• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.189-196
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• 2020

PURPOSE. The aim of the present study was to investigate the effects of surface treatments on the bond strengths between polymer-containing restorative materials and two dual-cure resin cements. MATERIALS AND METHODS. In the present study, rectangular samples prepared from Lava Ultimate (LU) and Vita Enamic (VE) blocks were used. The specimen surfaces were treated using CoJet sandblasting, 50 ㎛ Al₂O₃ sandblasting, % 9 HF (hydrofluoric) acid, ER,Cr:YSGG laser treatment, and Z-Prime. Dual-cure resin cements (TheraCem and 3M RelyX U 200) were applied on each specimen's treated surface. A micro-tensile device was used to evaluate shear bond strength. Statistical analysis was performed using the SAS 9.4v3. RESULTS. While the bond strength using TheraCem with LU or VE was not statistically significant (P=.164), the bond strength using U200 with VE was statistically significant (P=.006). In the TheraCem applied VE groups, Z-Prime and HF acid were statistically different from CoJet, Laser, and Sandblast groups. In comparison of TheraCem used LU group, there was a statistically significant difference between HF acid and other surface treatments. CONCLUSION. The bonding performance between the restorative materials and cements were material type-dependent and surface treatment had a large effect on the bond strength. Within the limitations of the study, the use of both U200 and TheraCem may be suggested if Z-prime was applied to intaglio surfaces of VE. The cementation of LU using TheraCem is suitable after HF acid conditioning of the restoration surfaces.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.29-33
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• 2012

Objectives: The purpose of this study was to evaluate the microleakage of 4 temporary materials in teeth with Class II-type endodontic access preparations by using a glucose penetration model. Materials and Methods: Glucose reaction test was performed to rule out the presence of any reaction between glucose and temporary material. Class II-type endodontic access preparations were made in extracted human premolars with a single root (n = 10). Each experimental group was restored with Caviton (GC), Spacer (Vericom), IRM (Dentsply-Caulk), or Fuji II(GC). Microleakage of four materials used as temporary restorative materials was evaluated by using a glucose penetration model. Data were analyzed by the one-way analysis of variance followed by a multiplecomparison Tukey test. The interface between materials and tooth were examined under a scanning electron microscope (SEM). Results: There was no significant reaction between glucose and temporary materials used in this study. Microleakage was significantly lower for Caviton and Spacer than for Fuji II and IRM. SEM observation showed more intimate adaptation of tooth-restoration interfaces in Caviton and Spacer than in IRM and Fuji II. Conclusions: Compared to IRM and Fuji II, Caviton and Spacer can be considered better temporary sealing materials in Class II-type endodontic access cavities.

• 대한치과보철학회지
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• 제38권4호
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• pp.438-445
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• 2000

The ideal restorative material should mimic the properties of the tissues it replaces. Dental composite resins have been used widely as restorative materials due to its advantages such as excellent esthetics and ease of manipulation. But inadequate wear resistance has been a major factor limiting the use of composite restorative materials. Improved manufacturing techniques have allowed the development of hybrid composites, with a greater percentage volume filler loading, which have improved physical and mechanical properties. However they are lacking in the study of wear resistance. The purpose of this study was to evaluate the wear of human enamel against ceromer by the use of a pin-on-disk type wear testers. Discs of ceromer(Targis ; lvoclar Vivadent, Amherst. NY) and discs of type III gold alloy as a control were used f9r test specimens. Intact cusp of premolar and molar were used for enamel specimens. The wear of enamel was determined by weigh-ing the cusp before and after each test, and the weight converted to volumes by average densi-ty of enamel. Surface profilometer was used to quantify wear of the ceromer and gold specimens. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces The results were as follows; 1. Ceromer produced less enamel wear than gold(p<0.05) 2. The wear volume of ceromer was greater than that of gold(p<0.01) 3. The hardess of ceromer was lower than that of gold, but there was no correlation between the hardness and wear of the ceromer and gold. 4. SEM analysis revealed that there were many voids and microcracks in the wear tract of ceromer In gold group, many minute V-shaped grooves were examined.

