• Journal of Oral Medicine and Pain
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• 제15권1호
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• pp.117-124
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• 1991

The purpose of his study was to investigate the variations of occlusal contact pattern according to chewing side preference. The author selected 59 dental students (mean age 23.6 years) who had no signs and symptoms of masticatory disorders and divided into two groups, that is, bilateral chewing side group and unilateral chewing side group, respectively. For recording, T-Scan System(Teksan Inc., USA) was used and the recorded occlusal contacts were examined as to the number of occlusal contacts, points distribution in dental arch, time sequence and force snapshot. The obtained results were as follow s: 1. Total number of occlusal contacts were more in unilateral chewing side group and there were significant difference in number between right and left side or between chewing and less-chewing side in all two groups. 2. All items related to time sequence showed no statistical significant difference between two groups in any case. 3. Unilateral chewing side group had more occlusal contact force than bilateral group, especially in chewing side. From the above finding, the author considered that there was occlusal unbalance in unilateral chewing side group. 4. Chewing side preference would possibly have more effects on the occurrence rate of anterior tooth contact that the rate of prolonged their contact but proved.

• 국제물리치료학회지
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• 제11권1호
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• pp.1954-1959
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• 2020

Background: Due to aging, blood flow rate decreases, also posture and chewing habit may be changed. Objective: To identify that changes in blood velocity in the common carotid arteries (CCAs) in old persons with unilateral chewing habit (UCH) and forward head posture (FHP) in the elderly. Design: An observational cross-sectional study. Methods: Chewing habits, FHP, and CCAs velocities were assessed in 85 elderly subjects. Chewing habits were measured by visual observation. CCAs measured the peak systolic velocity (PSV), end-diastolic velocity (EDV), minimum diastolic velocity, and resistivity index. The subjects were divided into UCH and bilateral chewing habit groups depending on chewing habit. The subjects were also divided into >49 degrees and <49 degrees for comparison of blood flow between the left and right CCAs. Results: In the UCH, the chewing side had significantly higher EDV (P=.003), PSV (P=.023) than the non-chewing side. There was no significant difference in velocity between the CCAs in the FHP. Conclusion: This study shows that the blood flow velocity of the chewing side of UCH was higher, and unilateral chewing affects the CCAs velocity and thus highlight the importance of chewing habit in the elderly than head posture.

• 대한치과교정학회지
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• 제25권3호
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• pp.311-321
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• 1995

이상적 교합이란 치아의 교합이 저작계의 다른 부분과 기능적으로 조화를 이루고, 중심교합상태에서 양측으로 동시에 균일한 접촉을 이루는 것을 말한다. 악골의 양측을 이용한 균형된 저작은 양측의 균등한 견치유도와 기능적 능력에 의해 가능해지지만 교합간섭이나 저작계에 대한 기능적 요구의 감소로 좌우측중 어느 한쪽만을 선호하는 편측저작양상이 유도되기도 한다. 편측저작은 악골의 발육 교합 및 안면의 전체적인 형태에 이르기까지 악안면 전체에 형태적, 기능적인 부전을 초래할 잠재성을 가진 증상이나 이에 대한 연구가 많지 않다. 본 연구는 저작습관의 분포를 알아보고, 저작습관에 따른 교합력의 차이와 안면골격형태를 비교 연구할 목적으로 시도하였다. 부산대학교 치과대학 재학생 186명을 대상으로 설문지를 이용하여 저작습관에 따라 양측저작군과 편측저작군으로 나누어 저작습관의 분포를 조사하였고, 이 중 두개안면부의 성장발육에 영향을 미칠만한 질병에 이환되지 않았고 측모가 양호하며 Angle분류 I급의 교합상태를 보이면서 교정치료와 보철치료를 받은 경험이 없고 악관절 질환이 없는 자 중 양측저작자와 편측저작자 각각 25명을 선정하여 교합력계(MPM 3000)를 이용하여 최대교합력을 측정하고, 정모두부방사선규격사진을 촬영하여 안면골격형태를 비교연구하여 다음과 같은 결과를 얻었다. 1. 저작습관은 양측저작자($68\%$)가 많았으며, 편측저작자 중 $68\%$는 우측을, $32\%$는 좌측의 저작을 선호하였다. 2. 양측저작군은 좌우측의 최대교합력이 비슷하였고, 편측저작군은 저작측이 비저작측보다 교합력이 컸으며 특히 여자에서 그 차가 뚜렷하였다. 편측저작군은 양측저작군에 비해 저작측은 교합력이 컸으며, 비저작측은 작았지만 유의성은 없었다. 저작습관에 상관없이 남자가 여자보다 교합력이 컸으며 남자는 여자의 교차력의 약2배정도이었다. 남녀를 합한 경우 편측저작군의 저작측은 양측저작군의 교합력과 비슷하였으나 비저작측은 그것보다 작았다. 3. 정모두부방사선규격사진을 이용하여 안면골격형태를 비교한 결과 양측저작군의 좌우측, 편측저작군의 저작측과 비저작측간에 차이가 없었다.

• 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.

