Comparison of Cervical and Mid Coronal Dentine Using a Desensitizing Bioactive Glass Toothpaste: A Pilot Study

Aim: The aim of the present studywas to compare the effect of a calcium sodium phosphosilicate (NovaMin®) desensitizing agent (a bioactive glass) on both cervical and midcoronal dentine sections using scanning electron microscopy (SEM). Methods: Sections of both cervical and mid coronal dentine were prepared and etched with 5% citric acid for 5 minutes; these sections were then brushed with 2mg of Sensodyne Repair and Protect (NovaMin®) for 2 minutes with a powered toothbrush (Oral B, Braun) and left in artificial saliva (AS) for an hour at 37o degrees. One group, a control, was brushed only with distilled water and another group was subjected to a one-minute acid challenge with 5% citric acid. Samples were then prepared for anaylsis with SEM. Results: The dentinal tubules identified on the root surface were narrower and less numerous compared to a mid-coronal section. In the test group, there was evidence of bioglass occlusion in 100% of the tubules after treatment.After the acid challenge approximately 6% of tubules were not occluded at all and 42% were only partially occluded with less than 50% of the diameter of the tubule closed. Conclusions: The bioactive glass toothpaste (NovaMin®) appeared to occlude all of the dentinal tubules by more than 50% of their diameter and partially resisted an acid challenge on the cervical dentine section. The use of a cervical dentine section appeared comparable to the images of mid coronal dentine and would be more relevant for the evaluation of potential desensitizing products in the treatment of Dentine hypersensitivity. The sectioning of cervical dentine however may be more challenging than the sectioning of mid coronal dentine.