• 대한치과보철학회지
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• 제40권6호
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• pp.560-571
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• 2002

Jaw relations and the recording methods have been controversial aspects of dentistry. The purpose of this study was to quantify the relative muscle activity of the masseter and temporal muscles in relation to different intermaxillary relations recorded by intra-oral tracer during maximal clenching and to decide the optimal mandibular position. Ten volunteers with healthy TMJ were studied. Intra-oral tracer was assembled and bite block was fabricated in the articulator. Intra-oral tracer was placed in the mouth, and four mandibular positions were recorded. EMG activity was recorded on a BIO-PAK system (Bio-Research Associates, Inc. USA.) in masseter and temporal muscle and compared in each mandibular positions. The results were as follows: 1. In comparison with maximum intercuspation, the chewing position was the most similar followed by tapping position, myocentric position and posterior border position. However the differences were not statistically significant. 2. In comparison of bilateral symmetry of masseter muscle, tapping position was the most symmetrical followed by chewing position and maximum intercuspation. Myocentric position and posterior border position were not symmetrical. (P<.05). 3. In comparison of bilateral symmetry of anterior temporal muscle, chewing position was the most symmetrical followed by posterior border position, maximum intercuspation, myocentric position and tapping position. However the differences were not statistically significant. 4. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on left side, posterior border position was the greatest followed by myocentric position, taping position, chewing position and maximum intercuspation. And the proportionality of posterior border position was greater than that of maximum intercuspation. (P<.05). 5. In comparison of proportionality of anterior temporal muscle to masseter muscle activity on right side, myocentric position was the greatest followed by posterior border position, tapping position, maximum intercuspation and chewing position. However the differences were not statistically significant.

• 대한치과보철학회지
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• 제33권1호
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• pp.75-84
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• 1995

This study was designed as a reference of vertical dimension in prosthetic treatment. The author analyzed six facial measurements, namely, (1) the height of lower face at maximum intercuspal position, (2) the height of lower face at resting position, (3) midface, (4) external ear and lateral wall of orbit, (5) interpupillary distance, (6) distance between pupil and mouth in the 100 Won-kwang Univ. Dental collage students(50 : male, 50 : female), who have normal occlusion, no posterior prosthesis, no experience of orthodontic treatment, and no deformity of facial soft tissue and no temporomandibular dysfunction. The results of this study were as follows : 1. The length of midface was shortest and the inter-pupillary distance was longest in both male and female. 2. The length difference with the length of midface and lower face at maximum intercuspal position was 5.64mm in male and 2.23mm in female, so the lower face was longer, 3. The facial measuring component, similar to lower face at maximum intercuspation, was the length of between medial wall of external ear and lateral wall of orbit. It's difference was 1.3mm in male, 1.77mm in female, and the lower face was shorter. 4. The difference of lower facial length in resting position and maximum intercuspation was 2.48mm in male, 2.24mm in female, the length of resting position was therefore longer. 5. The most clost correlation with the height of maximum intercuspal positioning lower face was resting lower face in both groups.

• 대한치과보철학회지
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• 제40권6호
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• pp.577-589
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• 2002

There are several variations in normal mastication. In them, unilateral mastication is chewing, predominantly on a preferred side of the dentition and hardly on e non-preferred side. Continual unilateral mastication may alter the coordination of masticatory muscles. Although they studied about these EMG of masticatory muscles, there were no information about characteristics of masticatory muscle activity in unilateral mastication. Therefore, In this study, we investigated the activity of the masseter and anterior temporal muscles during rest, clenching in maximum intercuspation and gum chewing in habitually unilateral mastication group compared with normal group and tried to know effects of continual unilateral mastication on activity of masticatory muscles. The results of this study were as follows 1. In electromyographic activity during rest, in bilateral mastication group pattern of muscle activity of right and left side was symmetrical. But, in unilateral mastication group, records of anterior part of temporal muscle was higher than that of bilateral mastication group (p<.01) and patterns of muscle activity of right and left side in both muscle were asymmetrical.(p<.05) 2. In electromyographic activity during clenching in maximum intercuspation, records of superficial part of masseter muscle were higher than anterior part of temporal muscle in both group. Muscle activity of temporal muscle in unilateral mastication group was a little higher han bilateral mastication group and asymmetry of activity pattern in temporal and masseter muscle was shown but these differences were not statistically significant. (p<.05) 3. In electromyographic activity during gum chewing, temporal muscle was activated earlier than masseter muscle and maximum bite force is derived from masseter muscle in both group. In unilateral mastication group, electromyographic activity of masseter and temporal muscle of preferred chewing side, regardless of right or left side chewing, was higher than that of bilateral mastication group and especially, difference in masseter muscle was statistically significant. (p<.01) Based on the above results, our study suggested that recording of masticatory muscle activity will be helpful in the effective diagnosis and treatment of some types of the parafunctional habits.

