Objective:To investigate the effects of oxidation of titanium on bonding strength of titanium and porcelain. Methods: 24 specimens with a size of 28 mm ?3 mm?0.5 mm were cast from pure titanium and divided into 4 groups, 6 specimens each group. Group 2, 3 and 4 were degassed at 750, 800 and 900 ℃ respectively, group 1 not degassed as negative control, then a uniform thickness of 1mm of Noritake super porcelain Ti-22 was veneered on 8 mm?3 mm in the central portion of each specimen. The specimens were subjected to a three-point bending test on a load-test machine with a span of 20 mm, and the failure loads were recorded and analyzed statistically. The opposite side of specimens of each group were observed by thin-film X-ray diffraction. Results: The failure loads (N) of group 1, 2, 3 and 4 were 10.33, 9.98, 5.53, 3.37. The oxide of group 1 was Ti6O only, the oxide of the gropu 2, 3, and 4 were Ti6O and TiO2 and the amount of TiO2 increased significantly as the temperature iss increasing. Conclusion: The oxide adherence strength value for pure titanium decreased while the oxide temperature is increasing. The higher of the degassed temperature of the specimens, the more TiO2 can be found in the oxide film and the smaller the failure load is, which indicats that oxidation of titanium has a negative effect on the bonding strength of porcelain and titanium.

Although the incidence of melanoma is increasing rapidly, its proportion is relatively low among all the malignant tumors in China, and oncologists commonly pay little attention. The first consultation place for melanoma patients is mainly the department of dermatology. Dermatologists have unique advantages in the diagnosis and treatment of melanoma since they can comprehensively integrate clinical diagnosis, pathological diagnosis, surgical treatment and drug treatment. In recent years, Chinese scholars have made great progress in melanoma research, such as regulation of cell death, epigenetic modification, resistance to targeted drugs, tumor microenvironment and tumor immune regulation. Interferon α-1b, a unique new drug in China, not only can be used for adjuvant treatment of high-risk stage Ⅱ and Ⅲ melanoma, but also shows good efficacy in the treatment of stage Ⅳ melanoma, and adverse reactions to it are far less than those to interferon α-2b. Unlike the White population, the common subtypes of melanoma are acral and mucosal melanomas in the Asian population. The combination of interferon α-1b with programmed death receptor-ligand 1 inhibitor, targeted drugs or angiogenesis inhibitors is bringing hope for patients with stage IV melanoma.

OBJECTIVE: Sintering of porous coated anatomic porous layer bonding technology remains controversial because of poor understanding to its essence.ESSENCE: Sintering is a technology that the bonding temperature exceeds 5 ℃ or higher than the base-alloy solids temperature of 1 230 ℃, resulting in base-alloy produce a series of serious problems, such as grain boundary racks, handle broken and so on.HAZARDS: In sintering temperature, the low melting point eutectlc phase and the brittle metal compounds flow out of the grain boundary to bond the small metal balls and the handle, which greatly reduces the fatigue strength. The grain boundary cracks formed and expanded ultimately leading to handle broken.DISCUSSION: The cause of a handle broken is neither notch nor metallurgical defects but sintering process, because high sintering temperature results in grain-boundary lacunas.CONCLUSION: Sintering is not suitable for connecting the force components. High sintering temperature produces grain-boundary lacunas which can expand into cracks and ultimately result in handle broken under some condition.

Objective:To study the feasibility of microarc oxide treatment on the enhancement of titanium-ceramic bonding strength. Method:Titanium samples in the size of 25 mm?3 mm?0.5 mm were prepared with smooth surface(group 1),rough surface(group 2) and microacrc oxide treated surface(group 3). Nickel-chromium alloy samples in the same size were prepared (group 4). The surface of the samples was observed by scanning electron microscope(SEM) and dispersive spectrometry analysis. Then, the samples were bonded to porcelain. The bonding interface was observed by SEM. The bonding strength of the samples was measured by a three-point bending test according to ISO 9693.Results:Microarc oxide treated surface was rough and porous. The interface of microarc oxide treated surface bonded to porcelain was compact. The bonding strength(MPa) of the samples of group 1,2,3 and 4 to porcelain was 30.79?1.3,36.12?3.03,45.84?3.15 and 48.35?3.06 respectively(group 3 vs group 1 or 2 P0.05). Conclusion:The microarc oxide treatment on titanium can increase the titanium-ceramic bond strength.

