• 대한치과보철학회지
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• 제25권1호
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• pp.137-154
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• 1987

The purpose of this investigation was to determine the surface characteristics and the fittness of the resilienct denture lines. Firstly, 50 samples ($2.0{\times}4.0{\times}0.3cm$) of 4 resilient lining materials (Molloplast B, Coe Super Soft, Mollosil, Coe Soft) and one conventional acrylic resin (K-33) were processed according to manufacture's direction and examined the surface characteristics by use of surface profilometer and scanning electron microscopy. Secondly, 50 identical maxillary casts were made and 50 denture bases were pro cessed of 4 resilient liners and one conventional acrylic resin and they were stored in the room temperature water bath of 1 day, 1 week, 2 weeks, 3 weeks, 4 weeks and 6 weeks after processing. The original casts were cut away 1 cm from the posterior border, the dentures were seated, and the existing space was measured at seven regions according to the storage time by use of the modified thickness guage. The results were as follows. 1. Surface roughness (Rz) were $4.00{\pm}1.60{\mu}m$ in Mollosil, $4.47{\pm}2.21{\mu}m$ in Molloplast B, $7.46{\pm}1.70{\mu}m$ in Coe Super Soft, $12.70{\pm}2.39{\mu}m$ in Coe Soft and $13.03{\pm}2.74{\mu}m$ in K-33. 2. The generation of porosity was far more active in cold-cured resilient liners (Coe Soft and Mollosil) than in heat cured resilient liners (Molloplast B, and Coe Super Soft) and conventional heat cured resin (K-33). 3. Denture bases showed the greatest discrepancy at the central portion of the posterior palatal border and the intimate contact in the buccal flange regardless of denture base materials. 4. When the denture bases were stored in the water for 1 day and 6 weeks after processing, the sum of average discrepancies in the seven regions of the denture base was the greatest in K-33 followed by Molloplast B, Mollosil, Coe Soft and Coe Super Soft but followed by Coe Soft, Molloplast B, Mollosil, Coe Super Soft in that order respectively. 5. There was not a significant difference (p>0.05) in Coe Super Soft, K-33 but there was a significant difference (P<0.01) in Molloplast B, Mollosil, Coe Soft at the amount of dimensional changes according to the storage time.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.615-630
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• 2002

Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• 대한치과보철학회지
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• 제37권1호
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• pp.51-70
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• 1999

Dental porcelain is one of the materials of choice for restoration where esthetics is of concern, but has a considerable potentials of wear. The wear of enamel is variable when opposed by different porcelain systems and surface conditions, and the exposed dentine and opaque porcelain due to clinical failure is expected to have high potentials of wear. The purpose of this study was to investigate the wear effects of self-glazed, polished incisal porcelain. polished dentine and opaque porcelain against human enamel in the laboratory by use of a pin-on-disk type wear tester. 4 types of dental porcelain($Vita-{\Omega}$, Ceramco-II, Vintage powder $Vita-{\alpha}$ of In-Ceram system) and type IV gold alloy as cotrol group were used for test specimens. Intact buccal cusps of maxillary premolar were used for enamel specimens, and the cusp converged to a point and was devoid of visible abrasion, caries, decalcification. The upper part was the cusp of a maxillary premolar and the lower part was a porcelain specimen. The enamel wear was deter-mined by weighing the cusp before and after each test. Surface profilometer was used to quantitate wear of the porcelain 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 Self-glazed porcelain produced more enamel wear than polished porcelain, especially the enamel wear of $Vita-{\alpha}$ self-glazed porcelain was 3.2 times more than that of other groups. 2. Opaque porcelain produced least porcelain wear, $Vita-{\alpha}$ self-glazed porcelain produce greatest porcelain wear, but there was no statistically significant difference between the groups(p>0.05). 3. The enamel wear of dentine porcelain was 3.8 times more than that of polished inisal porcelain(p<0.05), and the enamel wear of opaque porcelain was 1.9 times more than that of polished inisal porcelain, but there was no statistically significant difference between the groups(p>0.05) 4. Overglazed porcelain produced less enamel wear than self-glazed porcelain, and more enamel wear than polished porcelain, but there was no statistically significant difference between the groups(P>0.05). 5. The hardness number of $Vita-{\Omega}$ dentine and Ceramco-II opaque porcelain was larger, but that of Vintage dentine and $Vita-{\alpha}$ self-glazed porcelain was similar to other groups. 6. Examination of SEM photographs revealed that overglazed porcelain had smoother surface than self-glazed porcelain, and self-glazed porcelain had smoother surface than polished porcelain. Much polishing scratches and larger porosities were observed on the opaque porcelain specimen, and much polishing scratchess and small porosities were observed on the dentine porcelain specimen.

