To evaluate the effects of treatment of posterior crossbite (PXB) in the mixed dentition with the Function Generating Bite (FGB) appliance on the transverse dimension of the dental arches.

Materials and Methods

This study included 84 PXB patients (female = 46; male = 38; mean age, 8.2 ± 1.8 years) and 69 control (C) patients (female = 31; male = 38; mean age, 8.9 ± 1.4 years). Measurements were taken with digital calipers on maxillary and mandibular study casts before (T0) and after (T1) treatment for the following measures: intermolar (IMD), intermolar gingival (IMGD), intercanine (ICD), and intercanine gingival distances (ICGD).


At T0, there was a significant difference in all maxillary measurements between the PXB and C groups (P < .001), reflecting maxillary hypoplasia in PXB patients. At T1, there was no difference between the groups. In PXB patients, the mean increase between T0 and T1 for IMD was 4.34 ± 2.42 mm; this difference measured 3.51 ± 2.19 mm for IMGD, 2.78 ± 2.37 mm for ICS, and 1.89 ± 1.7 mm for ICGD. There was no significant difference in mandibular measurements between groups at T0 and T1.


Functional therapy with FGB is effective in significantly increasing the transverse dimension of the maxillary dental arch in PXB patients. Considering its efficacy in treating masticatory dysfunction, FGB may be considered a good treatment option for the correction of PXB in growing children.

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Author notes


PhD Student, Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy.


Professor, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Dental School, University of Brescia, Brescia, Italy.


Professor, Department of Biotechnological and Applied Sciences, University of L'Aquila, L'Aquila, Italy.


Private Practice, Turin, Italy.


Professor, Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy.