“…When these conditions are met, the scale is considered internally consistent . Contrary to what was reported by the developers of the NTST, our assessment of its internal consistency showed that this scale is not homogeneous; its overall internal consistency is poor, half of its items do not have a similar item–test correlation, one item presents a lower than recommended item–test correlation (i.e., 0.30), and two items (i.e., lip posture at rest and frenulum thickness) are inversely correlated with the scale formed by all other items…”