• Restorative Dentistry and Endodontics
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• 제35권5호
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• pp.368-373
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• 2010

연구목적: 본 연구는 감염 조절용 차단막을 여러 겹으로 사용했을 때 광중합기의 광강도와 파장, light diffusion 등에 미치는 영향에 대해 조사하였다. 연구 재료 및 방법: 감염 조절용 차단막은 투명 랩 (크린랩)을 사용하였고 광중합기는 할로겐 광중합기 (Optilux 360)와 LED 광중합기 (Elipar FreeLight 2)를 사용하였다. 차단막을 1겹, 2겹, 4겹, 8겹으로 광중합기의 광섬유말단을 감싸고 휴대용 광강도 측정기 (Cure Rite)로 광중합기의 광강도를 측정하였다. 광중합기를 주문제작한 optical breadboard에 고정시킨 후 휴대용 spectroradiometer (CS-1000)를 이용하여 광중합기의 파장을 측정하였고, DSLR (Nikon D70s)을 이용하여 광중합기의 light diffusion을 사진 촬영하였다. 결과: 광강도 측정 결과는 차단막의 두께가 증가할수록 광강도가 유의하게 감소하였으나 할로겐 광중합기에서 1겹과 2겹 사이에는 유의차가 없었으며, 4겹 이상의 차단막을 투과할 때 광강도가 더 많이 감소하였다. 여러 겹의 차단막을 투과한 광중합기의 전체적인 파장 형태와 peak wavelength의 변화는 관찰되지 않았다. Light diffusion 사진 촬영 시, LED 광중합기에서는 차단막의 두께가 미치는 영향이 없었으나 할로겐 광중합기에서는 차단막을 4겹 사용했을 때부터 중합광이 조사되는 각도가 감소하기 시작하여 8겹 사용했을 때 통계적으로 유의하게 감소하는 것을 볼 수 있었다 (p < 0.05). 결론: 광중합형 복합레진을 광중합할 경우 감염 조절용 차단막이 찢어지는 경우를 대비하여 1겹으로 사용하기 보다는 2겹으로 사용하는 것이 환자간의 교차감염을 예방하는데 유리할 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제31권2호
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• pp.79-85
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• 2006

생활치 미백제와 알콜 전처리 과정이 상아질 접착에 미치는 영향을 평가하고자 발거치 55개의 치관부 협측 상아질면에서 $Opalescence^{(R)}$(Ultradent사 미국)로 미백처리 후 즉시 $One-step^{(R)}$ 상아질 접착제(Bisco사, 미국)를 전 처치한 $Z-250^{(R)}$ 복합레진(3M-ESPE사, 미국) 접착군, 미백처리 2주후 레진 접착군, 미백처리 후 70% 에탄올 처리군, 그리고 미백처리하지 않은 대조군으로 나누어 실험한 다음 전단접착강도를 측정하고 95% 유의수준에서 일원변량분석법으로 통계분석 하였다. 생활치 미백제가 상아질 접착력을 현저히 감소시켰다. 미백처리 2주 후 레진 접착군은 미백처리하지 않은 대조군과 유의한 차이가 나타나지 않았으며 70% 에탄을 처리군은 미백처리하지 않은 대조군보다는 접착력이 낮았으나, 미백처리 2주 후 레진 접착군과는 차이가 없고 즉시 접착군보다는 높은 접착강도를 나타내었다. 따라서 임상에서 치아미백 후 즉시 레진수복을 할 경우, 에탄올로 전처리하면 상아질에서 레진 접착력을 회복할 수 있을 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제34권4호
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• pp.371-376
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• 2009

이 연구에서는 Mineral Trioxide Aggregate (MTA)와 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) 레진을 혼합하여 치근단 역충전 재료로 사용하였을 때의 미세누출을 MTA, 포틀랜드 시멘트와 비교하였다. 발치된 사람 치아의 근관형성 및 충전 후 치근단 절제와 역충전 와동을 형성하였다. MTA, Portland cement, MTA와 4-META/MMA & TBB레진을 혼합한 각각의 재료로 치근단을 역충전한 후 methylene blue dye에 72시간 동안 침적하여 염료가 침투한 길이를 10배 현미경 하에서 측정하였다. MTA와 4-META/MMA & TBB 레진 혼합 충전 군에서는 포틀랜드 시멘트나 MTA 충전군보다 통계적으로 유의하게 적은 미세 누출을 보였으며, 포틀랜드 시멘트와 MTA 충전군의 미세 누출 정도는 통계적으로 차이가 없었다. 이 실험의 결과로 보아 MTA와 4-META/MMA & TBB레진 혼합 재료는 치근단 역충전시 포틀랜드 시멘트나 MTA에 비해 낮은 초기 미세누출을 보여, 치근단 봉쇄 효과가 우수한 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.54-69
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• 1996

