• Journal of Periodontal and Implant Science
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• 제25권2호
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• pp.397-406
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• 1995

The purpose of this study was to evaluate the changes of interproximal bone density by means of videodensitometer and to examine the clinical applicability of videodentitometer to assess the periodontal disease activity.Twelve interproximal sites, with periodontal pockets deeper than 5mm and vertical loss of bone on standard dental radiograph, were treated by subgingival curettage. The papilla bleeding index, the plaque index, the degree of mobility, the depth of pockets, and the level of attachment were measured. Standardized reproducible radiographs were taken by using the occlusal stent with parallelling film holder. The density of the interdental bone was measured on the radiographs by a videodensitometer at three levels: the most 'superficial' level; the 'deep' level, arbitrarily 1.5mm below: and the 'apical' level, where no bony changes were to be expected. The clinical parameter and the radiographical change were measured at initial, and 1 month, 3 months, and 6 months after treatment.The results were as follows :1. The papilla bleeding index and the degree of mobility decreased significantly until 3 months after subgingival curettage and showed the Same level in the remaining experimental periods. 2. The pocket depth mainly decreased due to the gingival recession until 1 month after treatment, but to the attachment gain after 1 month. 3. The density of the interdental bone did not show a significance increase until 1 month after treatment, but showed a steady increase throughout the 6 months of observation. 4. The close relationships were shown between the decrease in pocket depth and the gain of attachment and the improvement of bone density at 6 months after treatment.

• 대한소아치과학회지
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• 제23권3호
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• pp.667-673
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• 1996

The prevalence of class III malocclusion is approximately 5$\sim$9%, and about one fourth of this malocclusion is due to underdeveloped maxilla. Maxillary protraction appliance is an orthopedic device which promote the growth of a deficient maxilla by applying extraoral force to actively growing patients. The object of using maxillary protraction appliance is to guide a normal growth of maxilla and mandible and improve the occlusal relationship and also improve the facial profile. The author treated three patients whom were diagnosed as a class III malocclusion due to deficient maxilla using maxillary protraction appliance and the followings are the conclusions : 1. In these cases, anterior crossbite was corrected by anterior movement of maxilla and downward backward rotation of mandible and simultaneously, anterior facial height was increased. 2. The amount of dental change compare to skeletal change was greater as the patients got older. 3. When 500gm of force to each side was applied, the treatment period has been decreased. 4. As a result of applying the force between maxillary first primary molar and canine, there was a small degree of changes in palatal plane. So, it can be concluded that the maxillary protraction appliance is effective in treating growing patients with a deficient maxilla.

• Journal of Oral Medicine and Pain
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• 제24권2호
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• pp.189-206
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• 1999

This study was performed to investigate the factors affecting muscle activity and cephalometric variables according to change of head postures. For this study, 150 patients with temporomandibular disorders and 80 dental students without any signs and symptoms of temporomandibular disorders were selected as the patients group and as the normal group, respectively. Head position to body-midline in frontal plane and upper quarter posture to body plumb line in sagittal plane were observed clinically and electromyographic(EMG) activity of anterior temporalis, masseter, sternocleidomastoideus, and trapezius on clenching were recorded with $BioEMG^{(R)}$ in four head postures, which were natural head posture(NHP), forward head posture(FHP), $20^{\circ}$ upward head posture(UHP), and $20^{\circ}$ downward head posture(DHP). Cephaloradiographs were also taken in the same head postures as in EMG taking, but that was taken only in NHP for the patient group. Cephalometric variables measured were SN angle, CVT angle, atlas inclination angle, occlusal plane angle, Me-C2 angle, pharyngeal width, occiput~axis distance, area of pharyngeal space, and cervical curvature. The data were analyzed by SAS statistical program. The results of this study were as follows : 1. Between the patient and the normal group, there were significant difference in distance from plumb line to acromion, eye-tragus angle, electromyographic activity of the four muscles, and cephalometric variables of linear measurement. 2. There was no consistent pattern of correlation between upper quarter posture, EMG activity and cephalometric variables in any case without relation to cervical curvature and head position in frontal plane. 3. Sternocleidomastoid muscle only showed variation of electromyographic activty with changes of head postures, but all the muscles did show correlation with head postures. 4. All the cephalometric variables measured in this study showed difference of mean value by head posture, and CVT angle, pharyngeal width, occiput-atlas distance, and area of pharyngeal space showed correlation between these variables with change from NHP to FHP, and from NHP to UHP.

