• The Journal of the Korean dental association
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• v.21 no.11 s.174
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• pp.867-871
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• 1983

• 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 the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.45-56
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• 2022

The purpose of this study is to evaluate changes of occlusion following the placement of preformed metal crown in the permanent first molar affected by severe caries or hypomineralization. The study was conducted on 24 patients who met the criteria among the patients with occlusion in the permanent first molar reaching the occlusal plane. Restorative treatment was performed on one first molar using preformed metal crown. Before treatment, immediately after treatment, after 4 weeks, and after 8 weeks, the T-scan III was used for measuring distribution of bite force at the maximum intercuspal position, and overbite was measured with digital vernier calipers and change of dental midline was surveyed. After 8 weeks, questionnaires survey was conducted. In most cases, immediately after treatment, the distribution of bite force between the restored side and non-restored side of arch was reversed compared to before treatment, and the overbite was decreased. However, after 4 weeks, bite force of the left and right side was balanced and the distribution of bite force on the restored and non-restored permanent first molars had similar values. Also, the changed overbite and midline were returned to pre-treatment status and there was no significant temporomandibular joint and masticatory discomfort after treatment. In this study, it was confirmed that spontaneous occlusal equilibrium was achieved one month after the placement of preformed metal crown.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.125-134
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• 2023

When the patient with class III malocclusion needs extensive oral rehabilitation due to multiple missing teeth, accurate diagnosis, and careful analysis, such as the patient's occlusal relationship, facial changes, and evaluation of the temporomandibular joint are essential. Orthognathic surgery is often performed for aesthetic improvement, depending on the patient's chief complaint. If it is not possible due to certain circumstances, partial aesthetic improvement can be achieved through minimal elevation of the vertical dimension. As this patient may have unexpected issues, such as temporomandibular joint disorder, oral habits like bruxism, and masticatory muscle tension, it was determined whether the patient could adjust to a reversible temporary removable partial denture. After this, the maxillary implant-supported fixed prostheses and the mandibular fixed prostheses were used to achieve stable posterior support and to partially improve the maxillary anterior esthetics. The patient was satisfied with the results both aesthetically and functionally. The prognosis is expected to be good if regular check-ups are conducted.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.91-99
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• 2000

This study was done to identify the changes of bite force and occlusal contact between before and after stabilization splint therapy. 16 female patients, accepted for orthodontic treatment at the Department of Orthodontics, College of Dentistry, Chosun University, were selected as the sample of this investigation. For comparisons, the samples of 16 were divided into just before stabilization splint, 1 month after stabilization splint, 2 months after stabilization splint, and 3 months after stabilization splint and used the T-scan system to identify the bite force and occlusal contact changes for each group. Statistical analysis of the data was carried out ANOVA tests, and Turkey tests using $SPSS/PC^+$. The results were as follows : 1. Bite force change from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 2. Bite force changes from 1 to 3 months after stabilization splint therapy showed no statistical significance (p>0.05). 3. The changes of anterior occlusal contacts showed no statistical significance regardless of the wearing periods of stabilization splint (P>0.05). 4. The changes of posterior occlusal contacts from just before treatment to 1 month after stabilization splint therapy was statistical significantly decreased (P<0.05). 5. The changes of posterior occlusal contacts Outing 1 to 3 months after stabilization splint therapy showed no statistical significance (P>0.05). 6. Posterior teeth rather than anterior teeth were more influenced by the changes of the number of occlusal contacts. To sum up above results, we may respect to capturing and stabilizing centric relation Position just 1 month after stabilization splint therapy.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.4
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• pp.309-315
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• 2016

Recently, finite element analysis technique has been widely used for structural and mechanical understandings of human body in the dentistry field. This research proposed an effective finite element modeling method based on CT images, and parametric studies were performed for the occlusal simulation. The analyses were performed considering linear material behaviors and nonlinear geometrical effect, and validated with the experimental results. In addition, the skull models with two different molar relations such as Class I and full-CUSP Class II were generated and the analyses were performed using the proposed analytical method. As results, the relationships between the mandibular movement and occlusal force of both two models showed similar tendency in human occlusal force. However, stress was evenly distributed from teeth to facial bone in the skull model with Class I, while stress concentration was appeared in the model with full-CUSP Class II due to the changes of occlusal surfaces of the model.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.195-201
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• 2022

Hemimandibulectomy and free fibular flap (FFF) in patients with squamous cell carcinoma could disturb the functional movement of the mandible. The muscular function in the sectioned side was compromised because of the incompetency of the muscle attachment to the mandible, leading to the unstable occlusal contact in the centric and eccentric occlusion. In this report, we present a case of a 63-year-old male who underwent cancer surgery and reconstruction with fibular graft, and he needed a fixed dental prosthesis to restore tooth loss in the anterior region. Occlusal contact change and instability were found according to the bite force in the centric relation and eccentric movement. This case report aimed to present the prosthetic procedure for fabricating the functionally optimized fixed prosthesis wherein the functionally generated path (FGP) technique and digital imaging method were applied to replicate mandibular movement and vertical dimension of the patient.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.204-214
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• 2023

