OBJECTIVE: To evaluate the effect of desensitising agents on human dentine morphology and composition. METHODS: Randomly assigned human coronal-dentine specimens were subjected to: (a) no treatment (smear-layer control, n=4); (b) acid etching with 6% citric acid (demineralised control, n=4); (c) treatment with desensitising agents (12 cycles of 60 s treatment with 60 s between-treatment rinsing, n=6 per agent); and (d) exposure to acidic challenge (pH 5.0 for 90 s, n=6 per agent). The tested products were: Listerine® Advanced Defence Sensitive (LADS; 1.4% potassium oxalate) mouthrinse, Colgate® Sensitive Pro-Relief™ mouthrinse, and toothpaste slurries (paste/water 1:2 wt/wt ratio) of Colgate® Sensitive Pro-Relief™ paste, Crest® Sensitive paste and Sensodyne® Repair and Protect paste. All dentine surfaces were studied by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman microscopy and high vacuum scanning electron microscopy with energy-dispersive X-ray microanalysis (HV-SEM/EDX). RESULTS: Desensitising slurry treatments occluded tubule orifices of acid-etched dentine, creating a randomly distributed surface pattern of particle aggregates. The greatest intratubular penetration of occluding particles was found in dentine treated with LADS. The atomic ratios of Ca/N and Ca/P, and the mineral/matrix ratios increased after toothpaste-slurry treatments compared with the acid-etched dentine. However, the acidic challenge removed most surface precipitates and further demineralised these substrates. Before the acidic challenge, the surface features were least affected in specimens treated with Sensodyne® Repair and Protect. After the acidic challenge, the sub-surface occlusion features were least affected in specimens treated with LADS. CLINICAL SIGNIFICANCE: Although most tested products achieved occlusion of dentinal tubules and provided evidence of mineral deposits, the deposit formed by LADS demonstrated the greatest resistance to acidic challenge, which simulates intra-oral demineralisation phases.
n class="abstract_title">OBJECTIVE: To evaluate the effect of desenpan>sitisinpan>g agenpan>ts onpan> class="Species">human dentine morphology and composition. METHODS: Randomly assigned human coronal-dentine specimens were subjected to: (a) no treatment (smear-layer control, n=4); (b) acid etching with 6% citric acid (demineralised control, n=4); (c) treatment with desensitising agents (12 cycles of 60 s treatment with 60 s between-treatment rinsing, n=6 per agent); and (d) exposure to acidic challenge (pH 5.0 for 90 s, n=6 per agent). The tested products were: Listerine® Advanced Defence Sensitive (LADS; 1.4% potassium oxalate) mouthrinse, Colgate® Sensitive Pro-Relief™ mouthrinse, and toothpaste slurries (paste/water 1:2 wt/wt ratio) of Colgate® Sensitive Pro-Relief™ paste, Crest® Sensitive paste and Sensodyne® Repair and Protect paste. All dentine surfaces were studied by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman microscopy and high vacuum scanning electron microscopy with energy-dispersive X-ray microanalysis (HV-SEM/EDX). RESULTS: Desensitising slurry treatments occluded tubule orifices of acid-etched dentine, creating a randomly distributed surface pattern of particle aggregates. The greatest intratubular penetration of occluding particles was found in dentine treated with LADS. The atomic ratios of Ca/N and Ca/P, and the mineral/matrix ratios increased after toothpaste-slurry treatments compared with the acid-etched dentine. However, the acidic challenge removed most surface precipitates and further demineralised these substrates. Before the acidic challenge, the surface features were least affected in specimens treated with Sensodyne® Repair and Protect. After the acidic challenge, the sub-surface occlusion features were least affected in specimens treated with LADS. CLINICAL SIGNIFICANCE: Although most tested products achieved occlusion of dentinal tubules and provided evidence of mineral deposits, the deposit formed by LADS demonstrated the greatest resistance to acidic challenge, which simulates intra-oral demineralisation phases.