Gappy, uneven and sharp teeth in babies

When my little girl started getting her teeth the bottom two came in first followed by the top two (central incisors) they both appeared within a week of each other. When her top two came through there was a huge gap between the two and I was a little shocked. She started using a dummy since she was little but only uses it for her naps and bedtime she doesn't use it during the day, I thought this might be the reason for the big gap. My niece sucks her thumb and she too has a big gap so I was beginning to think that there was a link.