• 폴리머
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• 제29권2호
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• pp.198-203
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• 2005

용융 압출 발포에 의하여 폴리락틱산(PLLA) 지지체를 제조하고 발포 조건이 지지체의 구조와 기계적 특성에 미치는 영향을 살펴보고 이를 염 추출법에 의하여 제조된 지지체와 비교하였다. 발포제를 함유한 PLLA 용융체가 압출기 및 다이에서 체류하는 시간이 발포제의 무게를 최대로 감소시키는 시간과 일치하여야 최적의 PLLA 지지체의 구조를 얻을 수 있음을 확인하였다. PLLA지지체의 구조를 유지하기 위해서는 발포제의 함량을 $10\;wt\%$ 이하로 조절해야 하며 PLLA 지지체의 다공도는 PLLA의 압출기에서의 체류시간에 가장 큰 영향을 받음을 알 수 있었다. 용융 압출 발포에 의하여 얻어진 지지체는 일반적으로 염 추출법에 의하여 제조된 지지체보다 다소 낮은 다공도를 갖지만 발포 조건의 조절에 의하여 적절한 다공 크기와 다공의 연결성을 가지며 동시에 우수한 기계적 특성을 가져 경조직 재생(hard tissue regeneration)용으로 사용이 가능할 것으로 사료된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.250.2-250.2
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• 2014

Currently, teeth whitening method which is applicable to dental surgery is that physician expertises give medical treatment to teeth directly dealed with a high concentration of hydrogen peroxide and carbamide peroxide. If hydrogen peroxide concentration is too high for treatment of maximized teeth whitening effect [1], it is harmful to the human body [2]. To the maximum effective and no harmful teeth whitening effect in a short period of time at home, we have observed the whitening effect using carbamide peroxide (15%) and a low-temperature atmospheric pressure plasma jet which is regulated by the Food and Drug Administration. The gas supplied conditions of the non-thermal atmospheric pressure plasma jet was with the humidified (0.6%) gas in nitrogen or air at gas flow rate of 1000 sccm. Also, the measurement of chemical species from the jet was carried out using the optical emission spectroscopy (OES), the evidence of increased reactive oxygen species compared to non-humidified plasma jet. We have found that the whitening effect of the plasma is very excellent through this experiment, when bovine teeth are treated in carbamide peroxide (15%) and water vapor (0.2 to 1%). The brightness of whitening teeth was increased up to 2 times longer in the CIE chromaticity coordinates. The colorimetric spectrometer (CM-3500d) can measure color degree of whitening effect.

• 대한치과의사협회지
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• 제11권12호
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• pp.783-786
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• 1973

The healing response may very with the tissue, the site and the degree of wound. the author observed histochemically the epithelial regeneration in the har palate wound of healthy male albino rats, varying in age from 120 to 150 days, and weighing about 100 gm. The deep wounds were made antero-posterior linealy by surgical knife to the depth of bone level. They were sacrified by ether anesthesia on 1, 2, 4, 7, 10 and 14 days after wounding. the staining methods used were Mcmanus' PAS reaction, Mowry's modification of the Hale reaction employing Muller's colloidal iron reagent, alloxan-Schiff reaction and hematoxylin-eosin stain. The results were as follows : 1. In the wound healing of hard palate, the epithelium had marked PAS positive reaction in the granular and the prickle cell layers on the from 2nd to 7th day. 2. Alloxan-Schiff reactions of regenerated epithelium were slightly increased on 7th day.

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.277-285
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• 2001

Periodontal disease is characterized by inflammation and subsequent loss and/or damage to tooth-supporting tissues such as bone, cementum,and periodontal ligament. Periodontal ligament and cementum are the key tissues in the initial process of regeneration following periodontal disease. Therefore, studies on cementoblasts, which form cementum are emphasized. It is still unclear which cells cementoblast differentiate from. This study was conducted under the hypothesis that PDL fibroblast can differentiate into either cementoblast or osteoblast depending on the conditions of surrounding tissue. Clinically, with excessive traction force of orthodontic appliances or excessive occlusion hypercementosis is observed, and this has been confirmed histologically. Consequently, activation of cementoblast can be expected in rats when mechanical stimuli are given to PDL fibroblast. Therefore, the purpose of this article is to prove that PDL fibroblast differentiates into cementoblast in rats under mechanical stimuli using histologic and molecular methods. In this study, twenty rats were given hard diet. Ten of them were sacrificed after 1 week, and the others were sacrificed after two weeks. Slides were made from tooth specimen, and they were studied under the microscope. In addition, PDL fibroblast and cementum from the extracted teeth were analyzed with Northern blotting. In histologic examination, as time passed, PDL fibroblast migrated to the dentin side, differentiated into cementoblast, and formed new cementum. In Northern blotting, it was found that mRNA expression of cementoblast-specific proteins such as BSP, OC, OPN, and type I collagen were more prominent in rats sacrificed after 2 weeks of hard-diet than rats sacrificed after 1 week. From these findings we can conclude that PDL fibroblast can differentiate into cementoblast under mechanical stimuli. We think that 'Rat Models' used in this study will be beneficial to future studies regarding cementoblast.

