Effect of Nd:YAG laser irradiation on shear bond strength of glass-lonomer luting cement to dentin surface.
OBJECTIVE
The purposes of this study were to evaluate the shear bond strength of luting glass-ionomer cement to a dentin surface treated by pulsed Nd:YAG laser irradiation, and to prove the hypothesis that the bond strength of glass-ionomer luting cement to dentin is favorably altered after Nd:YAG laser irradiation.


METHODS
Sixty-four extracted human molars with an exposed flat dentin surface were divided into four groups (n = 16). After painting black ink on their surfaces, the teeth of groups 1, 2, and 3 were irradiated by an Nd:YAG laser at 1.064-microm wavelength at 1, 2, and 3 W, respectively; group 4 was untreated and served as a control. Some specimens of each group were used for morphologic and atomic analytic study, and the others were used for shear bond testing. The shear bond test was performed after cylindric titanium specimens were cemented with glass-ionomer cement on a circular dentin area and specimens were immersed in distilled water. The tested specimens were also morphologically investigated.


RESULTS
Shear bond strength of group 3 was significantly higher than that of the control group. Morphologic observation of the cement-dentin interface showed good adaptation of the luting cement to laser-treated dentin. Analysis of atomic contents on the dentin surface showed a significant increase of calcium:phosphorus ratio after laser irradiation.


CONCLUSIONS
The dentin surface was modified morphologically and chemically, and the shear bond strength of glass-ionomer luting cement to dentin was increased by Nd:YAG laser irradiation at 3 W.
Kobayashi
Claudia Ayumi
CA
Department of Fixed Prosthodontics, Showa University School of Dentistry, Japan.
Fujishima
Akihiro
A
Miyazaki
Takashi
T
Kimura
Yuichi
Y
Matsumoto
Koukichi
K
Osada
Takayuki
T
Fukunaga
Hideki
H
Kawawa
Tadaharu
T
D000538:Aluminum Silicates; D002118:Calcium / Q000032:analysis; D001840:Dental Bonding; D003804:Dentin / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D009354:Neodymium; D010758:Phosphorus / Q000032:analysis; D033081:Shear Strength; D013054:Spectrophotometry, Atomic; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry; D015019:Yttrium
D000538:Aluminum Silicates; D005899:Glass Ionomer Cements; D014867:Water; D010758:Phosphorus; D009354:Neodymium; D015019:Yttrium; D014025:Titanium; D002118:Calcium