Evaluation of the effect of oil pulling on the optical properties of natural teeth and various aesthetic materials

This study aims to evaluate the effect of oil pulling on the optical properties of various aesthetic materials and natural teeth that were extrinsically stained at coffee solution. A total of 70 samples, including natural permanent teeth and aesthetic CAD/CAM materials (Tetric CAD (TC), Telio CAD (T), Cerasmart (CS), Lava Ultimate (LU), and IPS E.max ZirCAD (ZC); dimensions of 5x5x1 mm), were examined (n=10). The L*, a*, and b* values of the samples were measured at baseline (L0*, a0*, b0*) using a spectrophotometer (VITA Easyshade, Germany). The L*, a*, and b* values of the samples, which were immersed in a coffee solution for extrinsic staining, were recorded on the 7th, 14th, and 21st days (L7k*, a7k*, b7k*, L14k*, a14k*, b14k*, L21k*, a21k*, b21k*). After staining, oil pulling (with coconut oil) was applied to the samples at 7th, 14th, and 21st days, After oil pulling process L*, a*, and b* values (L7op*, a7op*, b7op*, L14op*, a14op*, b14op*, L21op*, a21op*, b21op*) were again recorded. Color changes values (∆E00*) were calculated. Statistical analysis was performed using One-Way ANOVA, Tukey's Post-hoc Tests, and Paired Sample T-tests (p<0.05). Oil pulling significantly affected the optical parameters of all groups that exposed to extrinsic staining (p<0.05). Oil pulling increased L* values at TC, DD, and ZC groups on the 7th day; LU, CE, TC, T, ZC and DD groups on the 14th day; and LU, TC, T, ZC, and DD groups on the 21st day (p<0.05). a* values increased at LU, CE and T groups on the 7th and 14th days;and at LU, T and ZC groups on the 21st day (p<0.05). b* values decreased at LU, CE, TC and T groups on the 7th and 14th days; and at LU, CE, TC, T, DD and ZC groups on the 21st day (p<0.05). Oil pulling reduced ∆E00* values at all groups on the 7th, 14th, and 21st days (p<0.05), (except for the T group on the 7th day, p= 0,462). The ∆E00* values of the LU, TC, and DD groups were found to be 'clinically unacceptable' (∆E00*>1.8) at all time points. ZC group demonstrated the best color stability, maintaining 'clinically acceptable ' level after oil pulling process for all time points. Applying oil pulling method to extrinsically stained natural teeth/ aesthetic restorative materials increased brightness and led to color changes towards the blue and red spectrums. As a result, we can say that oil pulling method positively affected the optical properties. Keywords: Oil pulling, CAD-CAM colour, coconut oil.