• 구강회복응용과학지
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• 제39권4호
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• pp.276-284
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• 2023

발치 후 시간이 지남에 따라 치조골이 흡수되는 것은 자연스러운 현상이다. 치조골 소실과 상부 연조직의 감소는 추후 임플란트 식립 및 임플란트의 장기 생존 가능성에 어려움을 준다. 이번 증례보고는 치주질환에 이환된 발치와에 치조제 증강술과 연조직 대체제 중 이종 콜라겐 기질을 함께 이용하여 임플란트 식립 부위의 연조직과 경조직을 증가시키는 데 중점을 둔다. 각각의 증례에서 치조골의 너비가 6 mm, 8 mm, 4 mm로 증가하였고, 임플란트 주변으로 치간 유두의 재생과 각각 4 mm, 6 mm, 4 mm의 협측 각화치은을 보여준다. 증대된 치조골은 임플란트 수술을 용이하게 하며 치간 유두와 각화치은은 심미적인 보철이 가능하게 한다. 이 연구는 치주질환이 이환된 발치와를 가진 환자에게 치조제 증강술을 시행하고 연조직 대체제를 추가로 사용함으로써 임플란트 식립을 위한 보다 나은 환경을 제공하고 심미적이고 예지성 있는 임플란트 수술을 위한 긍정적인 효과를 보여준다.

• 식물조직배양학회지
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• 제24권3호
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• pp.183-188
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• 1997

본 시험은 L. longiflorum 'Gelia'의 캘러스 유지 및 증식, 캘러스 선발, 액체현탁배양 등의 단계로 수행하였다. 재분화를 억제시키면서 캘러스를 유지 증식시키기 위하여 MSH배지에 2.4-D 0.5 mg/L , NAA 1.0 mg/L, BA 0.3 mg/L를 첨가한 배지가 가장 효과적이었으며 재분화를 억제시키기 위해 2,4-D의 첨가는 필수적이었다. 당은 30 g/L 첨가가 캘러스 생육에 가장 적합하였고 50 g/L 이상 고농도는 캘러스 생육에 억제적이었다. 또한 0.42%의 한천을 첨가한 반고형배지에서 캘러스의 생육이 증진되었다. 4~5회 계대배양된 캘러스에서 유사배발생 캘러스(ELC)가 관찰되었다. ELC의 증식과 캘러스의 유연성을 증진시키기 위해 $\textrm{NO}_{3^-}$ 와 $\textrm{NH}_{4^+}$의 비율을 달리하여 배양한 결과, 전반적으로 NO$_3$-의 함량이 높은 배지에서 배양된 캘러스는 생육과 유연성이 양호하였다. 그러나 체세포배발생 가능성이 있는 캘러스의 증식에는 효과적이지 못했다. 액체배양은 MSH배지에 NAA 1.0 mg/L, BA 0.3 mg/L, 16.7% conditioned배지(30 mL당 1 mL), casein hydrolysate 2.0g/L를 첨가한 액체배지에 배지 30 mL당 1.5 g의 캘러스를 배양했을때 가장 캘러스 증식효율이 높았다. 광학현미경으로 조직을 관찰한 결과 1년 이상 장기배양된 캘러스에서 기관분화가 가능했고 배발생 초기단계의 세포도 관찰되어 백합 'Gelia' 캘러스로부터 체세포배 형성이 가능함을 알 수 있었다.

• Journal of Periodontal and Implant Science
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• 제48권3호
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• pp.182-192
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• 2018

Purpose: The purpose of the present study was to validate an experimental model for assessing tissue integration of titanium and zirconia implants with and without buccal dehiscence defects. Methods: In 3 dogs, 5 implants were randomly placed on both sides of the mandibles: 1) Z1: a zirconia implant (modified surface) within the bony housing, 2) Z2: a zirconia implant (standard surface) within the bony housing, 3) T: a titanium implant within the bony housing, 4) Z1_D: a Z1 implant placed with a buccal bone dehiscence defect (3 mm), and 5) T_D: a titanium implant placed with a buccal bone dehiscence defect (3 mm). The healing times were 2 weeks (one side of the mandible) and 6 weeks (the opposite side). Results: The dimensions of the peri-implant soft tissue varied depending on the implant and the healing time. The level of the mucosal margin was located more apically at 6 weeks than at 2 weeks in all groups, except group T. The presence of a buccal dehiscence defect did not result in a decrease in the overall soft tissue dimensions between 2 and 6 weeks ($4.80{\pm}1.31$ and 4.3 mm in group Z1_D, and $4.47{\pm}1.06$ and $4.5{\pm}1.37mm$ in group T_D, respectively). The bone-to-implant contact (BIC) values were highest in group Z1 at both time points ($34.15%{\pm}21.23%$ at 2 weeks, $84.08%{\pm}1.33%$ at 6 weeks). The buccal dehiscence defects in groups Z1_D and T_D showed no further bone loss at 6 weeks compared to 2 weeks. Conclusions: The modified surface of Z1 demonstrated higher BIC values than the surface of Z2. There were minimal differences in the mucosal margin between 2 and 6 weeks in the presence of a dehiscence defect. The present model can serve as a useful tool for studying peri-implant dehiscence defects at the hard and soft tissue levels.

