Table 1.

Heterogeneity between studies

Heterogeneity of studies
Variables	List
Different study designs	Retrospective [36,44], prospective [32,34], randomised [58,64].
Different overall aims	Assessment of the molding of the nasal cartilage [27,44], molding of the alveolar possesses [40,42].
Mixed criteria for evaluating results	Landmarks on casts [26], cephalometry, facial photographs [43,44], photographs on cast [45,46], three-dimensional optical scanner on the cast [64], three-dimensional optical facial scanner [62,63].
Inadequate sample sizes	Small sample size [17,19], without control group [27].
Inconsistent follow-up period	Before the primary surgery (during the first 18 months), after the primary surgeries [22,23,26].
Heterogeneity of appliances	Hotz plate [41,43], Grayson NAM [40].
Variable age of the patient	When the appliance was used, when primary surgeries were performed.
Mixed level of surgeon experience [12]

NAM = nasoalveolar molding.