text: Although it is commonly believed that using a pacifier will lead to dental problems, it does not appear to lead to long-term damage if used for less than around three years. However, prolonged use of a pacifier or other non-nutritive sucking habit (such as finger or blanket sucking) has been found to lead to malocclusion of the teeth, that is teeth sticking out or not meeting properly when they bite together.  This is a common problem and the dental (orthodontic) treatment to correct it can take a long time and can be expensive.  A Cochrane Review of the evidence found that orthodontic braces or psychological intervention (such as positive or negative reinforcement) were effective in helping children stop sucking habits where that was necessary. An orthodontic brace that used a palatal crib design seems to have been more effective than a palatal arch design.
  There appears to be no strong evidence that using a pacifier delays speech development by preventing babies from practicing their speaking skills.
  Benefits
  Researchers have found that use of a pacifier is associated with a substantial reduction in the risk of sudden infant death syndrome. They are divided over whether this association is sufficient reason to prefer pacifier use. Some argue that pacifiers should be recommended on the strength of an association, just as back sleeping was recommended on the strength of an association. Others argue that the association is not strong enough or that the mechanism is unclear.
  Pacifiers have also been found to reduce infants'  crying during painful procedures such as venipuncture.
  Some parents prefer the use of a pacifier to the child sucking their thumb or fingers.
  Researchers in Brazil have shown that neither "orthodontic" nor standard pacifiers prevent dental problems if children continue sucking past the age of three years.