• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.52.1-52.8
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• 2019

Background: A compact passive oxide layer can grow on tantalum (Ta). It has been reported that this oxide layer can facilitate bone ingrowth in vivo though the development of bone-like apatite, which promotes hard and soft tissue adhesion. Thus, Ta surface treatment on facial implant materials may improve the tissue response, which could result in less fibrotic encapsulation and make the implant more stable on the bone surface. The purposes of this study were to verify whether surface treatment of facial implant materials using Ta can improve the biohistobiological response and to determine the possibility of potential clinical applications. Methods: Two different and commonly used implant materials, silicone and expanded polytetrafluoroethylene (ePTFE), were treated via Ta ion implantation using a Ta sputtering gun. Ta-treated samples were compared with untreated samples using in vitro and in vivo evaluations. Osteoblast (MG-63) and fibroblast (NIH3T3) cell viability with the Ta-treated implant material was assessed, and the tissue response was observed by placing the implants over the rat calvarium (n = 48) for two different lengths of time. Foreign body and inflammatory reactions were observed, and soft tissue thickness between the calvarium and the implant as well as the bone response was measured. Results: The treatment of facial implant materials using Ta showed a tendency toward increased fibroblast and osteoblast viability, although this result was not statistically significant. During the in vivo study, both Ta-treated and untreated implants showed similar foreign body reactions. However, the Ta-treated implant materials (silicone and ePTFE) showed a tendency toward better histological features: lower soft tissue thickness between the implant and the underlying calvarium as well as an increase in new bone activity. Conclusion: Ta surface treatment using ion implantation on silicone and ePTFE facial implant materials showed the possibility of reducing soft tissue intervention between the calvarium and the implant to make the implant more stable on the bone surface. Although no statistically significant improvement was observed, Ta treatment revealed a tendency toward an improved biohistological response of silicone and ePTFE facial implants. Conclusively, tantalum treatment is beneficial and has the potential for clinical applications.

• 대한소아치과학회지
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• 제30권1호
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• pp.25-32
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• 2003

구강 질환으로 중요한 치아우식증은 구강 세균 중 Streptococcus mutans가 주 원인균이며, 치면에 부착, 증식 및 산생성 과정을 거쳐 치아우식을 유발한다. Streptococcus salivarius는 사람의 구강에 정상적으로 존재하는 세균이다. 본 연구에서는 소아의 구강으로 부터 분리된 9주의 S. salivarius의 특성과 S. mutans 및 Streptococcus oralis에 대한 영향을 연구하여 다음과 같은 결과를 얻었다. 1. 비커 와이어 검사에서 S. mutans 배양시 형성된 인공치태 무게는 204.9 mg이었으나, S. mutans와 분리된 S. salivarius의 혼합 배양시 형성된 인공치태 무게는 1.9 mg에서 20.6 mg으로 S. mutans 단독 배양시와 큰 차이가 있었다(p<0.05). 배양 후 생균수 검사에서는 큰 차이가 없었다. 2. M17 액체배지에서 배양된 분리균주의 배양 상청액을 가한 비커 와이어 검사에서 형성된 인공치태 무게는 평균 117.1 mg인데 반해, 5% 자당이 함유된 M17 액체배지에서 배양된 분리균주 배양 상청액을 가한 비커 와이어 검사에서는 평균 47.7 mg이었다. 3. 분리된 S. salivarius의 배양 상청액을 thin layer chromatography를 실시한 결과, 분리균주가 형성한 중합체는 프럭탄 (fructan)이었다. 4. 비커 와이어 검사에서 프럭탄의 일종인 inulin과 levan 모두 S. mutans의 인공치태 형성을 억제하지 못하였다. 이상의 결과를 종합하면 프럭탄을 생성하는 S. salivarius는 S. mutans의 인공치태 형성을 억제하였다.

• 대한소아치과학회지
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• 제35권3호
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• pp.399-417
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• 2008

교합력과 교근의 두께 및 면적 그리고 두개안면골 형태간의 연관성을 평가하고자 하였다. 성인 141명의 교합력 측정, 측방 및 후전방 두부규격방사선사진 그리고 교근 표층의 초음파진단영상을 촬영한 후, 이들 간의 관계를 통계분석으로 비교, 평가하였다. 교합력과 두개안면골의 형태간에는 남녀 모두 유의한 상관관계가 있으며, 교합력과 교근 간에는 남녀 모두 유의한 상관관계가 없었다. 그러나 교근은 남자의 두개안면골 형태에서 유의한 상관관계를 보였고, 특히 교근의 두께 및 면적이 증가할수록 상악너비가 유의하게 감소하게 나타났다. 이는 남자의 교합력은 심층 교근과 관계가 크고, 여자의 교합력은 표층 교근과 관계가 큰 것이 원인으로 판단된다.

