Glass carbomer cement is a new dental material developed from the traditional glass ionomer cements. It has better mechanical and chemical features when compared to the conventional glass ionomer cements. The purpose of this in silico investigation was to examine the influence of glass carbomer and composite resin materials with class I cavity design on stresses happening in the inlay. Finite-element analysis and three-dimensional modelling were used to examine the stress in the glass carbomer and hybrid composite inlays resulting from a 300-N point load on occlusal surfaces. Two different inlay materials, glass carbomer cement and hybrid composite resin, were evaluated. The maximum von Misses stress values in the composite resin inlays were significantly lower than those in the glass carbomer inlays. The results from this study showed that the resistance of the glass carbomer against the forces was higher than that of the composite resin inlays. The stresses were concentrated mostly at similar regions. The obtained results suggest that glass carbomer may be recommended as a preferred filler restorative material in teeth with much structure loss.