The Basic Study On Cytotoxicity And Corrosion Of Metal Ceramic Alloys

More and more scholars pay more attention to the cytotoxicity and corrosion of the dental alloys. Researches show dental alloys in oral cavity can release metal ions which can cause some toxicity effect such as depressing metabolism of the cell, restraining cell proliferation et al.Metal-ceramic alloys are wildly used in clinic nowadays. But affected by the saliva the metal ceramic alloys in the patient's mouth will release some mental ions, which may cause the gingivitis or even discoloration of the gingival tissue.It is important to investigate the corrosion mechanism and cytotoxicity of the metal-ceramic dental alloys.This study focused on three main topics. Firstly we use MTT assay to compare four metal-ceramic dental alloys. Secondly we compare the cytotoxicity and corrosion of the Ni-Cr metal-ceramic alloys and re-cast Ni-Cr metal-ceramic alloys. At last we use electrochemical method to research the corrosion principle of Co-Cr metal ceramic alloys -a new metal ceramic allovs without Ni or Be.1. Cytotoxicity of four metal-ceramic alloys used for ceramic-bonding full crownFour metal ceramic alloys are select. Ni-Cr metal-ceramic alloys Co-Cr metal- ceramic alloysand Ni-Cr metal-ceramic alloy containing Ti Au metal-ceramic alloy.MTT assay and morphologic change is used to assess the cytotoxicity of four metal-ceramic alloys. The result showed that Ni-Cr metal-ceramic alloy , Ni-Cr metal ceramic alloy containing Tiand Co-Cr metal ceramic alloy all caused obvious suppressing effect of the L-929 mousefibroblasts proliferation. So dentists should be more cautious when choosing the metal ceramic denial alloys for patients.2. Electrochemistry' corrosion of the Co-Cr metal ceramic dental alloyTo avoid the side effect of the Ni and Be, scholars are investigating new non- precious metal ceramic dental alloy. Wirobond LFC is a new product of BEGO company. It possesses the advantage of non-precious and precious metal ceramic alloy: Without containing Ni and Be, having bigger elasticity modulus than precious metal ceramic dental alloy, can be used to fabricate long fixed bridge, having good binding with LFC porcelain power.Electrochemistry method is used to research the corrosion of the Co-Cr metal- ceramic alloy in the artificial saliva. The polarization curve of Co-Cr metal ceramic alloy showed the Ecorr was 0.7003 ±0.0163 V and the Etp was 0.7429±0.0157 V While the Ecorr and Etp of the Ni-Cr metal ceramic dental alloy were -0.6535±0.0134 V and 0.6212 ± 0.0184 V. The result showed that the capability of anti-corrosion of the Co-Cr metal ceramic dental alloy is better than the Ni-Cr metal ceramic dental alloy.3. To compare the cytotoxicity and corrosion of the Ni-Cr and re-cast Ni-Cr metal- ceramic alloyRecast Ni-Cr metal-ceramic alloy is used wildly in mam dental manufactory such as remainedsprues, failure castings. Will the cytotoxicity and corrosion of recast Ni-Cr metal ceramic dentalalloy be changed? Will recast Ni-Cr metal ceramic dental alloy cause discoloration of the gingivaltissue easier9This study adopt MTT assay to detect the activity of lactate dehydrogenase and then comparethe cytotoxicity of Ni-Cr and recast Ni-Cr meta-ceramic alloy. And atom absorption spectruminstruments are used to measure the quantity of released Ni element of the two group alloys.Electrochemistry method is used to research the corrosion principles of the alloys in the artificialsaliva.The result showed that the absorbency degree of the recast Ni-Cr metal ceramic dental alloy(0.1750±0.0118) is less than the Ni-Cr metal ceramic dental alloy (0.1870±0.0157) .But there is no significant difference in the two group (p>0.05). The concentration of the released Ni element of recast Ni-Cr metal ceramic dental alloy is 0.6250±0.0867mg/L, which exceeds that of the Ni-Cr metal ceramic dental alloy: 0.2600±0.1217mg/L. There is significant difference in the two groupThe Ecorr and Etp of the Ni-Cr metal ceramic dental alloy are -0.6535±0.0134 V and 0.6212...