• Imaging Science in Dentistry
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• v.33 no.2
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• pp.85-90
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• 2003

Purpose : To investigate the differences between the position of the mandibular condyles in temporomandibular joints of patients presenting with normal occlusion and skeletal class III malocclusion. Materials and Methods: Forty-two subjects with normal occlusion and thirty-seven subjects exhibiting skeletal class III malocclusion prior to orthodontic treatment were included in the study. Transcranial radiographs of each subject were taken at centric occlusion and 1 inch mouth opening. The positional relationship between the mandibular condyles with articular fossae and articular eminences at two positional states were evaluated and analyzed statistically. Results: The mandibular condyles of the skeletal class III malocclusion group were found to be located more anteriorly from the center of the articular fossae compared to the normal occlusion group in centric occlusion. The mandibular condyles of the skeletal Class III malocclusion group were located more superiorly from the middle of articular height than those of the normal occlusion group in centric occlusion. However, these differences were not statistically significant. At 1 inch mouth opening, the mandibular condyles of the skeletal class III malocclusion group were placed more posteriorly from the articular eminences than those of the normal occlusion group. The mean angle of the articular eminence posterior slope were 56.51 ° ± 6.29° in the normal occlusion group and 60.37° ± 6.26° in the skeletal Class III malocclusion group. Conclusions: The mandibular condyles of the skeletal Class III malocclusion group were placed more anteriorly at centric occlusion and more posteriorly at 1 inch mouth opening when compared with those of the normal occlusion group.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.3
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• pp.343-350
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• 2000

The goal of this study is the comparison of upper airway size and change of skeletal Class I group and skeletal Class III group (before operation, within 2 weeks after operation, 6 months after operation) respectively. At first, we measured the lines between selected upper air way landmarks on lateral cephalometric x-ray film of skeletal Class I 40 persons whoes age were 23-26 years old, ,and did the same lines of landmarks of skeletal Class III 44 persons who had not been operated yet, were within 2 weeks after operation, were 6 months after operation. And we compared it respectively and analyzed it with paired t-test. We studied the relationship of those on produced data. 1. Skeletal Class III group was narrower in nasopharyngeal air way space than that of skeletal Class I group, and increased in thickness of oropharyngeal, hypopharyngeal wall within 2 weeks after operation, and reduced in nasopharyngeal, oropharyngeal air way space, and did in thickness of nasopharngeal, hypopharyngeal wall 6 months after operation. 2. Skeletal Class III group reduced in nasopharyngeal, oropharyngeal air way space, and increased in thickness of nasopharyngeal, oropharyngeal, hypopharyngeal wall within 2 weeks after operation, restored the thickness of nasopharyngeal, oropharyngeal wall, but did not restored nasopharyngeal, oropharyngeal, hypopharyngeal air way space. 3. Vertical length from hyoid bone to mandibular plane did not have signifacant difference from Class I group but after operation, it increased more than Class I group significantly. 4. The size of airway reduced after operation. Among this, oropharyngeal airway most reduced.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.166-178
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• 2021

Objective: To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. Methods: Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis. Results: The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = -0.42, p < 0.01) and inferior airway space (β = -0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. Conclusions: Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.2
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• pp.91-99
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• 2024

In the case of skeletal class III edentulous patients, the stability of dentures can be achieved by using a crossbite by considering the residual ridge relationship when fabricating complete dentures. Forming the anterior teeth in a normal occlusal relationship in a skeletal class III ridge relationship may reduce the stability of the denture by increasing the anterior cantilever. However, when patients use complete dentures, not only functional aspects but also aesthetic aspects are important. The aesthetics of complete dentures depends on how the anterior artificial teeth are arranged, and cases of complete denture fabrication using normal occlusion or edge-to-edge bite in edentulous patients with skeletal class III ridge relationships have been reported. In this case, complete dentures were fabricated for an edentulous patient with a skeletal class III edentulous patients by forming anterior edge-to-edge bite considering neutral zone in maxillary anterior teeth, and good aesthetic and functional results were obtained.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.627-646
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• 1992

The purpose of this study was to investigate the relationship among the activity of the craniofacial muscle and craniofacial form and occlusal state. In this study, subjects were consisted of 23 male adults with skeletal Class III malocclusion and 30 male adults with normal occlusion. The measurements in oral exam, lateral ceghalogram, and E.M.G. recordings of anterior temporal, masseter, and upper lip muscles at rest position, clenching in centric occlusion, chewing of gum, swallowing of juice, were analyzed with SPSS system. The results were as follows: 1. At rest position upper lip muscle activity of skeletal Class III group was significantly higher than that of normal group. 2. Both clenching and chewing masseter and temporal muscle activity of normal group were significantly higher than that of skeletal Class III group. 3. During swallowing of juice, upper lip muscle activity of skeletal Class III group were significantly higher than that of normal group. 4. The activities of masseter and anterior temporal muscle during clenching and chewing were significantly correlated with hypodivergent facial form and number of occluded teeth. 5. The activity of upper lip during swallowing had positive correlation with mandibular prognathism.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.107-117
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• 1987

