• Restorative Dentistry and Endodontics
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• 제36권5호
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• pp.409-418
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• 2011

연구목적: 이 연구는 상아질 표면에 Er:YAG 레이저를 조사하지 않는 군, 레이저를 조사한 군, 레이저를 조사한 후 부가적인 산처리를 한 군으로 분류하여 2단계 단일병 전부식 접착시스템과 자가부식 프라이머 접착시스템을 이용하여 복합레진을 접착하였을 때 이러한 표면처리가 복합레진의 미세전단 결합강도와 결합계면에 미치는 영향을 비교하기 위하여 시행하였다. 연구 재료 및 방법: 32개의 발거된 대구치의 교합면측 상아질을 이용하였고, 상아질의 표면처리는 1군과 4군에서 각각 인산과 자가부식 프라이머로 하였으며, 2군과 5군은 Er:YAG 레이저로 에칭처리하였고, 3군과 6군은 레이저로 에칭한 후 다시 각각 인산과 자가부식 프라이머로 하였다. 1군, 2군, 3군은 Single Bond 2와 Z 250 (3M ESPE)을 이용하였고, 4군, 5군, 6군은 Clearfil SE Bond와 Clearfil AP-Z (Kuraray)을 이용하여 상아질 면에 Tygon tube를 접착하였다. 각 군의 미세전단 결합강도를 측정한 후 통계 처리하였고, 또한 6개의 시편에서 복합레진과 상아질 계면을 주사전자현미경하에서 관찰하였다. 결과: Single Bond 2를 사용한 군에서 2군의 결합강도는 1군과 3군보다 통계학적으로 낮게 나타났으며, Clearfil SE Bond를 사용한 군에서 4군, 5군, 6군의 결합강도는 각각 통계학적으로 유의한 차이를 나타내었다(p < 0.05). 2군과 5군은 아주 짧고 가는 레진테그가 관찰되었고, 3군과 6군은 길고 가는 레진테그와 레진테그의 측지가 관찰되었다. 결론: 레이저로 에칭 처리한 상아질에 대한 부가적인 산 처리나 자가부식 프라이머의 처리는 상아질의 접착력을 향상시켰다.

• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.124-130
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• 2020

PURPOSE. The aim of this in vitro study was to evaluate the effect of sintering procedures on marginal discrepancies of fixed partial metal frameworks fabricated using different sintering-based computer-aided design and computer/aided manufacturing (CAD/CAM) techniques. MATERIALS AND METHODS. Forty resin die models of prepared premolar and molar abutment teeth were fabricated using a three-dimensional (3D) printer and divided into four groups (n = 10) according to the fabrication method of metal frameworks used: HM (via hard milling), SM (via soft metal milling), L25 (via direct metal laser melting [DMLM] with a 25 ㎛ layer thickness), and L50 (via direct DMLM with a 50 ㎛ layer thickness). After the metal frameworks were fabricated and cemented, five vertical marginal discrepancy measurements were recorded in each site (i.e., buccal, facing the pontic, lingual, and facing away from the pontic) of both abutment teeth under a stereomicroscope (×40). Data were statistically analyzed at a significance level of 0.05. RESULTS. No statistically significant differences (P>.05) were found among the four axial sites of metal frameworks fabricated by sintering-based CAD/CAM techniques. The HM and L25 groups showed significantly (P<.001) lower marginal discrepancy values than the SM and L50 groups. CONCLUSION. Marginal discrepancy in the sites facing the pontic was not influenced by the type of sintering procedure. All fabrication methods exhibited clinically acceptable results in terms of marginal discrepancies.

• Restorative Dentistry and Endodontics
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• 제27권3호
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• pp.257-269
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• 2002

