• Journal of Periodontal and Implant Science
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• 제30권2호
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• pp.403-420
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• 2000

The treatment and prevention of periodontitis is focused on the reduction and the elimination of pathogenic bacteria, especially A. actinomycetemcomitans and black pigmented bacteria such as P. gingivalis. To prevent recurrent disease, the recolonization of these bacteria should be inhibited in the periodontal pocket. Since the replacement therapy was introduced in periodontics by Hillman et al, Jeong et al reported that hydrogen peroxide-producing Lactobacillus acidophilus V-20 completely inhibited P. gingivalis and A. actino - mycetemcomitans in vitro and mouth gargling with Lactobacillus acidophilus V-20 in periodontitis patients during the maintenance phase improved clinical condition and reduced the No. of P. gingivalis and A. actinomycetemcomitans at 4 weeks of treatment. Prior to replacement therapy with bacteria, dynamics of microbial colonization should be considered. This study was performed to evaluate the change in the viable cell number of Lactobacilli and P. gingivalis after oral administration of L. acidophilus V-20. In periodontal health, gargling increased the No. of Lactobacilli in saliva, buccal mucosa, supragingival plaque from the first week, which maintained for 2-3 weeks after gargling stop, and then returned to the undetectable baseline level at the ninth week. In the periodontal pocket of moderate periodontitis patients, daily irrigation for 1 week and weekly irrigation for subsequent 3 weeks decreased the viable cell number of P. gingivalis during the period of irrigation and increased the number of Lactobacilli, which was maintained from the second to the seventh week. L. acidophilus V-20 was isolated for the first 2 weeks of oral administration, and the 3 different strains of Lactobacilli were isolated continuously for remaining period and identified as L. ali - mentarius, L. casei subspecies casei and L. fructosus. The first two Lactobacilli strains completely inhibited P. gingivalis in vitro and all the isolated Lactobacilli strains reduced the artificial plaque formation by 55-63%. These results showed that mouth gargling or pocket irrigation with L. acidophilus V-20 increased the No. of intraoral Lactobacilli and caused to decrease in the No. of P. gingivalis. This suggests that the replacement therapy by these Lactobacilli might be useful in the maintenance care of periodontal patients.

• 대한치과보철학회지
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• 제37권1호
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• pp.1-22
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• 1999

In order to investigate various physical and biological properties of dental magnetic attachments studies on retentive characteristics, corrosion properties, cytotoxicity of different magnetic systems for dental applications were done. For the study of retentive characteristics changes of retentive force by increasing air gap, wear properties of various attachment systems and loss of magnetic force by heat treatment were measured. Forte study of corrosion property of magnet covering metal electrochemical corrosion was done in artificial saliva and 0.9% NaCl solution between $-1,000mV_{SCE}\;and\;+1,000mV_{SCE}$. Anodic polarization curves are obtained about 6 types of samples and 2 types of solution. Corroded surfaces were examined with metallurgical microscope, scanning electron microscope and surface profilometer. For the study of cytotoxicity of magnetic attachment and its field cell growth and agar overlay test were done. The results of this study were as follows. 1. In Magnetic attachments using closed circuit retentive force at zero air gap was greater than magnets using open circuit, but decrease of retentive force by increasing air gap was also greater than open systems. 2. After 40,000 cycles of wear test all mechanical attachment resulted in varing degree of retention loss but in magnetic attachments no loss of retentive force was observed. 3. The magnetic attachment using Neodymium magnet showed early loss of retentive force about $200^{\circ}C$ but attachment using Samarium magnet showed some resistance to heat treatment and complete retention loss was observed about $500^{\circ}C$. The keeper was not influenced by heat treatment in retention. 4. In electrochemical corrosion test Dyna magnetic attachment covering metal showed the highiest corrosion resistance and Shiner magnet covering metal showed the least corrosion resistance and examination of corroded surface with metallurgical microscope, scanning electron micro-scope and surface profilometer also showed same results with anodic polarization corves. 5. The result of cell culture tests on the magnet covered with metal showed least recognizable cytotoxicity.

