• 한국구조물진단유지관리공학회 논문집
• /
• 제23권1호
• /
• pp.113-121
• /
• 2019

본 연구에서는 시멘트 복합재료와 직접 혼합 가능한 자기치유 마이크로 캡슐을 제조하였으며, 자기치유 마이크로 캡슐이 혼합된 시멘트 복합재료의 품질 및 균열 치유 성능 특성을 평가하였다. 종래의 경우 자기치유 캡슐 제조와 균열 치유 특성 평가에만 치중되어 평가되어 왔다. 따라서 자기치유 마이크로 캡슐은 시멘트 복합재료와 혼합시 시멘트 복합재료의 품질에 미치는 영향이 있기 때문에 이에 대한 검토를 수행하였다. 자기치유 마이크로 캡슐을 혼합한 시멘트 복합재료의 테이블 플로우 및 공기량 평가 결과 혼합율에 관계없이 테이블 플로우 및 공기량은 큰 영향이 없는 것으로 나타났다. 압축강도 및 쪼갬인장강도는 캡슐 혼합율이 증가할수록 강도가 감소하는 경향이 나타났다. Water Flow에 따른 균열 치유 특성 평가 결과 초기 투수량이 감소하는 결과가 나타났으며, 시간 경과에 따라 반응 생성물 발생하여 균열이 치유되는 것을 확인 할 수 있었다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제22권3호
• /
• pp.84-89
• /
• 2018

최근 자기치유 재료에 대한 연구는 보수하기 힘들거나, 보수비용이 많이 소요되는 구조물에 대해 구조물 스스로 손상을 치유하여 사용수명을 증가시키기 위해 많이 수행되어오고 있다. 현재 널리 사용되고 있는 자기치유 평가 방법으로는 투수시험이 있다. 하지만, 자기치유 평가 방법에서 자기치유 성능은 콘크리트의 초기 균열 폭에 큰 영향을 받지만 일관된 기준을 가지고 있지 않은 실정이다. 따라서, 본 연구에서는 기존 연구에서 사용한 균열 폭과 투수량을 기반으로 균열 폭-투수량의 상관관계와 시간-투수량의 상관관계를 분석하였다. 또한, 광학현미경을 이용하여 측정한 초기 균열 폭은 신뢰성이 떨어지므로 Poiseuille flow에서 ${\alpha}$값을 도출하여 시간-균열 폭에 대한 상관관계를 분석하여 시간-투수량과 시간-균열 폭에 대한 경향을 분석하였다.

• 대한치과보철학회지
• /
• 제44권3호
• /
• pp.314-324
• /
• 2006

Statement of problem. Osseointegration is important mechanism of dental implant but it is not easy to evaluate. Indirect measurement is non-invasive and clinically applicable but they need more study about correlation between indirect values and degree of osseointegration. Purpose. The aims of this study were to evaluate the coefficient of correlation between indirect measurement and direct measurement under different healing time, and assessment of effect of initial insertion torque to the implant stability. Material and Methods. 20 rabbits received 3 implants on each side of tibia. Three kinds of implants (machined surface implant, Sandblasted with Large grit and Acid etched implant, Resorbable Blast Media treated implant) were used. During the surgery implant insertion torque were measured with $Osseocare^{TM}$. After the 1, 4, 8, 12 weeks of healing time, animals were sacrificed and stability values (Implant Stability Quotient with $Osstell^{TM}$, removal torque with torque gauge) were measured. Results. The Bone quality of rabbit tibia was classified into 2 groups according to the insertion torque. Resonance frequency analysis (ISQ) and removal torque showed positive correlation until $4^{th}$ week (r=0.555, p=0.040). After $8^{th}$ week (r=0.011, p=0.970) the correlation became weak and it turned negative at $12^{th}$ week (r=-0.074, p=0.801). Insertion torque and ISQ showed changing correlation upon the healing time ($1^{st}$ week: r=0.301, p=0.033, $4^{th}$ week: r=-0.429, p=0.018, $8^{th}$ week: r=0.032, p=0.865, $12^{th}$ week: r=-0.398, p=0.029). Insertion torque and removal torque has positive correlation but it was not statistically significant ($1^{st}$ week: r=0.410, p=0.129, $4^{th}$ week: r=0.156, p=0.578, $8^{th}$ week: r=0.236, p=0.398, $12^{th}$ week: r=0.260, p=0.350). Conclusion. In this study, bone quality may affect the degree of osseointegration positively during healing time and correlation between ISQ and degree of osseointegration can be different according to the healing time and bone quality.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제22권1호
• /
• pp.33-42
• /
• 2000