Objective : The purpose of this study was to evaluate the resin infiltration into dentin of one-bottle adhesive systems and self-etching primer bonded to Class V cavities using confocal laser scanning microscope(CLSM). Material and Methods : Forty Class V cavities were prepared from freshly extracted caries-free Human teeth. These teeth were divided into two groups based on the presence of cervical abrasion: Group I, cervical abrasion : Group II, wedge-shaped cavity preparation. Resin-dentin interfaces were produced with two one-bottle dentin bonding systems-ONE COAT BOND(OCB; Coltene$^R$) and Syntac$^R$SPrint$^{TM}$(SS; VIVADENT)-, one self-etching priming system-CLEARFIL$^{TM}$ SE BOND (SB : KURARAY)- and one multi-step dentin bonding system-Scotchbond$^{TM}$Multi-Purpose (SBMP, 3M Dental Products)-as control according to manufacturers' instructions. Cavities were restored with Spectrum$^{R}$(Dentsply). Specimens were immersed in saline for 24 hours and sectioned longitudinally with a low-speed diamond disc. The resin-dentin interfaces were microscopically observed using CLSM. The quality of resin-infiltrated dentin layers were evaluated by five dentists using 0~4 scale. Results : Confocal laser scanning microscopal investigations using primer labeled with rhodamine B showed that the penetration of the primer occurred along the cavity margins. Statistical analysis using one-way ANOVA followed by Duncan's Multiple Range test revealed that the primer penetration of the group 2(wedge-shaped cavity preparation) was more effective than group 1(cervical abrasion) and that of the gingival interfaces was more effective than the occlusal interfaces. In the one-bottle dentin bonding systems, the resin penetration score of OCB was compatible to SBMP, but those of SS and self-etching priming system, SB were lower than SBMP.

• Journal of Periodontal and Implant Science
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• 제52권1호
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• pp.65-76
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• 2022

Purpose: The present study measured changes in arteriolar and venular capillary flow and structure in the gingival tissues during the development of plaque-induced gingival inflammation by combining dynamic optical coherence tomography (OCT), laser perfusion, and capillaroscopic video imaging. Methods: Gingival inflammation was induced in 21 healthy volunteers over a 3-week period. Gingival blood flow and capillary morphology were measured by dynamic OCT, laser perfusion imaging, and capillaroscopy, including a baseline assessment of capillary glycocalyx thickness. Venular capillary flow was estimated by analysis of the perfusion images and mean blood velocity/acceleration in the capillaroscopic images. Readings were recorded at baseline and weekly over the 3 weeks of plaque accumulation and 2 weeks after brushing was resumed. Results: Perfusion imaging demonstrated a significant reduction of gingival blood flow after 1 and 2 weeks of plaque accumulation (P<0.05), but by 3 weeks of plaque accumulation there was a more mixed picture, with reduced flow in some participants and increased flow in others. Participants with reduced flux at 3 weeks also demonstrated venular-type flow as determined by perfusion images and evidence of the development of venular capillaries as assessed by the velocity/acceleration ratio in capillaroscopic images. After brushing resumed, these venular capillaries were broken down and replaced by arteriolar capillaries. Conclusions: After 3 weeks of plaque accumulation, there was wide variation in microvascular reactions between the participants. Reduced capillary flow was associated with the development of venular capillaries in some individuals. This is noteworthy, as an early increase in venous capillaries is a key vascular feature of cardiovascular disease, psoriasis, Sjögren syndrome, and rheumatoid arthritis-diseases with a significant association with the development of severe gingival inflammation, which leads to periodontitis. Future investigations of microvascular changes in gingival inflammation might benefit from accurate capillary flow velocity measurements to assess the development of venular capillaries.

• 대한치과교정학회지
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• 제36권5호
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• pp.360-368
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• 2006

치과용 재료의 표면특성은 세균 부착에 중요한 역할을 한다. 본 연구의 목적은 다섯 종류의 광중합 교정용 접착제(불소를 방출하지 않는 세 종류의 콤포지트 레진, 불소를 방출하는 콤포지트 레진 한 종류, 레진 변형 글래스아이오노머 시멘트 한 종류)의 표면특성을 평가하는 것이다. 표면거칠기는 공초점 레이저주사전자현미경을 이용하여 측정하였고, 접촉각과 표면에너지 요소는 sessile drop method를 이용하여 분석하였다. 본 연구의 결과 교정용 접착제간 표면거칠기는 각 재료간 표면거칠기 차이가 $0.05\;{\mu}m$ 이하로 상대적으로 적지만 각 재료 사이에 유의성 있는 차이를 보였다. Transbond XT와 Enlight는 Monolok2와 Lightbond 보다 유의하게 덜 거칠었다. 접촉각과 표면에너지 구성성분은 접착제 사이에 유의성 있는 큰 차이를 보였는데 특히 레진 변형 글래스아이오노머와 콤포지트 레진 접착제간에 접촉각과 표면에너지에서 커다란 차이를 보였다. 레진 변형 글래스아이오노머의 경우 콤포지트 레진 접착제에 비해 유의하게 작은 접촉각과 높은 표면에너지를 보였으며 콤포지트 레진 접착제보다 강한 극성, 특히 강한 염기성 경향을 보였다 본 연구는 레진 변형 글래스아이오노머가 콤포지트 레진 접착제에 비해 세균 부착에 유리한 환경을 제공한다는 것을 보여주었다.

