My DS is 18mo. He still only has three teeth which we brush twice a day, he only drinks milk and water and has a healthy diet. He only drinks from a free-flow cup and never took a bottle to bed. But despite following all this I've realised today that he has a build up of what looks like plaque on his two bottom front teeth at the gum line. I tried to brush it off but it wouldn't come off. I debated trying to scrape it off with my fingernail but didn't want to hurt his gums.
I'm so upset, I'm worried this is going to affect his adult teeth and I feel like a terrible Mum. I just don't understand where I've gone wrong 