[EO-19] Shear bond strength to denture base resin of novel hard relining material containing S-PRG filler
[Abstract]
[Objective]
We aimed to assess the influence of S-PRG (surface pre-reacted glass-ionomer) filler content in hard reline material on shear bond strength to denture base resin.
[Method]
S-PRG filler particles (Shofu) were integrated into a hard relining material powder (Denture liner, Shofu) at concentrations of 5, 10, and 20 wt%. A hard relining material without S-PRG filler served as the control. The surface of the denture base resin (Fit Resin, Shofu) specimens underwent polishing with an automatic polishing device, followed by the application of denture liner adhesive (Shofu). The hard relining material containing S-PRG filler mixed with 1.7g/1.0ml powder/liquid ratio was bonded to denture base resin using a mold 2.3mm in diameter and 2.5mm in height. The specimens were immersed in warm water (50°C-60°C) containing a polymerization accelerator (Shofu) for approximately 3 minutes for curing. After curing, specimens were kept in ultrapure water for 24 hours. Shear bond tests were performed immediately on the specimens (referred to as the "24h group") or after 10,000 thermal cycles (referred to as the "TC group") using a universal testing machine with a crosshead speed of 1.0 mm/min (n=15/group). Shear bond strength was statistically analyzed using the Shapiro-Wilk test, followed by either a one-way analysis of variance and Tukey’s test or the Kruskal-Wallis test and Dunn’s test (α=0.05).
[Results and Discussion]
In the 24h group, shear bond strength was significantly lower in S-PRG20% (6.1 MPa) compared to the control (15.5 MPa), but no significant difference was observed between control, S-PRG5% (15.1 MPa), and S-PRG10% (12.4 MPa). In the TC group, control (22.6 MPa) and S-PRG5% (19.6 MPa) exhibited the highest shear bond strength, whereas S-PRG10wt% (14.2 MPa) and S-PRG20% (0.8 MPa) showed significantly lower shear bond strength compared to the control. Shear bond strength tended to be higher in the TC group than in the 24h group for each of the control, S-PRG5%, and S-PRG10% groups. This study suggests that the addition of S-PRG filler to hard reline material decreases shear bond strength in a dose-dependent manner, and thermal cycling may improve bond strength.
[Objective]
We aimed to assess the influence of S-PRG (surface pre-reacted glass-ionomer) filler content in hard reline material on shear bond strength to denture base resin.
[Method]
S-PRG filler particles (Shofu) were integrated into a hard relining material powder (Denture liner, Shofu) at concentrations of 5, 10, and 20 wt%. A hard relining material without S-PRG filler served as the control. The surface of the denture base resin (Fit Resin, Shofu) specimens underwent polishing with an automatic polishing device, followed by the application of denture liner adhesive (Shofu). The hard relining material containing S-PRG filler mixed with 1.7g/1.0ml powder/liquid ratio was bonded to denture base resin using a mold 2.3mm in diameter and 2.5mm in height. The specimens were immersed in warm water (50°C-60°C) containing a polymerization accelerator (Shofu) for approximately 3 minutes for curing. After curing, specimens were kept in ultrapure water for 24 hours. Shear bond tests were performed immediately on the specimens (referred to as the "24h group") or after 10,000 thermal cycles (referred to as the "TC group") using a universal testing machine with a crosshead speed of 1.0 mm/min (n=15/group). Shear bond strength was statistically analyzed using the Shapiro-Wilk test, followed by either a one-way analysis of variance and Tukey’s test or the Kruskal-Wallis test and Dunn’s test (α=0.05).
[Results and Discussion]
In the 24h group, shear bond strength was significantly lower in S-PRG20% (6.1 MPa) compared to the control (15.5 MPa), but no significant difference was observed between control, S-PRG5% (15.1 MPa), and S-PRG10% (12.4 MPa). In the TC group, control (22.6 MPa) and S-PRG5% (19.6 MPa) exhibited the highest shear bond strength, whereas S-PRG10wt% (14.2 MPa) and S-PRG20% (0.8 MPa) showed significantly lower shear bond strength compared to the control. Shear bond strength tended to be higher in the TC group than in the 24h group for each of the control, S-PRG5%, and S-PRG10% groups. This study suggests that the addition of S-PRG filler to hard reline material decreases shear bond strength in a dose-dependent manner, and thermal cycling may improve bond strength.