• Journal of Periodontal and Implant Science
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• 제42권2호
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• pp.59-63
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• 2012

Purpose: This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods: HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results: A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions: These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.157-166
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• 2020

PURPOSE. The aim of this study was to evaluate the clinical performance and reliability of plasma sprayed nanostructured zirconia (NSZ) coating. MATERIALS AND METHODS. This study consisted of three areas of analysis: (1) Mechanical property: surface roughness of NSZ coating and bond strength between NSZ coating and titanium specimens were measured, and the microstructure of bonding interface was also observed by scanning election microscope (SEM). (2) Biocompatibility: hemolysis tests, cell proliferation tests, and rat subcutaneous implant test were conducted to evaluate the biocompatibility of NSZ coating. (3) Mechanical compatibility: fracture and artificial aging tests were performed to measure the mechanical compatibility of NSZ-coated titanium abutments. RESULTS. In the mechanical study, 400 ㎛ thick NSZ coatings had the highest bond strength (71.22 ± 1.02 MPa), and a compact transition layer could be observed. In addition, NSZ coating showed excellent biocompatibility in both hemolysis tests and cell proliferation tests. In subcutaneous implant test, NSZ-coated plates showed similar inflammation elimination and fibrous tissue formation processes with that of titanium specimens. Regarding fatigue tests, all NSZ-coated abutments survived in the five-year fatigue test and showed sufficient fracture strength (407.65-663.7 N) for incisor teeth. CONCLUSION. In this study, the plasmasprayed NSZ-coated titanium abutments presented sufficient fracture strength and biocompatibility, and it was demonstrated that plasma spray was a reliable method to prepare high-quality zirconia coating.

• 구강회복응용과학지
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• 제21권1호
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• pp.33-42
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• 2005

This study was performed to investigate the surface properties and in vitro biocompatibility of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed using a regulated DC power supply. The applied voltages were given at 240, 280, 320, and 360 V and current density of $30mA/cm^2$. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. Samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ during 30 days. The results obtained were summarized as follows; 1. The oxide films were porous with pore size of $1{\sim}5{\mu}m$. The size of micropores increased with increasing the spark forming voltage. 2. The main crystal structure of the anodic oxide film was anatase type as analyzed with thin-film X-ray diffractometery. 3. Needle-like hydroxyapatite (HA) crystals were observed on anodic oxide films after hydrothermal treatment at $300^{\circ}C$ for 2 hours. The precipitation of HA crystals was accelerated with increasing the spark forming voltage. 4. The precipitation of the fine asperity-like HA crystals were observed after being immersed in Hanks' solution at $37^{\circ}C$. The precipitation of HA crystals was accelerated with increasing the spark forming voltage and the time of immersion in Hanks' solution. 5. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal as increasing the spark forming voltage and the time of immersion in Hanks' solution.

• Journal of Pharmaceutical Investigation
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• 제24권2호
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• pp.73-83
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• 1994

Applications of liposomes as a drug carrier for the oral delivery of poorly-absorbable macromolecular drugs have been limited, because of their instability in gastrointestinal environments including pH, bile salts, and digestive enzymes. Two polysaccharides, dextran(DX) and pullulan(PL), were introduced to the preformed liposomes in order to enhance the stability. Palmitoyl derivatives of polysaccharides, palmitoyldextran(PalDX) and palmitoylpullulan(PalPL), were synthesizd and introduced to the liposomes during preparation for the same purpose of stability. The effects of these polysaccharides coating were evaluated basically by physical properties of particle size distribution and optical microscopy, then compared with uncoated liposomes by the observations of both in vitro stability and in vovo absorption characteristics. The geometric mean diameters of polysaccharide-coated liposomes were greater than that of uncoated liposome, showing the outermost polysaccharide-coated layer under the optical microscopy. In vitro stabilities of uncoated or polysaccharides-coated liposomes were measured by turbidity changes in various pH buffer solutions containing sodium choleate as bile salts. While uncoated liposome was very sensitive to bile salts, polysaccharides-coated liposomes were stable in relatively higher concentrations of sodium choleate, giving the results of better stability of PalDX- and PalPL-coated liposomes than that of DX- and PL-coated liposomes. After liposomal encapsulation of acyclovir(ACV), an antiviral agent as a model drug, it has been administered orally to rats as dose of ACV 40 mg/kg. Plasma concentrations of ACV were assayed by HPLC and analyzed by model-independent pharmacokinetics. Pharmacokinetic parameters of Cmax, tmax, and [AUC] have been compared.

