Maxillary expansion using a miniscrew retained expansion device during lingual orthodontic treatment

Abstract

A deficiency in transverse basal development of the maxilla can lead to an arch length and/or a width discrepancy. Limited alveolus bone volume, which directly depends on the underlying basal bone, creates an upper dental arch that is too narrow in relation to the lower arch creating unilateral or bilateral posterior crossbite(s). The cause of this maxillary deficiency is often related to abnormal nasal breathing associated with abnormal tongue function that compromises the volume of expansion of the maxilla during the growth period. The two maxillary bones determine the volume of the alveolar bone, and also the volume of the inferior area of the nasal fossae due to their palatal processes, worsening nasal breathing, which is often already deficient. Treating this maxillary deficit can require a surgical-medical case management of malfunctions by an ENT which can possibly involve maxillary expansion performed orthopedically before the mid-palatal suture becomes ossified in children (synostosis at approximately 15 years of age), or done as a surgically-assisted procedure for adults. Classically, the expander transmits, by the intermediary of the dentition, horizontal forces which make it possible to progressively expand the two halves of the maxilla by distraction and thus progressively to create bone and soft tissue on the median zone of the palatal processes of the maxilla. This type of expander usually causes no problems for adults who receive orthodontic treatment using traditional dental brackets because the dental pressure of the expander uses the same braces that are supporting the brackets placed on the posterior teeth. It is a very different matter when using the lingual technique whose additional cost and complexity is justified when the patient demands esthetic treatment. The use of a classic expander that is attached to the palatal surfaces of first molars will interfere with the system of lingual bonding, which is located on these same surfaces. Therefore, it is difficult to simultaneously perform both treatments.