• 대한소아치과학회지
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• 제41권3호
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• pp.233-240
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• 2014

어린이용 영양제의 우식 유발능에 관해 알아보기 위하여 국내에서 시판 중인 건강기능식품 어린이용 영양제 4종에 대한 생체외 연구를 시행하였다. 어린이용 영양제 4종을 실험군으로, 10% 자당을 양성 대조군, 인공 타액을 음성 대조군으로 하였다. 실험군 및 대조군의 pH, 완충능, 산생성능, 우치 법랑질 침식능을 검사하였다. 실험군 4종의 pH 모두 탈회 임계 pH인 5.5보다 낮았다. 완충능은 Hama Vitamin Pharm이 가장 크고, Smart Chewable Vitamin A가 가장 작았다. 4개의 실험군은 음성 대조군보다 유의하게 높은 산생성능을 보였다(p < 0.05). 우치 법랑질 침식능 검사 결과, 4종의 실험군과 양성 대조군에서 표면미세경도가 유의하게 감소하였다(p < 0.05). 표면미세경도 감소율은 실험군 중에서 Hama Vitamin Pharm이 유의하게 높았고, Hikid Plus는 유의하게 낮았다(p < 0.05).

• 대한화학회지
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• 제62권3호
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• pp.181-186
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• 2018

니트로사민류는 이차아민과 아질산이 니트로소화 반응을 통해 생성되는 화합물이며, 고무의 가공시 가황과정을 거치면서 생성되는 것으로 밝혀졌다. 최근 고무제품 중에서 니트로사민류가 검출되면서 큰 이슈가 되고 있다. 콘돔은 인체에 삽입되는 일회용 의료기기로써 피부 및 점막에 직접 접촉하므로 안전성이 매우 중요하다. 이에 본 연구에서는 ISO 29941 방법을 준용하여 콘돔 중 니트로사민류의 분석법을 개발하였다. 콘돔 시료를 증류수에 넣어 용출시키고, 용출액에서 분석대상 물질을 추출하기 위해 디클로로메탄으로 액체-액체 추출을 실시하였으며, 농축 후 LC-MS/MS에서 정량분석하였다. 분석법의 정확도는 85.8~108.7%, 정밀도는 11.5% 이하, 검출한계는 0.11(NDPA, NDBA) ~ 0.48(NPYR) ng/mL이었다. 31건의 콘돔시료 중에서 증류수 용출에 의해 검출된 물질은 NDBA 2건이었고, 인공타액(pH 4.5) 용출로 검출된 물질은 NDMA 1건, NDEA 4건, NDBA 26건이었다. 니트로사민류의 총량은 모든 시료에서 $500{\mu}g/kg$을 초과하지 않았다.

• 대한소아치과학회지
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• 제37권1호
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• pp.82-90
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• 2010

