Hydrolitic Stability of Hydroxyapatite Reinforced Composites Materials for Dental Restoration

C. DOMINGO, R.W. ARCÍS, E. OSORIO, R. OSORIO, R. RODRÍGUEZ-CLEMENTE, M.A. FANOVICH AND M. TOLEDANO

DENTAL MATERIALS

Elsevier

Año: 2003 p. 478 - 486

0109-5641

Objetives: The purpose of this study was to analyze the behavior in water, related to mechanical properties, of experimental composites for dental restoration. Methods: The studied materials were composed of a visible light-curing monomer mixture (either Bis-GMA and TEGDMA or HEMA) and micrometric , nanometric or a mixture of both sizes hydroxyapatite particles as a reinforcing filler. Filler particles were modified with a coupling agent (citric, hydrosuccinic, acrylic or methacrylic acid or silane). The hydrolytic stability of the evaluated materials was studied through total elution and water-uptake tests. Percent net-mass variations was daily monitored and analyzed as a funtion of time. Mechanical performance was examined through flexural properties and Vickers hardness. Morphological surface changes were observed with scanning electron microscopy. ANOVA statistical analysis was performed (P< 0.05). Results: In general, the use of HEMA instead of TEGMA did not substantially worsen the composite quality. Dental composites containing only nanometric particles of hydroxyapatite as a filler are unsuitable for clinical performance. Midway-filler composite resins loaded with micro-HAP àrticles, coated with citric, acrylic or methacrylic acid displayed low percent elution and water-uptake values. Mechanical properties were similar or even superior to those measured for silane treated particles. Significance: More research is needed to further improve the interaction of nano-HAP particles with the polymeric matrix, either as a single filler or, preferentially, mixed with micro-HAP, that will allow to increase the total loading of reinforcing filler and, to improve the mechanical properties.