Investigation of the Effect of Different Surface Treatments Applied to Titanium Dental Implant Abutments on the Retention of CAD/CAM Zirconium-Supported Ceramic Crowns.

Background: The aim of this study was to investigate the effect of abutment surface treatments (sandblasting and acid or alkali treatments) on the bonding of titanium dental implant abutments and zirconium-supported ceramic crowns with resin-reinforced glass ionomer cement.

Aim: The aim of this research was to determine the optimal surface conditioning method for titanium abutments by comparing the tensile bond strength of resin-reinforced glass ionomer cement after sandblasting, acid etching, and alkali treatment.

Methods: Seventy-six dental implant abutments (AnyOne; MegaGen Co. Ltd., Kyungsan, South Korea) were used in this study. Zirconia-based ceramic crowns for mandibular first molars were fabricated on the titanium abutments. The abutment samples were divided into four groups: a) sandblasting, b) sandblasting followed by acid treatment, c) sandblasting followed by alkaline treatment, and d) a control group. The samples were subjected to surface treatment and imaged using an electron microscope (SEM). The samples of each group were cemented onto ceramic crowns using a glass ionomer reinforced with the radiopaque resin GC FujiCEM Evolve. The specimens were placed in copper anodes with acrylic resin, leaving the neck of the implant analogues and crowns on the exposed abutments. All samples were subjected to a thermal cycling test (5,000 cycles) prior to tensile testing, followed by a tensile test on a universal testing machine, and the bond strength values were recorded. The data obtained were statistically analysed using a one-way ANOVA and the Tukey test.

Results: This study showed that surface treatment significantly affects the tensile bond strength between titanium abutments and zirconia-supported crowns. The highest bond strength was observed in the group treated with 48% H2SO4 after Al2O3 sandblasting, while the lowest was in the untreated control group. Although sandblasting alone was effective, subsequent alkali treatment significantly reduced bond strength. SEM analysis confirmed that acid-treated surfaces had the most favorable roughness for micromechanical retention. Proper surface conditioning is essential for the long-term success of implant-supported restorations.

Conclusion: This study showed that surface treatments significantly influence the bond strength between titanium abutments and zirconia crowns. The highest tensile strength was achieved with Al2O3 sandblasting followed by 48% H2SO4 acid etching. In contrast, alkali treatment reduced bonding effectiveness. Acid etching after sandblasting is recommended for improved long-term retention of implant-supported restorations.