• Journal of Periodontal and Implant Science
• /
• 제34권4호
• /
• pp.711-722
• /
• 2004

The purpose of this study is to evaluate the regenerated bone histollogically using titanium reinforced ePTFE(TR-ePTFE) membrane and to investigate cell occlusiveness, wound stabilization and tissue integration of TR-ePTFE membrane. Adult male rabbits (mean BW 2kg) and TR9W (W.L.Gore&Associate.INC,USA) were used in this study. Intramarrow penetration defects were surgically created with round carbide bur(HP long #6) on calvaria of rabbits. TR-ePTFE membrane was applied to defect. Then guided bone regeneration was carried out using TR-ePTFE membrane and resorbable suture. At 2,4,8,12 weeks after the surgery, animals were sacrificed. Nondecalcified specimens were processed for histologic analysis. The result and conclusion of this study were as follows: 1. TR-ePTFE membrane had good ability of biocompatibility and cell occlusiveness. 2. space making for guided bone regenerayion was good at TR-ePTFE membrane. 3. Tissue integration was not good at TR-ePTFE membrane. So, wound stabilization was not good. 4. At 8 weeks, 12 weeks after GBR procedure, bone formation was seen. From the above results, TR-ePTFE membrane fixed tightiy on alveolar bone might be recommended for the early bone formation.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2017년도 춘계학술대회 논문집
• /
• pp.155-155
• /
• 2017

Surface modifications are commonly utilized to adjust the properties of the titanium and its alloy surface to the specific needs of the medical applications, but there are disadvantages such as poor osteoconductive properties and low adhesion of bone cell to implant surface. In order to improve these disadvantages, changes in surface properties have an important effect on osseointegration during implantation. In this paper we applied new technological method for improving a unique surface modification using the characteristic of an electrolytic Solution. Thus, in the electrolyte containing NaF in Na2SO4, TiO2 nanoporous was uniformly formed, and HAp nanoparticles were electrodeposited around the TiO2 nanopores, but in the electrolyte containing NH4F in (NH4)H2PO4, the coarse protrusions including HAp nano particles were regularly deposited onto the TiO2 barrier layer. The surface characteristics and the distributed elements and have been investigated by EDS analysis, and ultra-fine structure of surface are carried out using FE-SEM. To investigate the behavior of the anion, the analysis of chemical states was performed by XPS, and the narrow spectrums for Ti2P, Ca 2p, and P 2p seems to be almost similar depending on the characteristics of the electrolyte solution respectively. In addition, Ca 2p spectrum could be resolved into two peaks for Ca 2p3/2 and 2p1/2 at 347.4 and 351.3 eV, which are related to hydroxyapatite. And, the P peak can also be deconvoluted into two peaks for P1/2 and P3/2 levels with binding energy 134.2 and 133.4 eV, respectively. From the result of soaking test, the apatite morphologys were well-formed onto the modified surface according to the different conditions.

• Journal of Periodontal and Implant Science
• /
• 제30권2호
• /
• pp.429-442
• /
• 2000

Based on current evidence in the literature, it is known that endotoxin is a weakly adherent surface phenomenon and that power-driven instruments can be used to accomplish definitive root detoxification and maximal wound healing without overinstrumentation of root and without extensive cementum removal. And one of the newly developed curette tips used with low power of piezoelectric ultrasonic scaler, is effective to remove calculus and not to remove the excessive cementum. The purpose of this study is therefore, to assess the influence of ultrasonic power and various working parameters on root substitute removal when instrumentation is performed with the curette tip on piezoelectric ultrasonic scaler. This study assessed defect depth, width and area resulting from instrumentation using a piezoelectric ultrasonic scaler with a curette type tip in vitro to acrylic resin block as a root substitute. The working parameters was standardized by the sledge device which controls lateral force(0.5 N, 1 N, 2 N) and instrumentation time(5 sec, 10 sec, 20 sec) and power setting was adjusted 0,2,4,8 in P mode. Power setting had the greatest influence on defect depth compared to lateral force and instrumentation time(standardized regression parameter estimates${\pm}$standard error, $0.37{\pm}0.02$, $0.19{\pm}0.02$, $0.07{\pm}0.02$). The effects on defect area also greatest for power setting($0.57{\pm}0.03$) compared to lateral force and instrumentation time($0.33{\pm}0.03$, $0.12{\pm}0.03$). The effect of the power setting on the defect width($0.15{\pm}0.01$) is not so great as defect depth or defect area compared to lateral force($0.12{\pm}0.01$) and effect of instrumentation time is minimal($0.02{\pm}0.01$). It could be concluded that the power setting has the greatest influence on the defect depth and area in curette type tip with low power of piezoelectric ultrasonic device. Many parameters can be adjusted in various situation in clinical use of piezoelectric ultrasonic scaler but the power setting is the first parameter to be adjusted.

