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.