The purpose of this vitro study was to evaluate attachment and proliferation of human pulpal cells to the attachment glycoprotein-coated and non-coated culture dishes. Well known adhesive glycoproteins were used, such as type I collagen, type IV collagen, fibronectin, laminin, and vitronection. Each adhesive glycoproteins applied onto the culture dishes. In this study, the protein coated and non-coated dishes were classified as each groups. Human pulpal cells onto each culture dishes. After 90 minute, 4 hour and 24 hour incubation attached cells in each group were counted with hematocytometer for evaluation of the attachemnt of human pulpal cells. The configurations of attached human pulpal cells were done by SEM observation. The results as follows : 1. After 90 minute incubation the score of attachment of human pulpal cells was best in laminin-coated group among groups. Then fibronectin, type IV collagen group were better, and all proteins were higher than control. 2. After 4 hour incubation the numbers of attachment of human pulpal cells were most in fibronectin coated group. 3. After 24 hour incubation all of adhesive glycoproteins showed high and similar attachemtn effect to human pulpal cells. 4. In SEM observation, fibronectin and type IV collagen groups showed well spreaded human pulpal cells, then laminin group was moderately spreaded, and vitronectin group was mildly spreaded as well as control group.

• 한국통신학회논문지
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• 제38A권8호
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• pp.650-655
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• 2013

광저장장치의 DC-억압을 위한 멀티모드 코딩 기법 중 Guided Scrambling (GS) 코딩기법이 널리 사용된다. 홀로그래픽 저장장치를 위한 DC-억압 GS코딩에서는 후보코드 선택기준으로 심볼의 균등한 분포 및 심볼간 천이의 최대화 기준이 고려되었다. 본 연구에서는 후보코드행렬의 digital sum value (DSV)의 $l_{\infty}$-norm을 최소화하는 minimum DSV (MDSV) 기준 GS코딩을 정수계획법 모형으로 수식화하고, 제안된 모형을 사용하여 MDSV 기준과 최대천이강도 기준이 적용된 GS코딩의 성능을 제어비트수, 행렬크기 및 스크램블링 다항식들의 조합에 대하여 평가한다.

• Restorative Dentistry and Endodontics
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• 제14권1호
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• pp.97-105
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• 1989

This study was conducted to evaluate and compare the apical leakage among the retrograde filling materials; retrograde filling with non-zinc amalgam, cavity varnish and non-zinc amalgam, z.o.e cement, Glass Ionomer cement, scotch bond and silux. Sixty single rooted teeth were divided into six groups and each tooth was individually prepared for its particular group. The specimens were incubated at $37^{\circ}C$ for 24 hrs and then were infiltrated by 2% methylene blue for 7 days. Apical leakage was evaluated by measuring the degree of dye penetration between the filling material and the canal wall. The results were as follows: 1. The scotch bond and silux group showed the least amount of apical leakage and the control group showed the greatest amount of apical leakage. 2. The groups retrofilled with cavity varnish and amalgam, glass-Ionomer cement, scotch bond and silux showed significantly good apical seal than control group. 3. The groups retrofilled with glass Ionomer cement, scotchbond and silux showed significantly good apical seal than the groups retrofilled with Amalgam and Zinc oxide eugenol cement.

• 대한물리치료과학회지
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• 제3권1호
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• pp.843-853
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• 1996

The purpose of this study was to determine whether extension exercise is effective in reducing low back pain. Nine patients with low back pain were randomly assigened to one of two groups-one was an experimental group in which the patient were treated with extension exercise(McKenzie method) and conservative therapy. The other was a control group in which the patients were treated with conservative therapy only. Treatment was performed for a period of ten days during Which we examed each patient three times: the first exam was done at the begining of treatment, the second after fives days, and the third after ten days. We used 'The Oswestry low back pain disability questionnaire'(r=.99) as the examination tool. The results were as follows: 1. Both experimental and control groups showed nonsignificant differences before and after treatment, and the between group difference was also non-significant(P>.05). 2. There was no effective reduction of low back pain by MecKenzie's extension exercise(p>.05). We admit that our study protocol had several shortcomings. If they had been accounted for, the result might have been different. Further study should be done with a better experimental design, a larger sample, and a longer experimental duration.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.720-730
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• 1997

