• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.468-473
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• 2014

PURPOSE. This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS. To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by $10^{\circ}-20^{\circ}$ and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (${\alpha}=.05$). RESULTS. Precision discrepancies for the canine, premolar, and molar were $3.7{\mu}m$, $3.2{\mu}m$, and $7.3{\mu}m$, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were $6.2{\mu}m$, $11.2{\mu}m$, and $21.8{\mu}m$, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION. In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.359-363
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• 2013

This article describes the treatment provided to a patient with the maxillary anterior teeth exhibiting severe secondary caries beneath the previous restoration and a white spot lesion on the adjacent incisor. Two implants were placed after extraction of hopeless teeth with the guided bone regeneration technique. A white spot lesion of the adjacent incisor was treated with minimally invasive treatment. This clinical report describes the multidisciplinary treatment for the white spot lesion and esthetic restoration of missing anterior teeth.

• 영어영문학
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• 제58권6호
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• pp.1215-1233
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• 2012

This essay is an attempt to critique the notion of hybridity that has so far facilitated a liberal multiculturalist reading of White Teeth. For an alternative framework, it posits the multiethnic subject-making to examine in what ways the novel questions the premises of liberal multiculturalism. In this vein, this study suggests that Smith throws some significant light on the underside of holding multiple racial/ethnic identities while not bypassing its utopian possibilities. In case of the first-generation male characters, their crossracial/homosocial friendship becomes a platform for a mode of egalitarian belonging across the racial divide. It further implies a symbolic union between working-class white and nonwhite immigrant. The younger generation, in contrast, undergoes problems of racial, ethnic, cultural affiliations in far more complicated ways than the older one. Above all, White Teeth demonstrates the subtle workings of liberal multiculturalism, within which the younger characters are constructed to be a multiethnic subject in varied modes. It delineates the formation mainly by exploring the persisting legacies of Britain's imperial history that partake in their subject-making. The novel, in doing so, obliquely suggests that the younger generation is to confront the past that is a seminal part of their present life rather than have the freedom to throw it away to be a carefree member of a multicultural society.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.452-456
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• 2013

PURPOSE. The aim of this study was to evaluate the repeatability of the digitizing of silicon rubber impressions of abutment teeth by using a white light scanner and compare differences in repeatability between different abutment teeth types. MATERIALS AND METHODS. Silicon rubber impressions of a canine, premolar, and molar tooth were each digitized 8 times using a white light scanner, and 3D surface models were created using the point clouds. The size of any discrepancy between each model and the corresponding reference tooth were measured, and the distribution of these values was analyzed by an inspection software (PowerInspect 2012, Delcamplc., Birmingham, UK). Absolute values of discrepancies were analyzed by the Kruskal-Wallis test and multiple comparisons (${\alpha}$=.05). RESULTS. The discrepancy between the impressions for the canine, premolar, and molar teeth were $6.3{\mu}m$ (95% confidence interval [CI], 5.4-7.2), $6.4{\mu}m$ (95% CI, 5.3-7.6), and $8.9{\mu}m$ (95% CI, 8.2-9.5), respectively. The discrepancy of the molar tooth impression was significantly higher than that of other tooth types. The largest variation (as mean [SD]) in discrepancies was seen in the premolar tooth impression scans: $26.7{\mu}m$ (95% CI, 19.7-33.8); followed by canine and molar teeth impressions, $16.3{\mu}m$ (95% CI, 15.3- 17.3), and $14.0{\mu}m$ (95% CI, 12.3-15.7), respectively. CONCLUSION. The repeatability of the digitizing abutment teeth's silicon rubber impressions by using a white light scanner was improved compared to that with a laser scanner, showing only a low mean discrepancy between $6.3{\mu}m$ and $8.9{\mu}m$, which was in an clinically acceptable range. Premolar impression with a long and narrow shape showed a significantly larger discrepancy than canine and molar impressions. Further work is needed to increase the digitizing performance of the white light scanner for deep and slender impressions.

• 대한심미치과학회지
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• 제13권1호
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• pp.31-39
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• 2004

For the prosthodontic results which are compatible with esthetics to be fulfilled, the first prerequisite would be periodontal intervention and stability, the second one may be functional competency and the ultimate goal should be ascribed to esthetic considerations. Other words, esthetic dentistry is a whole entity which encompasses the biological stability of the periodontium, physical accuracy of the prosthodontic structure and finally, the beauty which can be found in natural dentition. It also implies the harmonized lip line which reveals the well-balanced tooth morphology and health gum profiles (Red-White Esthetics). Largely, there lie some differences in the input system of the 3-dimentional data from the prepared abutments between respective computer-assisted systems available now. But the manufacturing systems (CAM) are very similar between them, to say, comprise numeric control systems with whole 3-dimensional milling units according to the restorations to be made. Now the author is going to present CAD/CAM Zirconia All Ceramic Restoration on the topics for the Red-White Esthetics, periodontal control and maintenance, treatment for the discolored teeth, post & core build-up works for the devitalized teeth, characteristics of the Zirconium oxide All Ceramics, fabrication procedures, clinical considerations and its application to diverse clinical situations.