• 대한치과보철학회지
• /
• 제36권2호
• /
• pp.379-388
• /
• 1998

본 연구는 악안면보철용 실리콘의 색안정성을 연구하기 위하여 실리콘 재료로 MDX 4-4210 Silicone(Dow Coming. Midland, Mich.)과 A-2186(Factor II, Lakeside, Az)을 사용하고 Mars Violet. Golden Yellow, Red yellow, Raw Sienna등 4종의 색소(Factor II, Lakeside, Az)를 이용하여 시편을 제작한 후 1군은 섭씨5-55도에서 700회 thermocycling하였고, 2군은 10%의 비눗물(Ivory, Proctor & Gamble Inc,. Toronto, Ontario)에 담아 섭씨15-55도에서 700회 thermocycling하였다. 3군은 10%의 비눗물에 담아 75일간 실온에서 보관하였으며 4군은 실온의 암실에 75일간 보관하였다. 5군은 초여름인 6월 중순부터 75일간 햇볕이 잘드는 곳에 위치하였다. 이를 측색색차계(Model TC-6FX, Tokyo Denshoku Co., Japan)를 이용하여 측정하고 색변화를 연구한 결과 다음과 같은 결론을 얻었다. 1. $L^*$값의 경우 모든 실험군에서 대조군에 비해 유의하게 감소하였다. 2. $a^*$값의 경우 대부분의 실험군에서 증가하였으나 Raw sienna, Mars violet색소를 사용한 실험 3.4.5군의 MDX4-4210의 경우 감소하는 경향을 보였다. 3. $b^*$값은 실험1.2.3군의 경우 대부분 감소하였고 실험4.5.군의 경우에서 증가하였으나 3.4.5군의 경우에서 대부분 유의한 차이가 없었다. 4. ${\Delta}E$의 값은 실험군에서 대부분 감소하였으나 4군의 A-2186에서 증가하는 경향을 보였고 실험2군의 Red yellow, Mars violet을 사용한 MDX4-4210에서 비교적 큰 변화를 보였다. 5. $L^{\ast}$값과 a값의 변화량의 합은 A-2186의 경우에서 크게 나타났으나 ${\Delta}E$값의 변화량은 MDX4-4210에서 크게 나타났다. 6. $L^*$값의 변화량의 합은 실험4군에서 크게 나타났으며 $a^*$값은 1군에서, $b^*$값과 ${\Delta}E$값의 변화량의 합은 2군에서 크게 나타났다.

• 공업화학
• /
• 제10권6호
• /
• pp.939-943
• /
• 1999

최근에 생분해성 고분자를 이용한 의료용재료로의 응용에 대한 관심이 고조되고 있다. 본 연구에서는 천연고분자(xanthan, locust bean, guar gum, chitosan 및 algin)를 생체재료로 사용할 목적으로 용액주조법에 의하여 분해성 필름을 제조하였다. 천연고분자로부터 제조한 생체재료의 가능성을 피부이식제로서 생체적합성 측정에 의하여 평가하였다. 이들을 실험동물의 등부위에 피하 삽입하여 필름의 시간에 따른 구조적, 중량적변화와 랫드의 혈액학적 변화를 측정하여 생체적합성을 연구하였다. 랫드에 대한 테스트결과 locust bean과 guar gum은 삽입 24시간, 48시간 후 조직에서의 생체 이물 반응에 의한 생체 부적합성을 나타내었으며, 일부 천연고분자로부터 제조한 분해성 필름은 단기간의 이상적인 생체재료로서의 가능성을 나타내었다.

• 한국산학기술학회논문지
• /
• 제16권4호
• /
• pp.2958-2965
• /
• 2015

공중합체인 PLGA는 생분해성 고분자로서 의료용 이식재료로 사용되고 있으며, 이를 이용한 멤브레인은 양호한 생분해 특성 및 지속적 약물 전달체로서 치조골 유도제로 적용할 수 있다. 본 연구는 락티드, 글리콜리드 합성 및 공중합과정을 거쳐 상전이법을 이용하여 PLGA 멤브레인을 제조하였으며, 멤브레인의 광학적(NMR, IR), 기계적(인장강도), 열적(DSC)특성을 조사하였다. 또한 PLGA 멤브레인의 생분해 특성은 PBS (Phosphate Buffered Solution)이 담긴 항온조($60^{\circ}C$) 내에서 분해시간에 따른 표면분해 정도, 멤브레인의 질량변화 및 용액의 pH 변화로 측정하였다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2018년도 춘계학술대회 논문집
• /
• pp.25-25
• /
• 2018

