Study On Metal-ceramic Bonding Strengths Of Several Base Metal-ceramic Alloys Frequently Used Clinically

Since non-precious porcelain-fused-to-metal restoration has such advantages as cheep cost,good qualities in the aspects of good-looking,high bonding strength,good biocompatibility and good mechanical function, they have been widely used for dental prosthesis production, and it has been used more and more commonly in clinic. However, Ni-Cr alloy its low cost and good biocompatibility and good mechanical function, it become domestic Ni-Cr alloy as metal substrates have been widely used in clinic , but the long-time clinical practices and experimental investigations demonstrate that the Ni-Cr alloy have lots of adverse effects like stomatitis, rash or gum coloring, etc, clinic have lots of adverse effects like stomatitis, rash or gum coloring, So they also must be replaced by other materials. Pure Ti and Ti alloys and little-Ti-containing alloy, etc, What's more, the favorable bonding strength between metal and porcelain ensures the adherence of porcelain to the metal base under the motivation of different direction forces during the usual tooth movement. we have employed the three-point bending test to investigate many materials including Ti, Ti-alloy, little-Ti-containing alloy, Ni-Cr alloy, and used the electron microscope to observe their interfaces.We choose Ti, Ti-alloy, little-Ti-containing alloy, Ni-Cr alloy as subjects. 108 sheets were divided into 9 groups, each group included 12 sheets. HeraCeram JC porcelain cement was fused and adhered to the group A1:Ni-Cr(H),B1:Ni-Cr(northwest)and F1:little-Ti-containing alloy; Vita porcelain cement was fused and adhered to the group A2:Ni-Cr(H),group B2:Ni-Cr(northwest) and group F2: little-Ti-containing alloy; Noritake Ti22 porcelain cement was fused and adhered to the group C:pure Ti,group D:Ti6Al4V and group E: Ti6Al7Nb. By three-point bending test was employed to detect the metal-ceramic bonding test. To make test specimens by the same method, each group included 2 sheets. There were 18 sheets altogether. Test specimens were invested with selfcuring resin, finished with SiC, cleaned and goldblasted. Than metal-ceramic combinational interface were observed and analyzed by SEM.Result:1.The bonding of Ni-Cr:A1:46.05±3.16, A2:42.05±3.26, B1:44.04±3.69, B2:47.47±2.92, A1﹥B1, B2﹥B1 (P>0.05); A1﹥ A2 (P<0.05). The electron microscopy revealed the bonding was tight between the cement and the metal base and no obvious air bubble or interlayer was found in each group.2.The bonding of pure Ti and titanium alloys:C:36.49±2.98 MPa, D:39.93±2.96 MPa, E:39.35±2.88 MPa, D and E>C(P<0.05), D>E(P>0.05). The electron microscopy revealed the bonding was tight between the cement and the metal base and no obvious air bubble or interlayer was found in each group.3.The bonding of little-Ti-containing alloy: F1:41.08±2.98 MPa, F2:42.29±3.38 MPa, F2>F1(P>0.05). The electron microscopy revealed the bonding was tight between the cement and the metal base and no obvious air bubble or interlayer was found in each group.4.Their bonding strengths stepped up in the order of pure titanium, titanium alloys, little-titanium-containing alloy, Ni-Cr alloy.Conclusion:1. The experiment drew a conclusion that the bonding strengths of the four kinds of base metal-ceramic alloys was all beyond 25 MPa, the baseline of ISO.2. The bonding strength of Ni-Cr(H)- HeraCeram is higher than Ni-Cr(H)-Vita(P<0.05); and the bonding strength of Ni-Cr(northwest)-Vita is higher than Ni-Cr(northwest)- HeraCeram,(P>0.05); Ni-Cr(northwest) alloy can fused with Vita porcelain or HeraCeram porcelain.3. The bonding strength of Ti-6Al-4V-Noritake Ti22 or Ti-6Al-7Nb-Noritake Ti22 is higher than Ti-Noritake Ti22 respectively(P<0.05), but there has no significance between Ti-6Al-4V and Ti-6Al-7Nb, may be Ti-alloy is better than Ti in clinical use.4. The bonding strength of little-Ti-containing alloy-Vita is higher than little-Ti-containing alloy-HeraCeram(P>0.05), so little-Ti-containing alloy may be fused with Vita porcelain or HeraCeram porcelain.5. The bonding strength of Ni-Cr alloy-porcelain is the highest,but the anti-causticity and the biocompatibility should be improved; the anti-causticity and the biocompatibility of pure Ti and Ti-alloy is good, but the bonding strength should be improved; the little-Ti-containing alloy is a type of new material, its long-term effect remains to be confirmed.