• 대한소아치과학회지
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• 제27권4호
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• pp.558-563
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• 2000

1960년대 최초로 Ruby 레이저의 개발 이래로, 치과용 드릴인 고속용 핸드피스를 대신해 치아 경조직 삭제에 레이저의 적용이 시도되어져 오고 있는데, 최근 Er:YAG레이저의 개발로 경조직 삭제시 이들의 삭제 효능과 치질의 온도상승에 관한 연구에 관심이 증대되었다. 과거 여러 종류의 레이저에 비해 2.94um Er:YAG 레이저는 파장의 특성이 치질의 수분과 하이드록시아파타이트에 매우 흡수율이 높아 치질내 수분이 고열에 의해 증기화되어 폭발하므로써 치질이 제거되므로 crack이나 탄화된 부위가 없이 와동 변연부가 명확하고 깨끗하며 효과적인 치질의 삭제가 가능하다. 삭제시 치질내 온도 상승이 레이저의 경조직 적용시 고려되는 중요한 문제점으로 대두되나 이는 물분사와 적적한 레이저 parameter의 사용으로 열 발생을 최소화하면 치수 손상이 발생하지 않는다고 보고 된다. 본증례는 치수에 근접하지 않은 우식 병소의 처치를 주소로 내원한 소아 환자들에 있어서 Er:YAG 레이저 적용시 기존의 고속용 삭제 기구에 비해 소음과 진동이 적어 소아 환자들의 치과 치료에 대한 공포감이나 동통을 최소로 하며 적절한 레이저 parameter와 물분사의 사용으로 치수에 대한 열자극이나 치질의 변색과 같은 임상적인 문제를 초래하지 않고 효과적으로 우식 병소의 제거 및 와동 형성을 시행할 수 있었다.

• Restorative Dentistry and Endodontics
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• 제34권6호
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• pp.467-476
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• 2009

본 연구의 목적은 아말감과 복합레진의 수복 과정과 수복 후 상아세관액의 흐름(dentinal fluid flow, DFF)을 측정하기 위함이다. 치근을 절제한 제 3 대구치를 자체 제작한 미세 유체 흐름 측정장치에 연결한 후 1급 와동을 형성하여 아말감과 복합레진 수복을 시행하였다. DFF의 측정은 와동 형성부터 수복 후 30분까지 연속적으로 이루어졌고, 수복 후 3, 7일에 재 측정하였다. 주수 하에 와동 형성 시 DFF는 inward로, 끝난 후에는 outward로 바뀌었다. 아말감 충전 시 DFF는 inward로 바뀌었고 충전 완료 후 미약한 outward DFF를 보였다. 복합레진 수복의 경우, 산 처리 후 수세와 건조 시 각각 inward와 outward DFF를 보였고 primer도포 후 공기 분사는 급격한 outward, 소수성 본딩제를 적용하는 단계에서는 outward 였던 DFF가 감소하여 0에 가까워지거나 약간 inward 흐름을 보였다. 접착제와 복합레진의 광중합은 급격한 inward의 DFF를 일으켰다. 수복 후 30분, 3일, 7일째 수복 재료에 따른 DFF의 감소에 통계적으로 유의한 차이는 없었다 (p>0.05).

• 한국치위생학회지
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• 제6권4호
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• pp.283-294
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• 2006

The purpose of this study was to examine the state of smoking among some college students, the smoking motivation of smoker students, what made them quit smoking and how they got ready for giving up smoking, as smoking had a huge impact on national health and there was a desperate necessity for preventive antismoking education programs to let students keep away from smoking. After a survey was conducted with self-administered questionnaires from October 1 through November 1, 2006, the responses from 400 students were gathered, and 384 answer sheets were analyzed except 16 incomplete ones. The findings of the study were as follows: 1. By gender, 62.4% of the male students and 28.6% of the female students were smokers, and the state of smoking was statistically significantly different according to their gender(p<0.05). 2. The largest number of the male students, which accounted 44.1%, started smoking in their high school days, and 39.5% of the females did that in middle school. As for a daily mean amount of smoking, 41.8% of the male students, the greatest percentage, smoked 10 to 19 cigarettes a day, and one to nine cigarettes were most common among the females, which represented 57.9 %. But the gap between the two was insignificant(p>0.05). As many as 83.6% of the males and 86.8% of the females had ever attempted to quit it. 3. Concerning awareness of antismoking policies, they felt that a raise in cigarette price would lead to less smoking, and that antismoking advertisement or posters through television or newspaper would deliver the same results as well. There was a statistically significant difference among their awareness(p<0.05). 4. Regarding preparation stage for quitting smoking, 31.3% of the male smokers had no intention to give it up, and 23.2% considered it. 36.7%, the largest percentage, got ready to refrain from it. Among the female smokers, 34.2% had no plans to abstain from smoking, and 36.8% took it into consideration. 23.7% got ready to do that. The females who got ready for that were outnumbered the males who did. 5. As to connections between the state of smoking and relevant knowledge, the students didn't have a good knowledge on that, and a statistically significant difference existed between the smokers and nonsmokers in smoking knowledge. 6. As for knowledge about oral diseases, they were highly cognizant of the relationship of smoking to tooth discoloration, nicotine stomatitis and bad breath, but they didn't know well about its relationship to delayed recovery from dental treatment, implant failure and ozena. Their smoking condition made a statistically significant difference to their knowledge(p<0.05). In the future, sustained research efforts should be channeled into determining how much smoking affects health and concerns oral diseases, and antismoking counseling programs should be prepared to bolster people's awareness of oral health.

