Objectives <p>The current study aims to assess the dentin bonding performance of primary molars with dentinogenesis imperfecta type II (DGI-II). Moreover, we assess the efficacy of calcium phosphate polymer induced liquid precursor (Ca/P-PILP), a biomimetic remineralization material, in improving the resin bonding performance of DGI-II dentin.</p> Materials and methods <p>Dentin specimens from normal and DGI-II primary molars were treated with either Ca/P-PILP or double-distilled water. Morphology of these dentin specimens were observed using scanning electron microscopy (SEM), and the calcium and phosphorus contents were determined by energy-dispersive X-ray spectroscopy (EDS). Micro-tensile bond strength (µTBS) analysis was conducted to evaluate the resin bonding strength of dentin.</p> Results <p>SEM results showed that compared with normal dentin, DGI-II dentin exhibited significantly fewer dentinal tubules with nearly no intact tubular structures. Meanwhile, the dentin collagen fibers exhibited disorganized arrangement and compromised structural integrity. Compared with normal dentin, DGI-II dentin displayed inferior bonding performance with resin as shown by µTBS analysis, and EDS analyses showed that DGI-II dentin contained lower calcium and phosphorus contents. After treatment with Ca/P-PILP, the calcium and phosphorus contents of DGI-II dentin were significantly increased as shown by EDS analyses, and µTBS analysis showed that the bonding performance of DGI-II dentin was improved, while no notable effect was observed in normal dentin.</p> Conclusions <p>Primary molars with DGI-II display structural defects and reduced calcium and phosphorus contents in dentin. The reduced mineral contents are partially responsible for the compromised bonding performance of DGI-II dentin, for Ca/P-PILP which effectively enhances the mineral contents of DGI-II dentin improves the resin bonding performance of DGI-II dentin.</p>