• 한국구조물진단유지관리공학회 논문집
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• 제10권3호
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• pp.195-202
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• 2006

하수시설 콘크리트의 열화현상은 하수시설의 특수한 환경조건상 황산화세균 등의 서식에 의해 발생된 황화수소($H_2S$)에 기인하는 생화학적 부식이 대표적인 것으로 알려져 있으나, 국내의 경우 근본적으로 방지대책이 전혀 고려되지 않은 채 정비사업이 수행되고 있어 근본적으로 황산화세균을 억제할 수 있는 보수재료 공법의 개발이 시급히 필요한 실정이다. 이에 본 연구에서는 항균금속을 포함한 도포형 항균제를 개발한 후, 개발된 항균제의 황산화세균에 대한 항균성능과 항균제를 도포한 단면복구재의 부착강도, 흡수 및 투기저항성, 중성화 깊이, 염화물이온 침투깊이 및 화학저항성 등의 기초물성을 평가하였다.

• 보존과학회지
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• 제32권4호
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• pp.459-469
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• 2016

본 연구는 2014년도에 개발된 문화재 복원용 에폭시 수지를 이용해 충전제에 따른 물성변화에 대해 알아보고, 복원제로서의 적용 가능성을 판단해보고자 하였다. 개발된 수지와 9종의 충전제가 혼합된 퍼티의 물성 결과를 바탕으로 기존 재료들과의 비교를 통해 에폭시 퍼티의 안정성, 우수성 및 적용성에 대해 분석하고 대체 재료로서의 가능성을 확인해 보았다. 물성 측정 결과 접착력과 색상변화량, 경도는 석회, 마모율과 경화 시간은 마이크로 바룬, 인장 강도와 압축 강도는 규조토, 비중은 석고와 백색 무기안료 혼합 충전제가 각각 배합된 재료가 가장 우수한 결과 값을 나타내었다. 특히 마모율에서는 석회를 제외한 모든 재료가 기존 재료에 비해 약 2.5 ~ 20배 정도의 높은 값을 보여 매우 우수한 절삭력을 가진 재료로 판단된다. 또한 경화 시간에서는 약 0.5 ~ 9배를 증진시켜 빠른 경화 시간으로 작업에서의 편리성이 증진되었으며, 수축 및 변형도 일어나지 않고 손에 묻어나는 현상도 개선되어 유물에 대한 안전성도 확보할 수 있었다. 황변현상은 약 0.5 ~ 27배의 낮은 변화량을 보여주어 변화량을 개선하고, 유물과의 이질감 및 재처리로 발생되는 유물의 피로도를 줄여줄 수 있는 재료로 판단된다.

• 대한소아치과학회지
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• 제26권1호
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• pp.62-68
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• 1999

One of the many dilemmas that the clinical restorative dentist must face is treating young adolescent patient who prematurely loses his permanent teeth. Temporary prosthetic replacement can be achieved with removable denture, orthodontic band-wire fixed denture, adhesion bridge, composite resin splint with reinforcing material until the patients go through growth and development. But, all of these have limitations. Advances in restorative materials and reinforcement materials have made possible new techniques which are as much esthetic, conservative and more economic and stronger than adhesion brides. Two cases are being presented where gas-plasma treated, woven polyethylene fabric to reinforce composite resin was used to fabricate a temporary prosthetic restoration to replace a missing maxillary central incisor. This relatively noninvasive and basically reversible procedure allows the patient to decide the final restoration as he or she goes thorough maturation of the hard and soft tissues.