The study was designed to examinate the discrimination rate of 4 antero-posterior cephalometric measurements from Angle's malocclusion groups. The material was 246 cephalometric radiographs taken from 42 Normal occlusions, 83 Class I malocclusions, 64Class II Division I malocclusions, 57Class III malocclusions. ANB angle, APDI, AB/OP angle, and Wits appraisal as measurements of antero-posterior skeletal relationship were measured on the cephalometric radiographs and statistically analyzed by the Canonical Discriminant Function. The results of this study were as follows: 1. ANB angle, APDI, AB/OP angle, and Wits appraisal were clinically useful measurements for the evaluation of the antero-posterior skeletal relationship. 2. The rates that discriminate actual malocclusion groups were $77.45\%$ in Wits appraisal, $74.02\%$ in AB/OP angle, $71.08\%$ in ANB angle, and $70.59\%$ in APDI. 3. The discrimination rate of actual Class III malocclusion show above $93\%$, but actual Class I and Class II division I malocclusions were relatively low.

• Journal of Oral Medicine and Pain
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• v.26 no.2
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• pp.147-156
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• 2001

The purpose of this study was to identify the difference of vertical movement of mandible according to Angle's molar relationship and by skeletal factors affect to vertical movement of mandible. 172(age ranged from 20 to 30) subjects who go to college within territory of Kwangju city without any experience of temporomandibular disorder, extraction and orthodontic treatment. were selected for this study. The subjects were classified into class I(male:30, female:49), class II(male:18, female:24) and class III(male:18, female:33) according to Angle's molar relationship. The distance was measured between incisal edge of maxillary and mandibular central incisor and between bottom of central fossa of maxillary and mandibular 1st molar with ruler. The arch length and width were measured on the diagnostic cast. Cephalometrics were taken and then traced. Landmarks were identified and analyzed. 1. Maximal interincisal opening of male is larger than that of female in class I, class II and class III. Among each group maximal interincisal distance is the largest in class III. Maximal intermolar distance of male is superior to that of female in class I, class II, and class III, but there is no siginficant difference among them. 2. On maximal opening movement of Angle's classification class I and class II, total mandibular length, mandibular ramal length, madibular inferior border length and upper arch width were important variables and facial length, upper arch length and lower arch length had negative relationship to that. On maximal opening movement of Angle's class III, the upper arch length, the lower arch length and anterior facial length were important variables especially when compared with class I and II, and upper arch width had negative relationship. These results suggest that maximal opening movement is affected by facial morphology in all classes, but each group is affected by different facial skeletal variables. Accordingly, facioskeletal variables might be considered as diagnosis and treatment to improve the amount of mouth opening.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.6
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• pp.506-513
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• 2006

The purpose of this study was to examine the familial tendency of the patients with mandibular prognathism in three generations and to define the relationship between the familial tendency and the skeletal class III morphology. The probands of this study were 103 orthognathic surgery patients with skeletal Class III malocclusions who had undergone (48 men, 55 women) mandibular set-back surgery. A questionnaire was given to patients who sought surgical treatment for excessive mandibular length, and all answers were confirmed in interviews. Lateral cephalograms were analyzed in cranial base parameters, mandibular positional parameters and mandibular skeletal parameters. In the examined families, 58.3% had at least one member other than the proband who had mandibular prognathism. The affected ratio of total relatives was 4.5%, and the value was higher in first-degree (13.4%) than second-degree (5.9%) and third-degree relatives (1.7%). The affected ratio was 51.9% in the offsprings who had at least one affected father or mother. The comparison of the groups according to the familial tendency showed no significant craniofacial skeletal measurments. In conclusion, skeletal class III malocclusion showed high familial tendency, suggesting a significant genetic influence in the etiology. However, the patient's familial tendency did not show the special craniofacial patterns compare to the subjects without familial tendency.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.537-548
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• 1996

To investigate the relationship between the calcification stages of mandibular canines and the skeletal maturity stage of the hand-wrist in subjects with normal occlusion and Class III malocclusion, hand-wrist radiographs and panoramic radiographs were taken from subjects of normal occlusions(94 males, 88 females) and Class III malocclusions(75 males, 76 females) who had no systemic diseases and no history of orthodontic or prosthodontic treatment. Fishman's method for the skeletal maturity stages of the hand-wrist and Demirijian's method for the calcification stages of mandibular canines were used and analyzed. The results were as follows : 1. In subjects with normal occlusion and Class III malocclusion, skeletal maturity of the hand-wrist and calcification of mandibular canines at various ages occured earlier in females than in males(p<0.05). 2. Comparing the skeletal maturity stages of the hand-wrist and the calcification stages of mandibular canines between subjects with normal occlusion and Class III malocclusion, there were no significant differences between the groups. 3. The correlation coefficient between the calcification stages of mandibular canines and the skeletal maturity stages of the hand-wrist. in subjects with normal occlusion and Class III malocclusion showed a high association(p<0.01). 4. In stage 4 of the skeletal maturity of the hand-wrist, the frequency distribution of calcification G stage among the various calcification stages was highest both in normal occlusion and in subjects with Class III malocclusion. However, there was no significant difference in the frequency distribution of calcification stages between the groups.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.19-25
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• 2022

Purpose: This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT). Materials and Methods: This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA). Results: No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females. Conclusion: Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.