• 구강회복응용과학지
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• 제17권3호
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• pp.145-154
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• 2001

In the past, many dentist were interested mainly in the mechanical aspects such as tooth preparation and retainer types for making dental restoration. But, these days, the concept of restorative treatment emphasizes the importarce of gnatic system and masticatory muscles in addition to oral cavity. So, the current considerations for the fixed prosthodontic treatment include the stabilization of temporomandibular joint and neuromuscualr system and the relationship of periodontal ligament and occlusion. To achieve the above objectives, occlusal splint has been used as one of the mouth preparations for restorative treatment. The objectives of occlusal splint are as follows; 1. To use as preliminary application for periodontal-occlusal treatment 2. To provide proper vertical dimension 3. To control abnormal habits and parafunction 4. To treat the temporomandibular disease and myofascial pain 5. To establish the new therapeutic position In some cases, the patients had improper vertical dimension and occlusal interferences caused by prostheses reconstucted using centric relation recorded without considering the health of TMJ and manticatory muscle. And these prosthesis act as primary source that cause pathologic phenomenon in periodontal ligament, muscles and TMJ. Physiologically, in order to make the treatment occlusion guided by proper centric relation method, the method should be guided after the use of occlusal splint for some period. The main objective of prosthetic treatment is to maintain the function and health of stomatognathic system. So, one of the most important things that have to be performed by clinicians is a clinical ability to do the correct diagnosis and treatment planning based on the stomatognatic function and occlusion.

• The Journal of Advanced Prosthodontics
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• 제10권1호
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• pp.8-17
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• 2018

PURPOSE. The study aimed to identify the accuracy and reproducibility of preparations made by gypsum materials of various colors using quantitative and semi-quantitative three-dimensional (3D) approach. MATERIALS AND METHODS. A titanium maxillary first molar preparation was created as reference dataset (REF). Silicone impressions were duplicated from REF and randomized into 6 groups (n=8). Gypsum preparations were formed and grouped according to the color of gypsum materials, and light-scanned to obtain prepared datasets (PRE). Then, in terms of accuracy, PRE were superimposed on REF using the best-fit-algorithm and PRE underwent intragroup pairwise best-fit alignment for assessing reproducibility. Root mean square deviation (RMSD) and degrees of similarity (DS) were computed and analyzed with SPSS 20.0 statistical software (${\alpha}=.05$). RESULTS. In terms of accuracy, PREs in 3D directions were increased in the 6 color groups (from 19.38 to $20.88{\mu}m$), of which the marginal and internal variations ranged $51.36-58.26{\mu}m$ and $18.33-20.04{\mu}m$, respectively. On the other hand, RMSD value and DS-scores did not show significant differences among groups. Regarding reproducibility, both RMSD and DS-scores showed statistically significant differences among groups, while RMSD values of the 6 color groups were less than $5{\mu}m$, of which blue color group was the smallest ($3.27{\pm}0.24{\mu}m$) and white color group was the largest ($4.24{\pm}0.36{\mu}m$). These results were consistent with the DS data. CONCLUSION. The 3D volume of the PREs was predisposed towards an increase during digitalization, which was unaffected by gypsum color. Furthermore, the reproducibility of digitalizing scanning differed negligibly among different gypsum colors, especially in comparison to clinically observed discrepancies.

• 대한치과교정학회지
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• 제48권1호
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• pp.48-56
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• 2018

Objective: The purpose of this study was to determine the effects of carbonated water on etched or sealed enamel according to the carbonation level and the presence of calcium ions. Methods: Carbonated water with different carbonation levels was manufactured by a soda carbonator. Seventy-five premolar teeth were randomly divided into a control group and 4 experimental groups in accordance with the carbonation level and the presence of calcium ions in the test solutions. After specimen preparation of the Unexposed, Etched, and Sealed enamel subgroups, all the specimens were submerged in each test solution for 15 minutes three times a day during 7 days. Microhardness tests on the Unexposed and Etched enamel subgroups were performed with 10 specimens from each group. Scanning electron microscopy (SEM) tests on the Unexposed, Etched, and Sealed enamel subgroups were performed with 5 specimens from each group. Microhardness changes in different groups were statistically compared using paired t-tests, the Wilcoxon signed rank test, and the Kruskal-Wallis test. Results: The microhardness changes were significantly different between the groups (p = 0.000). The microhardness changes in all experimental groups except Group 3 (low-level carbonated water with calcium ions) were significantly greater than those in the Control group. SEM showed that etched areas of the specimen were affected by carbonated water and the magnitude of destruction varied between groups. Adhesive material was partially removed in groups exposed to carbonated water. Conclusions: Carbonated water has negative effects on etched or sealed enamel, resulting in decreased microhardness and removal of the adhesive material.

