The Impact of Incorporating Five Different Boron Materials into a Dental Composite on Its Mechanical Properties

The aim of this study is to comparatively investigate changes in mechanical properties by adding five different types of boron derivatives to a microhybrid dental composite structure. In this study, which evaluated upper and lower surface microhardness (VHN), roughness (Ra), and color stability (Delta E), a total of 126 discs were used (n = 7; per each subgroup). All boron derivatives were added to the dental composite structure in equal proportions in a dark room to create experimental composites (5% w/w). To enable comparison, a default composite without the addition of any boron derivative served as the negative control group. Before measurements, all samples were incubated at 37 degree celsius for 24 h. For surface microhardness, roughness, and color stability, all experimental groups were statistically significant within themselves (p < 0.001). The group with borax pentahydrate exhibited the highest VHN value on the upper surface, while the lowest value was observed in the group with etifert. It was found that all experimental groups showed a decrease in lower surface microhardness compared to the control group (p < 0.001). Although the eticol-ceramic-added group had the lowest roughness values, this group also exhibited significantly higher increment E values compared to the other groups. Surface roughness showed a negative correlation with increment E and upper surface microhardness values for all experimental groups (respectively p = 0.038; r = -0.185/p = 0.006; r = -0.245). To sum up, the addition of boron derivatives to composites, except for etifert, increased upper surface microhardness values; however, except for eticol-ceramic, surface roughness values also increased. Nevertheless, the addition of boron derivatives, except for eticol-ceramic, ensures color stabilization.