When it comes to dealing with pet rat tooth care and teeth issues, hopefully there's not going to be anything that you need to do. As long as your rat has normal dentition, normal teeth alignment, and not any dental problems, there isn't much that you should ever have to do with their teeth. They don't require routine trimming, they don't require any type of routine care, unless there's a problem.
One of the problems that we sometimes see, are rats that are born, or develop malocclusions, where the front incisor teeth don't line up. And in this case, because their teeth are constantly growing throughout their lives, the teeth won't wear down normally, and may overgrow. In this instance, the teeth are either going to have to be trimmed at regular intervals, or they're going to have to go through a permanent removal of those front incisor teeth.
As I mentioned, rat teeth generally are continuously growing through life, by nature of the way that they eat, and the way that they consume certain foods, especially rodent block type foods. They'll keep their teeth worn, they'll wear them down normally, and a normal, healthy rat will not require any type of routine dental care.