Ti-75合金在口腔修复应用的腐蚀性

为评价Ti－75合金在口腔修复应用的耐腐蚀性，用动电位极化技术测试了五种材料在人工唾液中的腐蚀性。结果显示Ti-75合金自腐蚀电位介于TA2和TC4之间，破裂电位高于CO－Cr、Ni－Cr合金；Ti－75测试面未见腐蚀，而Co－Cr、Ni－Cr合金均有全面腐蚀和点蚀；结合极化曲线整体形态分析，结论：Ti－75合金的耐蚀性与TA2、TC4相似，但优于临床现用的Co－Cr、Ni－Cr合金。     

口腔修复中电偶腐蚀的研究

随着口腔修复技术和材料科学的迅猛发展,金属(或合金)、尤其是异种金属(或合金)在口腔修复领域的联合应用越来越广泛.但合金在口腔中的腐蚀,尤其是异种合金在口腔唾液中的电偶腐蚀不容忽视并已引起学者重视.本文就近年口腔修复领域中有关电偶腐蚀方面的文献进行综述.     

两种低贵金属合金的腐蚀性能实验研究

目的　评价两种牙科低贵金属合金的腐蚀性能。方法　运用动电位极化技术评价了Au -Pd -Ag ,Ag -Pd ,两种低贵合金的腐蚀性能并与Co -Cr ,Ni-Cr,Cu -Al以及Au -Pt合金比较。试验介质为fusayama人工唾液 (37 C ,pH =5 ) ,采用电子能谱扫描分析腐蚀产物。结果　自腐蚀电位EocAu-Pd -Ag和EocAg -Pd分别为 - 2 6mv ,40mv远比Ni-Cr合金 (Eoc =- 2 2 3mv)、Co -Cr合金 (Eoc =- 16 5mv)为正 ,但低于传统Au -Pt合金。极化曲线表明电位一定时 (<6 0 0mv)Au -Pd -Ag合金 ,Ag -Pd合金的电流密度比Cu -Al合金与Ni-Cr合金低 ,与传统Au -Pd合金接近。ESCA腐蚀产物拟合结果表明Au -Pd -Ag合金、Ag -Pd合金腐蚀主要以Ag为主 ,而Au、Pd均无化合物形成。结论　两种低贵合金具有良好的耐腐蚀性能 ,低贵合金腐蚀主要以Ag相腐蚀为主     

口腔金属修复体所致过敏性疾病的临床研究

目的:采用皮肤斑贴试验和口内金属修复体成分检测,探讨患者的临床症状与齿科金属过敏的相关性。方法:对2例可疑齿科金属过敏患者进行齿科金属系列斑贴试验,并同时检查患者金属修复体成分,结合二者判断2例患者的皮肤或者黏膜过敏症状与齿科金属修复体的相关性。结果:2例患者的斑贴实验阳性反应过敏原与口内金属修复体成分相一致,因而推测患者的临床症状与齿科金属致敏性具有相关性。经拆除患者的金属修复体,改用全瓷材料治疗牙列缺损,随访观察发现临床过敏症状好转。结论:齿科金属的致敏性可导致一些口腔黏膜或者皮肤的过敏症状,影响患者的生活质量。口腔科医生在进行修复治疗的时候应充分了解所使用金属合金的致敏率,减少高致敏率合金的临床应用,或在修复前采用斑贴试验,指导患者更安全有效的选择合适的材料。     

CW—PA型烤瓷Ni—Cr—Nb合金的研制及临床应用

CW-PA 型烤瓷 Ni-Cr-Nb 合金是以 Ni、Cr 为主,并合有少量 Mo、Nb、Si、Al 元素的非贵金属合金。该合金具有良好的物理机械性能和化学稳定性。经五种生物学检测试验,证明合金有良好的组织相容性,是一种安全的口腔修复材料。在临床上用该合金与 Vita 和 Uuibond 瓷粉配套使用,为201例病员制作了254件金瓷冠桥修复体,获得满意的修复效果。     

