If you want a toothbrush that gives you real-time feedback and works even when your phone is out of reach, Kolibree could be a good option. Its smart toothbrushes, like the hum and hum Kids, use AI and Offline Mode to offer personalized feedback and interactive brushing experiences. Even without your phone, the toothbrushes offer detailed feedback to help you brush better, the way dentists recommend.
Another good option is Private LLM, an AI chatbot for iOS and macOS that works offline. It's not a toothbrush, but it offers a variety of features like AI-powered language services and a private, local assistant that doesn't need a network connection. That could be a good way to get general oral hygiene tips and advice without sharing your data.