This study was performed to observe the histopathological response to the bonding resin directly applied on the remaining pulp tissues. 40 teeth from 3 adult dogs were pulpotomized with a sterile round bur and sharp excarvater. In the control group, $Ca(OH)_2$ powder was applied on the pulp tissue and the cavities were sealed with IRM cement. In the experimental group 1, Superbond C&B was applied on the remaining pulp and the cavities conditioned with 10-3 solution were filled with the mixture of the MMA liquid, PMMA powder and Catalyst. Multi-purpose adhesive was used on the remaining pulp tissue in the experimental group 2 and Z-100 was filled in the cavities. In the experimental group 3, Clearfil photobond applied and directly photo-cured on the pulp tissue, then the cavities were treated with CA agent (10% citric acid and 20% $CaCl_2$ aqueous solution) for 20 seconds, washed and applied with Clearfil photobond then filled with Protect liner. The experimental animals were sacrified at the 1st, 2nd, and 4th week. The specimens were routinely processed and stained with H-E for light microscopic observation. The results were as followed : 1. In the experimental group 1, the number and characteristics of the dentin bridge formation case was similar to those in the control group and less cases were observed in the experimental group 2 and 3 than experimental group 3. The inflammatory response in experimental group 1 was less than that in the control group at 1st week but there had been little difference at between 2nd and 4th week. 2. The number of the dentin bridge in experimental group 2 was less than that in control group and experimental group 1. The inflammatory response of the experimental group 1 was similar to that of experimental group 1 but less than that of the control group. A number of bleeding and vascular congestion were observed. The least inflammatory response was seen in the experimental group 2 among all groups. 3. In the experimental group 3, one case of the dentin bridge formation was observed and that was the same as that in the experimental group 2 but smaller than that of the control and experimental group 1. The inflammatory response of the experimental group 3 was least at the 1st week and most at the 4th week in the all group.

• Restorative Dentistry and Endodontics
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• 제25권4호
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• pp.599-605
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• 2000

Among the effects of tooth bleaching on composite resins, degree of color change and dye deposition onto composite resins after office bleaching were investigated in vitro. Seventy two disc-shaped resin samples were fabricated with hybrid type composite resin, Z-100 under 3 different environments(24 samples for each environment) characterized by 3 kinds of light-curing intensity and duration($250mW/cm^2$-20sec., $250mW/cm^2$-40sec., $550mW/cm^2$-20sec.). As control, one-third samples of each group were not treated with bleaching agent. The remaining two-thirds samples of each group were treated with bleaching agent(bleaching group). Then, before thermocycling procedure in coffee bath, the half of the samples treated with bleaching agent were polished(polishing group) with polishing system. SofLex, but the other half(not-polishing group) and control group were not polished. Another 72 samples were also made with microfilled type composite resin. Sillux Plus and treated according to the experimental procedures mentioned above. The color of each resin sample was measured before bleaching, after bleaching, and after thermocycling preceded by bleaching. And color difference was evaluated. It was concluded as follows: 1. The amount of color change of resin samples after office bleaching was not statistically significant(p>0.05). But the samples which were treated with bleaching agent showed more color change than that of control group. 2. After thermocycling in coffee bath, the amount of color change of resin samples between control and bleaching group was not statistically significant(p>0.05). 3. After thermocycling in coffee bath, the polishing procedure of resin samples showed no statistically significant difference(p>0.05) between polishing and not-polishing group in the aspect of color change.

• Restorative Dentistry and Endodontics
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• 제40권1호
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• pp.37-43
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• 2015

Objectives: Some antioxidants are believed to restore dentin bond strength after dental bleaching. This study was done to evaluate the influence of antioxidants on the bond strength of bleached bovine dentin. Materials and Methods: Thirty incisors were randomly assigned to 10 groups (two unbleached control and eight bleached groups:immediate bonding IB, 4 wk delayed bonding DB, 10% sodium ascorbate treated SA, 10% ${\alpha}$-tocopherol treated TP groups). Teeth in half of groups were subjected to thermal stress, whereas the remaining groups were not. Resin-dentin rods with a cross-sectional area of $2.25mm^2$ were obtained and microtensile bond strength was determined at a crosshead speed of 1 mm/min. Fifteen specimens were prepared for SEM to compare the surface characteristics of each group. The change in dentin bond strength from thermal stress and antioxidant treatment was evaluated using two-way analysis of variance (ANOVA) and Sheffe's post hoc test at a significance level of 95%. Results: The control group exhibited the highest bond strength values, whereas IB group showed the lowest value before and after thermocycling. The DB group recovered its bond strength similar to that of the control group. The SA and TP groups exhibited similar bond strength values with those of the control and DB groups before thermocycling. However, The TP group did not maintain bond strength with thermal stress, whereas the SA group did. Conclusions: Applying a 10% sodium ascorbate solution rather than 10% ${\alpha}$-tocopherol solution for 60 sec is recommended to maintain dentin bond strength when restoring non-vitally bleached teeth.