• 대한치과보철학회지
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• 제37권3호
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• pp.383-394
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• 1999

The indirect technique for making cast restoration requires that dies be as accurate and durable as possible. Currently, stone is the most commonly used material for die. However, it has some problems such as the weakness in its strength and low abrasion resistance. Recently, epoxy resin die systems have become available. The purpose of this study was to examine two commercially available resin die systems and evaluate some characteristics for their clinical performance. This study evaluated the dimensional accuracy of epoxy resins and their wettability with impression materials. In this study, the first experiment was about dimensional accuracy of different die materials. The master model was made of stainless steel. 10 models were made of two epoxy resins (Die-epoxy, Tri-epoxy) and a die stone (Fujirock) each. Occlusal diameter (Dimension I), occluso-gingival height (Dimension II), and interabutment distance (Dimension III) were measured in each model. Next, the contact angles of die materials with impression materials were observed. The blocks were made of polyether, hydrophilic additional silicone, polysulfide impression materials. By drop-ping the same amount (0.05ml) of Tri-epoxy, Die-epoxy, and die stone on the blocks, 10 samples of each die material were made. After setting of materials, the contact angles were measured. The results of this study were as follows. 1. The expansion of stone die and the shrinkage of resin dies in occlusal diameter were observed, and stone and Tri-epoxy were expanded and Die-epoxy was shrinked in occluso-gingival height. There was little change among materials in interabutment distance (p<0.05). 2. In comparison with the master model Tri-epoxy had the least variation in measurement of the three die systems examined. Die-epoxy was next, and die stone showed the greatest variation. 3. The compatibility of die stone for polyether, hydrophilic additional silicone, polysulfide decreased in order, wherease epoxy materials had the decreased compatibility for polyether and polysulnde, hydrophilic additional silicone in order. It was not statistically different between polyether and polysulfide (p<0.05). 4. The contact angles of Tri-epoxy, Die-epoxy, die stone were getting bigger in order.

• 대한치과교정학회지
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• 제28권1호
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• pp.113-122
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• 1998

본 연구는 조선대학교 부속 치과병원 교정과에 내원하여 교정치료를 시행하고 있는 환자중 Panadent 교합기 및 condylar position indicator(CPI)를 이용하여 중심위-중심교합 편위양을 측정한 결과, 전후방 및 수직적 편위양이 1.00mm이내, 측방편위양이 0.30mm 이내인 정상범주를 넘는 부정교합 환자 47명을 대상으로 하여 3개월간 교합안정장치를 24시간 장착하고, CPI 및 transcranial projection을 이용하여 교합안정장치 장착전과 장착후의 하악과두의 위치변화를 관찰한 결과 다음과 같은 결론을 얻었다. 1. CPI상의 모든 군에서 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.001). 2. transcranial projection상의 superior joint space의 Rt와 Lt+Rt/2에서 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.05). 3. CPI상의 모든 superior-inferior components군에서 교합안정장치 사용 전, 후의 중심교합-중심위 사이에 통계적인 유의성이 있었다(p<0.01). 4. transcranial projection상의 superior joint space의 Rt를 제외한 모든 군에서 교합안정장치 사용 전, 후의 중심교합-중심위 사이에 통계적인 유의성이 없었다. 이상의 결론을 종합해 볼 때 중심교합-중심위 사이의 변화를 평가하는데는 transcranial projection보다 CPI가 보다 유용하며, 교합안정장치는 하악과두의 전, 후방적 위치변화보다는 수직적 위치변화에 미치는 영향이 보다 큰 것으로 보인다.

• 대한치과교정학회지
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• 제31권3호
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• pp.347-355
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• 2001

상하악 전치부 치열은 치아의 형태 변위, 선천결손 등에 의해 종종 교합관계나 심미성에 문제점을 나타내게 된다. 이러한 문제점을 극복하기 위해 임상의는 전치부 비율을 진단시 이용하게 되나, 치열궁 형태, 견치간 폭경(intercanine width), 치열궁 장경(segment depth)과 치열궁 둘레(arch perimeter)에 따른 전치부 비율의 변화로 인해 이러한 비율을 전치부 교합관계 예측에 직접 적용하는데는 한계가 있다. 이에 본 연구에서는 한국성인 정상교합자 모델(남자:20쌍, 여자:20쌍)에서 상하악 전치부 치열궁 형태를 least square method로 조사하였다. 한국인 정상교합자의 상하악 전치부 치열궁 형태는 다항 함수(polynomial function), 베타 함수(beta function), 하이퍼볼릭 코사인 함수(hyperbolic cosine function) 순으로 곡선 접합(curve fitting)하였으며, 이러한 곡선 접합도는 남녀, 상하악에 관계없이 일정하였다. 또한 곡선접합(curve fitting)된 치열궁 형태를 바탕으로 견치간 폭경(intercanine width), 치열궁 장경(segment depth)과 치열궁 둘레(arch perimeter)간의 상관관계를 구하였다. 이러한 상관관계는 견치간 폭경에 따른 치열궁 형태 예측과 보다 정확한 전치부 비율에 대한 정보를 제공할 것이다.