• 폴리머
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• 제30권2호
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• pp.135-139
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• 2006

인체 뼈의 주성분인 수산화인회석(hydroxyapatite, HAP)이 충전된 고분자 복합체를 제조하고 이들의 치과적 물성을 분석하여 치과용 수복재료로의 응용성을 확인하고자 하였다. 복합체 제조에 사용된 기질인 아크릴계 단량체는 가시광선으로 경화시켰다. 실험 결과, HAP는 무게비로 65%까지 첨가되었으며 중합깊이는 6.0 mm 정도로서 일반적 치과용 수복재료로의 응용이 가능함을 확인하였다. 제조된 고분자 복합체의 중합전환율은 HHP 첨가량이 늘어날수록 약간 감소하였으며 중합수축률은 HAP 변화량에의 의존성이 거의 없었다. 복합체의 기계적 물성은 HAP함량이 증가할수록 간접인장강도는 증가하였고 굴곡강도는 큰 변화가 없었다. 그러나 그 값들은 치의학에서 규정한 값들을 상회하여 치과용 재료로의 응용 가능성이 매우 높음을 확인할 수 있었다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.159-169
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• 2000

The purpose of this study was to examine the tissue response to experimental furcation perforations immediately treated with Super EBA, Ketac Silver, MTA and Emdogain using surgical microscope. Forty experimental furcation perforations were created in the mandibular and maxillary premolars and molars of 4 adult dogs and immediately repaired with experimental materials. The animals were sacrificed after 16 weeks and radiographic and histologic results were evaluated. The results were as follows. 1 All materials tested in this experiment revealed a certain degree of extrusion of the filling materials and infiltration of inflammatory cells into the periodontal space. Except MTA group, epithelial down-growth of the surrounding gingiva was found in all experimental groups. 2. Both Ketac Silver and Emdogain group showed the greatest degree of inflammatory reaction and bone resorption. 3. Super EBA group showed moderate inflammation and newly bone formation under the perforation area. 4. MTA group showed minor inflammation, new bone regeneration toward restorative materials and partially cementum growth onto the surface of the material. This group demonstrated a favorable prognosis.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.52.1-52.11
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• 2020

Objectives: Yttria-stabilized tetragonal phase zirconia has been used as a dental restorative material for over a decade. While it is still the strongest and toughest ceramic, its translucency remains as a significant drawback. To overcome this, stabilizing the translucency zirconia to a significant cubic crystalline phase by increasing the yttria content to more than 8 mol% (8YTZP). However, the biocompatibility of a high amount of yttria is still an important topic that needs to be investigated. Materials and Methods: Commercially available 8YTZP plates were used. To enhance cell adhesion, proliferation, and differentiation, the surface of the 8YTZP is sequentially polished with a SiC-coated abrasive paper and surface coating with type I collagen. Fibroblast-like cells L929 used for cell adherence and cell proliferation analysis, and mouse bone marrow-derived mesenchymal stem cells (BMSC) used for cell differentiation analysis. Results: The results revealed that all samples, regardless of the surface treatment, are hydrophilic and showed a strong affinity for water. Even the cell culture results indicate that simple surface polishing and coating can affect cellular behavior by enhancing cell adhesion and proliferation. Both L929 cells and BMSC were nicely adhered to and proliferated in all conditions. Conclusions: The results demonstrate the biocompatibility of the cubic phase zirconia with 8 mol% yttria and suggest that yttria with a higher zirconia content are not toxic to the cells, support a strong adhesion of cells on their surfaces, and promote cell proliferation and differentiation. All these confirm its potential use in tissue engineering.

• Archives of Plastic Surgery
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• 제50권6호
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• pp.563-567
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• 2023

Ear keloids are challenging lesions to treat due to high recurrence rates postexcision. Conservative compression techniques as adjunct treatment have been reported to be effective. An innovative technique of using computer-aided design/computed-aided manufacturing to print a customized auricular splint improves efficiency and comfort level for patients compared with conventional methods. The ear is scanned using an intraoral scanning 2 weeks postsurgery. A two-piece auricular splint is designed on the digital model, incorporating perforated projections for three nylon screws for retention of the splint. The splint is printed with clear acrylic material, postprocessed, and finished. The patient is taught to assemble the components of the splint and instructed to wear for at least 8 hours daily. The surgery site reviewed for any ulceration, pain, or recurrence of keloid for 6 months. During the 6-month review, the excision scar remained flat and pink. The patient also reports unrestricted daily activities. The digital workflow increases comfort for the patient and reduces the number of hours required to produce a customized auricular splint compared with conventional methods. A fully digital workflow for a printed auricular splint should be considered for adjunctive treatment to excision of ear keloids.