“…At the first appointment (T0), patients were asked to sign the informed consent document to participate to the study. An instructed operator collected the following periodontal clinical indexes by means of a probe (UNC probe 15; Hu-Friedy, Chicago, IL, USA): Plaque Index (PI) (values from zero to three, respectively representing no plaque, thin plaque layer, moderate plaque layer, and abundant plaque layer) [ 17 ]; Bleeding on Probing (BOP) (values from zero to three, respectively representing no inflammation with no bleeding, mild inflammation with no bleeding, moderate inflammation with bleeding on probing, and severe inflammation with tendency to spontaneous bleeding) [ 11 ]; BEWE index assessed with Intact Tooth ® smartphone application (values from zero to three, respectively representing no erosion, initial loss of surface texture, hard tissue loss less than 50%, and hard tissue loss more than 50%) [ 17 ]; Visual Analogue Scale (VAS) for dental sensitivity (values from zero to 10 referred by the patient) [ 18 ]; Schiff Air Index (values from zero to three, respectively representing no response to air stimulus, response to air stimulus but with no request of discontinuation, response to air stimulus and request of air discontinuation, and response to air stimulus perceived as painful and request of discontinuation) [ 18 ]. Then, a professional supragingival and subgingival oral hygiene procedure was conducted using a piezoelectric instrument (Multipiezo, Mectron S.p.a, Carasco, Italy) and Gracey curettes (Hu-Friedy, Chicago, IL, USA).…”