A micro-computed tomography evaluation of the change in volume of different bulk-fill composite materials caused by polymerization shrinkage

Abstract

Aim: Composite resins contain different monomers and fillers that are directly affected by polymerization shrinkage. Therefore, an accurate and reliable method is needed to measure the volume changes. The aim of this study was to evaluate the amount of volume change associated with polymerization shrinkage in four different bulk-fill composite materials in class II restorations using a micro-CT device, which has high resolution and provides 3-dimensional images.
 Methodology: A total of 40 human 3rd molar teeth were used. First, standard class II cavities were opened on the mesial surfaces of all the teeth, and then the first micro-CT images were obtained. The same adhesive material was applied to all the teeth. The teeth were then separated into four groups, and a different bulk-fill composite was applied to each group; Filtek (FTK), X-tra Fil (XTF), Tetric Evo Ceram (TEC), and Filtek One (FLO) and the second micro-CT images were obtained. Then after polymerization of the materials, the final micro-CT images were taken, and analyses were made according to the scanning results. The Kruskal Wallis and Mann Whitney U-tests were used in the statistical evaluation of the data. 
 Results: The volumetric gap formed after polymerization of the composite resins was not determined to be statistically significant (p>0.05).
 Conclusion: The volumetric difference (%) between the composite resin and the dental tissue following polymerization was seen to be greatest in XTF and least in FTK. It was concluded that the volumetric gap caused by the polymerization shrinkage of the tested materials may be due to the structure of the material.
 
 How to cite this article: Cangül S, Adıgüzel Ö, Sağmak S, Evran B. A micro-computed tomography evaluation of the change in volume of different bulk-fill composite materials caused by polymerization shrinkage. Int Dent Res 2021;11(2):75-82. https://doi.org/10.5577/intdentres.2021.vol11.no2.4
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

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“…Composite resin is one of the first choices among direct restorative materials due to its superior aesthetic properties, adhesion to the tooth structure, and conservative tooth preparation (1). Composite resins also have some disadvantages, such as polymerization shrinkage, change in surface hardness over time, water absorption, water solubility, low mechanical properties, and short clinical life (2). Studies to extend the survival of composite resins are carried out by modifying the inorganic, organic, and silane phases (3).…”