IADR Abstract Archives
Long-term Bond Strength to Zirconia After Ultra-short Pulsed Laser Treatment
Objectives: To evaluate the long-term (6-months) microtensile bond-strength (µTBS) of a 3-mol% yttria-stabilized tetragonal zirconium-dioxide (3Y-TZP) to a dual-cure resin-cement after treatment with ultra-short pulsed laser (USPL), generating different surface patterns.
Methods: Seventy-eight 3Y-TZP blocks of 10x10x5mm3 were prepared and randomly distributed into five groups for surface analysis (additional negative control [NC]) (n=6) and four groups for microtensile tests (only positive control, n=12). The following surface treatments were applied: Sandblasting with Al2O3 particles (SB) as a positive control group; and three laser groups irradiated with USPL (12ps pulses/Nd:YVO4/1064nm/2-34J/cm2) with different irradiation patterns: crossed-lines (LC), random-hatching (LR) and parallel waves (LW). Topography and surface roughness (Ra/Rz) were analyzed through scanning electron microscopy (SEM/20Kv) and 3D-laser profilometry. For µTBS, each ceramic block was duplicated in composite-resin and both were cemented using a dual-cure resin cement (Panavia-2.0). Half of the samples were stored in water (37°C) for 24h and the other half for 6 months. 10-12 sticks (1.0mm2) were obtained from each block and µTBS was tested (0.5mm/min). Data were analyzed with parametric tests both for roughness and µTBS (one-way ANOVA/Tukey’s test; α=5%).
Results: SEM analysis revealed that laser treatment caused micro-retentions on the zirconia surface for all tested patterns. Laser-treated zirconia presented significantly higher roughness than SB, except for LR. After 24h, the highest bond strength means (MPa) were achieved by LC and LW (p < 0.05). After 6 months, LC (21.2±5.1µm) and LW (21.4±4.4µm) still showed significantly higher bond strengths than SB (6.0±3.2µm) and LR (6.6±3.7µm) (p < 0.05).
Conclusions: Two USPL irradiation patterns (12ps/waves and crossed-lines) significantly increased long-term bond strength (six months water-storage) of zirconia to dual-curing resin cement compared to the current gold-standard (sandblasting), in vitro. If such a durable bonding may also be observed clinically, must be confirmed in future in vivo studies.
Methods: Seventy-eight 3Y-TZP blocks of 10x10x5mm3 were prepared and randomly distributed into five groups for surface analysis (additional negative control [NC]) (n=6) and four groups for microtensile tests (only positive control, n=12). The following surface treatments were applied: Sandblasting with Al2O3 particles (SB) as a positive control group; and three laser groups irradiated with USPL (12ps pulses/Nd:YVO4/1064nm/2-34J/cm2) with different irradiation patterns: crossed-lines (LC), random-hatching (LR) and parallel waves (LW). Topography and surface roughness (Ra/Rz) were analyzed through scanning electron microscopy (SEM/20Kv) and 3D-laser profilometry. For µTBS, each ceramic block was duplicated in composite-resin and both were cemented using a dual-cure resin cement (Panavia-2.0). Half of the samples were stored in water (37°C) for 24h and the other half for 6 months. 10-12 sticks (1.0mm2) were obtained from each block and µTBS was tested (0.5mm/min). Data were analyzed with parametric tests both for roughness and µTBS (one-way ANOVA/Tukey’s test; α=5%).
Results: SEM analysis revealed that laser treatment caused micro-retentions on the zirconia surface for all tested patterns. Laser-treated zirconia presented significantly higher roughness than SB, except for LR. After 24h, the highest bond strength means (MPa) were achieved by LC and LW (p < 0.05). After 6 months, LC (21.2±5.1µm) and LW (21.4±4.4µm) still showed significantly higher bond strengths than SB (6.0±3.2µm) and LR (6.6±3.7µm) (p < 0.05).
Conclusions: Two USPL irradiation patterns (12ps/waves and crossed-lines) significantly increased long-term bond strength (six months water-storage) of zirconia to dual-curing resin cement compared to the current gold-standard (sandblasting), in vitro. If such a durable bonding may also be observed clinically, must be confirmed in future in vivo studies.