The purpose of this study was to compare the wound healing process after skin incision using scalpel, $CO_2$ laser and pulsed Nd:YAG laser in rats. After skin on the back was incised 3 cm long, rats were sacrificed at 1, 3, 7, 14, 21 and 28 days. Macroscopic, histologic and immunohistochemical examinations using the collagen type IV and the CD34 antibodies which are necessary to the forming process of new capillary were performed. Results obtained were as follows ; Macroscopically the initial wound healing of the laser group was about $1{\sim}2$ weeks slower than that of the scalpel group. There weren't however any remarkable differences in all groups in 4 weeks after incision. By histologic finding, acute inflammatory cells were more prominent during the initial wound healing in the scalpel group than in the other groups. Epithelialization started in the order of scalpel, $CO_2$ and Nd:YAG laser group after skin incision. By the Masson's trichrome stain, collagen synthesis in the Nd:YAG laser group was more slowly initiated than in the other groups. But it was completed at the $3{\sim}4$ weeks in all groups. Immunohistochemically, collagen type IV and CD34 expression were markedly increased at 2 weeks in the scalpel and $CO_2$ laser group. Meanwhile, in the Nd:YAG laser group, these reactions were observed later tan the other groups. Collagen type IV and CD34 expression were decreased in all groups after 4 weeks. These results suggest that $CO_2$ and Nd:YAG laser showed similar healing process compared with scalpel and a potential substitute for scalpel in skin incision.

• Journal of Periodontal and Implant Science
• /
• 제47권2호
• /
• pp.106-115
• /
• 2017

Purpose: The possibility of immediate or early loading has become popular in implant dentistry. A prerequisite for the immediate or early loading of an implant prosthesis is the achievement of initial stability in the implant. Moreover, in response to clinicians' interest in verifying clinical stability to determine the optimal time point for functional loading, a non-invasive method to assess implant stability has been developed on the basis of resonance frequency analysis (RFA). The primary objective of this study was to monitor the stability of sandblasted, large-grit, and acid-etched (SLA) implants with different diameters during the early phases of healing by RFA. The secondary objective was to evaluate how the initial stability of implants varied depending on different surface modifications and other contributing factors. Methods: Thirty-five implants (25 SLA implants and 10 resorbable blasting media [RBM] implants) placed in 20 subjects were included. To measure implant stability, RFA was performed at baseline and at 1, 2, 3, 4, 6, and 10 weeks after surgery. Results: The longitudinal changes in the implant stability quotient (ISQ) values were similar for the SLA implants with different diameters and for the RBM implants. During the initial healing period, the ISQ decreased after installation and reached its lowest values at 1 week and 2 weeks, respectively. The mean ISQ values in the SLA implants were significantly higher in ${\varnothing}5.0mm$ implants than in ${\varnothing}4.0mm$ implants. Men showed a higher ISQ than women. Mandibular sites showed a higher ISQ than maxillary sites. Conclusions: All implants used in this study are suitable for immediate or early loading under appropriate indications. A wider diameter and SLA surface treatment of implants could improve the stability, if the implant is fixed with at least 30 Ncm of insertion torque.

• 한국구조물진단유지관리공학회 논문집
• /
• 제24권1호
• /
• pp.59-66
• /
• 2020

본 연구에서는 보수 모르타르와 직접 혼합 가능한 결정성장형 자기치유 고상캡슐을 제조하였으며, 자기치유 고상캡슐이 혼합된 보수 모르타르의 품질 및 균열 치유 성능 특성을 평가하였다. 자기치유 고상캡슐을 혼합한 보수 모르타르의 테이블 플로우 및 공기량 평가 결과 혼합율에 관계없이 테이블 플로우 및 공기량은 큰 영향이 없는 것으로 나타났다. 압축강도는 캡슐 혼합율이 증가할수록 강도가 감소하는 경향이 나타났다. 정수위 투수시험에 따른 균열 치유 특성 평가 결과 초기 투수량이 감소하는 결과가 나타났으며, 시간 경과에 따라 반응 생성물 발생하여 균열이 치유되는 것을 확인 할 수 있었다.

