Primary Failure of Eruption: A Rare but Desperate Condition for Orthodontic Treatment.

Tooth eruption is a highly complex mechanism that is controlled by many factors. Various mechanical, systemic, or genetic factors can cause eruption disorders. Primary failure of eruption (PFE) is known as an eruption disorder occurring due to non-syndromic genetic factors. It is frequently seen in the first and second molars and causes posterior open bite. It can be observed unilaterally or bilaterally. Studies show that mutations in many different genes that control the tooth eruption mechanism, mainly the PTH1R and KMT2C genes, constitute the genetic basis of PFE. Primary eruption disorders are very difficult to treat. It is known that the application of active orthodontic forces causes local ankylosis in the tooth and the failure of the tooth to return to its normal position. For this reason, determining the correct diagnosis and treatment method is very important. Although there are different treatment methods, the results of research about the success of these treatment methods are quite limited. This review aims to explain the etiology, diagnosis, and treatment of PFE in light of current genetic studies.