# The Effects of Activated Carbon Toothpastes on Orthodontic Elastomeric Chains--An In Vitro Study
## 4 Discussion
while Ortho Classic(r) lost the most, regardless of the toothpaste used, with the highest tensile strength on day zero and the lowest on day 28. Ortho Classic(r) EC showed more significant tensile strength degradation with all three toothpastes than the 3M Unitek(r) and Ormco(r) EC groups. However, the Ortho Classic(r) EC tensile strength degradation was significantly higher when brushed with Colgate Max White(r) compared to brushing with Colgate and Dr Organic(r) toothpastes (third null hypothesis rejected). The difference in the behaviour of Ortho Classic(r) EC compared to 3M Unitek(r) and Ormco(r) EC groups over time seems to be related to the materials constituting the ECs and not to extrinsic factors. A similar, earlier in vitro investigation by [PERSON] et al. [14] concluded that tensile the strength degradation of ECs brushed with Crest(r) and Sensodyne(r) whitening toothpastes was greater than that of their control groups over time. However, the investigators used only one type of EC (3M Unitek(r)), and the brands of whitening toothpastes used were different from ours. Also, in another study, [PERSON] et al. [5] found similar degrading effects resulting from two of the most widely used whitening mouthwashes (Plux and Listerine) on an EC manufactured by Morelli (Sorocaba, Brazil). Nevertheless, a direct comparison between the previous and present studies is compromised by the heterogeneity of the materials used. Our experiments show significant inherent discrepancies in the resistance to rupture among the three EC brands, with the Ormco(r) ECs being significantly more resistant before exposure to external elements. This resistance to rupture was significantly lower on day 28 in all groups. The activated carbon contained in the toothpastes did not significantly affect the value of the rupture point over time, except for Ormco(r) ECs, where the group brushed with Dr Organic(r) Extra White toothpaste had significantly weakened resistance to rupture compared to the groups exposed to Colgate Max White(r) toothpaste, which contains activated carbon, and Colgate Total(r) toothpaste, which does not (second null hypothesis rejected). Transparent ECs have improved the aesthetic aspect of fixed orthodontic appliances. However, ECs are prone to discolouration due to their intrinsic components and the effects of extrinsic factors. [PERSON] et al. [26] indicated a reference value of 3.3 \(\Delta\)E as the threshold for a clinically visible and relevant colour discrepancy. None of the ECs tested reached this level of discolouration. Our investigation concluded that toothpastes altered the EC colour similarly, except for the significantly greater discolouring impact of Dr Organic(r) Extra Whitening toothpaste on the Ormco(r) and Ortho Classic(r) brands of ECs (third null hypothesis rejected); 3M Unitek(r) ECs were not affected in this way. This discolouration was not observed with Colgate Max White(r) toothpaste, which also contains activated carbon, possibly due to the different levels of activated carbon approved by each manufacturer. This study indicates that the type of EC material used contributes to their strength decay and resistance to rupture over time. The tensile strength of Ortho Classic(r) ECs was the most significantly degraded, regardless of the toothpaste used, compared to the other EC brands. Further in vivo studies are recommended to gain a complete understanding of the elastomeric behaviour of more brands of ECs in the oral cavity, but we were able to show that activated carbon toothpastes have different effects on ECs over time, probably depending on their different compositions. Dr Organic(r) Extra Whitening toothpaste, which contains activated carbon, significantly weakened the rupture point and altered the colour of Ormco(r) and Ortho Classic(r) ECs. Given that the two toothpastes containing activated carbon did not have similar effects, it might be reasonable to advise patients wearing ECs to avoid using toothpastes with bleaching agents when using ECs until further evidence becomes available.