A Study Of Nd:YAG Laser Etching On The Bonding Strength Of Titanium To Porcelain

Objective: To investigate the effects of Nd:YAG laser treatment of titanium on microstructure and the bonding strength of porcelain to titanium.Methods: 33 non-cast titanium strips were progressively polished by 240 #,400 #,800 # and 1000 # silicon carbide sandpaper under running water,then the 30 strips were divided into three groups(Group A to C,11 strips per group)randomly.Group A : sandblasted;Group B: Nd:YAG laser irradiated at 20 A,15s;Group C: Nd:YAG laser irradiated at 20 A,30s.Following surface treatments,microstructural and chemical analysis were performed by means of electron microscope examination and EDS,and the surface roughness was measured..Low-fusing porcelain was applied onto the titanium specimens according to the manufacturer’s instructions.Bonding strength of the samples was measured by a three-point bending tester according to ISO9693.Electron microscope examination and EDS analysis were also performed for one specimen of each group after the shear bond strength test to evaluate the nature of the fracture surface.Results: There was a significant difference in surface roughness with respect to surface treatment(p<0.05).There were different in the surface morphology and the phase components of three groups.EDS analysis showed that specimen of A group was consisting of Ti element,O elements and Al elements;specimens of group B or group C was consistingof Ti element only.Group C(31.42 ± 2.47MPa)produced the highest bond strength among the groups(p < 0.001).The bond strength of group B(27.97±2.19MPa)is higher than group A(p < 0.05).Bonding strength of group B and group C were higher than the minimum requirement of ISO 9693.The electron microscope examination image after debonding of group C showed porcelain retained on the surface.Conclusion: Laser etching of titanium surfaces using an Nd:YAG laser was effective in improving surface roughness and wettability of titanium.Laser treatment may be an alternative method to sandblasting for enhancing the bonding strength of low-fusing porcelain to titanium.