I bought the HealthyMouth gel - great company, definitely pricey though. I considered the water additive but wasn't sure Jackson would drink it so opted for the gel. I can't say I've seen a significant difference, because I started it after his professional cleaning... so they are still very shiny white. But I do use it once a week or so. He tolerates it well, but the tube is sooo tiny and for $60, it just seems like so little.
