Stability of Dental Composites in Water and Artificial Saliva

Antarinia Craciun,Mindra Badea,Miuta Filip,Marioara Moldovan,Ana Ispas,Mariana Constantiniuc,Maria Crisan,Ioan Petean,Doina Prodan

doi:10.37358/mp.20.2.5351

Abstract

The aim of this in vitro study was to evaluate the characteristics of four commercial dental composites: two dual-curing luting resin cements and two indirect composites for crowns and bridges. The novelty of the study consists in the use of combined characterization methods for the investigated materials, namely: after maintaining the samples in the water/ artificial saliva, besides sorption, the surface degradation of the samples was observed after their immersion period; thereafter, the immersion medium was lyophilized and then the percentage of residual monomer found in the medium was determined by HPLC. After 44 days, small concentrations of monomers have been determined in the aqueous/saliva extracts. SEM images show that the samples from each class of material, with a higher content of inorganic filler, exhibit a larger erosion of the surfaces after contact with water compared to the other two samples that show a larger erosion of surfaces after contact with saliva than with water. The surface of the dual-curing resin cement with a higher content of inorganic filler is the smoothest from the samples exposed to saliva, instead the other resin cement is the roughest, as shown by AFM analysis. The overall observation reveals that the samples kept in saliva are rougher than the ones kept in water. Smooth surface materials of both classes of materials ( with a higher content of inorganic filler) have absorbed a higher amount of water / saliva compared to materials with a rougher surface.Water sorption in the composite resins is influenced by the hydrophilicity of the monomers, the nature and size of the inorganic filler particles, and the quality of the matrix / filler interface.

Highlights

Adhesion and esthetics of resin based dental materials are the main features that recommend the use of composites on large-scale in dental medicine
Upon contact with the liquids in the oral environment, an expansion of the organic matrix occurs due to the absorption phenomenon; this stress factor leads to the deformation of the resin-dentine bond, influencing the state of stress in the structure of the restored tooth [1]
The novelty of the study consists in the use of combined characterization methods for four commercial dental composites: two dual-curing luting resin cements and two indirect composites for crown and bridgesin order to establish the material with the best properties

Summary

Introduction

Adhesion and esthetics of resin based dental materials are the main features that recommend the use of composites on large-scale in dental medicine. Upon contact with the liquids in the oral environment, an expansion of the organic matrix occurs due to the absorption phenomenon; this stress factor leads to the deformation of the resin-dentine bond, influencing the state of stress in the structure of the restored tooth [1]. The hygroscopic stress can cause micro-cracks or microfractures on the restored surface, due to hydrolytic degradation of bonds inside both the polymeric matrix and the resin–filler interface [2,3,4,5]. The resin polarity controls the speed and extent of water absorption in polymer networks. The water sorption of restoration composite materials can have a positive effect offsetting the shrinkage of polymerization by relaxing the stress caused by it. The sorption may depend on the storage time and medium of the specimens [4, 7]

Methods

Results

Conclusion