• 대한치과교정학회지
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• 제44권6호
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• pp.312-319
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• 2014

Objective: Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. Methods: The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. Results: Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. Conclusions: All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

• 대한치과보철학회지
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• 제30권4호
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• pp.565-573
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• 1992

This clinical study was to analyze occlusal contacts in maximum intercuspation on distal extension partial denture and to compare tooth contact state between the denture teeth and abutment teeth by time mode and force mode using the T-scan system. The subjects ware twenty-one adult patients with upper natural teeth and lower distal extension partial denture. Conclusion : 1. The patient with simultaneous occlusal contacts both denture tooth and abutment and bilaterally in Kennedy Class I cases was one-sixth, but there was no one with symmetric occlusal and equal force among bilateral denture teeth and abutments. 2. The five-fifteenth of Kennedy Class I case patients resulted in simultaeous occlusal contacts bet-ween denture teeth and abutments but no one has the symmetric occlusal contacts and unifarm force between denture teeth and abutment teeth.

• Journal of Oral Medicine and Pain
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• 제31권3호
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• pp.245-254
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• 2006

구강안면 영역의 통증이나 치아결손, 부정교합 같은 치아적 요소가 편측저작습관의 주요요인으로 여겨지나, 치아적 요소가 선호하는 저작측에 영향을 주지 않는다는 연구들도 있다. 본 연구에서는 컴퓨터화된 교합분석 시스템인 T-Scan II 시스템을 사용하여 편측으로 저작하는 대상자와 양측으로 저작하는 대상자 사이에 교합양상의 특이점이 있는지 조사하고 편측 저작자의 주저작측과 비저작측 사이의 차이를 함께 평가하고자 하였다. 편측저작습관에 대한 설문을 통하여 20명의 편측 저작자(평균 $25.25{\pm}2.84$세)와 20명의 양측 저작자(평균 $27.00{\pm}5.07$세)를 선정하였으며 치아적 문제나 악골의 통증이나 기능이상 같은 문제가 있는 경우는 모두 제외하였다. 습관적 폐구와 측방운동시의 교합양상은 T-Scan II 시스템을 이용하여 측정하였다. 습관적 폐구는 시간에 따라 초기, 중기, 말기로 나누었다. 각 세 단계에서의 접촉점의 수와 교합력의 비율을 좌우 양측으로 나누어 조사하였다. 습관적 페구 동안의 경과시간 및 치아 활주면적, 좌우측 각각의 측방운동시간이 측정되었다. 편측 저작 습관을 가진 사람들의 경우 양측 저작을 하는 사람에 비해서 치아의 평균 교합 면적이 작았다(p<0.005). 습관적 편측저작자에서 저작측과 비저작측을 비교해보았을 때 비저작측의 교합면적은 저작측에 비해 작았으나 (p<0.005), 편측저작자의 저작측과 양측저작군의 어느 한쪽의 교합면적 사이에는 유의한 차이가 없었다. 최초접촉부터 최대교두감합위까지의 경과 시간 및 측방운동 시간, 치아의 활주 면적 및 교합력의 좌우 비율도 양측저작군과 편측저작군 사이에 유의한 차이가 없었다. 이러한 결과는 저작시 좌우측 중 교합면적이 작은 측을 피하여 교합효율이 높은 방향으로 저작을 한다는 것을 의미한다.

