Abstract
INTRODUCTION AND AIMS: This study aimed to investigate the distribution and morphology of cracks in natural cracked teeth and evaluate the potential of self-assembling peptide hydrogels (L-gel: Nap-FFG-DHTKE and D-gel: Nap-(D)F(D)FG-DHTKE) as biomimetic "bioglues" for crack repair. METHODS: Cracked teeth were examined using root canal microscopy and scanning electron microscopy (SEM). The hydrogels were synthesized and tested for gelling and mineralization potential. Demineralized and cracked enamel specimens were treated with L-gel, D-gel, deionized water, or sodium fluoride (1000 ppm). Mineralization was assessed via SEM, X-ray diffraction (XRD), energy-dispersive spectrometry (EDS), and nanoindentation. The biocompatibility of the hydrogels was evaluated using CCK-8 assays and Calcein/PI staining. RESULTS: A total of 156 cracks (3-4 mm long) and 177 cracks (1-3 μm wide) were identified. SEM revealed distinct crack propagation patterns. Both hydrogels showed stability and mineralization potential, with L-gel group exhibiting denser crystal deposition and a more enamel-mimetic surface after 7 and 14 days of treatment. XRD and EDS confirmed hydroxyapatite (HAP) crystal formation with a natural HAP-like calcium-to-phosphorus ratio. Nanoindentation tests showed comparable microhardness and Young's modulus to natural enamel. L-gel effectively sealed cracks with uniform crystal growth over a 14-day period, while D-gel formed sparse deposits. Both hydrogels were biocompatible at concentrations below 500μM. CONCLUSION: Self-assembling peptide hydrogels, particularly L-gel, demonstrate promising potential for hard tissue regeneration and crack repair in teeth due to their effective mineralization potential, biocompatible nature, and ability to mimic natural enamel structure. CLINICAL RELEVANCE: A thorough analysis of tooth cracks is crucial for developing targeted and effective repair strategies. Self-assembling peptide hydrogels offer a promising approach for enhancing clinical outcomes in dental crack repair and hard tissue regeneration.