• 대한치과의사협회지
• /
• 제37권5호통권360호
• /
• pp.319-326
• /
• 1999

• Journal of Microbiology and Biotechnology
• /
• 제20권4호
• /
• pp.803-808
• /
• 2010

Poly-${\gamma}$-glutamic acid (${\gamma}$-PGA) is a natural edible polypeptide in which glutamate is polymerized via ${\gamma}$-amide linkages. First, we assessed the eye irritancy potential of ${\gamma}$-PGA in rabbits. Additionally, we studied the effects of ${\gamma}$-PGA on corneal wound healing, due to the anti-inflammatory properties and water retaining abilities of ${\gamma}$-PGA. In this study, the effects of ${\gamma}$-PGA on corneal wound healing after an alkali burn were evaluated. Thirty eyes wounded by alkali burning in 30 white rabbits were divided into three groups: group A was treated with 0.1% 5,000 kDa ${\gamma}$-PGA for 2 days; group B was treated with 0.1% hyaluronic acid; and group C was not treated, as a control. The area of corneal epithelial defect was examined at 12, 24, 30, 36, 42, and 48 h after corneal alkali wounding to determine initial wound healing. We found that ${\gamma}$-PGA promoted corneal wound healing, compared with controls, and showed similar effects to hyaluronic acid. These results indicate that ${\gamma}$-PGA stimulates corneal wound healing by an anti-inflammatory effect and enhancing cell migration and cell proliferation. ${\gamma}$-PGA is a promising biomaterial that may be a substitute for hyaluronic acid in corneal wound healing treatment.

• Journal of Periodontal and Implant Science
• /
• 제39권3호
• /
• pp.339-348
• /
• 2009

Purpose: The purpose of the present study was to analyze the implant stability quotient(ISQ) values for Korean non-submerged type implant and determine the factors that affect implant stability. Methods: A total of 49 Korean non-submerged type implants were installed in 24 patients, and their stability was measured by resonance frequency analysis(RFA) at the time of surgery, and 1, 2, 3, 4, 8, 12 weeks postoperatively. The data for implant site, age, sex, implant length and diameter, graft performing, bone type, and insertion torque were analyzed. Results: The lowest mean stability measurement was at 3 weeks. There was significant difference between implant placement and 12 weeks. There was significant difference between implant placement and 12 weeks in diameters of 4.1 mm and 4.8 mm. Also, there were significant differences between diameters of 4.1 mm and 4.8 mm at implant placement and 12 weeks after surgery. This result suggests that the factor related to implant diameter may affect the level of implant stability. No statistically significant relationship was found between the resonance frequency analysis and the variables of maxilla/mandible, sex, anterior/posterior, implant length, age of patient, graft performing, bone type, insertion torque during initial healing period. Conclusions: These findings suggest that the factor related to implant diameter may affect the variance of implant stability, and ISQ value of implant was stable enough for proved stability level during initial healing period.

• Journal of Periodontal and Implant Science
• /
• 제39권sup2호
• /
• pp.287-291
• /
• 2009

Purpose: The objective of this clinical presentation was to present a clinical case series report of socket preservation, sinus augmentation, and bone grafting using a horse-derived biomaterial. Methods: A horse-derived biomaterial was used in 8 patients for different indications including socket preservation following tooth extraction, osseous bone grafting, and sinus augementation procedures. Surgeries were performed by a well trained specialist and clinical radiographs were obtained at designated intervals. Biopsy cores of 2 ${\times}$ 8 mm prior to implant placement was obtained following a healing interval of 4 - 6 months. A clinical and histologic evaluation was performed to evaluate the clinical effectiveness and biocompatibility of the biomaterial. Results: All surgeries in 8 patients were successful with uneventful healing except for one case with membrane exposure that eventually resulted with a positive outcome. Radiographic display of the healing phase during different intervals showed increased radiopacity of granular nature as the healing time increased. No signs of adverse effect or infection was observed clinically and the tissues surrounding the biomaterial seemed well-tolerated with good intentional healing. The augmented sinuses healed uneventfully suggesting in part, good biocompatibility of the biomaterial. Dental implants placed following socket preservation were inserted with high initial torque suggesting good initial stability and bone quality. Conclusions: Our results show that at least on a tentative level, a horse-derived biomaterial may be used clinically in socket preservation, sinus augmentation, bone grafting techniques with good intentional healing and positive results.