• 대한소아치과학회지
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• 제21권2호
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• pp.547-554
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• 1994

Posterior crossbites are abnormal buccal, or lingual relationship of a tooth or teeth of the maxilla, the mandible, or both when the teeth of the two arches are in occlusion and involve the molars and premolars. Posterior crossbites are classified as dental, muscular(functional), or skeletal. In an effort to avoid occlusal interferences caused by the inadequate arch width, the patient deviates the mandible laterally upon closure to achieve maximum intercuspation. This is described as functional posterior crossbite. Correction of functional posterior crossbites in the primary & early mixed dentition as early as possible after diagnosis has been recommended, because crossbites do not automatically improve with the eruption of the permanent teeth. Functional posterior crossbites, if left untreated, may have deleterious effects on the development and function of the TMJ. The diagnosis and management of three cases is presented. Each patient with functional posterior crossbites is treated using the bilateral maxillary expansion appliance.

• The Journal of Advanced Prosthodontics
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• 제12권2호
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• pp.49-54
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• 2020

PURPOSE. The purpose of this study was to compare the performance of Accura to that of the T-scan for indicating occlusal contacts. MATERIALS AND METHODS. Twenty-four subjects were selected. Their maxillary dental casts were scanned with a model scanner. The Stereolithography files of the casts were positioned to align with the occlusal plane. Occlusal surfaces of every tooth were divided into three to six anatomic regions. T-scan and Accura recordings were made during two masticatory cycles. The T-scan and Accura images were captured at the maximum bite force and overlapped to the cast. Photographs of interocclusal records were used as the reference during overlap. The occlusal contacts were counted to compare the T-scan and Accura. McNemar's test was used for statistical significance and the corresponding P-values were calculated from a chi-square distribution with one degree of freedom. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Accura were calculated relative to the T-scan values as a control. RESULTS. No statistical differences (P>.05) were found between the T-scan and Accura methods. The accuracy of Accura was 75.8%, sensitivity was 82.1%, specificity was 60.1%, PPV was 82.9%, and NPV was 60.1%. CONCLUSION. Accura could be another possible option as a computerized occlusal analysis system for indicating occlusal contacts at maximum intercuspation.

• 구강회복응용과학지
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• 제31권3호
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• pp.273-282
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• 2015

중심위에서 벗어나 있는 최대교두감합위는 상하악 치아의 조기접촉 및 사면활주의 직접적인 원인이며, 악관절 내장증, 치아마모, 치주질환 등을 일으킬 수 있다. 그러므로 광범위한 보철수복이 필요한 환자에서 중심위와 최대교두감합위의 불일치가 존재하는 경우 반드시 이를 제거하여 생리적인 교합양식을 회복해야 한다. 본 증례의 환자는 초진 시 약 3.5 mm의 사면활주와 다수의 우식 및 중등도의 치주질환을 앓고 있었다. 보철수복을 통해 기능 및 심미성을 회복하는 동시에 중심위와 최대교두감합위를 일치시켜 사면활주를 제거하였으며, ARCUSdigma II와 경두개 방사선 사진을 이용하여 생리적인 위치로 수정된 하악위와 변화된 개폐구 경로를 관찰하였다.

• 대한치과보철학회지
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• 제31권4호
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• pp.565-579
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• 1993

This study was accomplished to analyse and compare the occlusal contact patterns during eccentric mandibular movements in adult with normal occlusion. 50 subjects(male 27, female 23), who had natural occlusion and no symptom of temporomandibular disorder, were selected. Teeth contact patterns during mandibular eccentric movements were recorded and the distribution of tooth contacts in maximum intercuspation analysed by T-scan system. And then, tooth contact numbers recored by T-scan and silicone bite registration at centric occlusion were analysed and compared. The results obtained were as follows : 1. Antero-posteriorly, the qualitative center of occlusal contacts in centric occlusion were in the first molar areas, but there was a slight deviation in left-right directions. Thus, distribution of occlusal contacts were not bilaterally symmetric. 2. During the mandibular movements from centric occlusal position to right lateral and left lateral directions, the frequency that maxillary canine joined in lateral guidance was relatively high, but pure canine protected occlusion or pure group function occlusion had small frequency. 3. During mandibular protrusive movement, one or more maxillary central incisors frequently joined in protrusive guidance. 4. During mandibular eccentric movements, working and balancing side premature contact was observered in relatively high frequency. 5. In centric occlusal position, the numbers of occlusal contacts recorded on T-scan were relatively smaller than on silicone bite registration.