The occlusal treatment including prosthetic treatment should be considered when the pathologic symptom was observed with the excessive discrepancy between the centric relation occlusion (CRO) and the maximum intercuspal position (MIP). Through careful diagnosis, the malocclusion and interarch relationship can be analyzed, and occlusal adjustment, restorative treatment, orthodontic therapy, or orthognathic surgery can be performed depending on the degree of disharmony. The patient in this case report complained the unstable occlusion and loss of masticatory function that had been occurring for several years. At the time of the visit, the patient showed severe occlusal disharmony, with only the upper right second molar contacting the lower jaw at the maximum intercuspal position. Based on the analysis of the occlusion, it was difficult to solve the problem with just occlusal adjustment or restorative treatment. In addition, the patient had the skeletal class II malocclusion between the upper and lower jaws. Therefore, for resolving the severe skeletal class II malocclusion, pre- and post-orthodontic treatment, bilateral sagittal split ramus osteotomy (BSSRO) was performed. After that, the occlusal adjustment was performed for stable occlusion, and the missing teeth area was restored with dental implants. During the follow-up period, a periodic follow-up visits and additional occlusal adjustments were performed to achieve a stable centric occlusion and harmonious anterior and lateral guidance. As a result, the final prosthodontic treatment was completed, and the patient's masticatory function was restored.

• The korean journal of orthodontics
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• v.2 no.1
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• pp.15-21
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• 1971

부정교합과 구강영역의 악습관과의 관계를 구명해 보고자 본 저자는 구내 악습중 비교적 발생빈도가 높으며 부정교합에 미치는 영향이 크다고 생각되는 tongue-thrusting에 대한 다음과 같은 일연의 조사를 시행하였다. 1. Tongue-thrusting의 빈도와 부정교합의 유형과의 관계를 조사하였다. 2. 서울대학교 치과대학 부속병원에 내원한 263명의 부정교합 환자로부터 tongue-thrusting의 유무, 수유방법, 구내악습 및 상기도병변상태를 관찰하였다. 결과는 다음과 같았다. 1. 15세 내실 17세 남학생 1,356명중 tongue-thrusting을 보인 사람은 $12.7\%$였다. 2. Angle씨 3급 불정교합이 tongue-thrust swallowing과 가장 밀접한 관계가 있었다. 3. 인공 수유가 tongue-thrust swallowing의 원인이 된다는 명확한 근거는 없었다. 4. 상기도의 만성 병변은 tongue-thrust swallowing과 무관하였다.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.269-280
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• 1995

저작은 교합과 악운동 뿐만 아리라 근신경계, 고위 중추까지 복합적으로 관여하는 기능적 행위이다. 교합 양상은 다양하게 저작 형태에 영향을 끼치며 저작 효율에도 관여한다. 저작 형태는 다양한 모양을 가지나 두가지 전형적인 군 즉, 전방에서 관찰시 그 양상이 수직적이며 chopping운동을 닮은 군과 저작 형태가 주로 측방으로 이루어지며 grinding을 하는 군으로 나눌 수 있다. 본 연구의 목적은 저작 형태의 치아가 교합접촉 및 저작 효율에 미치는 영향을 고찰해 보고자 하는 것이다. 하악운동궤적기록기를 이용하여 정상교합을 가진 치과대학생중 전형적인 2가지 저작형태를 보이는 각 10명씩을 피검자로 선택하였다. 3가지 하악위 즉, 중심위, 작업측 비작업측에서의 교합접촉을 고무형 교합인기재로 기록하여 천공부의 직경이 1mm이하면 1점, 1-2mm또는 직선상이면 2점, 2mm이상이면 3점으로 평가하여 각 점수의 합으로 좌우 소구치 및 대구치의 접촉 지수를 측정하였다. 저작 효율을 평가하기 위해 땅콩 3g(${\pm}0.01g$)을 20회 저작하게 한 후 3회 입을 헹구어 뱉게 하였다. 체눈 크기가 각 0.425, 0.60, 0.85, 2.0, 4.0인 체에 거른 후 $65^{\circ}C$로 오븐에서 세시간 말려 무게를 측정하고 중심 크기$(M_{50})$과 저작효율치(R)를 계산 비교하여 다음과 같은 결론을 얻었다. 1. Chopping형은 grinding형에 비해 중심위에서 더 넓은 교합접촉을 보였다(P<0.01). 2. Grinding형은 chopping형에 비해 측방위에서 더 넓은 교합접촉을 보였다(P<0.01). 3. Chopping형은 중심크기($(M_{50})$)과 저작효율치(R)로 비교하였을 때 더 좋은 저작 효율을 보였다(P<0.01).