본 연구는 불소함유 접착테잎의 법랑질 침식 예방효과를 평가하기 위해건강한 소의 치아를 절단하여 아크릴 주형에 매몰하고 정중선에 홈을 형성하여 대조면과 불소 제제를 도포할 실혐면으로 나누었다. 시편을 무작위로 18개씩 4군으로 나누었다. 1군은 APF gel를 도포하고, 2군은 불소 바니쉬를 도포하였으며, 3군과 4군은 5% NaF를 각각 첨가한 methyl cellulose와 poly vinyl alcohol 테잎을 부착하였다. 시편을 콜라에 5분, 증류수에 10분씩 6회 번갈아 처리하며 5일 동안 반복하였다. 시간 경과에 따라 표면미세경도를 측정하고 5일후 각 시편을 절단하여 침식병소의 깊이를 측정하여 다음과 같은 결과를 얻었다. 1. 표면미세경도 값은 5일째만 제외하고 2군, 3군, 4군의 실험면이 각각의 대조면에 비해 컸다 (p<0.05). 2군, 3군, 4군의 실험면 역시 5일째만 제외하고 1군의 실험면에 비해 표면미세경도가 컸다 (p<0.05). 3군과 4군 사이에는 표면미세 경도의 유의한 차이가 없었다(p>0.05). 1군의 실험면과 대조면은 표면미세경도의 유의차가 없었다(p>0.05). 2. 침식병소의 깊이는 2군, 3군, 4군의 실험면이 각각의 대조면에 비해 컸다(p<0.05). 2군, 3군, 4군의 실험면은 1군의 실험면에 비해 침식병소의 깊이가 얕았다 (p<0.05). 2군, 3군, 4군의 실험면 사이의 침식병소의 깊이는 유의차가 없었다(p>0.05). 상기 결과로 보아 새로 개발된 불소함유 접착테잎은 기존의 불소 바니쉬와 같은 법랑질 침식 예방효과가 분명하게 나타나, 법랑질 침식에 감수성이 높은 어린이 환자에게 임상적인 예방법으로서 활용할 수 있는 가능성이 높다고 사료된다.

• 한국치위생학회지
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• 제5권2호
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• pp.131-145
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• 2005

There are normal inhabitants doing medically useful functions in the body. There are many kinds of bacteria performing specific functions in the oral cavity. Two strains of lactic add bacteria were isolated from normal inhabitants of children's oral cavity, which inhibited the production of volatile sulfur compounds by anaerobic bacteria. The authors identified the isolates by 16S rDNA partial sequencing. 1. Two isolates were Gram-positive bacilli and produced hydrogen peroxide. 2. When Streptococcus mutans was cultured in the media, the mean weight of formed artificial plaque on the orthodontic wires was $124.4{\pm}30.4$ mg, whereas being reduced to $5.2{\pm}2.0$ mg and $10.6{\pm}6.6$ mg in the media cultured with Streptococcus mutans and each isolate, respectively(p<0.05). 3. The number of viable cells of Streptococcus mutans was $3.4{\times}10^9$ per ml in the cultured solution, whereas those of Streptococcus mutans in the combined culture with each of isolates were $4.6{\times}10^8$ and $2.4{\times}10^8$ per ml. 4. The optical density was 1.286 in the supernatant of Fusoacterium nucleatum after vortexing for 30 minutes, whereas in the supernatant of combined Fusoacterium nucleatum and each isolate, they were reduced to 0.628 and 00497, which the percentages of coaggregation between them were 2904% and 57.8%, respectively. 5. The optical density of Fusoacterium nucleatum precipitate was 1.794 in the culture media containing cysteine and $FeSO_4$ being reduced to 1.144 and 0.915 in the coaggregated precipitates of Fusoacterium nucleatum and each isolate. 6. The similarity values of 16S rDNA sequence between each of isolates and Lactobacillus salivarius subsp. salicinius were 99.60% and 99.73%, respectively, meaning that isolates were Lactobacillus salivarius subsp. salicinius. These results indicated that two strains isolated from children's saliva, which inhibited the formation of plaque and the production of volatile sulfur compounds, were identified as Lactobacillus salivarius subsp. salicinius.

• 한국치위생학회지
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• 제21권5호
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• pp.507-515
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• 2021

