engleski

Flexural strength of composite resins containing ACP and inert fillers.

Aim: Adding amorphous calcium phosphate (ACP), the direct precursor of hydroxylapatite, to composite monomers results in a material which releases calcium and phosphate ions in aqueous environment with the potential of remineralizing carious lesions. However, ACP has no reinforcing capacity needed for the adequate mechanical strength of the material to be used for tooth restoration. The aim of the study was to determine if adding non-releasing fillers to the ACP containing material would improve flexural strength. Materials and methods: Ten materials were subjected to three point flexural test (ISO-4049), including two batches of ACP composite material without added fillers (40% ACP, 60% resins ; controls), and six ACP containing materials (all with 40% ACP) with added 5% or 10% silanized fillers. Silica fillers (12µm) (Aerosil DT, Evonik Degussa, Germany) and barium (0.7µm) or strontium glass fillers (1µm) (Schott, Germany) were included into the paste. Fuji II LC (GC, Japan ; glass ionomer) and CeramX (Dentsply DeTrey, Germany ; composite resin) served as controls too. The samples (22x2x2mm ; n=10) were polymerized (200s ; Bluephase C8, 1090mW/cm2, Ivoclar Vivadent, Liechtenstein), stored (water ; 24h ; 37°C), subjected to the three point flexural test (Zwick Z010 ; Zwick, Germany ; crosshead-speed 0.75mm/min), and statistically analyzed (Mann-Whitney-test ; p<0.05). Results: ACP-I+10%Barium-glass, ACP-II+10%Silica-glass: -not significantly different from control Fuji II LC. All other materials containing ACP and fillers: -significantly different from ACP-I+10%Barium-glass, ACP-II+10%Silica-glass ; -not significantly different from the ACP containing controls without fillers. CeramX: statistically different to all other materials. Conclusion: This study showed that ACP composite resins reinforced with 10% barium glass or 10% silica fillers have improved mechanical properties, similar to a currently used resin modified glass ionomer material. This study was supported by MZOS (065-0352851-0410), The National Foundation for Science, Higher Education and Technological Development (Croatia), Forschungsgemeinschaft Dental and NIDCR (DE13169).

amorphous calcium phosphate; composite resins; flexural strength

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