• 대한치과교정학회지
• /
• 제50권2호
• /
• pp.98-107
• /
• 2020

Objective: The aim of this study was to compare posterior tooth inclinations, occlusal force, and contact area of adults with different sagittal malocclusions. Methods: Transverse skeletal parameters and posterior tooth inclinations were evaluated using cone beam computed tomography images, and occlusal force as well as contact area were assessed using pressure-sensitive films in 124 normodivergent adults. A linear mixed model was used to cluster posterior teeth into maxillary premolar, maxillary molar, mandibular premolar, and mandibular molar groups. Differences among Class I, II, and III groups were compared using an analysis of variance test and least significant difference post-hoc test. Correlations of posterior dental inclinations to occlusal function were analyzed using Pearson's correlation analysis. Results: In male subjects, maxillary premolars and molars had the smallest inclinations in the Class II group while maxillary molars had the greatest inclinations in the Class III group. In female subjects, maxillary molars had the smallest inclinations in the Class II group, while maxillary premolars and molars had the greatest inclinations in the Class III group. Occlusal force and contact area were not significantly different among Class I, II, and III groups. Conclusions: Premolar and molar inclinations showed compensatory inclinations to overcome anteroposterior skeletal discrepancy in the Class II and III groups; however, their occlusal force and contact area were similar to those of Class I group. In subjects with normodivergent facial patterns, although posterior tooth inclinations may vary, difference in occlusal function may be clinically insignificant in adults with Class I, II, and III malocclusions.

• 대한치과교정학회지
• /
• 제46권5호
• /
• pp.280-289
• /
• 2016

Objective: The aim of this study was to analyze tooth movement and arch width changes in maxillary dentition following nonextraction treatment with orthodontic mini-implant (OMI) anchorage in Class II division 1 malocclusions. Methods: Seventeen adult patients diagnosed with Angle's Class II division 1 malocclusion were treated by nonextraction with OMIs as anchorage for distalization of whole maxillary dentition. Three-dimensional virtual maxillary models were superimposed with the best-fit method at the pretreatment and post-treatment stages. Linear, angular, and arch width variables were measured using Rapidform 2006 software, and analyzed by the paired t -test. Results: All maxillary teeth showed statistically significant movement posteriorly (p < 0.05). There were no significant changes in the vertical position of the maxillary teeth, except that the second molars were extruded (0.86 mm, p < 0.01). The maxillary first and second molars were rotated distal-in ($4.5^{\circ}$, p < 0.001; $3.0^{\circ}$, p < 0.05, respectively). The intersecond molar width increased slightly (0.1 mm, p > 0.05) and the intercanine, interfirst premolar, intersecond premolar, and interfirst molar widths increased significantly (2.2 mm, p < 0.01; 2.2 mm, p < 0.05; 1.9 mm, p < 0.01; 2.0 mm, p < 0.01; respectively). Conclusions: Nonextraction treatment with OMI anchorage for Class II division 1 malocclusions could retract the whole maxillary dentition to achieve a Class I canine and molar relationship without a change in the vertical position of the teeth; however, the second molars were significantly extruded. Simultaneously, the maxillary arch was shown to be expanded with distal-in rotation of the molars.

• 대한치과교정학회지
• /
• 제51권6호
• /
• pp.407-418
• /
• 2021

Objective: To investigate differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and Class II malocclusions. Methods: Forty Korean adult twin pairs were divided into Class I (C-I) group (0° ≤ angle between point A, nasion, and point B [ANB]) ≤ 4°; mean age, 40.7 years) and Class II (C-II) group (ANB > 4°; mean age, 43.0 years). Each group comprised 14 monozygotic and 6 dizygotic twin pairs. Thirty-three cephalometric variables were measured using lateral cephalograms and were categorized as the anteroposterior, vertical, dental, mandible, and cranial base characteristics. The ACE model was used to calculate heritability (A > 0.7, high heritability). Thereafter, principal component analysis (PCA) was performed. Results: Twin pairs in C-I group exhibited high heritability values in the facial anteroposterior characteristics, inclination of the maxillary and mandibular incisors, mandibular body length, and cranial base angles. Twin pairs in C-II group showed high heritability values in vertical facial height, ramus height, effective mandibular length, and cranial base length. PCA extracted eight components with 88.3% in the C-I group and seven components with 91.0% cumulative explanation in the C-II group. Conclusions: Differences in the heritability of skeletodental characteristics between twin pairs with skeletal Class I and II malocclusions might provide valuable information for growth prediction and treatment planning.