• 대한치과보철학회지
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• 제45권5호
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• pp.611-620
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• 2007

Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

• Journal of Periodontal and Implant Science
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• 제28권2호
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• pp.351-372
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• 1998

The purpose of this study was to evaluate in vitro effects of the loss of tooth substance and root surface changes following root planing with various periodontal instruments. The 39 extracted human teeth due to severe periodontal disease were included. The total 50 root surfaces of 30 teeth were root planed with following instruments : Group 1, with Gracey curette, Group 2, with ultrasonic scaler, Group 3, with rotating root planing bur, Group 4, with Gracey curette plus rubber cup polishing, and Group 5, with ultrasonic scaler plus rubber cup polishing. Following root planing, the amount of tooth substance loss was evaluated by measuring the weight of the removed tooth substance and then 5 specimens ($5{\times}5{\times}2mm$) were randomly selected from the each group for roughness measurement. Root planed areas of each specimen were subjected to five measurements using the Profilometer and an average surface roughness values(Ra) for each group was obtained. Statistical difference for roughness values of each group was analyzed using oneway ANOVA and student t-test. For scanning electron microscopic(SEM) examination of root surface changes following root planing, 15 root surfaces of remaining 9 teeth were root planed and 3 specimens were randomly selected. The mean loss of tooth substance removed was Group 1, $7.0{\pm}1.09mg$, Group 2, $1.3{\pm}1.00mg$, Group 3, $5.8{\pm}1.72mg$, Group 4, $8.7{\pm}1.34mg$, and Group 5, $4.5{\pm}1.68mg$ following root palning, respectively. These results indicate that curette is effective instrument in the respect of diseased root substance removal. The average surface roughness values are following results : Group 1 and Group 4 were the smoothest surface ($Ra=0.34{\pm}0.06{\mu}m$, $Ra=0.34{\pm}0.04{\mu}m$, respectively) and Group 2 was the roughest surface ($Ra=2.09{\pm}0.06{\mu}m$). Statistical analysis of roughness values demonstrated a highly significant difference (P<0.05) between each experimental groups. However, no statistically significant difference in roughness values were observed between the Group 1 and Group 4. The results in this study suggest that curette and/or polishing procedure should be done after root planing with ultrasonic scaler and caution should be used with dia-mond-coated bur during routine root planing procedure.

• 대한소아치과학회지
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• 제31권4호
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• pp.547-554
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• 2004

본 연구는 복합레진에서 치태 생성 에 영향을 주는 표면 거칠기 및 표면 자유에너지를 나타내는 물방울 접촉각을 측정하고, 치태 부착실험을 통해 두 가지 요소가 미치는 영향에 대하여 평가할 목적으로 시행되었다. 4종의 복합레진(Z-100, Filtek supreme, Durafil, Clearfil AP X)을 비연마군과 연마군으로 각각 5개씩 시편을 제작하였다. 표면 거칠기는 표면조도형상 측정기를, 접촉각은 접촉각측정기를 이용하여 각각 측정하였다. 치태부착 실험은, 시편을 배양액을 넣고 Streptococcus mutans Ingbritt을 접종하여 부착된 치태의 양을 측정하여 평가하였다. 1. 표면조도는 연마되지 않은 대조군에서는 (Z1, DF, CA)>FS의 순 연마된 실험군에서는 CA>Z1>(FS, DF)의 순으로 나타났으며, 실험군이 대조군에 비해 높은 표면 조도를 보였다(p<0.05). 2. 접촉각은 대조군에서는 CA>(FS, DF, Z1)의 순, 실험군에서는 (CA, DF)>(FS, Z1)의 순으로 나타났으며, 실험군이 대조군에 비해 낮은 접촉각을 보였다(p<0.05). 3. 치태침착은 대조군에서는 Z1>(DF, FS)>CA의 순, 실험군에서는 Z1>FS> (CA, DF)의 순으로 나타났으며, 실험군이 대조군에 비해 치태 침착이 더 많았다(p<0.05). 4. 치태 부착도에 대해서 표면 조도는 상관성이 없고, 접촉각은 강한 반비례 관계를 보였다(p<0.05). 즉 치태 부착에 대해 접촉각이 표면 조도 보다 더 큰 관련성을 보였다.

