Advisory Committee Chair
Daniel A Givan
Advisory Committee Members
Date of Award
Degree Name by School
Master of Science (MS) School of Dentistry
The purpose of this study is to measure the shear bond strength between dental cement and four different machinable, lithium disilicate glass ceramics, under varied etch time with hydrofluoric acid. Ten specimens each of 4 different machinable blocks of lithium disilicate were mounted in cylinders of pink acrylic resin. Each specimen was subjected to etching with hydrofluoric acid, rinsing with water from an air / water nozzle, drying with compressed air, application of a silane primer (Monobond Plus, Ivoclar Vivadent) for at least 60 seconds, then mounted in an Ultradent jig and Variolink Esthetic LC (Ivoclar Vivadent) cement extruded through an aperture, onto the prepared ceramic surface and light cured for 60 seconds, using a 3M Elipar curing light. The bonding procedure was repeated for 3 rounds, each time varying the duration of etching: in round 1, per the manufacturer’s instructions, in round 2 a 60 second etch and in round 3 per the manufacturer’s instructions, rinsing and drying with water followed by re-etching per manufacturer’s instructions. Between each round of bonding, the specimens were wet polished with 320 grit sandpaper and left to air dry for 24 hours. The 4 materials investigated were Amber Mill Block (HAAS BIOTECH), Tesserra (Cerec), IPS e.max CAD (Ivoclar Vivadent) and LiSi Block (GC America). Following bonding, all specimens were stored in distilled iv water for 24 hours at 37°C, then subjected to a shear bond strength test in an Instron machine with crosshead speed of 1mm/minute. A two-way ANOVA was performed to evaluate the effects of material type and etch method. Due to significant differences in the data an effects test was performed which determined that both effects as well as the combination of effects were significant. A one way ANOVA was performed holding each effect constant enabling a more in depth analysis of the other’s effect followed by Tukey’s post hoc tests to further analyze the findings. Material type and etch method not only individually affect the SBS of light cure resin cement to lithium disilicates, but the combination also affects the SBS.
Nayee, Mayur Chandrakant, "Effect of Etch Time on SBS of Machinable Lithium Disilicate Glass Ceramics Using Variolink Esthetic LC" (2022). All ETDs from UAB. 572.