Photothermal Effect and Biomineralization of Black Phosphorus Nanosheet-Composited Hydrogel Boosts Synergistic Treatment of Dentin Hypersensitivity

Dentin hypersensitivity (DH), marked by exposed dentinal tubules, presents as a sharp toothache triggered by stimuli and subsides when the stimuli are removed. To address the limitations of current commercial desensitizers in terms of acid resistance, friction resistance, and stability, a black phosphorus nanosheet-composited methacrylate gelatin hydrogel (GelMA/BP) is developed for DH treatment, leveraging the synergistic effects of photothermal therapy and biomineralization. Incorporating the BP nanosheet provided GelMA/BP with a stable photothermal response and the continuous release of phosphate anions, which blocked dentinal tubules by converting light energy into heat and initiating biomineralization. In vitro desensitizing therapy showed that the dentinal tubule diameter in the GelMA/BP50 group (0-1.13 µm) is significantly reduced compared to that in the DH-model group (0-3.14 µm). The GelMA/BP50 group achieved an 86% tubule occlusion rate, with acid resistance of 80%, friction resistance of 76%, and long-term stability of 74%. In vivo studies further validated the efficacy of GelMA/BP50, showing a reduction in tubule diameter (0-0.37 µm) and an occlusion rate of 79%, which alleviated toothache and increased intake and weight. These results demonstrate that this desensitizing hydrogel acts as an effective dentinal tubule sealant, offering promising clinical benefits for the topical treatment of DH.