Comparative Analysis of the tooth- colored Ivotion resin with commercially available resin teeth

Objective: The comparison between the monolithic Ivotion resin with commercially available resin teeth (Phonares SR II, Ivostar (Ivotion)) regarding their abrasion, hardness, and staining behavior. Material and Methods: Abrasion of the specimen was measured after the chewing simulation (50N; 10 000, 200 000, 600 000 cycles) with the GOM 2021 software by matching the pre- and post- chewing simulation scans (InEOS X5). Hardness of the materials was measured with the Vickers indenter using the FISCHERSCOPE 340 and the corresponding WIN- HCU software. 10 indentations (Max force: 1N, creep 10s, application of force 15s) were made for each specimen. Staining: CIELab values for the media coffee, red wine, black tea, and the control distilled water were measured after 1 day, 7 days, 14 days, and 30 days for all specimen using the VITAEasyShade spectrophotometer. Results: In case of abrasion of 10000 cycles a significant difference [F(2,22.94)=3.734, p<.05] is determined. When conducting post-hoc Bonferroni testing the most pronounced difference between Ivostar (M=.032, SD=.020) and Phonares (M=.016, SD=.013) becomes non-significant with p=.076). For Abrasion of 24000 cycles a significant difference [F(2,25.31)=32.579, p<.001] is determined as well. Post-hoc Bonferroni testing reveals that the differences appear between Phonares (M=.088, SD=.054) and Ivostar (M=.247, SD=.080) as well as between Phonares and Ivotion (M=.206, SD=.030). For Abrasion of 600000 a significant difference [F(2,26.18)=5.353, p<.05] is found as well. Post-hoc Bonferroni testing reveals that the differences appear between Phonares (M=.258, SD=.124) and Ivotion (M=.384, SD=.090). For microhardness testing regarding martens hardness (N/mm2) Welch test indicates a significant difference as well [F(2,70.17)= 8.15, p<.001]. Post-hoc comparison reveals that differences appeared between Phonares (M= 315.85, SD= 215.87) and Ivostar (M= 174.33, SD= 51.00, p<0.001) as well as Phonares and Ivotion (M= 177.05, SD= 53.55, p<0.001). In case of Vickers hardness a significant overall difference is determined as well [F(2,6968.17)= 7.00, p<.005]. Multiple comparisons reveal that differences appear between Phonares (M= 47.88, SD= 40.47) and Ivostar (M= 23.59, SD= 7.17, p<0.001) as well as Phonares and Ivotion (M= 23.66, SD= 7.39, p<0.001). For the staining experiment highest ΔE values were registered with black tea for all groups after 30-day immersion, with the highest values in the Ivotion group (ΔE 41.1; 40.0), followed by Phonares and Ivostar. Coffee can be regarded as more chromogenic than red wine, with ΔE values after the 30-day observation period of 27.4 and 24.3 in the Ivotion group, 9.3 and 8.6 for Phonares 8.3 and 9.3 for Ivostar. The least chromogenic substance evaluated, apart from the control group of distilled H20, was red wine with an increase of ΔE of 1.1; 1.2 for Ivotion, 3.4 and 5.6 for Phonares and 5.8 and 2.5 for Ivostar. L* values for this staining agent remained predominantly stable, a* values increased slightly from more negative values closer to zero, indicating an increase of red pigment. Conclusion For abrasion resistance a significant statistical difference between the material composition and their abrasion resistance was found and the null hypothesis was rejected. Regarding hardness a significant statistical difference between the material and hardness of the material was observed. For all indices (HM, HV, HIT, EIT), post- hoc Bonferroni comparison revealed the differences between P and IS as well as P and I The null hypothesis for hardness was rejected as well. With the help of descriptive statistics, a difference in the staining behavior of different media and materials was observed. An exemplary power analysis to calculate sample size in future studies we computed repeated measures ANOVA, stratified by medium and ΔE as well as the connected L* a* b* values. Studies may use these results to estimate sample size based on generalized eta-squared [55]. For all materials and parameters main as well as interaction effects are significant, η2g indicates large effects.