# The Effects of Activated Carbon Toothpastes on Orthodontic Elastomeric Chains--An In Vitro Study
## 4 Discussion  
ECs are frequently used for force transmission during orthodontic treatment. Numerous investigations have examined the mechanical impact of intraoral environmental factors on the degradation of EC tensile strength over time [2; 3; 19]. The growing interest globally in using whitening toothpaste has necessitated investigating the effect of whitening components on EC characteristics. The in vitro design of the present investigation offered the possibility of evaluating one covariate at a time (in this case, activated carbon) and avoiding the influence of other components present in the oral cavity, such as pigmentation caused by food and drink [20; 21]. However, despite the previously reported advantages, an in vitro study design falls short in simulating the oral environment, which includes enzymes, pH variation, natural microflora and temperature fluctuation. Therefore, it is imperative to exercise caution when generalizing the outcomes of such investigations to clinical circumstances [20; 21]. Throughout this investigation, the ECs were always stretched to a fixed distance between the pins installed on the acrylic plates without simulating the tooth movement that occurs during oral function. This might have affected the experimental outcome [14], and therefore, it is recommended that a randomized clinical trial be undertaken to further explore EC behaviour in a clinical setting. Numerous laboratory-based investigations have reported the decay of EC strength over time [2; 4; 19; 22; 23; 24; 25; 26]. [PERSON] et al. [23]. concluded that only 43-52% of the initial EC tensile strength was maintained in a simulated oral cavity environment following four weeks of use, while an EC group maintained in air retained 70-75% of the initial elasticity. However, different brands of EC show dissimilar effectiveness [24; 25]. This discrepancy might be attributed to processing variations and the different dimensional and morphological structures adopted [4; 25]. The duration of the present experiment was 28 days, which is the average interval between clinical consultations in an orthodontic clinical setting. In line with the above findings in the literature, our study revealed significant discrepancies over time in the mechanical properties of three of the most popular EC brands in orthodontics (3M Unitek(r), Ormco(r) and Ortho Classic(r)) following brushing with various toothpastes. One consistent result in our study was that toothpaste, both with and without activated carbon, had a comparable effect on the degradation of strength of 3M Unitek(r) and Ormco(r) ECs. It should be noted that of the three EC brands, Ormco(r) lost the least tensile strength, \begin{table}
\begin{tabular}{c l l c} \hline \hline
**EC Brand** & **Toothpaste** & \(\Delta\)**E (t28 \(-\) 10)** & **Min.-Max.** \\ \hline \multirow{3}{*}{3M Unitek®} & Colgate Total® & 0.67 a (\(\pm\)0.48) & 0.14–1.71 \\ \cline{2-4}  & Colgate Max White® & 0.66 a (\(\pm\)0.48) & 0.22–1.91 \\ \cline{2-4}  & Dr Organic® & 0.92 a (\(\pm\)0.69) & 0.14–2.79 \\ \hline \multirow{3}{*}{Ormco®} & Colgate Total® & 1.47 a,b (\(\pm\)1.00) & 0.14–3.26 \\ \cline{2-4}  & Colgate Max White® & 2.06 a,b (\(\pm\)1.15) & 0.77–5.09 \\ \cline{2-4}  & Dr Organic® & 2.55 b (\(\pm\)1.16) & 1.16–4.74 \\ \hline \multirow{3}{*}{Ortho Classic®} & Colgate Total® & 1.87 a,b (\(\pm\)1.99) & 0.30–7.72 \\ \cline{2-4}  & Colgate Max White® & 1.55 a,b (\(\pm\)1.93) & 0.14–6.24 \\ \cline{1-1} \cline{2-4}  & Dr Organic® & 2.66 b (\(\pm\)2.10) & 0.66–6.98 \\ \hline \hline \end{tabular} Multiple mean post hoc comparison through Tukey HSD test: different letters indicate significant different mean \(\Delta\)E values (\(p<0.05\)). t0 before starting the experiment and t28 is at the end of the experiment.  
\end{table} 
Table 3: Elastic chain (EC) colour change (\(\Delta\)E) between day 0 (t0) and day 28 (t28). Values presented as means (\(\pm\)standard deviation), (15 EC specimen, per group).