The effect of TiN coating on retention of conus telescopic crowns after repeated insertion/separation tests / 实用口腔医学杂志

ABSTRACT

Objective:To evaluate the effect of TiN coating on retentive force of conus telescopic crowns after repeated insertion/separation tests. Methods: Fourteen pairs of standard metal specimens fabricated by precision Computer Numerical Control (CNC) Lathe were randomly divided into experimental group and control group, seven pairs in each group. The external surfaces of inner crowns and internal surfaces of outer crowns of experimental group were coated with a 2.0 μm titanium nitride (TiN) by multi-arc ion plating method. The group without titanium nitride coating was served as control. The retentive forces of two group telescopic crowns was investigated by repeated insertion/separation tests. Statistical analysis of group t-test was performed by SPSS 13.0 software package. Results: The results demonstrated that the initial retentive force of titanium nitride group in our study were lower than that of uncoated titanium nitride group. The retentive forces of two groups gradually decreased depending on the number of insertion/separation cycles and the rate of retention attenuation was found to be statistically significant. It was also shown that the retentive force of titanium nitride coating group began to decrease after 3 000 cycles and declined slowly not only before 3 000 cycles but also after 7 000 cycles. Conclusion: Titanium nitride coating deposited on external surface of inner crowns and internal surface of outer crowns can significantly decrease retention attenuation rate of conus telescopic crowns and maintain persistent retentive force.