Tabriz University of Medical Sciences Journal of Dental Research, Dental Clinics, Dental Prospects 2008-210X 19 4 2025 12 31 Effect of polyacrylic acid pretreatment before CPP-ACP application in remineralization of demineralized root dentin: An in vitro study 227 232 10.34172/joddd.025.43997 EN Arezoo Ghasemi https://orcid.org/0009-0006-1275-3183 Elmira Jafari Navimipour https://orcid.org/0000-0002-2611-0326 Soodabeh Kimyai https://orcid.org/0000-0003-0703-5479 Parnian Alizadeh Oskuee https://orcid.org/0000-0002-6081-0115 Mehdi Daneshpooy https://orcid.org/0000-0002-1549-2488 Ziba Islambulchilar https://orcid.org/0000-0001-7037-4436 Sevda Riyahifar https://orcid.org/0000-0001-5197-1761 Journal Article 10.34172/joddd.025.43997 2025 08 10 2025 12 22 Background. This study evaluated the efficacy of polyacrylic acid (PAA) pretreatment before application of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) in remineralizing demineralized root dentin. Methods. Thirty-nine dentin specimens from extracted human third molars were prepared. All the specimens were standardized for Vickers microhardness at baseline (VHNba). Then the specimens were randomly divided into three groups (n=13): (1) untreated demineralized dentin, (2) CPP-ACP treatment, and (3) PAA pretreatment before CPP-ACP application. All the specimens were subjected to 72 hours of demineralization. Subsequently, treatments were administered according to group protocols and a 28-day pH-cycling regimen. Then, Vickers microhardness (VHN) was assessed after demineralization (VHNde) and after treatment (VHNre). The difference between VHNre and VHNde was calculated as ΔVHN and compared between the groups. Data were analyzed using one-way ANOVA, repeated-measures ANOVA, and post hoc Bonferroni tests (P<0.05). Results. Demineralization significantly decreased dentin microhardness in all the groups (P<0.001). In contrast, microhardness values increased significantly after applying the treatment protocol (P<0.001). Specimens that received PAA pretreatment before CPP-ACP application showed a considerably higher ΔVHN than those treated with CPP-ACP alone (P<0.0001). However, neither group returned to the initial values. Conclusion. Applying CPP-ACP, either alone or after pretreatment with PAA, increased the microhardness of demineralized root dentin and promoted remineralization. Pretreatment with PAA enhanced this remineralization effect, suggesting its potential use in conservative dentin treatment strategies.