Perception of xerostomia was assessed using the Visual Analogue Scale (VAS) validated for patient satisfaction by Brokelman et al. . The following guiding question was used: “how dry do you feel your mouth?”. The measurement was performed on a scale from 0 to 10 through which patients indicated the number related to their perception of oral dryness. Values 0–3 indicated none/mild dryness, 4–7 moderate and 8–10 severe.