• 대한소아치과학회지
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• 제29권3호
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• pp.430-438
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• 2002

본 연구에서는 Prodigy(Kerr, USA), Vitalescence(Ultradent, USA), Z 250(3M, USA), Filtek flow(3M, USA)의 4종의 복합레진을 사용하여 각 제품의 분해저항성을 평가하고자 하였다. 무게손실, 표면하 분해층 깊이, 용출된 Si 농도를 기준으로 각 레진의 분해저항성을 평가하여 다음과 같은 결과를 얻었다. 1. 무게손실량은 Prodigy와 Vitalescence사이, Z 250과 Filtek flow사이에는 차이를 보이지 않았으며 전후 제품군 간에는 차이를 보였다(p<0.05). 2. 분해층 깊이는 Z 250, Filtek flow, Prodigy, Vitalescence순으로 감소하였으며, 네가지 제품간에는 유의한 차이를 보였다(p<0.05). 3. Si 용출량은 Filtek flow, Z 250, Prodigy, Vitalescence 순으로 감소하였으며, 각 제품 간에는 유의한 차이를 보였다(p<0.05). 4. 각 제품의 무게손실과 분해층 깊이 사이(r=0.714, p<0.05), 무게손실과 Si 용출량 사이(r=0.770, p<0.05), 분해층 깊이와 Si 용출량 사이 (r=0.930, p<0.05)에는 높은 상관관계를 보였다. 5. 주사전자현미경 관찰시 NaOH 용액에 보관한 후 레진 기질과 필러 사이의 결합의 파괴를 관찰할 수 있었다. 6. 공촛점 레이저 현미경 관찰시 NaOH용액에 보관한 후 레진의 분해층 깊이를 관찰할 수 있었다.

• 대한치과보철학회지
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• 제53권4호
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• pp.337-344
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• 2015

목적: 본 연구의 목적은 지대치 삭제의 정확도와 metal coping의 변연적합도와의 상관관계를 알아보는 데 있다. 이를 통해, 세 가지 다른 제작 방식 (주조, milling, 기법)이 이 상관관계에 미치는 영향을 비교해 보고자 한다. 재료 및 방법: 두 개의 master medel을 서로 다른 방식으로 제작하였다; 첫 번째 모델은 치과의사에 의해 deep chamfer margin을 가지도록 지대치 삭제된 것이고, 두 번째 모델은 3-D designing software program을 이용하여 동일한 삭제원칙에 따라 제작되었다. 각각의 모델에 대하여 세 가지 제작 방식으로 코발트-크롬 코핑을 12개씩 제작하여, 총 72개의 시편을 얻었다. 각 시편을 master model상에 적합시키고 공초점 레이저 주사 현미경으로 변연적합도를 측정하였다. 결과: SLS system (P=.0231)과 주조방식(P<.0001)에서는 computer designed model이 hand prepared model에 비하여 유의하게 우수한 변연적합도를 보였다. 그러나 milling group에서는 두 모델 간에 유의한 차이를 나타내지 않았다(P=.9962). 결론: 본 연구에 한하여, 지대치 삭제의 정확도가 금속 코핑의 변연적합도에 미치는 영향은 그 제작 방식에 따라 달랐다. 제작 방식에 따른 변연적 합도는 SLS system이 가장 우수하였고 지대치 삭제의 정확도에 의해 영향을 받았다. 한편, milling 방식은 세 가지 방식 중 가장 큰 변연 격차를 나타내었으며 지대치 삭제의 정확도에 영향을 받지 않았다.