• 대한치과교정학회지
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• 제25권3호
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• pp.247-261
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• 1995

본 연구는 II급 1류 부정교합의 치료에 있어 치료전의 환자연령에 따른 부정교합치료의 양적 차이를 알아보고, Johnston analysis를 통해 협측 치열군의 교점이 어떤 방법으로 이루어지는지, 즉, 두개저에 대한 또한 상호간에 대한 상, 하악 각각의 성장양과 기저골에 대한 구치의 이동양을 측정하여 구치부의 교정이 어떻게 이루어지는지를 알아보고자 했으며 서울대학교병윈 치과진료부 교정과에 내원하여 II급 1류 부정교합으로 진단되어 상, 하악 제1소구치를 발치하여 치료를 받은 여자환자 52명중 치료전의 연령을 기준으로 성장기 아동군과 성인군으로 대별하여 치료전,후 두부방사선사진을 계측, 비교분석하여 다음과 같은 결론을 얻었다. 1. 치료전,후의 상악골의 전후방적인 위치변화에 대한 비교를 통해서 성장기 아동군과 성인군간의 유의한 차는 없었다. 그러나 하악골의 전후방적 위치변화에 있어서는 두 군간에 유의한 차이를 보였다. (P<0.05) 2. 치료 전,후 수직고경의 변화에 있어, 성장기 아동군에서는 전안면고경, 후안면 고경, 하안면고경 등이 성장과 치료의 효과로 유의성있게 증가하였으며(P<0.001), 성인군에서는 유의성있는 변화가 없었다. 3. 치료전,후 교합평면의 변화에 있어, 성장기 아동군에서는 교합평면의 경사도의 유의성있는 변화가 발견되지 않았으나, 성인군에서는 교합평면의 경사도가 유의성있게 증가하였다. (P<0.05) 4. Johnston analysis를 이용한 분석으로, total molar correction의 양에 있어서 성장기 아동군과 성인군에서 유의한 차이를 보였다. (P<0.05) 6. Johnston analysis를 이용한 분석에 의해 성장기 아동군에서는 total molar correction의 $63\%$가 하악골성장에 의해, $37\%$가 치아이동에 의해 이루어짐을 관찰했다. 성인군에서는 total molar correction의 $99\%$가 치아이동에 의해 이루어졌다.

• 대한치과보철학회지
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• 제45권1호
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• pp.1-11
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• 2007

Statement of problems: The concept of CR has also changed continuously.?In order to find out the factors that affect the centric slide, studies were carried out to compare the forms of wisdom teeth eruption, lateral movement, premature contact in CR, and anterior movement. Research and statistical methods were based on the report by the 1980 Korean dental association. Material and method: In our study, 403 dentists in their twenties and dentistry students who could understand CR and CO (and who did not receive occlusal, orthodontic treatment, without extreme caries and large prosthodontic care) were compared with the 25 year old results. A segment of line parallel to the upper incisor was marked on the lower incisor. When seen laterally, a line perpendicular to the occlusal plane was drawn on the foremost area of the upper incisor. This line was extended to the lower incisor and the two points (points at the lower and upper incisors) were used as reference points for the CO. After guiding the occlusion to the CR, two lines were marked by using the same method that was used for the CO. The point in which these lines meet became the reference point of CR occlusion Results and conclusions: Results of the experiment completed in 1980 show that all 307 research members had anterior-posterior and upper-lower displacement. Displacement measurements were $0.7{\pm}0.4mm$ for the anterior-posterior displacement, $0.99{\pm}0.50mm$ for the upper-lower displacement,0.18{\pm}0.31 mm for the lateral displacement, and $1.32{\pm}0.67mm$ for the total displacement. Results of the 2006 experiment show that all 409 research members had anterior-posterior and upper-lower displacement. The anterior-posterior displacement was $1.12{\pm}0.86mm$, the upper-lower displacement was $1.02{\pm}0.71mm$, the lateral displacement was $0.61{\pm}0.56mm$, and the total displacement was $1.80{\pm}0.99mm$. No specific differences were found between each group when comparing displacement according to the forms of wisdom teeth eruption. Since 1980, the percentage of unerupted teeth has increased from 35.16% (111/307 people) to 57.5% (236/409 people). Westernization of the Korean cranial form and intraoral structure has brought about these results. In our experiment, 26.7% (109/409 people) of the subjects were cuspid guided, while 7.3% (30/409 people) were mutually guided. No specific differences were found in the amount of displacement between the two groups. Only the subjects with anteriors coming in contact made up the largest percentage group (42.3%, 173/409 people) in our study. No specific differences were found between each group.

