• Journal of Periodontal and Implant Science
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• 제51권5호
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• pp.298-315
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• 2021

Purpose: Peri-implantitis therapy and implant maintenance are fundamental practices to enhance the longevity of zirconia implants. However, the use of physical decontamination methods, including hand instruments, polishing devices, ultrasonic scalers, and laser systems, might damage the implant surfaces. The aim of this systematic review was to evaluate the effects of physical decontamination methods on zirconia implant surfaces. Methods: A systematic search was conducted using 5 electronic databases: Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane. Hand searching of the OpenGrey database, reference lists, and 6 selected dental journals was also performed to identify relevant studies satisfying the eligibility criteria. Results: Overall, 1049 unique studies were identified, of which 11 studies were deemed suitable for final review. Air-abrasive devices with glycine powder, prophylaxis cups, and ultrasonic scalers with non-metal tips were found to cause minimal to no damage to implantgrade zirconia surfaces. However, hand instruments and ultrasonic scalers with metal tips have the potential to cause major damage to zirconia surfaces. In terms of laser systems, diode lasers appear to be the most promising, as no surface alterations were reported following their use. Conclusion: Air-abrasive devices and prophylaxis cups are safe for zirconia implant decontamination due to preservation of the implant surface integrity. In contrast, hand instruments and ultrasonic scalers with metal tips should be used with caution. Recommendations for the use of laser systems could not be fully established due to significant heterogeneity among included studies, but diode lasers may be the best-suited system. Further research-specifically, randomised controlled trials-would further confirm the effects of physical decontamination methods in a clinical setting.

• 대한치과교정학회지
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• 제31권6호
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• pp.567-578
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• 2001

본 연구는 metal stripper, diamond bur, cross-cut carbide bur을 이용한 기계적 삭제방법과 산을 이용한 화학적 삭제방법 등의 서로 다른 방법으로 삭제된 치아에서 삭제방법에 따른 법랑질 표면조도의 차이를 비교하고, 삭제된 법랑질 표면에 국소적 불소도포와 교정용 전색제를 적용시 치아우식 감수성에 미치는 영향을 알아보기 위해 교정적인 목적으로 발치된 100개의 소구치를 대상으로 주사전자현미경과 레이저 형광법을 이용하여 연구한 바 다음과 같은 결과를 얻었다. 1. 치간삭제방법에 관계없이 인접면 삭제 후 법랑질 표면에 형성된 열구는 세심한 연마과정을 통해서도 제거되지 않았다. 2. 기계적인 치간삭제 방법 중에 가장 활택한 법랑질 표면조도를 보이는 군은 crosscut tungsten carbide bur로 초기삭제 후 sof-$lex^{(r)}$ disk로 연마한 군이었다. 3. 기계적 방법이나 기계적과 화학적 방법을 동반하여 치간 삭제한 모든 군의 치아우식 감수성은 대조군보다 높았다. 그러나 치간삭제 방법에 따른 치아우식 감수성의 차이는 보이지 않았다(p<0.001). 4. APF-gel 이나 sealant을 도포한 군은 치간삭제 후 다른 처치를 하지 않은 군에 비해 치아우식 감수성이 낮았다(p<0.001). 5. APF-gel을 도포한 군이 sealant을 도포한 군보다 치아우식 감수성이 낮았다(P<0.05). 결론적으로, 치간삭제 후 활택한 법랑질 표면을 얻고자 하는 노력에도 불구하고 치간삭제를 실시한 치아는 그 삭제 방법에 관계없이 정상치아에 비해 치아우식 감수성이 높았다. 따라서 치간삭제 후 주기적인 불소의 사용이 치아우식을 예방하는 최선의 방법이라고 생각된다.

• 대한치과보철학회지
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• 제37권4호
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• pp.474-493
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• 1999