钛种植体与冠修复金属电偶腐蚀电流的研究

目的 通过对HBIC型钛种植体与口腔科常用修复烤瓷合金在中性和酸性人工唾液中的电偶腐蚀的综合评价,筛选更适合种植体上部结构的冠修复材料.方法 选择HBIC型钛种植体(T-H)以及镍铬合金(Ni)、钴铬合金(Co)、金铂合金(Au)、铸造纯钛(Ti),每种金属制成直径4mm、高10mm的圆柱体电极各40个.采用电化学方法,在自行配制的pH =6.8、pH =5.6两种人工唾液中检测4种合金分别与T-H组成的电偶对的电偶电流密度(Id),并绘制出各自的电流时间曲线.结果 在中性人工唾液中四种电流密度依次为IdNi＞ IdCo＞IdTi＞IdAu,其中Ni组与Au组、Ti组间有统计学差异(P＜0.05),Co组与Ni组、Ti组、Au组,Ti组与Au组间无统计学差异(P＞0.05).在酸性人工唾液中四种电流密度依次为IdNi＞IdCo＞IdAu＞IdTi,其中Ni组显著大于Ti组、Co组、Au组,有统计学差异(P＜0.05),Ti组、Co组、Au组三组间无统计学差异(P＞0.05).扫描电镜观察,酸性环境中镍铬合金发生少量坑状腐蚀形貌,其余合金与中性环境相比无明显变化.结论 两种唾液中镍铬合金组电偶电流较大.酸性环境能增大电偶腐蚀,对镍铬合金影响较大,镍铬合金不适宜作为钛种植体上部冠修复材料.     

牙科贵金属合金的过去和现状

牙科贵金属合金是以金(Au)为主的合金，在口腔医学主要是通过精密铸造应用，是我国过去以及目前国外广泛应用于口腔修复的主要金属材料。贵金属合金具有一定的优点：如抗腐蚀性能强．熔点适中便于操作，可接受金相热处理以控制所需机械性能等。我国在解放以后，由于众所周知的原因，根据当时的历史条件，研究采用了非贵金属材料代替贵金属应用于口腔修复，几十年来对口腔修复的发展起了很大的作用。     

烤瓷冠修复后牙龈着色病因分析一例

由使用不良修复材料、错误的牙体预备和粗糙的修复体制作等原因所致的牙龈病损在临床上十分常见[1-3].银汞充填物悬突引起的牙龈变色也较多[3-4].扫描电子显微镜(SEM)和X线能谱分析(energy dispersive X-ray analysis,EDX)显示,部分修复材料的残屑可以进入牙龈结缔组织内,在牙龈组织内可检测到Hg、Ag、Cu、Sn、Zn等元素[5-7].在因贱金属烤瓷修复引起的牙龈炎患者的牙龈组织内也可检测到Ni和Cr等元素.     

烤瓷冠修复后牙龈着色病因分析一例

由使用不良修复材料、错误的牙体预备和粗糙的修复体制作等原因所致的牙龈病损在临床上十分常见[1-3].银汞充填物悬突引起的牙龈变色也较多[3-4].扫描电子显微镜(SEM)和X线能谱分析(energy dispersive X-ray analysis,EDX)显示,部分修复材料的残屑可以进入牙龈结缔组织内,在牙龈组织内可检测到Hg、Ag、Cu、Sn、Zn等元素[5-7].在因贱金属烤瓷修复引起的牙龈炎患者的牙龈组织内也可检测到Ni和Cr等元素.     

烤瓷冠修复后牙龈着色病因分析一例

由使用不良修复材料、错误的牙体预备和粗糙的修复体制作等原因所致的牙龈病损在临床上十分常见[1-3].银汞充填物悬突引起的牙龈变色也较多[3-4].扫描电子显微镜(SEM)和X线能谱分析(energy dispersive X-ray analysis,EDX)显示,部分修复材料的残屑可以进入牙龈结缔组织内,在牙龈组织内可检测到Hg、Ag、Cu、Sn、Zn等元素[5-7].在因贱金属烤瓷修复引起的牙龈炎患者的牙龈组织内也可检测到Ni和Cr等元素.     

