The effect of different desensitizing strategies on eroded dentin: ex vivo study

Introduction: Conditions like gastroesophageal reflux disease, eating disorders, chronic alcoholism and others promote the contact of gastric acid (HCl) with the oral cavity, resulting in dental erosive lesions [ 1 ]. Study hypothesis: there are no differences on the microscopic aspect of eroded superficial and deep dentin after using two different desensitizing toothpastes. The aim of this study is to evaluate microscopic characteristics of eroded superficial and deep dentin when exposed to desensitizing toothpastes. Materials and methods: Sample was obtained from 2 human molars (intact, caries/fracture-free). Each tooth was sectioned in eight parts (4-superficial dentin and 4-deep dentin), giving rise to 16 dentin specimens, randomly assigned in 4 different groups which were divided into 2 subgroups (superficial (s), n = 2 and deep (d), n = 2): Group A s and A d - sound dentin; Group B s and B d - Intrinsic erosive challenge (ec) with HCl at pH 2,6 for 60s; Group C s and C d - ec and toothbrush, two minutes, twice a day, seven days with stannous fluoride toothpaste; Group D s and D d - ec and toothbrush, two minutes, twice a day, seven days with strontium chloride toothpaste. Dentin surface was analyzed with scanning electron microscopy, with magnifications of 1000×, 5000× and 10000×. The study was approved by the Ethics Committee for Health, of Egas Moniz (Reference Number: 523). Results: On superficial dentin: partial and heterogeneous occlusion of the tubules was observed in group D s ; in group C s there was no tubule occlusion. On deep dentin samples, partial tubule occlusion was observed in groups C d and D d , higher on group D d . Discussion and conclusions: Qualitative analysis of scanning electron microscopy images suggests that Strontium Chloride based toothpastes are capable of promoting a greater dentinal tubule occlusion. The use of Stannous Fluoride toothpaste showed less favorable results, with tubule occlusion occurring only on deep dentin.