• 한국자원식물학회지
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• 제21권3호
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• pp.184-191
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• 2008

This experiments were carried out to find out the effects of different explant materials, kinds and concentration of plant growth regulators, and total nitrogen and sucrose contents on the in vitro regeneration of Abeliophyllum distichum Nakai. The effects of growth regulators on regeneration from 3 explant sources (leaf, internode and node) were more or less same. Leaf explants produced only callus with 2ip (Isopentenyladenine) and NAA (Naphthaleneacetic acid) treatment and other regulators had no effects. Test with internode explants yielded about same results but callus was obtained with 2,4-D (2,4-Dichlorophenoxyacetic acid). Node explants resulted in shoot regeneration by all regulator treatment except NAA and 2,4-D, but control also showed similar results. Callus formation from internode and node explants was vigorous by 2ip, zeatin, and 2,4-D treatments and high NAA concentration resulted in higher callus formation. In this experiment, various mixed treatment of growth regulators were also employed, using node as explant material. Shoot regeneration was obtained with BA (Benzyl adenine) + NAA treatments but the results were comparable with control. Generally shoot and root regeneration was poor with all combined treatment except 2ip + NAA and 2,4-D + NAA. However, callus was formed readily with all treatments. In this experiment, combined treatments of regulators were applied on the callus derived from singular regulator treatment. The results showed no shoot and root regeneration with any combination of 2,4-D, IAA (Indoleacetic acid) and NAA, but soft milky white callus was formed in all the treatments. No shoot and root regeneration was observed with any combination of 2iP, NAA and IAA, but somewhat hard, light green callus was formed in all the treatments. Callus formation decreased with high kinetin concentration in case of kinetin + NAA treatment. The experiments with total nitrogen content of media showed that low concentrations of 15 and 30mM were effective for the shoot and root regeneration. Sucrose experiment demonstrated shoot regeneration with 1${\sim}$4% concentration, and root and callus formation with 2${\sim}$4%. No root and callus formation was observed with 0 and 1% sucrose.

• 구강회복응용과학지
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• 제23권2호
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• pp.145-155
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• 2007

The advent of osseointegration and advances in biomaterials and techniques have contributed to increased application of dental implants in the restoration of maxillary partial edentulous patients. Often, in these patients, soft and hard tissue defects result from a variety of causes, such as infection, trauma, and tooth loss. These create an anatomically less favorable foundation for ideal implant placement. Reconstruction of the atrophic maxillary alveolar bone through a variety of regenerative surgical procedures has become predictable; it may be necessary prior to implant placement or simultaneously at the time of implant surgery to provide a restoration with a good long-term prognosis. Regenerative procedures are used for horizontal and vertical ridge augmentation. Many different techniques exist for effective bone augmentation. The approach is largely dependent on the extent of the defect and specific procedures to be performed for the implant reconstruction. It is most appropriate to use an evidenced-based approach when a treatment plan is being developed for bone augmentation cases. The cases presented in this article clinically demonstrate the efficacy of using a autogenous block graft, guided bone regeneration, ridge split, immediated implant placement technique on the atrophic maxillary area.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제39권2호
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• pp.43-54
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• 2013

In an attempt to regain function and aesthetics in the craniofacial region, different biomaterials, including titanium, hydroxyapatite, biodegradable polymers and composites, have been widely used as a result of the loss of craniofacial bone. Although these materials presented favorable success rates, osseointegration and antibacterial properties are often hard to achieve. Although bone-implant interactions are highly dependent on the implant's surface characteristics, infections following traumatic craniofacial injuries are common. As such, poor osseointegration and infections are two of the many causes of implant failure. Further, as increasingly complex dental repairs are attempted, the likelihood of infection in these implants has also been on the rise. For these reasons, the treatment of craniofacial bone defects and dental repairs for long-term success remains a challenge. Various approaches to reduce the rate of infection and improve osseointegration have been investigated. Furthermore, recent and planned tissue engineering developments are aimed at improving the implants' physical and biological properties by improving their surfaces in order to develop craniofacial bone substitutes that will restore, maintain and improve tissue function. In this review, the commonly used biomaterials for craniofacial bone restoration and dental repair, as well as surface modification techniques, antibacterial surfaces and coatings are discussed.