Metal content of saliva of patients with and without metal restorations

Many in vitro studies have confirmed the corrosion of dental alloys. However, in vivo corrosion studies, for example, recording of the release of metal ions into saliva, are scarce, and data on the repeatability of the metal content measurements of saliva are lacking. The present study examined the metal content of saliva of patients with and without metal restorations and assessed the repeatability of these data. The composition of each patients oral cast alloys was analyzed using the energy-dispersive X-ray analysis of metal biopsy specimens and was compared to the metals found in saliva. Saliva analysis was performed using atomic absorption spectroscopy. Chemical analysis comprised the metals Ag, Au, Co, Cr, Cu, Fe, Ga, In, Ni, Pd, Pt, Sn, and Zn. The metals Ag, Cr, Cu, Fe, Ni, and Zn were found in saliva of patients without metal restorations, but these data showed statistically significant differences in the metal content between consecutively performed samples per patient. The metals Ag, Au, Cr, Cu, Fe, Ni, and Zn were identified in saliva of patients with metal restorations being higher in concentration than in control patients. In 77% of the cases at least one metal of the restoration was found in the patients saliva. However, the metal content showed statistically significant differences between replicate samples of the same patient taken at different times. The metal content of saliva is affected among other things by intraoral metal restorations, but present data do not support the idea that it is a reliable indicator for the systemic exposure to metals released from dental alloys.     

Long-term corrosion studies in vitro of amalgams and casting alloys in contact

One conventional amalgam and two amalgams with higher copper content were stored in contact with various dental casting alloys in phosphate-buffered 0.9% NaCl solution, pH 6, at 37 degrees C during 35 weeks. Every 7 weeks the solutions were changed, and the corrosion was measured by analyzing the solutions for the amount of Cu, Zn, Sn, Hg, Ag, Co, Cr, and Ni. In the first 7 weeks the amalgams immersed in contact with acrylic or Co-Cr alloys released small amounts of elements, whereas the release was larger when the amalgams were in contact with the gold alloys. During the rest of the experiment the release of elements tended towards the same level, independent of the casting alloy in contact. In general, the high copper amalgams released more corrosion products into the solutions than the conventional one. The release of corrosion products was strongly pH-dependent. Changing the solutions more often and saturating the solutions with oxygen decreased the amounts of Hg and Ag released.     

五种全冠修复合金材料的细胞毒性研究

目的 检测和比较五种全冠修复合金材料的细胞毒性作用。口腔修复合金材料在口腔环境中析出金属离子,合金材料通过这些金属离子对临近组织及远隔组织器官产生影响。方法 采用ＭＴＴ方法检测乳酸脱氢酶活性来测定合金析出离子对体外培养细胞的影响,比较五种合金包括贵金属和贱金属合金的毒性作用。用流式细胞检测仪分析合金析出离子是否诱导Ｌ－９２９细胞凋亡。结果 软质铬钴合金的细胞毒性最大,镍铬合金、银钯合金其次,钯合金     

Biological interactions of dental cast alloys with oral tissues.

OBJECTIVE: All dental cast alloys release metal ions into the oral environment which have the potential to interact with the oral tissues. Amount and type of metal elements released are varying and not directly related to the composition of the alloy. The aim of the present literature survey was to describe the interactions of dental cast alloys with living tissues and to relate them to clinically adverse local reactions of the oral tissues. RESULTS: Interactions of dental cast alloys with the oral tissues take place by different mechanisms; e.g. bacterial adherence promotion, toxic and subtoxic effects and allergy. Whereas bacterial adhesion promotion may be counteracted by adequate oral hygiene measures, the other mechanisms may lead to clinically adverse local reactions due to the metal present. However, the number of cases, where such a relation can be safely diagnosed, is small. Safe ground is felt with proven allergies. The comparatively high allergy rate towards nickel should be the impetus to replace those alloys whenever there is a suitable alternative. Medical and dental impairments as well as general medication may lead to symptoms allegedly attributed to metal restorations. CONCLUSIONS AND SIGNIFICANCE: Patients relating oral symptoms to metal restorations should be subjected to a thorough dental and general medical examination in order to exclude non-material related diseases being the cause for their complaints/symptoms. These cases are a challenge for the collaboration between the medical and dental professions.     