• 대한치과보철학회지
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• 제32권1호
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• pp.103-119
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• 1994

The purpose of this study was to evaluate the mandibular movements of TMD patients comparing to normal persons. Sirognathograph was used to measure five parameters of mandibular movements of twenty normal persons and eight TMD patients. Five parameters were (1) Maximum opening during maximum opening and closing, (2) Mean velocity during maximum opening and closing, (3) Maximum opening during unilateral chewing, (4) Mean velocity during unilateral chewing, (5) Consistency of mandibular movement during unilateral chewing. Based on above results, new Mandibular Movement Index(M.M.I.) was formulated and compared to Helkimo's Clinical Dysfunction Index by measuring two indices before treatment and 2 weeks, 4 weeks, 6 weeks, 8 weeks after treatment. The conclusions were as follows: 1, The amounts of maximum opening and mean velocity during maximum opening and closing of TMD patients were less than those of normal persons(p<0.01). 2. The amounts of maximum opening and mean velocity during unilateral chewing of TMD patients were less than those of normal persons(p<0.05) (P<0.01). 3. Although TMD patients showed limited mandibular movements during unilateral chewing, the consistency of mandibular movements was better than that of normal persons(p<0.05). 4. Both mandibular movement index and Helkimo's Clinical Dysfunction Index, were useful in diagnosing TMD patients.

• Journal of Oral Medicine and Pain
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• 제20권2호
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• pp.291-306
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• 1995

Mandibular movement is composed of border movement and functional movement. Border movement such as maximal mouth opening, hinge opening ad lateral eccentric movement has good reproducibility, but functional movement such as chewing, swallowing and speech has also reproducibility. Especially for chewing movement, individual reproducibility has been confirmed by many studies. Study of chewing pattern is still in controversy. In new approach for raising the diagnostic value, numeric parameters and morphologic characteristics could be used for evaluation of chewing pattern. This study was performed to investigate the differences between chewing pattern in controls and in patients with temporomandibular disorders. Sixty-three patients with temporomandibular disorders participated in this study, and they were divided into unilaterally affected subjects or bilaterally affected subjects. Then unilaterally affected subjects were classified into closed lock group, disk displacement with reduction group, and degenerative joint disease group. For recording of chewing pattern, subjects were asked to chew one piece of presoftened chewing gum on both sides, and the chewing movement was recorded with the Electrognatho- Graphy(Bio-Research Associates Inc., U.S.A.). Tooth contact pattern for occlusal stability (Total left-right statistics )was also recorded with T-Scan(Tekscan Co., U.S.A.). The dta related to chewing pattern and total left-right statistics were statistically analyzed by SAS/stat program. The obtained results were as follows : 1. In patient group, mean value of A-P distance and the ratio of A-P distance to vertical distance were larger than control group, but the value of lateral distance in affected side and the closing velocity in unaffected side were smaller than that of control group, respectively. 2. In case of unilateral affected patients, chewing pattern of other side had tendency to restricted movement and slow velocity in closed lock group or degenerative joint disease group than control group or disk displacement with reduction group. 3. In bilateral degenerative joint disease patients, contralateral side had tendency to large range of motion and slow chewing velocity than preferred chewing side. 4. The patients with restricted mouth opening below than 35mm had higher value of total left-right statistics than patient group mouth opening above 35mm. Also closed lock group had higher total left-right statistics than disk displacement with reduction group, degenerative joint disease group and control group. 5. There was some difference in morphologic characteristics of chewing pattern between in control group and in affected side of unilateral patient group, but no difference between control group and unaffected side of unilateral patient group. 6. There were positive correlations between vertical distance and A-P distance, between vertical distance and chewing velocity, between A-P distance and chewing velocity, and between opening velocity and closing velocity in unilateral affected patients.

• 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.

• 대한치과보철학회지
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• 제29권2호
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• Journal of Oral Medicine and Pain
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• 제21권2호
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• pp.265-277
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• 1996

The aim of this study was to investigate the electromyographic(EMG) activity of masticatory and cervical muscles according to chewing pattern in coronal plane during gum chewing. 70 patients with temporomandibular disorders and 30 dental students without any signs and symptoms of the disorders participated in this study. We measured the activity of masseter (MM), anterior temporalis(TA), sternocleidomastoideus(SCM) and trapezius muscle and recorded the chewing patterns using Biopak system synchronously. Chewing pattern was classified into S- or L-pattern by the midline opening path and short or long type by the lateral distance from midline. Obtained data were analyzed with SAS/STAT Program. The obtained results were as follows : 1. Generally, there was tended to be higher activity in the control group than in the patients group. 2. When comparing EMG activity according to preferred side, the muscle activity was tended to higher on the preferred chewing side than on the contralateral side. However, this difference is insignificant statistically 3. In unilateral affected patients, there was no difference in muscle activity between affected chewing side and unaffected chewing side except for the EMG of the temporalis anterior muscle. 4. Despite the varietal in each of the following variables, there mere no differences in EMG activity during gum chewing: chewing pattern in coronal plane and lateral distance of chewing. 5. The activity of SCM in chewing side was higher than that in contralateral side (p<0.001), but there was no difference in trapezius muscle. 6. In all of the control group, there was appeared L-chewing pattern than not involved the midline during preferred side chewing.

• 대한치과교정학회지
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• 제44권3호
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• pp.143-153
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• 2014

An 8-years old boy with facial asymmetry and unilateral posterior crossbite on the left side received orthopedic and orthodontic treatment. During the first phase of treatment, the narrow maxillary arch was expanded using an acrylic plate. Then, the acrylic plate was used as a bite block with occlusal indentations from the construction bite that was obtained with the incisors in a coincident dental midline. After the position of the mandible was stabilized, the second phase of orthodontic treatment was initiated using fixed appliances for detailing of the occlusion. Skeletal symmetry, ideal occlusion, and coincident dental midlines were thus achieved. Functionally, occlusal force balance and masticatory muscle activity were improved, and the chewing patterns were normalized.