pacifier question

my 3 week old has just started to become super cranky. she sleeps okay during the night, but now however it doesn't seem like she wants to be put down... I have another child so I'm not just having to tend to one child... I have a pacifier on stand by just in case... I'm just not sure if I should give it to her. my first didn't use one... I don't want it to effect her teeth and don't want dependence on it. I also nurse... and she seems to want to suck but she spits up quite a lot. please any advice is welcome...