Functional Remineralization of Dentin using Polymer Induced Liquid Precursors (PILP) and Biocem

Author(s): Girn, Vishavjeet | Advisor(s): Habelitz, Stefan | Abstract: Purpose: Functional remineralization (FR) of carious dentin requires recovery of the mineral content and mechanical properties. FR by the polymer-induced liquid-precursor (PILP) process has been demonstrated in the laboratory by using polyaspartic acid (pAsp). This study compares the ability of Biocem cement (NuSmile, Houston, TX, USA), Biocem modified with pAsp (20% and 40%), Fuji I and Fuji IX glass ionomers (GC Corp., Tokyo, Japan) in their ability to restore the mechanical properties of demineralized dentin matrix in artificial lesions. Methods: Artificial lesions were created by solution consisting of 0.05 M acetate buffer containing 2.2 mM calcium phosphate and adjusted to pH 5.0 for 66 hours. The lesions were rehydrated and treated in 5 groups: Biocem only, Biocem + 20% pAsp, Biocem + 40% pAsp, Fuji I, and Fuji IX (n=3) and then left to remineralize for 2 weeks. A group consisting of Biocem only, Biocem + 20% pAsp, Biocem + 40% pAsp was also remineralized for 6 weeks. The shrinkage after dehydration (indicating remineralization) was measured and compared. Results: For 2 weeks, the shrinkage was not reduced by Biocem only treatments, but was reduced by 54% (Pl0.01) and 75% (Pl0.01) with 20% or 40% pAsp added respectively. Fuji I and Fuji IX reduced shrinkage by 24% (Pg0.05) and 40% (Pl0.05), respectively. For 6 weeks, the shrinkage was not reduced by Biocem only or Biocem + 20% pAsp treatments, but Biocem + 40% pAsp reduced shrinkage significantly by 31% (Pl0.02). Conclusions: Results from 2 and 6 weeks of remineralization show addition of pAsp may enhance Biocem cement functionality by inducing FM. Further research is needed to demonstrate FM of dentin lesions from the laboratory to the clinic.