Quick Rinse, Strong Bond? Comparing Short Water Rinsing and Advanced Cleaning Methods After Hydrofluoric Etching of Lithium Disilicate Glass Ceramic

This study examined whether short water rinsing after hydrofluoric acid (HF) etching achieves comparable total bond strength (TBS) to more advanced cleaning protocols. Ninety-six lithium disilicate specimens were etched with 5% HF and then assigned to one of six post-etch cleaning methods: a 15 s water spray, 60 s water spray, brushing with a toothbrush, an ultrasonic bath with distilled water, an ultrasonic bath with 99% isopropanol, or a 37% phosphoric acid followed by an ultrasonic bath. The specimens were then bonded to acrylic tubes filled with composite resin. Half of the specimens were stored in water at 37 °C for three days, and the other half were stored for 150 days with 37,500 thermal cycles (5 °C/55 °C). TBS testing, failure mode evaluation, and microleakage testing were performed. Two-way ANOVA and Tukey's test were used for statistical evaluation. Aging for 150 days significantly reduced TBS in all groups. Cleaning with a 60 s water spray resulted in significantly higher TBS than phosphoric acid plus ultrasonic cleaning, regardless of storage time. No significant differences were found among the other cleaning methods. There was no change in microleakage among the different groups; the failure was predominantly cohesive. A 15 s water spray after HF etching was as effective as more complex cleaning protocols in terms of TBS and SEM-observed surface characteristics.