• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.100-106
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• 2002

The prevalence of Class III malocclusion is approximately 5% in the Caucasian population, rising to as mush as 50% in the Japanese and Korean population. Recent studies have suggested than 63% of this malocclusion display maxillary retrusion. If left untreated, the malocclusion tends to worsen. Consequently, early treatment is commonly indicated to obtain a more normal jaw relationship. This report is 2 cases treated patients who diagnosed as skelectal Class III malocclusion due to deficient maxilla using facemask.

• The korean journal of orthodontics
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• v.25 no.4
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• pp.375-401
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• 1995

Cause of skeletal Class III malocclusion in growing patients can be classified into maxillary deficiency, mandibular overgrowth, and combination of the two. Use of Protraction Head Gear(P.H.G.) has been recommended for treatment of growing Class III malocclusion patients, for it results in forward & downward movement of maxilla and backward & downward rotation of mandible. Numerous animal experiments were performed and clinical study data have been reported ; nevertheless, studies on soft tissue profile change and comparison of treatment effects among the patients who had undergone treatment are considered to be somewhat insufficient. The author selected 93 patients, who had been diagnosed as skeletal Class III malocclusion with maxillary deficiency and then treated with P.H.G. ; the sample group was divided according to sex, treatment beginning age, palatal suture opening(intraoral appliance), and facial growth pattern. For each group, changing patterns of hard and soft tissue profile observed, and comparision with 20 normal group(Angle's Class I) patients of statistical significance in amount of growth and treatment of hard and soft tissue was done. The following results were obtained. 1. Skeletal, dental, and soft tissue measurements indicated that more growth changes was induced in the sample group that used P.H.G. compared to the growth amount of normal group. 2. No statistical significance was observed in the amounts of maxillary forward movement and mandibular backward & downward rotation depending on treatment beginning age in both sex group. 3. R.P.E. showed more significant maxillary forward movement and less protrusion of upper incisor than La-Li. 4. There was no statistical significance in the amount of maxillary forward movement depending on facial growth pattern. On the other hand, measurements indicating mandibular downward & backward rotation indicated greater change in counterclockwise growth pattern group than the clockwise. 5. Changes in upper and lower lip thicknesses showed a close relationship with positional changes in underlying bone tissue and upper and lower teeth, and upper lip height and nasolabial angle increased and mentolabial angle decreased.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.329-339
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• 2022

The purpose of this study was to compare the palatal dimensions (volume, width, length, and height) in different malocclusions (Class I, II, and III) in mixed dentition using a three-dimensional digital scanner. The study was performed on 30 selected casts from 1400 casts that were taken at the Department of Pediatric Dentistry at Dankook University. Casts consisted of Class I, II, and III malocclusion groups in Hellman's dental age IIIA. The mean age was 8 years and 6 months ± 11 months. Each cast was scanned by three-dimensional digital scanner, Medit T710 (Medit, Seoul, Korea), and shaped into the three-dimensional image and calculated palatal dimensions using the Plan T program (SMD solution, Seoul, Korea). The values were statistically compared and evaluated by Kruskal-Wallis followed by the Mann-Whitney test. According to our results, subjects with Class II malocclusion showed lower palatal width and longer palatal length compared to those with Class I and Class III. For palatal height, Class III malocclusion subjects in mixed dentition exhibited a larger number than Class II and Class I. Lastly, for palatal volume, compared to other malocclusions, Class III showed higher results; however, there were no significant differences. The form of the palate differs in types of malocclusions and understanding of these differences is important in clinical significance. Based on this study, the understanding of the relationship between the shape of the palate and the skeletal pattern provides useful information about orthodontic treatment plans, early diagnosis of malocclusion, and morphological integration mechanisms. Orthopedic treatment in the maxilla should be performed during early and intermediate mixed dentition to enhance treatment efficiency.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.197-208
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• 1997

The purpose of this study was to evaluate the amount and interrelationship of the soft and hard tissue change after mandibular setback surgery in skeletal Class III malocclusion. The sample consisted of 25 adult patient (12 male and 13 female) who had severe anteropostrior skeletal discepancy. These patient had received presurgical orthodontic treatment and surgical treatment which is bilateral sagittal split ramus osteotomy. The presurgical and postsurgical lateral cephalograms were evaluated. The computerized statistical analysis was carried out with SPSS/PC program. The result were as follows: 1. After mandibular bilateral sagittal split ramus osteotomy, lower facial soft. tissue horizontal posterior changes were high significance value. but vertical soft tissue changes were low significance value. 2. After mandibular bilateral sagittal split ramus osteotomy, relative upper lip protrusion increased(p<0.01) and relative lower lip protrusion decreased(p<0.01) and lower facial soft tissue thickness increased(p<0.01).

