[How to push the limits in the transverse dimension? Facial asymmetry, palatal volume and tongue posture in children with unilateral posterior cross bite: a three-dimensional evaluation of early treatment].

Unilateral posterior crossbites have been reported to be one of the most prevalent malocclusions of the primary dentition in Caucasian children. Facial asymmetry due to lateral mandibular displacement in unilateral posterior crossbite, if not treated in the primary dentition period, may lead to an undesirable growth modification which results in facial asymmetry of skeletal origin. Irregular tongue function and posture have also been diagnosed as important etiological factors. Early orthodontic treatment seems to be profitable and desirable to create conditions for normal dental, functional and skeletal development of the orofacial region. Treatment success after correction of unilateral posterior crossbite in the primary dentition is highly questionable, as it is very difficult to objectively assess correction of facial asymmetry and irregular tongue function and posture in small, growing children. Although facial photography is an important diagnostic tool in orthodontics, its main disadvantage is that it represents a three dimensional subject in two dimensions. Tongue posture and function during clinical examination are difficult to assess and is therefore unreliable. Contemporary 3D diagnostics in unilateral posterior crossbite enables uninvasive, valid and objective assessment of facial morphology, palatal volume, tongue function and posture. It can, therefore, become in the future an important part of morphological and functional diagnostics in orthodontics and dentofacial orthopedics before, during and after orthodontic treatment. © EDP Sciences, SFODF, 2014.