Porcelain Research Articles

Фарфоровая безделица как тема

Фарфоровая безделица как тема

Clinical effect of CEREC chairside on atypical ceramic inlay restoring class II cavity

Objective To evaluate the clinical effect of CEREC chairside on atypical porcelain inlay restoring class Ⅱ cavity. Methods 30 patients that required re-treatment because of resin restoration failure and early posterior proximal caries were selected randomly. The original fillings, secondary carious tissues and undercut parts were removed. The clear and round edge lines were prepared. With Sirona CEREC Blocs, 35 atypical ceramic inlays were produced in accordance with CEREC AC CAD/CAM standard procedures. After clinical trial and modification, the inlays were bonded with 3M Veneer resin adhesive cement. Evaluation was done immediately and 3, 6, 12 and 24 months after restoration. Two senior prosthodontists did the evaluation according to the modified USPHS criteria. Results The evaluation results were all A when estimated immediately after restoration. None inlay falled off during the first two years. However, 3 inlay were found to be damaged when reviewed at the 24th month. There exsited two patients having mild symptoms of dentine hypersensitivity which appeared at the beginning and died out gradually. Generally speaking, more than 90% of inlay restorations had reached the USPHS criteria A. Color match and retention represented better effects. Conclusions CEREC atypical ceramic inlays can effectively restore Class Ⅱ cavity, short-term effect is good, but long-term effect still needs further observations. Key words: Ceramic inlay; Computer aided design/computer-aided manufacturing; CEREC

A 10-Year Clinical Evaluation of Resin-Bonded Fixed Dental Prostheses on Non-Prepared Teeth.

This study evaluated the conditions of the non-invasive resin-bonded fixed dental prostheses (FDP) and patient satisfaction up to 10 years of clinical function. A total of 23 patients who required fixed prostheses in the areas of mandibular anterior and premolar, and maxillary anterior region received resin-bonded restorations between 1999-2003. In 13 patients with 14 edentulous areas were restored with an adhesive pontic (natural tooth, acrylic and porcelain). Two indirect proximal veneers using resin composite were placed in each space in 10 patients having 13 edentulous spaces. All prostheses were bonded to the proximal surface of adjacent teeth using resin cement based on 4-META/MMA-TBB. No debonding of proximal veneers but 4 pontic debonding was observed which were rebonded and remained functional until final follow up. The abutments in pontic and proximal veneer groups were free of caries and hypersensitivity. Periodontal health was improved after treatment and was maintained for 10 years except for 4 abutments that still showed some bleeding on probing. Non-invasive resin-bonded FDPs are simple, pain-free, less costly treatment procedures that could provide acceptable clinical longevity with high patient satisfaction.

Research progress on clinical application of porcelain laminate veneer

Porcelain laminate veneer is one of the most widely used aesthetic dentistry methods at home and abroad now. It has advantages of natural luster of natural teeth, strong abrasive resistance, strong stain resistance, and maximally tooth tissue save, etc. At present, it is widely used in the anterior teeth restoration, and related reports on clinical application of porcelain laminate veneers are increasing day by day. The paper reviews the choice of indications and contraindications, types of materials, tooth preparation methods, and adhensive materials and methods related clinical application questions. Key words: Dental porcelain/TU; Reconstructive surgical procedures; Review

Colour-generating mechanism of copper-red porcelain from Changsha Kiln (A.D. 7th–10th century), China

Changsha Kiln, located at Changsha in Hunan Province, south of China, is famous for exported and coloured porcelain during the Tang Dynasty (A.D. 7th-10th century) period. Although the opinion that copper-red porcelain originates from Changsha Kiln is widely accepted in academic circles, chemical characters of glaze and colour mechanism of its copper-red porcelain have not been fully investigated and studied. Therefore, a shard of opaque glaze porcelain with red pigments which excavated at Changsha Kiln (A.D. 7th-10th century) was analyzed by Energy dispersive X-ray fluorescence (EDXRF), Synchrotron X-ray absorption near-edge spectroscopy (XANES), micro X-ray diffraction (μ-XRD), microscopy and scanning electron microscopy (SEM) methods. Combining with XANES and μ-XRD results, it indicates that metal copper is the major colouring-generation element status of the red hue. On the other hand, for the first time the study demonstrates that glaze of the sample from Changsha kiln is a typical phase separated-crystalline glaze with large particles surrounding acicular crystals which lead the opaque appearances. Because the sample from Changsha Kiln is Chinese ancient early stage copper-red porcelain relic, it will help to understand the origin of copper-red porcelain in China and enrich the knowledge of Chinese ancient ceramic culture.

Bonding Mechanism of Porcelain to Frameworks: Similarities and Dissimilarities between Metal and Zirconia

Bonding Mechanism of Porcelain to Frameworks: Similarities and Dissimilarities between Metal and Zirconia

The Role of Liners in Bonding Zirconia to Veneering Porcelain

The Role of Liners in Bonding Zirconia to Veneering Porcelain

Analytic Hierarchy Process-based Youth Basketball Reserve Personnel Training Mode Research

Basketball is constantly booming with China's material and cultural levels development. And basketball re- serve personnel quantity and quality stand for a nation basketball level. On the current all countries basketball levels rap- idly development situation in the world, cultivation of basketball reserve personnel has become an indispensible condition to be in an invincible position in intense basketball. The paper makes specific analysis of present youth basketball players' status, and trainers' training work experience, performances in the games, gets present youth basketball reserve personnel cultivation existing problems, and provides corresponding opinions for the problems. Utilize mathematics analytic hierar- chy process method, establish youth basketball reserve personnel training mode AHP model, by comparing mode of com- bination of sports and education, backup talent base model, youth club training mode weights, it gets mode that is most suitable for training China's youth basketball reserve personnel. By analysis, it gets conclusion that all trainer, training field, training equipment, educational investment and else have certain impacts on China's youth basketball reserve per- sonnel training mode, mode of combination of sports and education has the largest weight, is the most suitable mode for youth reserve personnel cultivation.

Porcelain surface roughness, color and gloss changes after orthodontic bonding.

The purpose of this study was to evaluate the alteration in surface characteristics after orthodontic debonding of two types of porcelain systems commonly used in prosthetic dentistry. For this purpose, porcelain specimens were fabricated from low-fusing (n = 20) and high-fusing (n = 20) porcelain. The baseline surface roughness, color, and gloss were evaluated using profilometry, color shade index, and gloss study. All specimens were bonded with brackets and debonded using a testing machine at a rate of 0.1 mm/minute crosshead speed. The porcelain surfaces were polished using a 12-fluted carbide composite removal bur (low-fusing, n = 20; high-fusing, n = 20). In addition, half of each porcelain group was further polished using a series of Sof-Lex discs (low-fusing, n = 10; high-fusing, n = 10). The postdebond porcelain surface characteristics roughness, color, and gloss were reevaluated and compared with baseline measurements. The results were analyzed with two-way analysis of variance and Tukey multiple comparisons test, with porcelain type (low-fusing or high-fusing) and polishing protocol (carbide bur or carbide bur and discs) serving as discriminate variables at alpha = 0.05 level of significance. Bonding and debonding increased all roughness parameters tested; however, no change was revealed between the two polishing protocols. Similarly, gloss and color index changes were significantly altered after resin grinding, regardless of the polishing method used. No difference was identified between the two porcelain types with respect to roughness, color index, or gloss. Orthodontic bonding alters the porcelain surfaces, and postdebond polishing does not restore the surface to the prebond state.

A retrospective study of six fractured platform-switching abutments

To explore the reasons for platform-switching abutment fracture, the treatment and prevention methods. Between March 2009 and December 2014, all of the fractured platform-switching abutments were evaluated. The fracture rate of platform-switching abutments was calculated and the gender, age, implant site, implant size, abutment size, prosthetic type, loading time and crown materials were analyzed. A total of 2 487 platform-switching implants were placed during this period and 6 abutments were fractured. The fracture rate was 0.24% (6/2 487). All of the 6 fractured abutments were placed in molar region. All occlusal planes were made of metal material. Five patients were male. All the fracture abutments could not be removed and the implants had to be removed and reimplanted. Without special abutment removing instruments, it is difficult to remove the fractured platform-switching abutment. In molar region, platform-switching implant system should be carefully used. Increasing implants number and splinting crowns with porcelain occlusal planes might reduce the abutment fracture risk.

