Please choose the correct ending to complete the given sentence: Health: [header] How to keep kids' teeth strong [title] Start early. [step] Children should start having their teeth brushed as soon as their first baby teeth appear. This should also be when they first visit the dentist.

Ending1: Kids shouldn't go before 2 weeks old. [substeps] It's important to start buffing and prepping younger children at four weeks old. Ending2: Children should then be encouraged to keep their teeth neat, and their teeth free from plaque. If you have a dental child, encourage them to do this every day or every two years. Ending3: Lean your child against your lap or arms. Using a small toothbrush, take a rice-sized amount of fluoride toothpaste, and gently brush the child's teeth. Ending4: [substeps] It's best if two or more children attend the dentist twice a year to ensure proper maintenance. Make sure to follow any medications your child is taking before your first appointment.

Answer format: ending1/ending2/ending3/ending4