Correction of unilateral crossbite in the deciduous dentition

SUMMARY A method for correcting unilateral crossbite in the deciduous dentition was tested in 25 young children. A composite guiding cusp was constructed on the buccal side of the upper canine or first or second primary molar on the crossbite side. This prevented the patient from biting into crossbite. Premature contacts between canines and primary molars were roughly ground without articulating paper. A new biting habit in which the midlines of the dental arches coincided was taught to the patient with the aid of a mirror. Reactions were studied by clinical examinations and by comparing models at the start of the treatment and six months later. The width of the dental arch was measured at the canines and first and second primary molars. The patients had learned the new biting habit after a month, and the upper dental arch was widened spontaneously by about 1.4 millimetres after six months. All crossbites were successfully treated and the first permanent molars erupted in the correct transverse relationship. The method seems suitable for the correction of unilateral crossbite in the deciduous dentition provided that the cause of the crossbite (dummy-sucking, thumb-sucking) is no longer present at the start of the treatment. Furthermore the method is obviously not efficient in cases of genuine mandibular prognathism