European Porcelain for the Royal Court in the Late Chosŏn Dynasty: Production, Analysis and Evaluation

본 연구는 19세기 말 20세기 초, 조선 왕실에서 서양식 연회와 일상용기로 사용했던 유럽 도자기 식기 및 집기에 주목하고 그 도자기들의 종류, 원료, 제조사, 생산연도 등을 분석하였다. 개항 이후 서구와 같은 근대국가 수립을 지향하며 여러형태의 서구식 의례를 도입하려 했던 대한제국정부는 궁중연회에서도 서양식 연회를 여는 경우가 늘어갔다. 이러한 연회에 사용할 식기류는 프랑스, 영국, 독일의 도자기 제조회사에서 수입했다. 또 황실의 일상생활에서 사용되었을 도자기 집기들 역시 이들 국가의 도자기제조사에서 수입되었다. 기존의 박물관 도록 및 이전 연구가 한국과 프랑스의 도자 교류나 대한제국기 공예품에 새겨진 왕실 문장 분석에 국한된 반면 본 연구에서는 기존 연구의 오류를 바로잡고 고종의 개혁정책이 황실 의례의 변화와 서양 자기의 도입에서 어떻게 드러나는지 살펴보았다. 또한 외교의 중심지였던 정동지역에 위치한 덕수궁과 손탁호텔에서 서양식 연회에 사용되었던 유럽 자기가 당시 최고의 산업 기술과 각 생산지의 원료로 제작되어 한국 이외의 여러 서양국가에도 보편적으로 수출된 것임을 알 수 있었다.

Preliminary Research on Bubble Characteristics of Ancient Glaze Using OCT Technology

The bubble is one of the most common feature in ancient glaze. The size and distribution of bubbles are closely associated with recipes of the raw materials for the body and glaze and the making process. To characterize the bubbles is essential for the study of ceramic production process, production places, times characteristics and so on. In order to explore the possibility of using the optical coherence tomography (OCT) imaging technology to characterize the bubbles and the bubble distribution characteristic in glaze of ancient porcelain, sweep frequency OCT imaging system is used to detect five different types ancient porcelain chips. According to the two dimensional sectional images and three dimensional tomographic images of the transparent layer of glaze obtained by the OCT imaging system, the two dimensional sectional images characteristics and three dimensional slices characteristics of the bubbles in glaze are studied. The bubble characteristics in the glaze and its possible causes that gases in the body of the ceramic overflow to the glaze layer in the firing process are comprehensively analyzed. Meantime, the size of bubble is calculated according to the two dimensional sectional images based on pixel, and the result is compared with the traditional microscopic test result. The bubble size, two dimensional sectional characteristics and three dimensional tomographic image characteristics of opaque glaze are also studied. Experimental results show that the bubble characteristics in glaze of different ancient porcelain chips are obvious difference, the result of the bubble size calculated based on pixel coincides with the result of the bubble size observed by traditional microscope with ten times magnification, slices of the body near the body-glaze binding region based on OCT imaging technology three dimensional tomography can effectively reflect the bubble characteristics in glaze. The measurement of using OCT imaging technology to characterize bubble characteristics of the glaze is proposed, and the feasibility and the validity of the measurement are certified, and the nondestructive detection of bubble characteristics in ancient porcelain glaze is realized. Especially for the analysis of bubble characteristics of opaque glaze, the OCT imaging technology overcomes the limitations of using the traditional microscope technology to study the distribution of bubble in glaze in the past, and provides a novel, reliable analysis method for the analysis of ceramic glaze bubble characteristics.

Effect of TiO2-SiO2-SnOx film with different firing temperatures on bond strength of low-fusing dental porcelain to pure titanium

To evaluate the influence of TiO(2)-SiO(2)-SnOx nano-coatings with different firing temperatures on the bond strength of low-fusing dental porcelain to pure titanium. The surface of pure titanium was coated uniformly with TiO(2)-SiO(2)-SnOx nano-coatings by solution-gelatin (Sol-Gel) technology and then fired at 300 °C (group A) or 750 °C (group B) for 1 h. The specimens without any coatings were the control group (group C). There were 10 specimens in each group. Dental porcelain was sintered on the surface of titanium specimens. Surface roughness and contact angle of the coatings were also detected. The titanium-porcelain bond strength was investigated according to YY 0621-2008 standards using three-point flexure bond test. The phase composition of the TiO(2)-SiO(2)-SnOx nano-coatings was characterized by X-ray diffraction(XRD). The interface of titanium-porcelain and TiO(2)-SiO(2)-SnOx nano-coatings were observed using scanning electron microscope (SEM). No rutile phase was found in these specimens of group A and group B. The surface roughness of group A, B, C was (0.97 ± 0.06), (0.99 ± 0.03), (0.96 ± 0.07) µm, respectively. No significant difference was found among the three groups. Compared with that of group C (64.37° ± 3.01°), contact angles detected in group A (52.04° ± 3.15°) and group B (85.27° ± 4.17°) were significantly different (P < 0.05). The bond strength of titanium-porcelain in group A [(35.66 ± 2.65) MPa] was significantly increased compared with those in group B [(26.18 ± 2.22) MPa] and group C [(31.66 ± 3.52) MPa]. SEM photomicrographs of titanium-porcelain interface morphology of the specimens before porcelain sintering showed that TiO(2)-SiO(2)-SnOx nano-coatings in group A were compact and homogeneous with petty cracks and those in group B was loose and arranged disorderly. TiO(2)-SiO(2)-SnOx nano-coating fired at 300 °C is significantly effective in improving the titanium-porcelain bond strength.