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.509-529
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• 1992

Skeletal Class III malocclusion is one of the most difficult type to treat and stabilize. For a child with developing skeletal Class III malocclusion, the treatment objective would be to stimulate maxillary growth, particulary one who has markedly deficient maxilla, and to restrain excessive mandibular growth. In order to stimulate the maxillary growth, maxillary protraction appliance is the one of the effective orthopedic appliances in skeletal Class III. The purposes of this study were as follows ; evaluation of the skeletal and dental changes of the maxillary protraction in children with Class III Maxillary deficiency , comparison of the clinical effects between the group with RPE and labiolingual intraoral appliances , comparison of the clinical effects and stability related to the ages of the patients : stability of the maxillary protraction about 1 year after retention. The subjects consisted of 60 children between the ages of 8 and 13.4 who were diagnosed as Class III with maxillary deficiency and were treated with Face Mask (Delaire Type) from the Dept. of Orthodontics Yong Dong Severance Hospital, Yonsei University. 48 children wore the RPE and 12 children wore Labiolingual Appliance. Lateral Cephalograms were taken for each patient at before and after correction of anterior cross-bite in 60 children, and after an observation period of 10 to 14 months in 19 children. X and Y coordinate of 10 landmarks were analyzed using a horizontal line through sella and rotated $6^{\circ}$ down anteriorly as the horizontal reference axis, and a perpendicular verticual line through sella as the vertical reference axis. Each of the 31 measurents (10 verticals, 10 horizontals, 2 angles and 9 others) was statistically analyzed using SPSS/PC statistics. The results are as follows; 1. After maxillary protraction the maxilla and maxillary teeth moved downward and forward, while the mandible and mandibular incisor rotated downward and backward. 2. Maxillary protraction with rapid palatal expansion appliance was more effective than with labiolingual appliance. 3. More downward movement of the posterior palatal plane obserbed with maxillary protraction doing the midpalatal suture opening than with protraction after finishing the palatal expansion 4. The clinical effects of protraction and changes of the retention periods were not statistically significant among the age groups. 5. During the retention period, maxilla and maxillary teeth, and mandible and mandibular teeth moved downward and forward, however the mandibular changes were larger than the maxillary changes.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.751-761
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• 1998

The purpose of this study was to find the characteristics of lateral crphalogram of skeletal class III malocclusion patients to whom orthognathic surgery was essential. For this study 37 patients with skeletal class III and going to treat or be treated orthognathic surgery(age 7-17) were selected to experimental group and 56 people with normal occlusion (age 8-13) were selected to normal group and the two groups were evaluated and statistically analyzed and the results were as follows 1. In comparison of experimental group and normal group in prepubertal group, there were significant differences in ANS-U1/Me-L1, Mx. Length/Mn. Length, S-N/Go-Me, Wits, ANB, SN-Pog, IMPA, Facial Convexity, APDI (p<0.05) 2. In comparison of experimental group and normal group in pubertal group, there were significant differences in ANS-U1/Me-L1, S-Go/N-Me, Mx.Length/Mn.Length, S-N/Go-Me, Wits, Saddle Angle, SNB, ANB, SN-Pog, IMPA, Interincisal Angle, Facial Convexity, APDI (p<0.05) 3. Among items showing characteristics of skeletal class III malocclusion, there were no significant differences between prepubertal group and pubertal group in other items except Mx. Length/Mn. Length,APDI (p<0.05) 4. The significant correlationship was the highest between Saddle Angle and SNB, SN-Pog and SNB, ANB and Facial Convexity in experimental group

• The korean journal of orthodontics
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• v.38 no.2
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• pp.83-94
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• 2008

Purpose: The first objective of this study was to compare the upper midface morpholgy, focusing on the soft tissues, between skeletal Class III maloccusion patients with midfacial depression and the norm. The second objective was to estimate and analyze the change in the upper midface soft tissues following surgical correction with maxillary advancement by Lefort I osteotomy and mandibular setback by bilateral sagittal split osteotomy (BSSRO). Methods: The samples consisted of 34 adult patients (15 males and 12 females) with an average age of 21 years, who had severe anteroposterior discrepancy with midfacial depression. These patients had received presurgical orthodontic treatment and surgical treatment which consisted of simultaneous Lefort I osteotomy and BSSRO. Results: The correlation coefficient between changes in maxillary advancement and changes in Or' (soft tissue orbitale) was 0.599 (p < 0.05). Change in maxillary plane angle and vertical change of the maxilla were not correlated with the change in Or' (p < 0.05). The ratio of soft tissue change in Or' to maxillary advancement was 43.57 %, and 81.54 % in Sn. Regression equations between maxillary movement and Or' were devised. The $r^2$ value was 0.476. Conclusions: The majority of measurements in the upper midface in skeletal Class III maloccusions when compared to the norm, showed significant differences. In Class III malocclusion with midfacial depression, maxillary advancement produces soft tissue change in the upper midface.

