| Summary: | Dentine hypersensitivity (DH) affects up to 57% of patients following exposure of unoccluded dentine tubules. However the aetiology is incompletely understood. These studies investigated the association of DH to tooth wear. A prevalence study investigated risk factors associated with tooth wear and DH on all tooth surfaces in 350 subjects aged 18-35 in SE England. Sextant cumulative scores for DH and tooth wear were validated and positive correlations existed between both (p < 0.0001). Two randomised, single blind in situ studies investigated the degree of dentine tubule occlusion provided by desensitising dentifrices following four days of twice daily brushing with agitated acid challenges on days three and four. In the first in situ study involving 28 healthy subjects, samples were imaged daily using Scanning Electron Microscopy (SEM) and graded using a ‘standard’ visual ordinal scale. On days one and two, an 8% strontium acetate and 8% arginine based desensitising dentifrice demonstrated more occlusion than control paste (p < 0.0001) and water (p < 0.0001, p = 0.0003). On day four, strontium demonstrated more occlusion than all other treatments (p < 0.0001). In a second in situ study involving 30 subjects, an innovative computerised and imaging method was created and validated to quantify tubule occlusion. Samples were imaged with Tandem Scanning Microscopy (TSM) and then SEM. Intra-class correlation of the number of un-occluded tubules counted visually and then by the computational analysis on 10% (n = 47) randomised SEM or TSM images was > 0.8. Positive Spearman correlations existed between the visual ordinal ‘standard’ and the SEM (r = 0.58) and TSM (r = 0.42) computational analyses (p < 0.001, n = 469). At day four, the TSM computational analysis and the ‘standard’ showed that an experimental dentifrice containing 5% calcium sodium phosphosilicate produced more occlusion than controls (p < 0.0001). These studies refute the null hypothesis that there is no association between DH, tooth wear and the patency of the dentine tubules. Accurate techniques were developed to measure DH.
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