Experimental Study Of The Bonding Characterization Of Dental Porcelain To Ni-Cr-Ti Alloys In The Shear Test

ObjectiveStudy the bonding capability of Vita general porcelain and Ni-Cr-Ti porcelain alloys manufactured by Institute of Metal Research of Chinese Academy of Sciences. Using shear test, Scanning Electron Microscope (SEM) accompanied by Energy Spectrum Analysis, approach the influence on ceramometal bonding when Ni-Cr porcelain alloy were added with Ti, compound rare earth metals and removed the element of Be.Materials and Methods1. Sample resourceNi-Cr-Ti porcelain alloys, manufactured by Institute of Metal Research of Chinese Academy of Sciences, belong to Nickle-Ceramic alloy. Besides the main components of Ni, Cr, Mo, the test alloys were divided of Ti-Be free-RE free group, Ti-Be free-RE group, Ti-RE-Be group according to the rest compositions which were abbreviated to R₁ group, R₂ group, R₃ group by turns. HI BOND base-metal alloy was chosen as a control and called R₄ group. The content of Ti in R₄ group is one third of that other three groups.2. Preparation of metal-ceramic specimens for shear test and SEMThirty-six specimens were cast from the four alloys respectively, nine of every group. A thickness of 2 mm Vita normal porcelain was fused on the central area of 4.4mm×3.8mm metal specimens. One of each group was remained for veneering porcelain at the end of it, and was observed with SEM and energy spectrum analysis.3. Test of shear bond strengthThe thirty-two specimens were placed in a special stainless steel mold and the ceramometal interface were subjected to load on a universal testing machine until porcelain failure.The shear bond strength were abtained according to P=F/S (MPa) . The data of the four groups were analyzed with a l-way analysis of variance (alpha=05) and Student-Newman-Keuls(SNK).4. Observation with Scanning electron microscope and energyspectrum analysisObserve the interface morphology of metal and porcelain, compare the effects of the four groups'composition and contents on ceramometal bonding .Results1. The results of shear testThe shear bond strength means of the four test groups were 28.1864±2.80702MPa, 26.1585±3.38148MPa, 25.1663±3.12508MPa by turns, that of the controll group was29.1436±3.28302 MPa. The data of the four groups were analyzed with a 1-way analysis of variance and Student-Newman-Keuls(SNK).No significant difference(p > 0.05) were observed among them.2. Scanning electron microscope and energy spectrum analysisObserve the interface morphology between the porcelain and metal, no crackle were found and they were contacted tightly, diffusion regions occurred which thickness was different. The composition and contents of the four groups' interfaces were closed.Elements of two sides disperse and form chemical compound, in which Cr dispersing from metal to interface while Al and Si from ceramic to interface and lastly,forming dispersing layer which brings excellent combination property. ConclusionThe shear bond strength of the self-made Ni-Cr-Ti porcelain alloys all can satisfy the clinical requirements.R₁ group contains Ti, R₂ group contains Ti and RE which are all beryllium-free can be used for better recommendation for clinical practice.Excellent chemical bonding occurred in the interface of the self-made Ni-Cr-Ti porcelain alloys of which Cr influenced the chemical reaction mainly and influence the combination property accordingly.