In-depth Occlusion of Dentinal Tubules Induced by Polyaspartic Acid-Calcium and Magnesium Complexes

Dentin hypersensitivity has been widely recognized to be caused by patent dentinal tubules (DTs). A polyaspartic acid-calcium and magnesium (PAsp-Ca&Mg) complex process has been demonstrated to induce biomimetic mineralization of collagen fibrils. This study investigated the in vitro and in vivo occlusion of the DTs by a PAsp-Ca&Mg complex process. Dentin disks were treated by citric acid to open the DTs and randomly divided into 4 groups. Two experimental groups (n = 18) were applied with PAsp-Ca&Mg suspension and phosphate solution or phosphate-fluoride solution in sequence for 10 min. Two positive control groups (n = 18) were treated with Gluma or Duraphat. All the dentin disks were incubated in artificial saliva for 24 h. DT occlusion was characterized by scanning electron microscopy, and dentin permeability measurement was conducted regardless of being subject to abrasive or ultrasonic and acidic challenge. The incisors of 3 New Zealand rabbits were used to verify the in vivo occlusion of the DTs. In vitro and in vivo results demonstrated in-depth occlusion of the DTs to ~100 μm by the PAsp-Ca&Mg complex process. When compared with control groups, the PAsp-Ca&Mg complex process could significantly reduce dentin permeability (P < 0.05) irrespective of abrasive or ultrasonic and acidic challenge. The PAsp-Ca&Mg complex process not only deeply occluded patent DTs but also significantly decreased dentin permeability and provided a paradigm for ion-doped DT occlusion. This provides a promising strategy for managing dentin hypersensitivity.