Evaluation of the effect of different amounts of boron addition on the surface roughness and antibacterial properties of three dimensional printed permanent crown resins

This thesis aims to assess color stability, surface roughness, and antibacterial properties before and after brushing, examining the impact of boron element addition in three dimensional printed permanent crown resin. In our study, samples were prepared by adding different amounts of sodium pentaborate (0%, 1%, 2% and 3%) to the permanent crown resin, which was polymerized with UV light and produced with a three dimensional printer. Four groups and a total of 148 samples were manufactured with a SLA based printer. All samples surfaces were finished with grid silicon carbide paper (600, 800, 1000, 1200 grid). Subsequently, a sandblasting process was performed using 110µm Al2O3 particles under a pressure of 2.5 bar. Afterwards, the surfaces were polished with polishing paste. The samples underwent a processing in a brushing simulator for a total of 10.000 cycles. Surface roughness measurements were obtained before and after brushing utilizing a profilometer and FE-SEM microscope, while color changes were assessed using a spectrophotometer device. The determination of the antibacterial properties of the prepared samples were in accordance with the ISO 22196 standard. Color change was statistically evaluated using the Kruskal-Wallis test, and multiple comparisons were performed with the Dunn test. Surface roughness values were analyzed using the two-way ROBUST ANOVA test and multiple comparisons were made with Bonferroni. Upon comparison of the groups after brushing, it was observed that that the increase in the sodium pentaborate ratio in the mixture increased the color change value. Similarly, it was determined that the surface roughness increased after the brushing process, and the highest surface roughness was found in the sample group containing 3% sodium pentaborate. It was observed that the antibacterial property increased due to the addition of boron in the samples.