According to repeated measurements and correction procedures, the accuracy of the phase-shifting profilometry was developed. At first, after 20 final models for maxillary complete denture were duplicated , the mucosa sur-faces of models were measured with the phase-shifting proflometry and each mirror view of these was calibrated. Maxillary casts were divided into 4 groups of 5 casts per each, and wax dentures with 2 sheets of baseplate wax and artificial teeth were made and then cured according to the curing method of each group. Group I ; quick curing with QC-20 acrylic resin Group II ; 9 hour curing with QC-20 acrylic resin Group III ; SR-Ivocap system Group IV ; metal base and quick curing with QC-20 acrylic resin. After curing, polishing, and storing at $37^{\circ}C$ in saline for 30 days, the forms of the impression surface of the dentures were measured with the phase-shifting profilometry. Then, the impression surface form of each denture was placed in the optimal position of com-parison with the mirror view of the same final cast. The amount and direction of distortion of each denture was analyzed and the effects of polishing and storage in each denture were compared, The obtained results were as follows : 1. In Group I, the denture was observed as the appearance distorted in the opposite direction of the mucosa and the postero-lateral part of palatal portion of the denture was observed as the appearance separated from the mucosa. Also, the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa. 2. In Group II, the postero-lateral part of palatal portion of the denture was observed as the appearance separated slightly from the mucosa. The bilateral buccal flanges of denture were observed as the appearance distorted severely in the direction of the mucosa. 3. In Group III the bilateral part of the residual ridge crest portions and the buccal flanges of the denture were observed as the appearance distorted in the direction of the mucosa, and specially, the buccal flanges of the maxillary tuberosities were distorted severely. 4. In Group IV, the acrylic resin base of the buccal portion of the denture was observed as the appearance distorted in the opposite direction of the mucosa. 5. The phase-shifting profilometry, done with repeated measurements and correction procedures, was effective in comparing the amount and direction of distortion at every position after the laboratory work and the delivery of maxillary complete denture.

• Journal of Periodontal and Implant Science
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• 제51권3호
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• pp.147-162
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• 2021

Purpose: This systematic review and meta-analysis was conducted to assess the effects of glycine powder air-polishing (GPAP) in patients during supportive periodontal therapy (SPT) compared to hand instrumentation and ultrasonic scaling. Methods: The authors searched for randomized clinical trials in 8 electronic databases for relevant studies through November 15, 2019. The eligibility criteria were as follows: population, patients with chronic periodontitis undergoing SPT; intervention and comparison, patients treated by GPAP with a standard/nozzle type jet or mechanical instrumentation; and outcomes, bleeding on probing (BOP), patient discomfort/pain (assessed by a visual analogue scale [VAS]), probing depth (PD), gingival recession (Rec), plaque index (PI), clinical attachment level (CAL), gingival epithelium score, and subgingival bacteria count. After extracting the data and assessing the risk of bias, the authors performed the meta-analysis. Results: In total, 17 studies were included in this study. The difference of means for BOP in patients who received GPAP was lower (difference of means: -8.02%; 95% confidence interval [CI], -12.10% to -3.95%; P<0.00001; I²=10%) than that in patients treated with hand instrumentation. The results of patient discomfort/pain measured by a VAS (difference of means: -1.48, 95% CI, -1.90 to -1.06; P<0.001; I²=83%) indicated that treatment with GPAP might be less painful than ultrasonic scaling. The results of PD, Rec, PI, and CAL showed that GPAP had no advantage over hand instrumentation or ultrasonic scaling. Conclusions: The findings of this study suggest that GPAP may alleviate gingival inflammation more effectively and be less painful than traditional methods, which makes it a promising alternative for dental clinical use. With regards to PD, Rec, PI, and CAL, there was insufficient evidence to support a difference among GPAP, hand instrumentation, and ultrasonic scaling. Higher-quality studies are still needed to assess the effects of GPAP.

• 대한치과보철학회지
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• 제38권3호
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• pp.336-347
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• 2000

Statement of problem. Luster loss in esthetic anterior ceromer restoration can occur and can be related with rough surface texture. Understanding durability of surface finishing methods like polishing and surface coating have critical importance. Purpose. This study evaluated the effect of tooth brushing and thermal cycling on surface luster of 3 ceromer systems (Artglass, Targis, Sculpture) treated with different surface finishing methods. Material and methods. Seventy-two samples were prepared: 12 for control group Z100, 12 for Artglass, 24 for Targis, and 24 for Sculpture. Half of the Targis and Sculpture were polished according to the manufacturer's recommendation. The rest of the samples were coated with staining and glazing solution for Targis and Sculpture, respectively. All specimens were subjected to 10,000 cycles between $5^{\circ}C\;and\;55^{\circ}C$ with 30 seconds dwell time. Tooth brushing abrasion tests were performed in a customized tooth brushing machine with 500g back and forth for 20,000 cycle. Luster comparisons were based on grading after direct observation, and light reflection area was measured with Image analysis software. Results. All materials showed an decrease in luster grade after thermal cycling and tooth brushing. The post-tooth brushing results revealed that the glazed Sculpture had greater mean luster grade than did any other groups. While, the stained Targis group showed greatest changes after tooth brushing (p < 0.05), polished Targis and Sculpture did not show significant changes. However, glazed Sculpture showed discretely fallen out glaze resin. Conclusion. From the results of this study, all of the ceromer specimens were much glossy than control composite group after tooth brushing. coatings used for Targis and Sculpture had not durability for long term use.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• The Journal of Advanced Prosthodontics
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• 제7권2호
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• pp.108-114
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• 2015

