• Restorative Dentistry and Endodontics
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• v.35 no.5
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• pp.387-394
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• 2010

Objectives: The purpose of this study was to evaluate the whitening efficacy and longevity of home bleaching. Materials and Methods: A total of 28 patients were divided into either experimental group (Opalescence F; 15% carbamide peroxide) or control group randomly. The patients in experimental group were instructed to wear individual trays applied with bleaching gel for 2 hours a day for 4 weeks. Any treatments weren't applied to the patients in control group. The color measurements of central incisors, lateral incisors & canines of upper and lower arch were recorded at base line, immediately after the finishment of treatmemt (4 weeks), 8 weeks and 12 weeks using Colorimeter (Chroma Meter, 2600d Konica Minolta co.) and Vitapan classical shade guide (Vita Zahnfabrik). Results: A significantly stronger color change was observed for overall teeth samples in experimental group immediately after treatment (at 4 weeks) compared to ones in control group (p < 0.05). There was also a significant difference between baseline and 8 weeks or 12 weeks separately though color rebouncing phenomenon occurred as time went by (p < 0.05). Conclusions: The clinical effecacy and longevity of home bleaching without combined application of in-office bleaching was observed through this experiment.

• Restorative Dentistry and Endodontics
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• v.29 no.1
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• pp.30-35
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• 2004

치아 미백술은 치아의 심미성을 향상시키는 가장 보존적인 방법의 하나로 인식되어져 왔으며 최근의 심미치과에 대한 관심의 증가와 함께 그 빈도가 급격히 증가하고 있는 술식의 하나이다. 일반적으로 치아 미백술 후 바로 접착수복을 할 경우 결합력이 감소하는 것으로 알려져 있으며 이를 해소하기 위해 일정시간 경과 후 접착수복 술식을 시행할 것을 권장 하고 있다. 자가산부식형 (self-etching primer system) 접착제는 기존의 접착제와 다른 성분으로 인해 치아미백제에 의한 영향에 대해 잘 알려져 있지 않은 상태이다. 이에 본 실험에서는 미백술을 시행한 법랑질 상에서 서로 다른 세 가지의 접착 시스템을 이용하여 미백술 후의 지연 시간이 결합력에 미치는 영향을 비교하고자 하였다. 발거한 대구치 68개를 물기가 있는 상태에서 근원심으로 절단하고 치관부를 자가중합 레진에 식립하여 시편을 제작하였다. 세 가지 접착제로 $One-step^{\circledR}$, Clearfil SE Bond $primer^{\circledR}$, One-up Bond $F^{\circledR}$를 이용하였다. 각 접착제를 미백을 시행하지 않는 대조군과 미백 시행 후 바로 접착한 즉시 접착군, 그리고 2주간 생리식염수에 보관한 후에 접착한 지연군으로 나누어 총 9개의 실험군으로 나누었다. 접착제를 처리한 면에 Clearfil $AP-X^{\circledR}$ 복합레진을 2mm충전하고, 40초간 광중합을 시행하였다. 24시간 후 전단접착강도를 측정하였으며, 그 결과는 다음과 같이 나타났다. $One-step^{\circledR}$의 경우, 즉시 접착군에서 지연 접착군보다 유의성 있게 낮은 접착강도를 나타내었다. Clearfil SE $Bond^{\circledR}$의 경우, 즉시 접착군과 미백을 시행하지 않은 군간에는 접착 강도에 유의한 차가 없었으나,지연접착군에서는 낮은 강도를 나타내었다. One-Up Bond F$^{\circledR}$의 경우, 즉시 접착군에서 유의성 있게 낮은 전단접착강도를 나타내었고, 전반적인 접착 강도가 다른 두 접착제에 비해서 유의성 있게 낮은 값을 보였다. $One-step^{\circledR}$을 사용할 경우 지연접착을 하는 것이 추천되며, Clearfil SE Bond$^{\circledR}$의 경우에는 즉시 접착을 시행하더라도 영향을 적게 받는 것으로 나타났으며, One-Up Bond $F^{\circledR}$의 경우 미백술 후 접착수복 과정에 사용에 제한이 있는 것으로 나타났다.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.165-173
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• 2013

The purpose of this study was to evaluate the surface change after 15% carbamide peroxide home bleaching to various restorative materials (composite resin [CR], resin modified glass ionomer [RMGI] and glass ionomer [GI]) and to observe the effect of surface condition of the materials on re-staining. Three esthetic restorative materials (Filtek Z250, 3M, USA; Fuji II LC, GC, Japan; Fuji II, GC, Japan) were used in this study. Twenty specimens per material group were made and divided into two groups (bleached and control). The specimens were immersed in coffee after applying bleaching agent. The color change and surface roughness were measured before and after bleaching and after immersion in coffee. The data were analyzed with SPSS 18.0. The results were as follows: 1. The color of all experiment groups was significantly changed after bleaching (p<0.05). RMGI was the greatest value of ${\Delta}E^*$ and ${\Delta}L^*$. GI and CR groups were in ordering (p<0.05). The ${\Delta}a^*$ value was decreased GI, RMGI and CR. RMGI was only significantly decreased in ${\Delta}b^*$ value (p<0.05). 2. The surface roughness before and after bleaching was significantly different on CR, RMGI and GI (p<0.05). 3. After staining with coffee, the value of ${\Delta}E^*$ was increased in GI, RMGI and CR, furthermore GI and RMGI showed significant difference in the bleaching groups (p<0.05). The ${\Delta}L^*$ value of GI and RMGI was significantly decreased. 4. The change of surface roughness after staining was not significantly different in all groups (p>0.05). The maintenance of color stability in esthetic restorations is one of the most important properties. Tooth whitening is for the aesthetic. Therefore, dental professionals should notice to patients about re-staining after tooth whitening. They should give an instruction that how to prevent and which kinds of agents could be stained.

• Journal of Gastric Cancer
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• v.5 no.4 s.20
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• pp.288-294
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• 2005

Purpose: Superficially spreading (SS) early gastric cancer (EGC) is characterized by wide horizontal extension without deep vertical invasion. It is a relatively rare form of EGC, and it's clinicopathological (C-P) characteristics are not evident. This study aimed to clarify their C-P characteristics. Materials and Methods: We defined SS EGC as invading less than the submucosal layer that measured more than 60 mm in diameter or wider than $5{\times}5cm \;(25cm^2)$ in width. The C-P characteristics and prognosis were compared between 69 patients with SS EGC and 319 patients with the common type EGC (EGC except SS type). Results: For SS EGC lymph node metastases, Lauren's diffuse type, lymphatic invasion were significantly higher than in common type EGC. In patients with SS EGC, all of the metastatic lymph nodes were anatomically distributed within the paragastric region, with fewer along the left gastric artery and common hepatic artery. In 6 cases of SS EGC with resection marqins less than 10 mm, there was no death during the follow-up period (4 to 13 years after operation) if margins were not involved. Age (>58 yrs), tumor site (upper 1/3), lymph node metastasis, submucosal invasion were statistically significant poor prognostic factor in univariate survival analysis. In multivariate survival analysis, age and lymph node metastasis were independent prognostic factors. However, tumor diameter or width was not a significant prognostic factor. Conclusion: Although SS EGC has histologically distinct properties, gastrectomy with free surgical margins and appropriate lymph node dissection $(D1+{\beta})$ could be a suitable treatment.