The measurements used in this study.

<p>A, Transverse and anteroposterior dimensions of the intra-arch measurements; B, tooth height measurements; C, tooth width measurements.</p

Comparison of the tooth height measurements between the plaster models and intraoral scans.

<p>Comparison of the tooth height measurements between the plaster models and intraoral scans.</p

Rapid maxillary expansion.

Intraoral photo of rapid maxillary expansion.</p

The color-coded visualization charts show the differences between the plaster models and intraoral scans after the registration process.

<p>According to the average surface differences shown in the color scale, mandibular molar regions presented discrepancies between the two models.</p

Intraoral scanners used in clinical dental practices.

<p>Intraoral scanners used in clinical dental practices.</p

Comparison of the measurements between the plaster models and intraoral scans by Bland-Altman analysis.

<p>Comparison of the measurements between the plaster models and intraoral scans by Bland-Altman analysis.</p

Shell/shell deviations between the plaster models and intraoral scans.

<p>Shell/shell deviations between the plaster models and intraoral scans.</p

Comparison of the tooth width measurements between the plaster models and intraoral scans.

<p>Comparison of the tooth width measurements between the plaster models and intraoral scans.</p

Comparison of the intra-arch measurements (transverse and anteroposterior dimensions) between the plaster models and intraoral scans.

<p>Comparison of the intra-arch measurements (transverse and anteroposterior dimensions) between the plaster models and intraoral scans.</p

Upper airway segments.

(a) nasopharyngeal airway (b) oropharyngeal airway (c) retropalatal segment of the oropharyngeal airway (d) retroglossal segment of the oropharyngeal airway.</p