Immunological studies on the peripheral blood mononuclear cells in metal allergy patients

Recently, the number of patients with dental metal allergy has risen significantly. The aim of this study was to evaluate the clinical availability of the lymphocyte stimulation test (LST) using metal reagents as a method for diagnosing metal allergy. In vitro, peripheral blood mononuclear cells (PBMC) from 18 patients with metal allergy and five healthy volunteers were examined by LST using 12 metal reagents (HAuCl4, PdCl2, NiSO4, CoCl2, CuSO4, SnCl4, K2Cr2O7, MoCl5, H2PtCl6, IrCl4, AgBr, FeCl3). To define metal allergy, a patch test (PT) was performed with metal reagents, and then the components of dental alloys in their mouth were analyzed. The expressions of CD 4, CD 8, CD 25, and CLA of metal-specific T cells were determined by flow cytometric analysis (FACS). PBMC from patients with positive PT showed LST positive for nickel sulfate (Ni), gold chloride (Au), palladium chloride (Pd) and cobalt chloride (Co). The results of LST in other metals indicated negative in spite of the positive result by PT. FACS results indicated the increase of CD 4 + T/CD 8 + alpha 4 + T cells, CD 4 + T/CD 8 + CLA+ T cells by stimulation with metal reagent. Thus, metal-specific T cells were stimulated in PT positive patients, so LST could be a more specific test for diagnosing dental metal allergy.     

Metal content of biopsies adjacent to dental cast alloys

Single case reports indicate that components of dental alloys accumulate in the adjacent soft tissue of the oral cavity. However, data on a wider range of dental alloys and patient groups are scarce. Therefore, the aim of the present study was to examine the metal content of oral tissues adjacent to dental alloys showing persisting signs of inflammation or other discoloration (affected sites) and of healthy control sites with no adjacent metal restoration in 28 patients. The composition of the adjacent alloys was analyzed and compared to the alloy components in the affected sites. Tissue analysis was performed using atomic absorption spectroscopy. Alloy analysis was performed with energy-dispersive X-ray analysis. In the affected sites, the metals Ag, Au, Cu, and Pd prevailed compared to control sites, reflecting the frequency distribution of single metals in the adjacent alloys. In most cases (84%), at least one of the analyzed metals was a component of the alloy and also detected in the tissue. Metal components from almost all dental cast alloys can be detected in adjacent tissue.     

Metallic pigmentation of human teeth and gingiva: morphological and immunological aspects

The composition of metallic pigmentations in gingiva and dental roots was determined by means of transmission electron microscopy with energy dispersive x-ray microanalysis. The systemic immune response to the metals found in the oral cavity was evaluated in 10 patients by using a modified lymphocyte proliferation test. Immunological results were compared with a group of five controls without metallic materials and pigmentation. Dense particles of various shapes and sizes, as well as of diverse extracellular and intracellular localization patterns, were detected in the pigmented lamina propria gingivae. Metallic deposits consisted predominantly of silver accompanied by selenium or sulfur or both. Besides, Ag, Au, Cr, Ni, Fe, Hg, Cu, and Ti were identified in dentinal tubules of teeth reconstructed with dental alloys. Nine patients with metallic pigmentations had a positive lymphocyte proliferative response to one or more metals present in their own metal reconstructions. Results of this study thus indicated that dental alloys-by virtue of their corrosion process-might pose a significant risk to immunologically susceptible patients.     