• 대한심미치과학회지
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• 제23권2호
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• pp.80-85
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• 2014

가지런한 치열을 얻기 위해 교정 치료는 치아 보존적인 의미에서 단연 First choice가 일 수 밖에 없다. 그러나 왜소치나 치아 크기의 불균형인 경우, 변색 치아나 파절, 심한 마모 치아인 경우 교정만으로는 심미적으로 완성도 높은 결과를 가져올 수 없다. 모든 치료에서 그러하지만, 특히 심미 치료에서는 치아 교정과 보철 치료, 혹은 치주 치료 및 임플란트등 항상 통합적인 진단과 치료계획이 필요한 경우가 많다. 그리고 다양한 치과 분야의 협진 진료가 필요한 환자에서는 안모와 치아의 심미적 만족뿐 아니라 기능적인 교합관계를 이룸으로써 장기간 안정적이며 조화로운 상태가 유지될 수 있는 치료가 전제되어야 한다. 본 증례는 전치부와 소구치에 cross bite가 있고, 상악 우중절치 절단에 마모가 있는 37세 여성 환자에서 교정과 라미네이트 수복치료를 동반한 경우이다. 치아교정을 통하여 전체적인 치아 위치를 재구성하여 기능교합을 이루었고, 최소한의 치질삭제로 라미네이트 수복치료를 함으로써 전치부 심미를 회복하였다. 최종 보철물을 장착하고 2년간 주기적인 follow up통해 예후를 관찰중이며, 부정교합의 재발이나 보철물 파절은 현재까지 관찰되지 않았다.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.295-301
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• 2014

PURPOSE. Numerous methods were used to etch the fiber posts to improve its bonding to root canal dentin. Our aim was to evaluate the efficacy of 37% phosphoric acid in etching fiber posts in comparison with 24% hydrogen peroxide. MATERIALS AND METHODS. Ninety human maxillary central incisors were taken and post space preparation was done. Ninety fiber posts were taken and divided into three groups (n=30) based on the surface treatment they received ($H_3PO_4$, $H_2O_2$, distilled water) and each group was further divided (n=10) based on the time period of application (15 seconds, 30 seconds, 60 seconds). All the posts were luted into canals using Rely X UniCem-2. Each tooth was then sectioned into six slices and subjected to push out test. Data obtained was subjected to statistical analysis at P<.05. The surface topography was evaluated using scanning electron microscopy. RESULTS. Highest bond strength values were noted in 15 seconds etched phosphoric acid group and 60 seconds etched hydrogen peroxide group with no significant difference between two groups. Surface topography revealed complete epoxy layer removal with no damage to its structural integrity in those groups. CONCLUSION. $H_3PO_4$ etching for a period of 15 seconds is an effective alternative in improving the adhesion of fiber post to root dentin.

• 대한치과교정학회지
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• 제45권5호
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• pp.236-244
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• 2015

Objective: The aim of this study was to investigate three-dimensional molar displacement after distalization via miniscrews and a horizontal modification of the trans-palatal-arch (TPA). Methods: The subjects in this clinical trial were 26 Class II patients. After the preparation of a complete set of diagnostic records, miniscrews were inserted between the maxillary 2nd premolar and 1st molar on the palatal side. Elastic modules connected to the TPA exerting an average force of 150-200 g/side parallel to the occlusal plane were applied. Cone-beam computed tomography was utilized to evaluate the position of the miniscrews relative to the adjacent teeth and maxillary sinus, and the direction of force relative to molar furcation. The distances from the central point of the incisive papilla to the mesiopalatal cusps of the 1st maxillary molars and the distances between the mesiopalatal cusps of the left and right molars were measured to evaluate displacement of the maxillary molars on the horizontal plane. Interocclusal space was used to evaluate vertical changes. Results: Mean maxillary 1st molar distalization was $2.3{\pm}1.1mm$, at a rate of $0.4{\pm}0.2mm/month$, and rotation was not significant. Intermolar width increased by $2.9{\pm}1.8mm$. Molars were intruded relative to the neighboring teeth, from 0.1 to 0.8 mm. Conclusions: Distalization of molars was possible without extrusion, using the appliance investigated. The intrusive component of force reduced the rate of distal movement.

• Restorative Dentistry and Endodontics
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• 제43권1호
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• pp.2.1-2.10
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• 2018

Objectives: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). Materials and Methods: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. Results: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). Conclusions: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.