This was an episode that I wasn't able to see until months after making my Season-end list, and that's really unfortunate. I think this could've been a contender for Top 10 of the Season, it was yet another great episode!
While the general themes of going to the dentist even when you're scared, and the theme of letting go of childhood memories for a better future are both themes that have been done a number of times before on children's books and TV shows, SpongeBob's twist on it is one I imagine resonating with kids for multiple reasons. First, SpongeBob really stuck up for Patrick by finding the perfect balance between being caring and emphasizing with Patrick's attatchment to the baby tooth, and being firm enough to have him let it go. Second, personifying Patrick's baby tooth was really adorable, and was contrasted with how much pain his toothache is giving him. Lastly, the ending is one of the most hilarious highlights in the entire Season. (The Tooth Fairy is actually a "Ferry" for transporting teeth to Tooth Island, such an excellent pun that the episode went all-out with. Also Squidward had to eat a bucket of chum because he lost a bet xD)
The rest... it's standard, the scene where Patrick gets chased down by worms wasn't anything new, but the story's still constantly on the move with locations, memories and an overall storybook sweetness that I think younger kids will really enjoy--it keeps the magic of the Tooth Fairy alive while still keeping SpongeBob's style, I think children will really want to go to the dentist after watching this. None of it feels remotely malicious, Patrick's a lovable if dim-witted child that's justifiably scared, and SpongeBob's a reasonable, kind guide to help him grow as a character.
Also, the animators once again proved how awesome they are. Just look at this gallery showing how many diverse hand-painted backgrounds, fluid movements and colorful designs, the personification of the teeth, and the animation sequences just for the sake of adding visual humor were all excellent as usual. Bonus points for the Dentist radio making fun of the background music score. <3
Grade: "A-" (It'd be around the Top 15 for the Season as a whole)