Patients with local adverse effects from dental alloys: frequency, complaints, symptoms, allergy

Data on the prevalence of adverse effects from dental cast alloys and on the characteristics of the related patient groups are scarce. Therefore, the aim of the present study was to investigate patients in a defined part of Germany attributing oral complaints or symptoms to dental cast alloys. All dentists in the area of Eastern Bavaria (with 1 million inhabitants) were asked to send corresponding patients to our department during a 3-year period. Out of this collection, patients with complaints or symptoms in the oral cavity were recruited and characterized with regard to number, age and sex distribution, type of subjective complaints and objective intraoral symptoms, and allergy status based on an alloy analysis. Patients reporting to our department with suspected local adverse effects from dental cast alloys represented 0.01% of the population. Thirty-four percent of the patients were 50-59 years old, with females prevailing (76%). A great variety of subjective complaints was reported, which mainly resembles those reported by patients with adverse effects attributed to other dental materials like amalgam or denture base materials. The main objective intraoral symptoms were gingivitis, anomalies of the tongue (lingua plicata, lingua geographica), discoloration of the gingiva, redness of the palate or tongue and lichenoid reactions of the oral mucosa. In not more than 10% of the patients, allergy was diagnosed as contributing to the complaints or symptoms.     

Study of the influence of the anodic potential on metal-components dissolution from dental alloys

This study aims to evaluate the influence of the anodic potential on metal-components dissolution from dental alloys and is intended to serve as an aid in the investigation of dental metal eruption (metal allergy). In the experiments, anodic potentials were applied electrochemically to various dental alloys in a 0.9% NaCl solution. Thereafter amounts of metal-component dissolution were measured by means of atomic absorption spectrophotometry. In addition, relations between metal-component dissolution and electrochemical characteristics (anodic polarization and charge transfer calculated from current density-time transients) were considered. Results: 1. Breakdown potentials determined on the basis of anodic polarization profiles agreed with potentials of remarkable increase in component dissolution. 2. Current density-time transients gave good indications of alloys' corrosion tendencies. Correlations between charge transfer and total amounts of metal-component dissolution were comparatively good. 3. Metal-component dissolutions in various alloys at fixed anodic potentials 1) Cu and Zn were found to dissolve slightly from gold alloys (types II and IV) at potentials above 200 mV (vs SCE). 2) Ag, Pd, Cu, and Zn were found to dissolve from the Ag-Pd-Cu-Au alloy at potentials above 100 mV. A comparatively large amount of Zn was released at low potentials. Amounts of Ag and Cu dissolution increased rapidly at 300 mV and 500 mV respectively. Although traces of it were detectable at low potentials, dissolution of Pd increased remarkably at 500 mV. 3) Ag, In, and Zn were found to dissolve from the Ag-In-Zn alloy at potentials above O mV. Amounts of In and Zn dissolution increased above 20 mV. The increase was especially remarkable in the case of In. 4) Sn and Zn were found to dissolve from the Ag-Sn-Zn alloy at potentials above -200 mV; Ag dissolved from the same alloy at potentials above 100 mV. Amounts of Sn and Zn dissolution increased at potentials above 100 mV. This was especially true in the case of Sn. 5) Ni, Cu and Si were found to dissolve from the soft type Ni-Cr alloy (9.0 wt% Cr) at potentials above -100 mV. Cr, Mn, and Fe dissolved from the same alloy at potentials above 0 mV; and Co at potentials above 200 mV. Metal-component dissolution was greater in the case of this alloy than in those of all the other alloys used in this study. A considerable amount fo Ni was released at 0 mV.(ABSTRACT TRUNCATED AT 400 WORDS)     

Five hundred patients reporting on adverse effects from dental materials: Frequencies,complaints, symptoms,allergies

Objective

Information on patients with real or claimed adverse reactions towards dental materials in large patient cohorts is rare. Therefore, the aim of the present study was to investigate patients reporting on complaints and symptoms to dental materials over a 16-year period.