• 지질공학
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• 제12권4호
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• pp.421-437
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• 2002

절리면에서의 이방성 및 전단거동을 정량적으로 파악하기 위한 목적으로 암석 절리면에 석고 몰드를 제작한 후 시멘트 몰타르를 이용하여 복제된 절리모델에 직접전단시험을 실시하였다. 시험 전 암석 시험편의 절리면에 대하여 기계식 단면측정기를 이용하여 절리면의 거칠기를 측정하고 이에 대한 결과를 수치화하였다. 수치화를 통하여 제시된 좌표값을 통하여 거칠기의 통계적 변수와 프랙탈 차원을 구하였다. 대부분의 절리모형에서, 낮은 수직응력 수준에서 전단변위에 따른 전단응력의 값이 지속되거나 상승하였다. 이는 자연상태의 절리면에 대하여 형성된 전리모형의 경우 단일 거칠기 특성에 의존되지 않음을 나타낸다 거칠기에 대한 여러 통계적 변수에 의해 제시된 단면의 특성과 전단강도와의 관계는 일정하지 않으며, 대부분 낮은 상관관계를 가지고 있음이 확인되었다. JRC를 이용한 Barton의 경험식과 실제 실험에서 주어진 값을 비교한 결과 Barton의 경험식은 거칠기에 대한 이방성의 영향을 고려하기 어려우며, 절리면에 대한 특성을 파악함에 있어서 적절하지 않은 것으고 판단된다. 프랙탈 차원의 경우 동일한 단면에 대하여 이방성을 고려할 수 있었으며, 이를 이용한 경험식을 사용한 결과 시험결과와 유사한 이방성을 인지할 수 있었다.

• 방사성폐기물학회지
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• 제8권3호
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• pp.247-260
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• 2010

한국원자력연구원 처분시스템개발과제에서는 처분용기 재료로 개발중인 저온분사코팅 구리에 대한 틈새부식(Crevice Corrosion) 시험을 실시하였다. 본 시험을 통하여 틈새에서의 부식의 발생여부와 발생되는 시점인 재부동태 전위(Repassivation Potential)를 측정하고자 하였다. 틈새부식 시험 방법으로 (1) ASTM G61-86 : Cyclic Potentiodynamic Polarization Measurements, (2) SWRI의 Potentiodynamic Polarization plus intermediate Potentiostatic Hold method, 그리고 (3) ASTM G192-08 (THE method) :Potentiodynamic- Galvanostatic -Potentiostatic Method 등의 3가지 방법을 소개하였다. 실제 저온분사 코팅구리의 부식시험에서는 ASTM G61-86에 따라서 틈새부식장치를 설치하고, 저온분사코팅구리가 KURT 지하수를 모사한 용액에서 어떻게 틈새부식이 일어나는지 살펴보았다. 전기적 부식조건으로는 Cyclic Polarization Test, Potentiostatic Polarization Test, 및 Electrochemical Impedance Spectroscopy 등을 사용하였다. 그리고 부식이 된 시편에 대해 Profilometer Measurement를 통해 실제 부식표면의 높낮이를 조사하여 틈새부식 유무를 관찰하였다. 최종적인 결론에서는 저온분사코팅구리는 틈새부식을 나타나지 않는다는 것을 확인할 수 있었다. 그리고 시험에 사용된 세종류의 구리에 대한 상대적인 부식평가를 한 결과, 부식전위를 나타내는 개방회로(Open Cell)에서의 전위는 구리의 제조방식과 상관없이 구리의 순도가 높을수록 높은 값을 보이는 것을 확인할 수 있었다. 결론적으로 KURT 심층지하수 조건에서는 구리는 틈새부식이 발생되지 않는다고 결론지었다.

