the present study were as follows; 1. There were no significant changes in the cranial base, posterior face, upper anterior face, ramus, chin and soft tissues by the chincap therapy. 2. The mandibular body showed significant differences in the minimum extention ratio and the overall shape ratio. This means that the vertical direction of growth was retarded by the chincap therapy. 3. The major direction of the growth in the maxillary basal bone was significantly more horizontal in the experimental group, which suggests that the vertical growth of maxilla was inhibited. 4. There was statistical difference in the major direction of the growth of the anterior face between groups. This may be due to the significant difference in the major direction of growth of the lower anterior face, supposed to be resulted from the mandibular rotation and/or displacement by the chincap therapy. The change in the oral functional space seemed to be caused by the same reason. 5. From the standpoint of these results, the retardation of growth, the changes of the growth direction and the morphological changes could be accepted partly, but the major effect of the chincap seems to be the rotation and the displacement of the mandible.

• The korean journal of orthodontics
• /
• v.25 no.3 s.50
• /
• pp.355-373
• /
• 1995

Craniofacial region is a musculodentoskeletal system that consists of many anatomical structures ; cranioskeletal structures, dental arches, and formation and functions of masticatory muscles have close correlations. Growth and development of craniofacial region are influenced by not only hereditory factors, but also environmental factors such as craniofacial muscles and surrounding tissues. On the contrary, however, study on changes in functions or adaptations of craniofacial muscles following changes of craniofacial skeletal structures has been somewhat insufficient. The author's purpose was to observe correlations between masticatory muscular functions and change patterns according to cranial skeletal structures and occlusion patterns, for this, comparative study of muscle activity changes of preand post- orthognathic surgery states in skeletal Cl III malocclusion patients was peformed. The selected sample groups were 15 normal male patients, 15 skeletal Cl III pre-orthognatic surgery patients and 15 skeletal Cl III post-orthognatic surgery patients. For each sample groups, cephalometric x-ray taking, masticatory efficiency test and measurements of muscle activities in anterior temporal muscle, masseter and upper lip in rest, clenching, chewing and swallowing were carried out. The following results were obtained : 1. In resting state of mandible, pre-surgery malocclusion group showed higher m. activities in ant. temporalis, masseter and upper lip than post-surgery group. Post-surg. malocc. group showed significantly high m. activity only in upper lip compared to the normal group. 2. In clenching state, post-surg. malocc. group showed higher m. activities in ut. temporalis, masseter and upper lip than pre-surg. malocc. group. 3. In chewing state, post-surg. malocc. group showed higher m. activities in ant. temporalis and masseter than pre-surg. malocc. group, on the other hand, decreased upper lip activity was noticed. 4. In swallowing state, post-surg. malocc. group showed lower upper lip activity than pre-surg. malocc. group but higher than that of the normal group. No significant difference in m. activities of ant, temporalis and masseter was noticed among the three groups. 5. Masticatory efficiency was lower in pre-surg. malocc. group than normal group, masticatory efficiency showed an increase in post-surg. malocc. group compared to the pre-surg. malocc. group. However, both groups showed significant differences compared to the normal group.

• The korean journal of orthodontics
• /
• v.30 no.3 s.80
• /
• pp.307-315
• /
• 2000

This study was performed to evaluate the reproducibility of natural head position according to skeletal malocclusion types and sex using cephalometric radiographs for establishing orthodontic diagnosis and treatment planning. The sample consisted of 90 young adults (male 45, female 45) who had the skeletal malocclusion. Cephalometric radiographs were taken in natural head position, and statistical analysis was performed and method error of 6 postural variables were estimated to evaluate the reproducibility of the natural head position. The following results were obtained : 1. In the reproducibility of the natural head position, postural variables had no statistical significance In male and female (P>0.05). 2. In the reproducibility of the natural head position, postural variables had no statistical significance in Class I, II, III, and total group (P>0.05). 3. The reproducibility of natural head position using method error was excellent in all groups.

• 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.

• The korean journal of orthodontics
• /
• v.24 no.4 s.47
• /
• pp.861-869
• /
• 1994

The purpose of this study was to investigate the relationship of nose profile with respect to skeletodental pattern, by measured and analyzed statistically the lateral cephalograms of 95 females (13 to 30 years old). Tge results were summerized as follows ; 1. The antero-posterior factors of the nose - nasofrontal angle, nasofacial angle, and dorsal length / ala length ratio were different among the malocclusion groups 2. There were no significant correlation between the the vertical nose factors and the skeletal factors 3. The Class I groups had a straight nose profile , the Class II groups had a convex profile ; the Class III groups had a concave profile.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.23 no.3
• /
• pp.667-673
• /
• 1996

The prevalence of class III malocclusion is approximately 5$\sim$9%, and about one fourth of this malocclusion is due to underdeveloped maxilla. Maxillary protraction appliance is an orthopedic device which promote the growth of a deficient maxilla by applying extraoral force to actively growing patients. The object of using maxillary protraction appliance is to guide a normal growth of maxilla and mandible and improve the occlusal relationship and also improve the facial profile. The author treated three patients whom were diagnosed as a class III malocclusion due to deficient maxilla using maxillary protraction appliance and the followings are the conclusions : 1. In these cases, anterior crossbite was corrected by anterior movement of maxilla and downward backward rotation of mandible and simultaneously, anterior facial height was increased. 2. The amount of dental change compare to skeletal change was greater as the patients got older. 3. When 500gm of force to each side was applied, the treatment period has been decreased. 4. As a result of applying the force between maxillary first primary molar and canine, there was a small degree of changes in palatal plane. So, it can be concluded that the maxillary protraction appliance is effective in treating growing patients with a deficient maxilla.