• 대한소아치과학회지
• /
• 제27권1호
• /
• pp.135-145
• /
• 2000

부정교합의 분류가 치아의 위치적 관계에 의해 구분되면, 동일한 집단에 속하더라도 이들의 안면두개골은 서로 다른 구조적 관계를 지니고 있어 이들을 동일시 할 수 없으며 안면두개골의 형태적 특징에 의한 분류가 필요하다. 저자는 $6\sim14$세 사이의 III급 부정교합 아동 135명의 측두방사선규격사진을 7, 9, 11, 13세의 연령으로 구분한 후, 중두개저각 $40.3^{\circ}$를 기준으로 이보다 작은 집단(하악전돌효과군)과 큰 집단(하악후퇴효과군)으로 분류하여 각 집단의 안면두개골의 형태적 특징을 횡단 누년적으로 비교 평가하였다. 모집단의 39.3%가 하악전돌효과군으로, 60.7%가 하악후퇴효과군으로 나타났으며, 두 개저, 비상악복합체 상악골 및 하악골의 전후방적 길이 그리고 전안면높이와 후안면높이 등의 수직적 길이가 하악후퇴효과군에서 크게 나타난 것으로 미루어 III급 부정교합 아동의 많은 수가 좁고 긴 얼굴형 (leptoprosopic faceform)에서 찾아볼 수 있는 형태적 특징을 많이 지니고 있으며, 두 군간에는 형태적, 구조적인 차이와 함께 시기적으로도 각기 다른 성장양태를 보이는 것으로 가늠된다.

• 대한소아치과학회지
• /
• 제34권4호
• /
• pp.599-612
• /
• 2007

I급과 III급 부정교합 어린이 두개안면골의 성장양상을 비교하고자, $7{\sim}11$세 146명의 치료전 측모두부계측분석에서 연령에 따른 두개저, 중안면, 하안면 구조물들의 차이를 평가하여 다음과 같은 결과를 얻었다. 1. III급은 I급에 비해 접사골연골결합의 성장이 더 늦은 시기까지 지속되었다. 2. 비상악복합체 전후방적 길이는 III급이 대체로 짧았고 높이는 유사하였다. 3. 하악골 길이와 하악체 길이는 III급이 모든 연령에서 다소 긴 경향이었으나 통계적 유의성은 없었으며, I급과 유사한 성장양상이었다. 4. 상하악골의 치아치조골 높이는 I급과 III급이 대체로 유사한 성장양상이었다. 5. I급은 전두개저 길이가 비상악복합체 및 하악골의 전후방 길이 증가에 뚜렷한 역할을 하였다. 6. III급의 전두개저 길이와 중두개저 길이는 연령이 증가하면서 하악골 길이와 상관성이 커졌다. 사춘기 이전의 시기에는 III급이 I급과 부분적으로 다른 골격적 특징을 지니고 있으나, 성장양상은 전반적으로 유사하게 나타났다. 따라서 III급의 골격성 부조화는 특징적인 골격적 차이가 나타나기 전 조기에 개선시키는 것이 바람직할 것으로 판단된다.

• 대한치과교정학회지
• /
• 제19권1호
• /
• pp.153-167
• /
• 1989

This study was undertaken to analyze the growth of mandible in surgically repaired unilateral cleft lip and palate. The subjects consisted of 63 unilateral cleft lip and palate individuals, 60 class III malocclusions and 60 normal occlusions ranging from 6 to 15 years old. Each group was divided into two age groups. (6-10 Y and 11-15 Y) The results obtained from UCLP compared with other groups were as follows: 1. The anteroposterior position of the chin was similar to that of the normal occlusions. 2. The shape of the mandible was similar to that of the class III malocclusions. 3. In mandibular size, ramus height was the smallest among three groups, but body length and overall mandibular length were similar to those of the normal occlusions. 4. The lower border of the mandible was the steepest among three groups and strong vertical or clockwise growth tendency was indicated. 5. The position of condyle in relation to the cranial base showed little difference in three groups. 6. In older age group , vertical growth tendency of the mandible decreased more or less.

