Magnesium-organophosphate bone adhesives repurposed as endodontic cements for dental applications

OBJECTIVES: This study investigated novel mineral-organic cements based on magnesium and organophosphates, originally developed as resorbable bone adhesives. The aim was to evaluate this new class of materials in a dental context, focusing on their suitability as temporary restorative materials in endodontic treatments. MATERIALS AND METHODS: Two thermally treated trimagnesium phosphate hydrates (Mg₃(PO₄)₂ ∙ xH₂O and Mg₃(PO₄)₂ ∙ 22H₂O (cattiite)) were each combined with two organophosphates (phosphoserine (OPLS) and sodium phytate (Na-IP6)), resulting in four adhesive formulations. These were compared with a commonly used material for temporary restorations (Cavit™) and a reference adhesive (TTCP + OPLS) regarding mechanical strength, sealing ability (methylene blue penetration) on bovine teeth, and structural integrity. RESULTS: Shear bond strength to dental hard tissues was significantly higher for the new cements compared to Cavit™, particularly for the OPLS + TMP ∙ xH₂O formulation (4.35 ± 0.71 MPa vs. 0.29 ± 0.16 MPa; initially on dentin). pH and temperature during setting remained within clinical limits. TMP ∙ xH₂O + OPLS also showed the favorable sealing behavior, while Cavit™ performed similarly. Porosimetry, SEM and micro-CT supported the favorable profile of this formulation. CONCLUSION: The combination of 400 °C sintered TMP ∙ xH₂O and OPLS proved most suitable in terms of handling, stability, and sealing. This system are promising candidates for temporary restorations, particularly in non-retentive cavities. CLINICAL RELEVANCE: The tested cements may serve as novel resorbable, adhesive alternatives for temporary restorations. Future applications could include pulp capping or perforation repair.