• Journal of Periodontal and Implant Science
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• 제46권2호
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• pp.96-106
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• 2016

Purpose: Stress distribution and mandible distortion during lateral movements are known to be closely linked to bruxism, dental implant placement, and temporomandibular joint disorder. The present study was performed to determine stress distribution and distortion patterns of the mandible during lateral movements in Class I, II, and III relationships. Methods: Five Korean volunteers (one normal, two Class II, and two Class III occlusion cases) were selected. Finite element (FE) modeling was performed using information from cone-beam computed tomographic (CBCT) scans of the subjects' skulls, scanned images of dental casts, and incisor movement captured by an optical motion-capture system. Results: In the Class I and II cases, maximum stress load occurred at the condyle of the balancing side, but, in the Class III cases, the maximum stress was loaded on the condyle of the working side. Maximum distortion was observed on the menton at the midline in every case, regardless of loading force. The distortion was greatest in Class III cases and smallest in Class II cases. Conclusions: The stress distribution along and accompanying distortion of a mandible seems to be affected by the anteroposterior position of the mandible. Additionally, 3-D modeling of the craniofacial skeleton using CBCT and an optical laser scanner and reproduction of mandibular movement by way of the optical motion-capture technique used in this study are reliable techniques for investigating the masticatory system.

• 한국표면공학회지
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• 제37권5호
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• pp.249-252
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• 2004

Effects of HA and TiN coating on the electrochemical characteristics of Ti-6AI-4V alloys for bone plates were investigated using various test methods. Ti-6AI-4V alloys were fabricated by using a vacuum induction furnace and bone plates were made by laser cutting and polishing. HA was made of extracted tooth sintered and then tooth ash was used as HA coating target. The TiN and HA film coating on the surface were carried on using electron-beam physical vapor deposition (EB-PVD) method. The corrosion behaviors of the samples were examined through potentiodynamic method in 0.9% NaCI solutions at $36.5\pm$$1^{\circ}C$ and corrosion surface was observed using SEM and XPS. The surface roughness of TiN coated bone plates was lower than that of tooth ash coated plates. The structure of TiN coated layer showed the columnar structure and tooth ash coated layer showed equiaxed and anisotrophic structure. The corrosion potential of the TiN coated specimen is comparatively high. The active current density of TiN and tooth ash coated alloy showed the range of about $1.0xl0^{-5}$ $A\textrm{cm}^2$, whereas that of the non-coated alloy was$ 1.0xl0^{-4}$ $A\textrm{cm}^2$. The active current densities of HA and TiN coated bone plates were smaller than that of non-coated bone plates in 0.9% NaCl solution. The pitting potential of TiN and HA coated alloy is more drastically increased than that of the non-coated alloy. The pit number and pit size of TiN and HA coated alloy decreased in compared with those of non-coated alloy. For the coated samples, corrosion resistance increased in the order of TiN coated, tooth ash coated, and non-coated alloy.

• Journal of Periodontal and Implant Science
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• 제49권3호
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• pp.193-204
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• 2019

Purpose: The reaction of cells to a titanium implant depends on the surface characteristics of the implant which are affected by decontamination. The aim of this study was to evaluate the cytocompatibility of titanium disks treated with various decontamination methods, using salivary bacterial contamination with dental pellicle formation as an in vitro model. Methods: Sand-blasted and acid-etched (SA) titanium disks were used. Three control groups (pristine SA disks [SA group]; salivary pellicle-coated SA disks [pellicle group]; and biofilm-coated, untreated SA disks [NT group]) were not subjected to any decontamination treatments. Decontamination of the biofilm-coated disks was performed by 14 methods, including ultrasonic instruments, rotating instruments, an air-powder abrasive system, a laser, and chemical agents. MG63 cells were cultured in the presence of the treated disks. Cell proliferation assays were performed on days 2 and 5 of cell culture, and cell morphology was analyzed by immunofluorescence and scanning electron microscopy (SEM). A vascular endothelial growth factor (VEGF) assay was performed on day 5 of culture. Results: The cell proliferation assay revealed that all decontaminated disks, except for the 2 groups treated using a plastic tip, showed significantly less cell proliferation than the SA group. The immunofluorescence and SEM analyses revealed that most groups showed comparable cell density, with the exception of the NT group, in which the cell density was lower and bacterial residue was observed. Furthermore, the cells grown with tetracycline-treated titanium disks showed significantly lower VEGF production than those in the SA group. Conclusions: None of the decontamination methods resulted in cytocompatibility similar to that of pristine SA titanium. However, many methods caused improvement in the biocompatibility of the titanium disks in comparison with the biofilm-coated, untreated titanium disks. This suggests that decontamination is indispensable for the treatment of peri-implantitis, even if the original biocompatibility cannot be restored.