• 대한기계학회논문집A
• /
• 제24권4호
• /
• pp.907-915
• /
• 2000

The movement of teeth and initial stress associated with the treatment of orthodontics have been successfully studied using the finite element method. To reduce the effort in preprocessing of finite element analysis, we developed two types of three-dimensional finite element models based on the standard teeth model. Individual malocclusions were incorporated in the finite element The movement of teeth and initial stress associated with the treatment of orthodontics have been successfully studied using the finite element method. To reduce the effort in preprocessing of finite element analysis, we developed two types of three-dimensional finite element models based on the standard teeth model. Individual malocclusions were incorporated in the finite element models by considering the measuring factors such as angulation, crown inclination, rotation and translations. The finite element analysis for the wire activation with a T-loop arch wire was carried out. Mechanical behavior on the movement and the initial stress for the malocclusion finite element model was shown to agree with the objectives of the actual treatment. Finite element models and procedures of analysis developed in this study would be suitably utilized for the design of initial shape of the wire and determination of activation displacements.

• 대한치과교정학회지
• /
• 제41권2호
• /
• pp.127-137
• /
• 2011

Objective: The aim of the study was to compare the opening and protrusive mandibular movements between Class I and Class II malocclusions in healthy adolescents by clinical and axiographic evaluations. Methods: Mechanical axiography was performed on non-orthodontically treated, temporomandibular disorder (TMD)-free adolescents (12 - 16 years) with Class I (n = 38, 16 boys, 22 girls) or Class II (n = 40, 19 boys, 21 girls) malocclusion. Opening and protrusive movements were measured clinically and axiographically. Intergroup comparisons were evaluated by t-tests. Results: In opening movement, the maximum clinical opening capacity was significantly different (p ${\leq}$ 0.05) between the groups. In protrusive movement, the Class II group had significantly greater maximum clinical protrusion (p < 0.001) and maximum axiographic protrusive length (p < 0.01) than the Class I group. No significant difference in the other opening and protrusive axiographic measurements was observed. Conclusions: TMD-free adolescents with Class II malocclusion have increased protrusive capacity compared with TMD-free adolescents with Class I malocclusion; however, the detected differences could be normal variations during adolescence.

• 대한치과교정학회지
• /
• 제22권1호
• /
• pp.159-168
• /
• 1992

To predict eruptive path of maxillary canine, 13 male and 11 female malocclusions were longitudinally studied for 4 years. And to study frequency and distribution of impaction of maxillary canine, 1500 malocclusions were studied. The path, velocity and duration of maxillary canine eruption were determined by periodic angular and linear measurement using periodic orthopantomograms and cephalograms. The following results were obtained. 1. Maxillary canine was erupted with $14.5^{\circ}$ distal tipping from initial stage $98.1^{\circ}$ to final stage $83.6^{\circ}$ of axial inclination on orthopantomogram. 2. Eruptive velocity of maxillary canine was fastest on stage 4, and mean eruptive velocity was 10.5mm per year on stage 4. 3. Eruption of maxillary canine was completed 12 year 5 months in male and 11 years 8 months in female. 4. To predict the duration for eruption completion by position of maxillary canine on cephalogram, regression equation was obtained. 5. Frequency of impaction of maxillary canine was 1.47% in malocclusion and more frequent in male. Distribution of buccal and palatal, right and left impaction was no different, but unilateral impaction was more frequent.

• 대한치과교정학회지
• /
• 제15권1호
• /
• pp.75-84
• /
• 1985

By observing the correlationships between the characteristics of the facial pattern and the methods of establishing the position of the lower central incisor to the five reference lines on the lateral roentgenocephalograms, the author tried to find the most useful method of them, the criteria of which were the independence of a variation according to facial patterns, the close relationships with soft tissue and lip balance, and the simple and consistent usefulness in clinical practice. The subject consisted of forty normal occlusions, forty class II div I malocclusions, forty class III malocclusions, ten treated claas II div 1 cases and ten treated class III cases, all were in 14-17 yrs of age. The findings of this study are as follows: 1. The position of the lower central incisor to EP, OP, MP and NB showed variations according to ANB, FMA, facial convexity and Holdaway angle. 2. The position of the lower central incise. to AP line (A-Pog) was not co..elated with ANB, FMA, facial convexity and Holdaway angle, so it can be used consistently, regardlesss of the facial pattern. 9. The lineal position of the incisal edge of the lower central incisor to AP line has a profound influence on harmonious soft tissue and lip balance.