ABSTRACT
Objective:To evaluate the effects of magnetron-sputtered ZrSiN/ZrO2 gradient coating on the bonding strength of commercially pure titanium to porcelain.Methods:50 cast titanium specimens were prepared according to the ISO 9693 standard,and divided into 2 groups(n =25).The ZrSiN/ZrO2 gradient coating was deposited on specimens by magnetron sputtering technique,and subsequently a low-fusing porcelain was applied for the samples in the expermental group,the samples in the control group were treated by surface sandblasting.The roughness and surface energy of the samples were measured(n =10).The bonding strength of titanium-porcelain specimens was analyzed by three-point bending test (n =10).Scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS) were employed to examine the properties of the delaminated and cross-sectioned surfaces.The results were analyzed by paired t-test (α =0.05) with SPSS 1 1.0 software.Results:The roughness of the experimantal group was lower(P ＜ 0.05) and the contact angle was larger(P ＜ 0.05) than those in the control group.The titanium-porcelain bond strength of gradient-coated group was greater than that of control group(P ＜0.05).The SEM and EDS examination results of delaminated and cross-sectioned surfaces also indicated that the gradient-coated group showed more porcelain residues.Conclusion:The bonding strength of porcelain-fused-to-titanium can be improved by magnetron sputtered ZrSiN/ZrO2 gradient coating.
ABSTRACT
PURPOSE: Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS: Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 microm aluminum oxide particles (Al2O3), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 microm Al2O3 + Al coating and air particle abrasion with 50 microm Al2O3 + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (alpha=.05). RESULTS: The highest bond strengths were obtained by air abrasion with 50 microm Al2O3, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION: Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.
Subject(s)
Adhesives , Aluminum Oxide , Collodion , Resin Cements , ZirconiumABSTRACT
Magnetron is often used as microwave power source in clinical linac magnetron.This paper introduces the structure and working principle of clinical linac magnetron.Specific techniques and relevant parameters adjustment in magnetron replacement are mainly discussed.
ABSTRACT
This article analyses and summarizes the clinical maintenance work of Elekta Precise Linac in five years.Afer the further research on its performances and errors,a better way is found to solve the main problem of clinical electronic linac,i.e.the way to reduce the Stop Rate of Linac in Radiotherapy.
ABSTRACT
The principle,structure and classification of magnetron of medical linear accelerator are expatiated.The maintenance of high voltage or the fault of the same kind of magnetron is put forward when the high voltage approaches or is surpassed.The diagnosis method is also given,thus improving the accuracy rate and repair rate and being helpful to medical practice.