• Restorative Dentistry and Endodontics
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• 제36권2호
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• pp.119-124
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• 2011

연구목적: 본 실험은 현재 임상에서 사용되고 있는 4가지 복합레진 연마 시스템의 연마 능력과 연마에 걸리는 시간을 평가하여 그 효율성을 알아보고자 하였다. 연구 재료 및 방법: 직경 4 mm, 높이 2 mm 의 테플론 몰드에 Z-250 (3M ESPE) 복합레진을 충전하고 양면을 슬라이드 글라스로 압접한 후 Optilux 501을 이용하여 각 면을 40초씩 중합하였다. 중합된 복합레진 디스크를 분리하고 #320 사포로 연마하여 동일한 거친면을 형성한 후 다음의 4가지 연마시스템을 이용하여 표면을 연마하였다: Sof-Lex (3M ESPE), Jiffy (Ultradent), Enhance (Dentsply/Caulk), and Pogo (Dentsply/Caulk). 연마된 면을 표면조도측정기를 이용하여 거칠기를 측정하고 연마에 소요된 시간을 측정하여 연마도와 효율성을 비교 평가하였다. 통계는 one-way ANOVA후 Duncan's multiple range test를 이용하여 군간의 비교를 하였다. 결과: 연마 후 표면조도는 Pogo에서 가장 낮게 나타났으며 Sof-Lex에서 가장 높게 나타났다. 연마에 소요된 시간은 Pogo에서 가장 짧게 걸렸으며 Sof-Lex, Enhance, Jiffy의 순으로 나타났다. 결론: One-step 연마 시스템인 Pogo는 복합레진의 연마에 있어 매우 짧은 시간에 매우 매끈한 면을 얻을 수 있는 것으로 나타나 수복물의 최종 연마에 매우 효율적으로 사용할 수 있는 것으로 평가되었다.

• The Journal of Advanced Prosthodontics
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• 제16권2호
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• pp.126-138
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• 2024

PURPOSE. The aim of this study was to evaluate the influence of different 3D dental resins, using a manufacturer recommended printer and a third-party printer, on cellular responses of human gingival cells. MATERIALS AND METHODS. Three NextDent resins (Denture 3D+, C&B MFH and Crowntec) were used to produce specimens on printers NextDent 5100 (groups ND, NC and NT, respectively) and Phrozen Sonic Mini 4K (groups PD, PC and PT, respectively). Human gingival fibroblasts were cultured and biocompatibility was evaluated on days 1, 3 and 7. IL-6 and IL-8 concentrations were evaluated at 3 days using ELISA. Surface roughness was evaluated by a contact profilometer. SEM and fluorescence micrographs were analyzed at days 1 and 7. Statistical analyses were performed using SPSS and mean differences were tested using ANOVA and post-hoc Tukey tests (P < .05). RESULTS. There was an increase in cellular viability after 7 days in groups PC and PT, when compared to group PD. ND group resulted in higher concentration of IL-6 when compared to PT group. SEM and fluorescence micrographs showed less adhesion and thinner morphology of fibroblasts from group PD. No significant differences were found regarding surface roughness. CONCLUSION. The use of different printers or resins did not seem to influence surface roughness. NextDent 5100 and Phrozen Sonic Mini 4K produced resins with similar cellular responses in human gingival fibroblasts. However, Denture 3D+ resin resulted in significantly lower biocompatibility, when compared to C&B MFH and Crowntec resins. Further testing is required to support its long-term use, required for complete dentures.