Vitiligo staging based on clinical and skin computed tomography features

Objective To determine the stage of vitiligo according to clinical and skin computed tomography (CT) features. Methods The stage of vitiligo was determined in 200 patients according to a questionnaire - based analysis of clinical features and skin CT findings respectively. Rapid progressive stage was defined as the score for vitiligous lesions or CT findings being higher than 2, slow progressive stage as the score varying from 1 to 2, and stable stage as the score less than 1. Skin samples were obtained at lesional sites receiving CT examination from 5 patients with progressive and 5 patients with stable vitiligo, and subjected to hematoxylin-eosin (HE) staining. Results No significant difference was observed between staging results based on clinical features and skin CT findings. The patients diagnosed with progressive vitiligo based on clinical features presented with grey-white or pale white patches with elevated or obscure boundaries, or trichrome vitiligo, while those with stable vitiligo presented with milky-white or porcelain- white lesions with sharp boundaries and pigmented islands. As CT showed, progressive vitiligo was characterized by a loss of integrity in dermal papillary rings at the dermo-epidermal junction level, obscure boundaries between vitiligo lesions and surrounding normal skin, presence of highly refractive cells at the dermo-epidermal junction level in the margins of vitiligo lesions, while stable vitiligo characterized by complete absence of dermal papillary rings at the dermo-epidermal junction level, sharp boundaries between the lesions and surrounding normal skin, and presence of highly refractive dendritic melanocytes. HE staining showed plenty of CD8+ T lymphocytes in the papillary dermis in the margins of progressive vitiligo lesions, but no CD8+ T lymphocyte was seen in those of stable vitiligo lesions. Conclusions Both clinical and skin CT features can be used to determine the stage of vitiligo, and the staging results are consistent with those based on histopathological findings. Key words: Vitiligo; Microscopy, confocal; Pathology, clinical; Stage; Disease attributes

Comparison of magnetic resonance imaging artifacts of five common dental materials

To compare five materials commonly used in dentistry, including three types of metals and two types of ceramics, by using different sequences of three magnetic resonance imaging (MRI) field strengths (0.35, 1.5, and 3.0 T). Three types of metals and two types of ceramics that were fabricated into the same size and thickness as an incisor crown were placed in a plastic tank filled with saline. The crowns were scanned using an magnetic resonance (MR) machine at 0.35, 1.5, and 3.0 T field strengths. The TlWI and T2WI images were obtained. The differences of various materials in different artifacts of field MR scans were determined. The zirconia crown presented no significant artifacts when scanned under the three types of MRI field strengths. The artifacts of casting ceramic were minimal. All dental precious metal alloys, nickel-chromium alloy dental porcelain, and cobalt-chromium ceramic alloy showed varying degrees of artifacts under the three MRI field strengths. Zirconia and casting ceramics present almost no or faint artifacts. By contrast, precious metal alloys, nickel-chromium alloy dental porcelain and cobalt-chromium ceramic alloy display MRI artifacts. The artifact area increase with increasing magnetic field.

The study of the colorimetric characteristics of the cobalt-chrome alloys abutments covered by four different all-ceramic crowns by using dental spectrophotometer

This study aims to evaluate the optical data of the different sites of the cobalt-chrome (Co-Cr) alloy abutments covered by four different all-ceramic crowns and the color difference between the crowns and target tab using a digital dental spectrophotometer. Ten Co-Cr alloy abutments were made and tried in four different groups of all-ceramic crowns, namely, Procera aluminia, Procera zirconia, Lava zirconia (Lava-Zir), and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic. The color data of the cervical, body, and incisal sites of the samples were recorded and analyzed by dental spectrophotometer. The CIE L*, a*, b* values were again measured after veneering. The color difference between the abutments covered by all-ceramic crowns and A2 dentine shade tab was evaluated. The L* and b* values of the abutments can be increased by all of the four groups of all-ceramic copings, but a* values were decreased in most groups. A statistical difference was observed among four groups. After being veneered, the L* values of all the copings declined slightly, and the values of a*, b* increased significantly. When compared with A2 dentine shade tab, the ΔE of the crowns was below 4. Four ceramic copings were demonstrated to promote the lightness and hue of the alloy abutments effecttively. Though the colorimetric baseline of these copings was uneven, veneer porcelain can efficiently decrease the color difference between the samples and thee target.

