A toothbrush stands for daily upkeep and how you present yourself to others. Sharing one, or losing it, is traditionally read as questions about closeness and personal boundaries.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.