We do heartgard and nexgard. Tried simparico trio but gave one dog very bad diarrhea, so stopped even though it was the most convenient. Also tried bravecto but since it’s every 3 months it was hard for us to remember to give/reorder. If teeth are the issue, maybe try smashing the heartgard up in a little unsalted peanut butter/wet food. We do that because one dog won’t eat it otherwise.