Tracing template used in this study: the red line in the maxillae connecting the anterior and posterior nasal spine (ANS-PNS line) represents the maxillary plane reference (MxPl); the red line in the mandible connecting the menton and the gonion (Me-Go line) represents the mandibular plane reference (MnPl); the yellow line in the maxillae is the line bisecting the maxillary residual ridge; the yellow line in the mandible is the line bisecting the mandibular residual ridge. The angles in green represent the maxillary and the mandibular incisal inclination adopted from dentate tracing.