• Restorative Dentistry and Endodontics
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• 제2권1호
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• pp.50-54
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• 1976

16 healthy teeth extracted have been selected and their color and structural change have been observed at the fixed temperatures of $200^{\circ}F$., $400^{\circ}F$., $600^{\circ}F$., and $800^{\circ}F$. respectively at the intervals of 10min. 30min and 60min. The results were as follows: 1) $200^{\circ}F$ Groop: At the 60 minutes interval, crown surface shows pattern simliars to mottled teeth and roots take on light yellowish colar and interglobular dentin tends to be rough. 2) $400^{\circ}C$ Groop: at the 30 minutes interval, cracks begin to show in the direction of long axis of the teeth and crown surface have been observed on the verge of fracture at the 60 minutes interval. 3) $600^{\circ}F$ Groop: Crowns take on grayish-white color thoroughout 10, 30 and 60 minutes intervals and roots reveal black color. Moreover the seperation of enamel from dentin has been confirmed at the 60 minutes interval and inner dentin has changed black. 4) $800^{\circ}F$ Groop: Crowns take on the same grayish-white color as at the $600^{\circ}F$ at the 10, 30 and 60 minutes intervals and roots reveal gray color at the 30 and 60 minutes intervals, while parts of the crown have fractured at the 10 minutes interval. Inner dentin has turned gray at the 60 minutes interval.

• 대한치과기공학회지
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• 제23권1호
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• pp.85-93
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• 2001

The purpose of this study was to evaluate the effects of commercial home-tooth bleaching agents on the color of tooth. Twenty five sound extracted teeth were randomly divided into five groups. The color differences between before and after treatment with five types of tooth bleaching agents (7.5% hydrogen peroxide Nite White $Excel^{(R)}$, 10% carbamide peroxide Nite White $Excel^{(R)}$, 16% carbamide peroxide Nite White $Excel^{(R)}$, 10% carbamide peroxide Insta-BriteTM, 20% carbamide peroxide Insta-$Brite^{TM}$) were evaluated. The results were as follows: 1. By 2 week home tooth bleaching agent applications, the values ($L^*$) of bovine teeth increased as high as 4.38 $\sim$ 8.80 when comparing to those of the samples before treatment, and the color difference (${\Delta}E^*$) showed as high as 10.16 $\sim$ 15.04. 2. 16% carbamide peroxide Nite White Excel induced significantly greater ${\Delta}L^*$ than other test edgroups except for 7.5% hydrogen peroxide Day White Excel, and significantly greater ${\Delta}E^*$ than other tested groups by 2 week bleaching agent treatments (p<0.01). 3. 16% carbamide peroxide Nite White Excel(${\Delta}L^*$=8.80, ${\Delta}E^*$=15.04) induced significantly greater ${\Delta}L^*$ and ${\Delta}E^*$ than 10% carbamide peroxide Nite White Excel(${\Delta}L^*$=5.01, ${\Delta}E^*$=10.16)(p<0.01), but significant difference between 10% carbamide peroxide Insta-Brite(${\Delta}L^*$=4.38, ${\Delta}E^*$=10.51) and 20% carbamide peroxide Insta-Brite(${\Delta}L^*$=5.63, ${\Delta}E^*$=11.23) was not shown in ${\Delta}L^*$ and ${\Delta}E^*$(p>0.01). 4. 16% carbamide peroxide Nite White Excel(${\Delta}L^*$=8.80, ${\Delta}E^*$=15.04) which were applied in night time induced significantly greater ${\Delta}L^*$ and ${\Delta}E^*$ than 7.5% hydrogen peroxide Day White Excel(${\Delta}L^*$=8.47, ${\Delta}E^*$=12.75) which were applied in day time. Conclusions: These results demonstrate that all the commercial home-tooth bleaching agents have appreciable bleaching effect on teeth, and the effects of home-tooth bleaching agents which are used during night time are affected by content of carbamide peroxide. Especially the whitening effect of home tooth bleaching agents that are used through night time is greater than that of short time-applying tooth bleaching agent.

• 대한치과보철학회지
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• 제59권4호
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• pp.469-477
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• 2021

상악 전치부 임플란트의 성공적인 수복을 위해서는 pink esthetics와 white esthetics가 모두 충족되어야 한다. Pink esthetics 부분의 경우 적절한 임시보철물의 역할이 중요하고, white esthetics 부분의 경우에는 최종 보철물의 색상과 형태가 중요하다. 다층 지르코니아는 기존의 단일구조 지르코니아에 비해 절단 부위의 투명도가 높기 때문에 추가적인 도재 축성 없이 자연스러운 보철물 제작이 가능하다. 따라서 본 증례에서는 상악 전치를 상실한 환자에서 적절한 임시보철물을 통해 기능과 심미성을 충분히 회복한 후 다층 지르코니아를 통해 white esthetics를 달성하였다.

• 대한치과교정학회지
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• 제1권1호
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• pp.15-20
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• 1970

저자는 흰쥐 27수의 하악제일대구치를 교정용 고무선으로 이동시킨후, 이동의 초기에 나타나는 치수의 반응을 조직학적 방법으로 관찰하는 것을 연구목적으로 하였다. 30 Gm부터 120 Gm까지의 힘을, 12수는 3일간, 15수는 7일간, 각 실험치아에 부여하였다. 관찰결과는 다음과 같았다. 1. 치수조직의 주변화는 치수혈관의 순환장애와 조상아세포의 공포형상으로 나타났다. 2. 적용시킨 힘의 증가에 따라서 상기 조직변화의 범위가 확대되었다. 3. 기외에 치근의 상아질과 백악질의 부분적 흡수도 볼 수 있었다.

• 대한치과의사협회지
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• 제50권8호
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• pp.507-515
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• 2012

The purpose of this article is to discuss the effect of aging on the treatment of replantation and transplantation of teeth in old patients. I case of replantation and 2 cases of transplantations in old patients are reported in this article. Patients aged 65 and over are included. They had several problems such as periapical lesion, crack or foot fractures. In those cases, the replantation and transplantation were treatment of choice. White ProRoot MTA was used in apical retrograde filling and perforation repair. After replantation and transplantation of teeth, follow-up visits showed signs of healing in 3 cases. Considerations and indications for replantation and transplantation are not much affected by age. Old patients are aware that replantation and transplantation can be performed comfortably and that age is not a factor in prediction success.