PURPOSE. The aim of this study was to evaluate effect of different surface treatment methods on the bond strength between aged composite-resin core and luting agent. MATERIALS AND METHODS. Seventy-five resin composites and also seventy-five zirconia ceramic discs were prepared. 60 composite samples were exposed to thermal aging (10,000 cycles, 5 to $55^{\circ}C$) and different surface treatment. All specimens were separated into 5 groups (n=15): 1) Intact specimens 2) Thermal aging-air polishing 3) Thermal aging- Er:YAG laser irradiation 4) Thermal aging- acid etching 5) Thermal-aging. All specimens were bonded to the zirconia discs with resin cement and fixed to universal testing machine and bond strength testing loaded to failure with a crosshead speed of 0.5 mm/min. The fractured surface was classified as adhesive failure, cohesive failure and adhesive-cohesive failure. The bond strength data was statistically compared by the Kruskal-Wallis method complemented by the Bonferroni correction Mann-Whitney U test. The probability level for statistical significance was set at ${\alpha}$=.05. RESULTS. Thermal aging and different surface treatment methods have significant effect on the bond strength between composite-resin cores and luting-agent (P<.05). The mean baseline bond strength values ranged between $7.07{\pm}2.11$ and $26.05{\pm}6.53$ N. The highest bond strength of $26.05{\pm}6.53$ N was obtained with Group 3. Group 5 showed the lowest value of bond strength. CONCLUSION. Appropriate surface treatment method should be applied to aged composite resin cores or aged-composites restorations should be replaced for the optimal bond strength and the clinical success.

• Tribology and Lubricants
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• 제23권6호
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• pp.298-300
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• 2007

Frictional characteristics of mesoporous $SiO_2$ thin films were evaluated with different pore sizes. The films were manufactured by sol-gel and self-assembly methods to have a porous structure. The pores on the surface may play as the outlet of wear particle and the storage of lubricant so that the surface interactions could be improved. The pores were exposed on the surface by chemical mechanical polishing (CMP) or plasma-etching after forming the porous films. The ball-on-disk tests with mesoporous $SiO_2$ thin films on glass specimen were conducted at sliding speed of 15 rpm and a load of 0.26 N. The results show considerable dependency of friction on pore size of mesoporous $SiO_2$ thin films. The friction coefficient decreased as increasing the pore size. CMP process was very useful to expose the pores on the surface.

• 한국표면공학회지
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• 제33권2호
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• pp.101-106
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• 2000

SOI (Silicon-On-Insulator) substrates were fabricated with varying annealing temperature of $25-660^{\circ}C$ by a linear annealing method, which was modified RTA process using a linear shape heat source. The annealing method was applied to Si ∥ $SiO_2$/Si pair pre-contacted at room temperature after wet cleaning process. The bonding strength of SOI substrates was measured by two methods of Razor-blade crack opening and direct tensile test. The fractured surfaces after direct tensile test were also investigated by the optical microscope as well as $\alpha$-STEP gauge. The interface bonding energy was 1140mJ/m$^2$ at the annealing temperature of $430^{\circ}C$. The fracture strength was about 21MPa at the temperature of $430^{\circ}C$. These mechanical properties were not reported with the conventional furnace annealing or rapid thermal annealing method at the temperature below $500^{\circ}C$. Our results imply that the bonded wafer pair could endure CMP (Chemo-Mechanical Polishing) or Lapping process without debonding, fracture or dopant redistribution.

• 한국치위생학회지
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• 제19권6호
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• pp.1067-1075
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• 2019

Objectives: The present study aimed to compare the accuracy of removable partial denture (RPD) frameworks fabricated by selective laser sintering (SLS) before and after electropolishing. Methods: A partially edentulous mandibular model was used as the working model. Scanning of the model was performed using a dental scanner. The framework was designed using CAD software. The metal framework was formed using an SLS 3D printer. 3D scans of the two fabricated prototypes produced before and after electropolishing were overlapped with reference data. The fit was calculated based on Root Mean Square (RMS). Fabrication accuracy was verified using the paired t-test to compare the discrepancy before and after electropolishing. Results: The mean (SD) values of RMS before and after electropolishing were 126.6 (34.19) and 75.86 (21.36), respectively. There was a statistically significant difference before and after electropolishing (p<0.05). Conclusions: Metal frameworks made with SLS 3D printers showed clinically acceptable fit after electropolishing.