Inclusion Criteria:  absence of systemic pathologies (ASA class I); not pregnant or lactating; good oral hygiene; with ≥1 sensitive tooth with exposed dentin on upper or lower dental arches; contemporary presence of exposed dentin both on the left and right counterpart of upper or lower arch.  Exclusion Criteria:  domestic or in-office professional fluoride application and bleaching 6 months before beginning of treatment; long-term use of anti-inflammatory, analgesic and psychotropic drugs; eating disorders, systemic conditions that cause or predispose patients to develop dentin hypersensitivity (for example, Gastroesophageal reflux disease); periodontal surgery and within the previous three months before the study; orthodontic treatment within the previous three months before the study.