After some after some advice please. My 20 month old will not let me brush his teeth. Im getting so stressed every night over it now. He clamps his mouth shut and I cant even get the brush in. Tried everything him brushing my teeth, giving him a toothbrush, trying to make it fun. His teeth are starting to look yellow and I know its due to not being brushed properly. I don't know what to do, any help??