Raman and EDXRF Study on Overglaze Decorations of Jingdezhen Ceramics

Overglaze decoration porcelain is an important category of ancient Chinese ceramics, which has significant artistic value and scientific value. Nondestructive analysis methods such as Raman spectroscopy and EDXRF were used to analyze the overglaze decorations on the Jingdezhen ceramic samples of Yuan, Ming and Qing Dynasty. The recipe and color mechanism of the overglaze pigments were discussed according to the chemical composition and phase composition analysis. The study found that dark red overglaze decorations of ancient Honglvcai, Wucai and famille rose in Jingdezhen are colored by hematite, yellow color is lead tin yellow, carmine decoration is colored by gold less than 0. 1 % in concentration, and green decorations are colored by bivalent copper ion. The result also indicates that the effective combination of Raman spectroscopy and EDXRF can play an important role in the deep research on ceramic artifacts, especially for the overglaze decoration pigments which are interveined each other.

Spectrophotometric analysis of feldspathic porcelain with silver ion

최근 심미에 대한 관심이 높아짐에 따라 도재를 이용한 고정성 보철 수복물 치료가 보철치료에서 큰 비중을 차지 하고 있다. 이러한 고정성 보철물은 환자의 구강 위생 능력과 식습관 그리고 유지 관리에 따라 수명에 많은 차이가 나게 된다. 윤의 논문에 따르면 고정성 보철물의 합병증은 생물학적 합병증과 기계적 합병증으로 나뉘게 되는데, 고정성 보철물의 생물학적 합병증은 치주 질환(37.5%), 치아 우식증(19.0%), 그리고 치수 질환(10.8%) 순이었고, 기계적 문제점은 변연 결함(18.4%), 보철물 파절(4.2%), 유지력 상실(3.9%), 치아 파절(3.6%), 그리고 식편압입(2.6%) 순이었다.

Management of Nguni goats to control gastrointestinal parasites and anthelmintic resistance at KwaMthethwa and Owen Sitole College of Agriculture area

Management techniques that can assist in treating only parasite infested animals can reduce anthelmintic resistance arousing from frequent dosing of all animals. This study aimed to investigate the application of FAMACHA© with no formal training of resource-poor farmers to identify anaemic or helminthes infested animals. Two sites (KwaMthethwa (KM) village and Owen Sitole College of Agriculture (OSCA) farm) with 40 animals each of mixed sex were used in this study. The animals grazed on natural pasture during the day and housed in Kraal at night. FAMACHA© chart scored animals on eye colour; 1 (Red, non-anaemic and acceptable), 2 (red-pink, non-anaemic and border line), 3 (pink, mildly anaemic and dangerous), 4 (pink-white, anaemic and fatal) or 5 (porcelain white, severely)). Eye scoring was over four seasons (autumn, winter, spring and summer) alongside faecal egg count (FEC) as a positive control to FAMACHA© diagnosis method. Anaemic animals varied (P<0.05) between the sites, 76.72, 40.34 and 49.37% for KM, OSCA and KM+OSCA, respectively. Comparison of FAMACHA© with FEC showed that only 61.53, 33.5 and 40.12% of the animals were anaemic at KM, OSCA and KM+OSCA, respectively, due to false positive results. Spring, autumn and summer were identified as seasons for frequent monitoring due to higher (P<0.05) gastrointestinal parasite especially Trichostrongylus axei and Moniezia expansa. Approximately 80% of all anaemic animals were identified by no skilled resource-poor farmers using FAMACHA©. This reinforces the economic (cheap) importance and reliability of FAMACHA© chart in parasite resistance management but emphasized on formal training as 20% false negative anemic animals is a lot for a resource-poor farmers. Key words: FAMACHA©, Anthelmintic, resistance, faecal egg count, Nguni goat.

Rehabilitation of the dominance of maxillary central incisors with refractory porcelain veneers requiring minimal tooth preparation.

Central dominance is an important element of an esthetic smile. Color, form, and size have been suggested as tools for assessing the dominance of maxillary teeth. A spectrophotometer can be used to determine the value, hue, and chroma. Correct sizing of restorations according to the central incisor dominance principle improves not only esthetics but also aspects of occlusion, such as anterior guidance. Refractory porcelain systems can effectively restore the color, shape, emergence profile, and incisal translucency. This report illustrates the esthetic and occlusal rehabilitation of the dominance of maxillary central incisors using fabricated minimal thickness refractory porcelain veneers.