I love dogs and have lived with them most of my life. I was brought up with Staffies, which in my youth were more like pit bulls. When we had our children we had spaniels which are far more user friendly and have softer mouths. However ALL DOGS HAVE TEETH! And since they have no hands they are far more likely to use them. My grandchildren live with their own well adjusted spaniels who know and adore them but they are always kept an eye on and supervised, especially when other children come to play.
My mother, now 88, still lives with the latest in the line of Staffies. It's a sore point with her that her 10 year old Staffie isn't allowed to meet the little ones. She can't understand that her beloved dog, who (she says) wouldn't hurt a fly, leads a very quiet life and doesn't know toddlers and is therefore likely to react unpredictably, isn't allowed near them. Staffies have abnormal jaw muscles so the smallest snap is going to scar. They've also been inbred to have short noses, so the soft pallet causes breathing problems, and overheat in warm weather which can make nervy ones short tempered. Too often people buy dogs with no knowledge of what they are taking on.
Littlenellie that dog should be put down. Vicious dogs are rarely happy dogs - and neither are the people who have to live with them.
Sorry I've gone on a bit.