• The korean journal of orthodontics
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• v.32 no.2 s.91
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• pp.117-127
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• 2002

The purpose of this study was to compare the arch width of the hyperdivergent group with that of the neutral group in Class III malocclusion based on the vertical patterns and to compare the arch width of Class III neutral group With that of normal occlusion group based on sagittal patterns. The subjects consisted of 118 pairs of studty casts, divided into three groups , 37 Class III hyperdivergent group(18 males and 19 females, SN-Mn plane angle>39.5$^{\circ}$), 40 Class III neutral group(20 males and 20 females, SN-Mn plane angle : 32 ${\pm}$ 2.5$^{\circ}$) and 41 Class I normal occlusion group(20 males and 21 females). The intercanine, interpremolar, and intermolar width of the maxillary and mandibular study casts were measured, then the ratios of dental width to basal width and mandibular width to maxillary width were obtained. Basal arch width and dental arch width were measured to obtain the pure basal arch relation in transverse plane as ruled out the transverse dental compensation. The results were as follows 1. There were no significant differences in any ratios between Class III hyperdivergent group and Class III neutral group as different vertical pattern. 2. As the ratios of dental arch width to basal arch width between normal occlusion group and Class III neutral group were compared, the maxillary teeth flared buccally to the basal bone, and the mandibular teeth tilted lingually to the basal bone in Class III neutral group. 3. The ratios of mandibular arch width to maxillary arch width in basal arch level were significantly different in all regions. Maxillary basal arch width of Class III neutral group was narrower than that of normal occlusion group. 4. The ratios of mandibular arch width to maxillary arch width in teeth level were not significantly different between normal occlusion group and Class III neutral group. In spite of discrepancies of maxillary and mandibular basal arch width, the dental arch width of Class III malocclusion group compensated very well. At the presurgical orthodontic treatment in clinic, it would not be desirable to decompensate for compensated dental arch width too much, for obtaining an appropriate arch compatibility and good results for orthognathic surgery.

• The korean journal of orthodontics
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• v.34 no.4 s.105
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• pp.313-324
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• 2004

The Purpose of this study was to investigate the predictors of relapse in orthodontic treatment of skeletal Class III malocclusion in growing patients. A total of 55 patients were studied and all subjects were divided into two groups according to their stability in the post-treatment stage. Of the sample, 33 patients were included in the stable group and the remaining 22 were assigned to the relapse group. Cephalometric data of the pre-treatment stage was taken and compared between the stable and relapse group. The following results were obtained through t-test: 1. This study presented statistical evidence to show that the major skeletal determinant of prognosis in Class III orthodontic treatment was not anteroposterior discrepancy .but vertical discrepancy, especially within the AB-maxillo mandibular triangle. Vertical angular measurements that showed statistically significant differences were AB-MP and ODI(P<0.01) and the vortical ratio measurements were MP-P/AL and PP-P/AL(P<0.05). 2. Relapse tendency increased with the steep occlusal Plane, especially the steep lower occlusal plane. As to occlusal plane, there were statistically significant differences in OP(L)-PP, OP-PP, AB-OP(L) and Wits appraisal(P<0.05). This study claimed that anteroposterior discrepancy was not necessarily the proper criteria to predict relapse. Vertical discrepancy had a significant effect on post-treatment stability.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.283-298
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• 2008

Objective: The purpose of this study was to investigate changes in the mandibular dental arch from presurgical orthodontic treatment and orthognathic surgery, and to evaluate the relationships between the pretreatment records and changes of mandibular dental arch in skeletal Class III malocclusion individuals. Methods: Lateral cephalometric radiographs and mandibular study models of 31 adults with skeletal class III malocclusion were taken and measured. All measurements were evaluated statistically by ANOVA, Scheffe's Post Hoc, and paired t-test, and correlation coefficients were evaluated. Results: No significant difference in Mn-LMMC, Mn-LIE, Mn-MnOcc was detected between pretreatment and presurgical groups. Statistically significant but low correlations were demonstrated between the initial arch length discrepancy (ALD) and change in ICW, IPW1 (r = 0.492, 0.615) and change in arch length (r = 0.641). No association was seen between the initial depth of curve of Spee and change in mandibular incisor angle and arch width or arch length. Regression analysis showed that the amount of change for arch length and IPW1 could be explained by 64.0% and 75.8% of the pretreatment variables respectively. Conclusions: This study suggests that orthognathic surgery results can be predictable by measuring the pretreatment records.