Rather than make the debuff only removable by brushing teeth, which forces the player(s) to brush their teeth and no amount of food, reading, booze or other actions removing it:

Have Brushing your teeth reduce stress by -5 points or increase Happiness by +5. Similar to smoking or eating a good meal. Toothbrush alone is -5. Toothbrush AND toothpaste is -10.

This would allow brushing teeth to be fully optional, but a simple alternative if making a meal, or reading a book is not an option.

THEN, have a -2 Happiness and +2 Stress accumulate. But just have it add up, so if they choose to eat food, read a book, smoke, drink, etc. it still goes away just like any other source of unhappiness/stress.

I believe this would give brushing teeth a good RP function, but not focus gameplay on always having a toothbrush and toothpaste on hand 24/7.

Example: After a long day of crafting and your character getting depressed, brushing your teeth reduces that by -10, so you go from Severely depressed to depressed. Not a major improvement, but still something that cheers you up a bit for having a self care day.

Brushing Teeth, reading a book, and watching TV, all reducing stress could make for really fun RP where you cheer up completely by hanging out, relax at your base, and just clean up.

Thank you for reviving this mod! Looking forward to having it on my server!