Flea repellent for dogs?

Shianne • My daughter was born with Cleft Palate! TTC #2!Instagram: @shianne_parham
Hey ladies random question but what flea and tick repellent do you use for your fur babies?? I have a small 5 pound Yorkie that I can't seem to rid fleas of! I am debating on frontline plus or k9 advantix II. Any advice or input would be highly appreciated. :)