Objective:To evaluate the effect of preoxidation on the bonding strength of titanium to porcelain.Method:12 titanium plates(25 mm?3 mm?0.5 mm) were pre-oxidated according to usual preoxidation procedure and 12 without preoxidation were used as the controls.The samples(6 in each group) were then bonded with bonding porcelain,opaque porcelain,dentin porcelain and glaze of Duceratin(Degussa) or Vita titankeramik(Vita) respectively.The bonding strength of Ti/porcelain was evaluated using three-point bending test according to ISO 9693 1990 standard. The interface of Ti/porcelain bonding was observed by SEM.Results:Bonding strength(MPa) of Ti/Duceratin preoxided group and the corresponding control was 41.910?2.778 and 33.097?5.297(P0.05),respectively.SEM observation showed inter-lock and tight bonding of Ti/porcelain in pre-oxidated interface,more cracks and gaps between Ti and porcelain in non-pre-oxidated interface.Conclusion:Pre-oxidation may improve bonding strength of Ti/Duceratin system, while has no significant effect on bonding strength of Ti/Vita titankeramik system.

0.05),while there was significant difference among other groups(P

Objective:To study the effects of different ratios between adhesive and solidification agent on the investment of titanium and to investigate the physical properties of the adhesive on different time intervals.Methods:Mixed adhesive with solidification agent according to different ratio:14∶1,14.5∶1,15∶1.Twelve wax sheet patterns(10 mm?10 mm?0.8 mm)were invested,and then the castings were fabricated.Manipulation performance,appearance of the casting mold,and color of the castings as well as their integrity and edge clarity were observed.The more ideal proportion was selected and determined.Dynamic viscosity,density and pH value of the adhesive were measured on different days(1,3,5 and 7 days).Results:With a adhesive or solidification agent ratio of 14∶1,the solidified time was comparatively short and unable to operate,while with a ratio of 15∶1,the solidified time was too long to solidify and led to the distorted castings.In group with a ratio of 14.5∶1,the primary gel time,intact mold and cast gate were appropriate.The surface of the castings showed bright,metal color after sand blasting.Dynamic viscosity,consistency and pH value of different days for the adhesive had no significant difference.Conclusion:Favorable casting can be fabricated for adhesive mixing with solidification agent when the ratio was 14.5∶1.The adhesive has steady capability in 7 days in practical condition.

0.05 ;Ti milled/VITA vs Ni Cr/VITA P

A broken metal handle accompanied by femoral trunk fracture, which would shorten service life of handles. Therefore, it is necessary to judge whether the notch is the main reason for handle broken. Some literatures thought that the pores of sintered porous coated anatomic (PCA) porous layer produce the notch on the handle surface and the notches lead to the handle broken being incorrect. The Apex of the pore is taken for the bottom of the notch, expanding into a crack, and it should also not grow to the base-alloy, accordingly, the above conclusion is wrong. Some reports pointed out the notch, apex of the pore, will expand into the crack, but it is not associated with the broken handle. Under the sintering temperature, the grain boundary apertures be generated on the base metal surface, the aperture is expanded into the crack, which leads to handle broken in the forced area. However, neither theoretical basis, nor a case of corroboration, can prove exist of notch. Actually, the broken handle is caused by the sintering technology. The high temperature of sintering joining results in grain boundary aperture, when encounter the largest forced area and expand into crack, it will break the handle.

INTRODUCTION: General joining techniques are at low level, which produces some potential problems in porous layer of porous coated anatomic (PCA).LIMITATIONS: The problems in general joining techniques are caused by limitations of each technique, which could not be solved using advanced measures.APPLICATION: The activated diffusion brazing technology is an effective way. Its many advanced processes can solve those potential problems.CONCLUSION: The stress-shielding problem caused by PCA porous layer can be solved by using small metal balls in the same diameter in combination with the advanced activated diffusion brazing technology. Moreover, the high performance brazing metals by activated diffusion brazing technology is harmless for humans.