I do mean any statistics -- some controlled experiments, sieving through surveys, anything. I'm constantly being told old wives' tales by friends and old doctors' tales by doctors. I'm not asking for well-done science here, just if anybody has investigated anything at all -- any data.
A study done in 2001 ended with the conclusion:
The study found that prolonged pacifier habits resulted in changes to the dental arches and the occlusal parameters that were different from the effects of digit sucking.
This is not to say that the changes to the dental arches were positive or negative, but that there most certainly was an impact. Note that "digit sucking" means thumb sucking.
Another study had similar results:
On the grounds of this study we conclude that prolonged pacifier-sucking (≥2 years) and use of a nursing bottle at night are risk factors for dental caries in children.
Length of how long pacifier is used matters:
While continuous nonnutritive sucking habits of 48 months or longer produced the greatest changes in dental arch and occlusal characteristics, children with shorter sucking durations also had detectable differences from those with minimal habit durations.
There seem to be no shortage of studies done in this matter.