연구목적: 본 연구는 액상발효유, 스터드 타입 및 드링크 타입 농후발효유가 정상법랑질 표면에 미치는 영향을 알아보고자 하였다. 연구방법: 3종의 유산균 발효유와 대조군인 제주삼다수에 우치시편을 8일 동안 매일 10분씩 4회 처리하고 그 외의 시간에는 인공타액에 침지하는 pH 순환처리를 시행한 후 표면미세경도 측정과 주사전자현미경을 이용하여 표면 형태를 관찰하였다. 연구결과: 3종의 유산균 발효유군 모두 대조군에 비해 표면경도차(ΔVHN)가 크게 나타났다. 이 중 액상발효유군은 표면경도차(ΔVHN)가 가장 크게 나타났으며, 주사전자현미경에 의한 법랑질 표면 형태 관찰에서도 가장 심한 표면 손상이 확인되었다. 결론: 유산균 발효유 종류에 따른 물리적 성상과 pH가 치아표면에 영향을 미치는 것으로 나타났다. 따라서 유산균 발효유의 치아부식증 발생 가능성을 고위험군에게 알림으로써 섭취 시 이를 고려하도록 하며, 치아부식증을 줄일 수 있는 예방적 연구가 계속적으로 필요하리라 생각된다.

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.160-171
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• 2021

Purpose. This in-vitro study evaluated and compared the color stability of 3D-printed and conventional heat-polymerized acrylic resins following aging, mechanical brushing, and immersion in staining medium. Materials and methods. Forty disc-shaped specimens (10 mm in diameter and 3 mm thick) were prepared from two 3D-printed [DentaBASE (DB) and Denture 3D+ (D3D)] and one conventional polymethylmethacrylate (PMMA) denture materials. The specimens were thermo-cycled, subjected to mechanical brushing, and were immersed in either coffee, lemon juice, coke, or artificial saliva (AS) to simulate one and two years of oral use. Color measurements of the specimens were recorded by a spectrophotometer at baseline (T0), and after one (T1) and two years (T2) of simulation. The color changes (ΔE) were determined and also quantified according to the National Bureau of Standards (NBS) units. Descriptive statistics, followed by factorial ANOVA and Bonferroni post-hoc test (α=.05), were applied for data analysis. Results. The independent factors, namely material, staining medium, and immersion time, and interaction among these factors significantly influenced ΔE (P<.009). Irrespective of the materials, treatments, and time, the highest and the lowest mean ΔEs were observed for PMMA in lemon juice (4.58 ± 1.30) and DB in AS (0.41 ± 0.18), respectively. Regarding the material type, PMMA demonstrated the highest mean ΔE (2.31 ± 1.37), followed by D3D (1.67 ± 0.66), and DB (0.85 ± 0.52), and the difference in ΔE between the materials were statistically significant (P<.001). All the specimens demonstrated a decreased color changes at T2 compared to T1, and this difference in mean ΔE was statistically significant (P<.001). Conclusion. The color changes of 3D-printed denture resins were low compared to conventional heat polymerized PMMA. All the tested materials, irrespective of the staining medium used, demonstrated a significant decrease in ΔE values over time.

• 대한소아치과학회지
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• 제36권1호
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• pp.38-45
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• 2009

본 연구는 상품화된 10% CPP-ACP 크림 (Tooth mousse, GC Co., Japan)이 0.05 % NaF 불소 용액 매일 양치법을 대체할 수 있는지 알아보기 위하여, 인공 탈회 병소를 가진 우치 법랑질에 대해 10일간 위 두 가지 방법 단독 혹은 복합 사용의 재광화 효과를 비교하였다. 0.1% thymol 용액에 냉장 보관한 소의 치아를 교정용 레진 (Orthodotic resin, Dentsply international Inc., USA)에매몰한 후 탈회 용액에 96시간 보관하였고, 총 60개의 시편을 5개의 군으로 나누었다; 비처치군 (1군), 0.05% NaF 용액 1분 (2군), Tooth mousse 3분 (3군), 0.05% NaF 용액 1분 처리 후 Tooth mousse 3분 (4군), Tooth mousse 3분 처리 후 0.05% NaF 용액 1분(5군). 재광화 정도는 10일간의 시편 처리 전 후의 Vickers hardness number를 측정하여 비교하였으며, 연구 결과는 다음과 같다. 1. 각 군에서 시편 처리 전후의 표면경도를 paired t-test를 이용하여 비교분석한 결과, 3, 4, 5 군에서만 유의할만한 표면 경도 증가가 나타났다(P < 0.05). 2. 각 군별로 평균 표면 경도 증가량은 5 > 4 > 3 > 2 > 1 군 순이었고, 각 군의 표면경도 증가량을 one-way ANOVA test로 비교분석한 후 Duncan test로 사후 검정한 결과, 4, 5 군은 1, 2, 3 군과 유의할만한 표면경도 증가를 보였으며 (P < 0.05), 다른 군들 간에는 유의할만한 차이를 보이지 않았다. 3. Tooth mousse를 우치에 10일간 적용시킨 결과 0.05% NaF 용액보다 더 많은 표면경도 변화량을 나타냈지만, 통계학적으로 유의할만한 차이는 없었다. 이상의 결과에서 Tooth mousse 사용은 불소 양치가 용이하지 않은 환자들에게 양호한 대체 방안이 될 것으로 사료되며, 또한 불소 적용시 Tooth mousse를 복합 사용하는 것이 추천될 수 있으리라 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.82-89
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• 2009

