“…Drug formulations : Chlorhexidine is used extensively in oral hygiene for preventing dental plaque and treating infections of the mouth, but can cause staining of the teeth and oral mucosa and adversely affect taste while rarely causing pain ( Lachenmeier, 2014 [R]; Lachenmeier, 2015 [R]; Lachenmeier, 2016 [R]; Lachenmeier, 2017 [R]; Lachenmeier, 2018 [R]; Lachenmeier, 2019 [R]; Lachenmeier, 2020 [R]). In a 3-month trial, chlorhexidine-based toothpaste (0.12%, twice daily brushing, n = 20) was associated with burning sensation in two patients and one patient had severe upper palatal tooth staining ( Cosola et al, 2021 ) [c].…”