Sayaka Hori’s research while affiliated with Kagoshima University and other places

This study evaluated the effect of 1% hydrofluoric acid (HF) treatment on the bonding of an adhesive cement (Panavia F 2.0) to an indirect resin composite (Estenia C&B). Pairs of composite disks (10 and 8 mm in diameter by 3 mm thickness) were prepared. Adhesive surfaces were pretreated with either airborne particle abrasion or HF etching before being soaked for 30 seconds, five minutes or 10 minutes, with or without application of silane coupling agent. Adhesive specimens were fabricated by cementing a pair of treated disks. Shear bond strength was determined before and after 50,000 times of thermocycling (4 and 60 degrees C). All data were statistically analyzed using two-way ANOVA and Bonferroni's test (a=0.05). Bond strength achieved with five minutes of HF etching (18.3+/-1.1 MPa) was significantly higher (P=0.0025) than that obtained with airborne particle abrasion followed by application of silane coupling agent (14.3+/-1.8 MPa) after thermocycling.

This study investigated the effects of silanation and adhesive monomer, 10-methacryloyloxydecyl dihydrogen phosphate (MDP), on the bond durability of resin cement to zirconia. Two sizes of zirconia disk were prepared. The bonding surfaces of the disks were air-particle abraded with 50 microm Al2O3, and then bonded with one MDP-containing or three non-MDP-containing cements to fabricate test specimens. For the silanated specimen group, air-particle abraded surfaces were treated with respective silane coupling agents, including two MDP-containing or two non-MDP-containing agents, before the bonding procedure. Five test specimens for each group were subjected to thermo-cycles before shear bond strengths were determined. The data were statistically analyzed. For test groups without silanation, the specimens bonded with MDP-containing resin cement showed significantly higher bond strength. In contrast, all specimens bonded with non-MDP-containing resin cements failed during the thermo-cycling process. For the silanated groups, the specimens pre-treated with MDP-containing silane coupling agent and bonded with non-MDP-containing resin cement exhibited the highest shear bond strength. The shear bond strength of specimens pre-treated with MDP-containing silane coupling agent and bonded with MDP-containing resin cement was the next highest. In contrast, all specimens pre-treated with non-MDP-containing silane coupling agent bonded with non-MDP-containing resin cements failed during the thermo-cycling process. Within the limitations of this study, MDP adhesion monomer was effective in improving the bond durability of resin cement to zirconia.

The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-microm alumina suspension, and then thermocycled between 4 and 60 degrees C in distilled water for 20,000 or 50,000 cycles with a dwell time of 60 seconds. Staining susceptibility and mean surface roughness, Ra, were examined, and surface texture was observed by scanning electron microscopy. Dye penetration test showed that the surfaces of all resin composites were more stained after thermal cycling. Mean Ra of all resin composites, except PT, significantly increased after 50,000 thermal cycles. Dislodgement of filler particles was observed for all resin composites after thermal cycling, except FS. It was concluded that thermal cycling significantly affected the surface texture of the seven examined resin composites.