• 대한치과보철학회지
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• 제43권5호
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• pp.684-693
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• 2005

Statement of problem: Ti-6Al-7Nb alloy is used instead of Ti-6Al-4V alloy that was known to have toxicity. Purpose: This study was performed to investigate the effect of electrolyte concentration on the surface characteristics of anodized and hydrothermally-treated Ti-6Al-7Nb alloy Materials and methods: Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1,000 SiC paper ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed at current density $30mA/cm^2$ up to 300 V in electrolyte solutions containing $\beta-glycerophosphate$ disodium salt hydrate $(\beta-GP)$ and calcium acetate (CA). Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. All samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 30 days. Results and conclusion: The results obtained were summarized as follows: 1. After hydrothermal treatment, the precipitated HA crystals showed the dense fine needle shape. However, with increasing the concentration of electrolyte they showed the shape of thick and short rod. 2. When the dense fine needle shape crystals was appeared after hydrothermal treatment, the precipitation of HA crystals in Hanks' solution was highly accelerated. 3. The crystal structures of $TiO_2$ in anodic oxide film were composed of strong anatase peak and weak rutile peak as analyzed with thin-film X-ray diffractometery. 4. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal in Hanks' solution.

• 구강회복응용과학지
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• 제22권1호
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• pp.101-110
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• 2006

This study was performed to investigate the surface properties and in vitro biocompatibility of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed using a regulated DC power supply. The applied voltages were given at 240, 280, 320, and 360 V and current density of $30mA/cm^2$. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. Samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ during 30 days. The results obtained were summarized as follows; 1. The oxide films were porous with pore size of $1{\sim}5{\mu}m$. The size of micropores increased with increasing the spark forming voltage. 2. The main crystal structure of the anodic oxide film was anatase type as analyzed with thin-film X-ray diffractometery. 3. Needle-like hydroxyapatie (HA) crystals were observed on anodic oxide films after hydrothermal treatment at $300^{\circ}C$ for 2 hours. The precipitation of HA crystals was accelerated with increasing the spark forming voltage. 4. The precipitation of the fine asperity-like HA crystals were observed after being immersed in Hanks' solution at $37^{\circ}C$. The precipitation of HA crystals was accelerated with increasing the spark forming voltage and the time of immersion in Hanks' solution. 5. The Ca/P ration of the precipitated HA layer was equivalent to that of HA crystal as increasing the spark forming voltage and the time of immersion in Hanks' solution.

• Archives of Pharmacal Research
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• 제28권10호
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• pp.1190-1195
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• 2005

The objective of this study was to develop an assay for mequitazine (MQZ) for the study of the bioavailability of the drug in human subjects. Using one mL of human plasma, the pH of the sample was adjusted and MQZ in the aqueous phase extracted with hexane; the organic layer was then evaporated to dryness, reconstituted and an aliquot introduced to a gas chromatograph/mass spectrometer (GC/MS) system with ion-trap detector. Inter- and intra-day precision of the assay were less than 15.1 and $17.7{\%}$, respectively; Inter- and intra-day accuracy were less than 8.91 and $18.6{\%}$, respectively. The limit of quantification for the current assay was set at 1 ng/mL. To determine whether the current assay is applicable in a pharmacokinetic study for MQZ in human, oral formulation containing 10 mg MQZ was administered to healthy male subjects and blood samples collected. The current assay was able to quantify MQZ levels in most of the samples. The maximum concentration ($C_{max}$ was 8.5 ng/mL, which was obtained at 10.1 h, with mean half-life of approximately 45.5 h. Under the current sampling protocol, the ratio of $AUC_{t{\rightarrow}last}$ to $AUC_{t{\rightarrow}{\infty}}$ was $934{\%}$, indicating that the blood collection time of 216 h is reasonable for MQZ. Therefore, these observations indicate that an assay for MQZ in human plasma is developed by using GC/MS with ion-trap detector and validated for the study of pharmacokinetics of single oral dose of 10 mg MQZ, and that the current study design for the bioavailability study is adequate for the drug.