Influence of a surface conditioner to pre-sintered zirconia on the biaxial flexural strength and phase transformation.

•A novel zirconia surface modification approach was proposed in this study.•A conditioner was applied on pre-sintered Y-TZP surface before sintering.•The phase transformation and flexural strength of Y-TZP specimens were evaluated.•X-ray diffraction revealed the phase stability in conditioner-coated Y-TZP.•This graded glass/zirconia structure did not affect the biaxial flexural strength.