I've routinely checked the dogs' teeth since day one. Last time I checked Mya's teeth they looked normal, nothing loose or broken. Its been almost 2 weeks since I last checked. Today I checked her teeth and the lower "eye tooth" is a grayish brown color. Its a puppy tooth as she hasn't lost those yet. I've pushed on it gently and its not loose, far as I can tell its not chipped, broken or painful. But I've never seen a puppy tooth look that way, even before its ready to fall out. Is it decaying? Getting ready to fall out? What could the cause be?