Keywords: DI water, deionized water; FIB, focused ion beam; HF, hydrofluoric acid; LTD, low temperature degradation; SEM, scanning electron microscopy; Y-TZP, yttria-stabilized tetragonal zirconia polycrystals; 3Y-TZP, 3 mol% Y-TZPZirconia; Etching; Dental; Ageing;