Shear bond strength of repaired composite resin restorations / 대한치과보존학회지

ABSTRACT

This study was performed to evaluate the interfacial shear bond strength of base (direct and indirect) and repair composites with aging and surface treatment methods. Direct composite resin specimens (Charisma(R), Heraeus Kulzer, Germany) were aged for 5 min, 1 hour, 24 hours, and 1 week in 37degrees C distilled water before surface treatment, and then divided into five groups Group 1, grinding; Group 2, grinding and application of bonding agent; Group 3, grinding, etching with 37% phosphoric acid for 30sec, and application of bonding agent; Group 4, grinding, etching with 37% phosphoric acid for 30sec, silane treatment, and application of bonding agent; Group 5, grinding, etching with 4% hydrofluoric acid for 30sec, silane treatment, and application of bonding agent. Indirect composite resin specimens (Artglass(R), Heraeus Kulzer, Germany) were aged for 1 week in 37degrees C distilled water and divided into seven groups Group 1 - Group 5, equal to Charisma specimens; Group 6, grinding, etching with 37% phosphoric acid for 60sec, silane treatment, and application of bonding agent; Group7, grinding, etching with 4% hydrofluoric acid for 60 sec, silane treatment, and application of bonding agent. The repair material(Charisma(R)) was then added on the center of the surface (5 mm in diameter, 5 mm in height). The shear bond strength was tested and the data was analyzed using one-way ANOVA and the Student-Newman-Keuls test. The following conclusions were drawn. 1. The shear bond strength of Charisma(R) specimens aged for 1 hour was significantly higher in Group 2 and Group 5 than in Group 1 (p<0.05), and that of Charisma(R) specimens aged for 1 week was significantly higher in Group 3 and Group 5 than in Group 1 (p<0.05). No significant difference was found in the bond strength of specimens aged for 5 min and 24 hours. 2. In Group 2 of the Charisma(R) specimens, there was significant difference between the bond strength of 24 hours and that of 1 week (p<0.05). 3. In Group 4 of the Charisma(R) specimens, the shear bond strength of specimens aged for 24 hours was significantly higher than the others(p<0.05). 4. There was no significant difference between the shear bond strength of the Artglass(R) specimens. 5. Most of the Charisma(R) specimens showed cohesive fractures. Artglass(R) specimens that were etched with acid (phosphoric or hydrofluoric) for 30 sec showed more cohesive fractures.