• 대한치과보철학회지
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• 제36권2호
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• pp.203-244
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• 1998

The human mandible is always under the condition of loading by the various forces extorted by the attached muscles. The loading is an important condition of the stomatognathic system. This condition is composed of the direction and amount of forces of the masticatory muscles, which are controlled by the neuromuscular system, and always influenced by the movement of both opening and closing. Mandible is a strong foundation for the teeth or various prostheses, nevetheless it is a elastic body which accompanies deformation by the external forces on it. The elastic properties of the mandible is influenced by the various procedures such as conventional restorative treatments, osseointegrated implant treatments, reconstructive surgical procedures and so forth. Among the treatments the osseointegrated implant has no periodontal ligaments, which exist around the natural teeth to allow physiologic mobility in the alveolar socket. And so around the osseointegrated implant, there is almost no damping effect during the transmission of occlusal stress and displacements. If the osseointegrated implants are connected by the superstructure for the stabilization and effective distribution of occlusal stresses, the elastic properties of mandible is restricted according to the extent of 'splinting' by the superstructure and implants. To investigate the change of elastic behaviour of the mandible which has osseointegrated implant prosthesis of various numbers of implant installment and span of superstructre, a three dimensional finite element model was developed and analyzed with conditions mentioned above. The conclusions are as follows : 1. The displacements are primarily developed at the area of muscle attachment and distributed all around the mandible according to the various properties of bone. 2. The segmentation in the superstructure has few influence on the distribution of stress and displacement. 3. In the load case of ICP, the concentration of tensional stress was observed at the anterior portion of the ramus($9.22E+6N/m^2$) and at the lingual portion of the symphysis menti($8.36E+6N/m^2$). 4. In the load case of INC, the concentration of tensional stress was observed at the anterior portion of the ramus($9.90E+6N/m^2$) and the concentration of tensional stress was observed at the lingual portion of the symphysis menti($2.38E+6N/m^2$)). 5. In the load case of UTCP, the relatively high concentration of tensional stress($3.66E+7N/m^2$) was observed at the internal surface of the condylar neck.

• 대한소아치과학회지
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• 제49권1호
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• pp.45-56
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• 2022

이 연구의 목적은 심한 우식 또는 저광화에 이환된 제1대구치에 기성금속관을 수복한 후 교합 변화에 대해 평가하는 것이다. 제1대구치가 교합 평면까지 도달하여 교합되는 환자 중 기준에 부합하는 24명의 환자를 대상으로 연구를 진행하였다. 하나의 제1대 구치에 기성금속관으로 수복치료를 진행하였다. 치료 전, 치료 직후, 4주 후, 8주 후 검진마다 T-Scan III을 사용하여 최대교두감합위에서 교합력 분포를 측정하였고 디지털 버니어 캘리퍼로 수직피개를 측정하였으며 정중선의 변화를 조사하였다. 8주 후 검진에서는 설문 조사를 진행하였다. 대부분 치료 전과 비교해서 치료 직후 악궁에서 수복한 쪽과 수복하지 않은 쪽 사이의 교합력 분포가 역전되었으며 수직피개는 감소했다. 하지만 4주 후에 좌, 우측 교합력이 평형을 이루었고 수복한 제1대구치와 수복하지 않은 제1대구치의 교합력 분포는 비슷한 값을 가졌다. 또한 변화한 수직피개, 정중선은 치료 전 상태로 회복되었고 치료 후 유의할만한 턱관절 및 저작 불편감은 없었다. 이번 연구를 통해 기성금속관 수복 후 한 달 뒤에 자발적인 교합 평형이 이루어진 것을 확인할 수 있었다.