Electron beam melting (EBM) is one of powder based additive manufacturing technology used to produce parts for high geometrical complexity and directly with three-dimensional computer aided design (CAD) model. It is kind of the most promising methods with additive manufacturing for a wide range of medical applications, such as orthopedic, dental implant, and etc. This research has been investigated the microstructure and mechanical properties of as fabricated and hot iso-static pressing (HIP) processed specimens, which are made by an Arcam A1 EBM system. The Ti-6Al-4V titanium alloy powder was used as a material for the 3 dimensional printing specimens. Mechanical properties were conducted with EBM manufacturing and computer numerical control (CNC) machining specimens, respectively. Surface morphological analysis was conducted by scanning electron microscopy (SEM) for their surface, dissected plan, and fractured surface after tensile test. The mechanical properties were included tensile stress-strain and nano-indentation test as a analysis level between nano and macro. As following highlighted results, the stress-strain curves on elastic region were almost similar between as fabricated and HIP processed while the ductile (plastic deformed region) properties were higher with HIP than that of as fabricated processed.

• Journal of Periodontal and Implant Science
• /
• 제43권2호
• /
• pp.96-100
• /
• 2013

Purpose: Chronic periodontitis (CP) seems to be associated with stress and depression, but little information on this possible association is available in the literature. Thus, the objective of this study was to evaluate the association among stress, the salivary cortisol level (SCL), and CP. Methods: Seventy systemically healthy subjects were included in the study from January to September 2011. Full medical and dental histories were obtained, and the following measurements were recorded: 1) probing depth; 2) clinical attachment level; 3) bleeding on probing; and 4) tooth mobility. Saliva samples were collected for the evaluation of SCL (via a highly sensitive electrochemiluminescence immunoassay), and all subjects also answered a questionnaire (i.e., the Zung Self-rating Depression Scale). The odds ratio (OR) with a 95% confidence interval (CI) was calculated, and one way analysis of variance and the Tukey-Kramer method were performed. Results: A total of 36 subjects with CP (51.4%) and 34 without CP were evaluated. Of them, all of the subjects with CP and one periodontally healthy subject were diagnosed with depression. Subjects with moderate CP had statistically significantly higher levels of SCL than subjects with a diagnosis of slight CP (P=0.006). Also, subjects with severe CP showed the same outcome when compared to those with slight CP (P=0.012). In addition, 46 subjects presented high SCL whereas 24 had a normal level. CP was found to be correlated with the SCL, with an OR of 4.14 (95% CI, 1.43 to 12.01). Conclusions: Subjects with a high SCL and depression may show an increased risk for CP.

• 대한의용생체공학회:의공학회지
• /
• 제17권1호
• /
• pp.61-70
• /
• 1996

In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony inyowth and secondary long term fixation. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone stem interface. An accurate evaluation of interf'ace micromotion and stress/strain fields in the bone-implant system may be relevant for better understanding of clinical situations and improving THA design. Recently finite element method(FEM) was introduced in'orthopaedic research field due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional finite element model of proximal femur with $Multilock^{TM}$ stem of 1179 blick elements to analyse the micromotions and mechanical behaviors at the bone-stem inteface in early post-operative period for the load simulating single leg stance. The results indicates that the values of relative motion for this well fit stem were $150{\mu}m$ in maximum $82{\mu}m$ in minimum and the largest relative motion was developed in medial region of Proximal femur and in anterior-posterior direction. The motion in the proximal bone was much greater than in the distal bone and the stress pattern showed high stress concentration on the cortex near the tip of the stem. These findings indicate that the loading on the hip joint in the early postoperative situation before achieving bony ingrowth could produce large micromotion of $150{\mu}m$ and clinicaly non-cemented THA patient should not be allowed weight bearing strictly early in the postoperative period.

• 대한의용생체공학회:의공학회지
• /
• 제32권3호
• /
• pp.198-206
• /
• 2011

Hearing devices like cochlear implant, vibrant soundbridge, etc. try to offer better sound for people. In hearing devices, several beamformers including conventional directional microphone are applicable to noise reduction. Each beamformer has different directional response and it could change sound intelligibility or quality for listeners. Therefore, we investigated the performance of three beamformers, which are first and second order directional microphone, and broadband beamformer(BBF) with a computer simulation assuming hearing device microphone configuration. We also calculated objective measurements which have been used to evaluate speech enhancement algorithms. In the simulation, a single speech and a single babble noisewere propagated from the front and $135^{\circ}$ azimuth degrees respectively. Microphones were configured in an end-fire array and the spacing was varied in comparison. With 3 cm spacing, BBF had about 3 dB higher enhanced SNR than that of directional microphones. However, enhancement of segmental SNR and frequency weighted segmental SNR were similar between the first order directional microphone and broadband beamformer. In addition when steady state noise was used, broadband beamformer showed the increased performance and had the highest enhanced SNR, and segmental SNR.