Please choose the correct ending to complete the given sentence: Health: [header] How to use the led light to whiten teeth with whitening trays [title] Brush and floss your teeth. [step] Clean teeth are instrumental for good contact between the whitening gel and the tooth surfaces. [title] Apply a small amount of the carbamide peroxide bleaching gel to the whitening tray.

Ending1: [step] It is important not to accidentally coat your teeth but to gather the proper amount. [title] Spray the gel onto your teeth with a wet sponge or toothbrush. Ending2: [step] Scrub the bristles of the hairbrush or floss under a soft toothbrush. [title] Pour the toothpaste onto the tray. Ending3: [step] ( if you do not have a tray, order an impression set with your first supply of whitening gel. ) [title] Insert the tray into your mouth. Ending4: [step] Use the toothpaste lightly to brush and floss your teeth. [title] Scrub your teeth, brushing gently with a soft toothbrush and a gentle circular motion for about 20 seconds.

Answer format: ending1/ending2/ending3/ending4