Two in vitro experiments were conducted to examine the effects of propionate precursors in the dicarboxylic acid pathway on ruminal fermentatation characteristics, $CH_4$ production and degradation of feed by rumen microbes. Fumarate or malate as sodium salts (Exp. 1) or acid type (Exp. 2) were added to the culture solution (150 ml, 50% strained rumen fluid and 50% artificial saliva) to achieve final concentrations of 0, 8, 16 and 24 mM, and incubated anaerobically for 0, 1, 3, 6, 9 and 12 h at $39^{\circ}C$. For both experiments, two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were prepared in a nylon bag, and were placed in a bottle containing the culture solution. Addition of fumarate or malate in both sodium salt and acid form increased (p<0.0001) pH of culture solution at 3, 6, 9 and 12 h incubations. The pH (p<0.0001) and total volatile fatty acids (VFA, p<0.05) were enhanced by these precursors as sodium salt at 3, 6 and 9 h incubations, and pH (p<0.001) and total VFA (p<0.01) from fumarate or malate in acid form were enhanced at a late stage of fermentation (9 h and 12 h) as the addition level increased. pH was higher (p<0.001) for fumarate than for malate as sodium salt at 3 h and 6 h incubations. Propionate ($C_3$) proportion was increased (p<0.0001) but those of $C_2$ (p<0.05) and $C_4$ (p<0.01 - p<0.001) were reduced by the addition of sodium salt precursors from 3 h to 12 incubation times while both precursors in acid form enhanced (p<0.011 - p<0.0001) proportion of $C_3$ from 6h but reduced (p<0.018 - p<0.0005) $C_4$ proportion at incubation times of 1, 3, 9 and 12 h. Proportion of $C_3$ was increased (p<0.05 - p<0.0001) at all incubation times by both precursors as sodium salt while that of $C_3$ was increased (p<0.001) from 6h but $C_4$ proportion was decreased by both precursors in acid form as the addition level increased. Proportion of $C_3$ was higher (p<0.01 - p<0.001) for fumarate than malate as sodium salt from 6 h incubation but was higher for malate than fumarate in acid form at 9 h (p<0.05) and 12 h (p<0.01) incubation times. Increased levels (16 and 24 mM) of fumarate or malate as sodium salt (p<0.017) and both precursors in acid form (p<0.028) increased the total gas production, but no differences were found between precursors in both chemical types. Propionate precursors in both chemical types clearly reduced (p<0.0001 - p<0.0002) $CH_4$ production, and the reduction (p<0.001 - p<0.0001) was dose dependent as the addition level of precursors increased. The $CH_4$ generated was smaller (p<0.01 - p<0.0001) for fumarate than for malate in both chemical types. Addition of fumarate or malate as sodium type reduced (p<0.004) dry matter degradation while both precursors in both chemical types slightly increased neutral detergent fiber degradability of feed in the nylon bag.