"Chibiusa's Picture Diary Chapter 3 - Beware of Cavities" is the 3rd chapter of the Chibiusa Picture Diary series from the Pretty Soldier Sailor Moon manga. It is written and illustrated by Naoko Takeuchi.
Usagi and Chibiusa have both developed cavities and had to visit the dentist - but all the staff at the dentist's office were really evil spirits determined to make the cavities worse.
The original version of the manga simply called this "Chibiusa's Picture Diary" (ちびうさ絵日記, Chibi Usa Enikki) but the re-release of the manga gave it the title "Beware of Cavities" (虫歯にご用心!, Mushiba ni Goyoujin!).