A new technique for incorporation of TiO nanotubes on a pre-sintered Y-TZP and its effect on bond strength as compared to conventional air-borne particle abrasion and silicatization TiO nanotubes application on pre-sintered Y-TZP.

Objective: This study evaluated the microshear bond strength of a resin cement to Y-TZP after different methods of TiO nanotubes (nTiO) incorporation on pre-sintered Y-TZP surfaces.

Methods: nTiO were synthesized and incorporated on Y-TZP slices as follows (n = 15): 1) nTiO mixed with isopropyl alcohol/manual application (MAl); 2) nTiO mixed with acetone/manual application (MAc); 3) nTiO mixed with isopropyl alcohol/high-pressure vacuum application (HPVAl); 4) nTiO mixed with acetone/high-pressure vacuum application (HPVAc). As controls, surfaces were sandblasted with AlO (OX) or Rocatec silicatization (ROC). All ceramics were sintered after nTiO incorporation. Surface treatments of OX and ROC were made after sintering. Surfaces were characterized by confocal laser microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Resin composite cylinders (1.40 mm diameter and 1 mm height) were cemented with a resin cement, stored in water at 37 °C for 24 h and thermocycled for 10 000 cycles before microshear bond strength evaluation. Data were analyzed with one-way ANOVA and Games-Howell (α = 0.05), and fracture analysis was performed using a stereomicroscope.

Results: EDS confirmed the presence of TiO on treated Y-TZP. The confocal analysis showed higher roughness for HPVAc and OX. There were significant differences between surface treatments (p < 0.001). HPVAl (22.96 ± 10.3), OX (34.16 ± 7.9) and ROC (27.71 ± 9.4) showed higher microshear bond strengths and were statistically similar (p > 0.05). MAC showed intermediary values, and HPVAc and MAl presented decreased bond strength, with a high percentage of premature debonding.

Conclusion: High-pressure vacuum application of nTiO mixed with isopropyl alcohol was able to produce bond strength values compared to conventional air abrasion and Rocatec silicatization.

Significance: The infiltration of TiO nanostructures on the pre-sintered Y-TZP is an interesting approach that can improve bond strength without the need of sandblasting methods.