**2.1 Prevalence of dentine hypersensitivity**

The published prevalence figures for dentine hypersensitivity range from approximately 1% to over 70% depending on how the figures are collected. For example, data from questionnaire studies report a higher prevalence of the condition, whereas data from clinical studies that examine the patient provide lower prevalence figures. The information from these types of studies may also depend on the location (university or hospital clinics, general dental practice, or specialist practice such as restorative or periodontics) and the country or culture of the population. For example, the traditional prevalence figures for DH *per se* are estimated to be 10% with an average of 33% across studies as reviewed by Cuhna-Cruz and Watana [11], whereas the prevalence figures for root sensitivity (RS) due to periodontal disease or its treatment is considerably higher (60–98% [12, 13]). DH/RS may therefore affect individuals over all age groups; however, from the literature, the peak prevalence is between the ages of 30 and 60 years with females numerically more affected than males [12]. There is also evidence from the published studies that the buccal (facial) tooth surfaces are most likely to be affected and there appears to be an association between DH/DS and gingival recession. According to the West et al.'s [14] study in young European adults aged 18 to 35 years, there is a link between a so-called healthy erosive diet, lifestyle and tooth wear with DH/RS.
