# Microbiological Changes during Orthodontic Aligner Therapy: A Prospective Clinical Trial
## 3 Results
### Microbiological Tests
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Bacteria Type** & **AA** & **Mean** & **SD** & **Min** & **Median** & **Max** & **Significance \({}^{*}\)** \\ \hline \multirow{4}{*}{_Aggregatihacter actinomycetemitans_} & Control T\({}_{0}\) & 0.00 & 0.00 & 0.00 & 0.00 & \\  & Control T\({}_{1}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\  & Trial T\({}_{0}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ \hline \multirow{4}{*}{_Porphyomonas_} & Control T\({}_{1}\) & 0.00 & 0.00 & 0.00 & 0.00 & 3.00 & \\  & Control T\({}_{1}\) & 0.80 & 1.64 & 0.00 & 0.00 & 4.00 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.43 & 0.95 & 0.00 & 0.00 & 3.00 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 0.22 & 0.46 & 0.00 & 0.00 & 2.00 & \\ \hline \multirow{4}{*}{_Tannerella forsythia_} & Control T\({}_{0}\) & 0.20 & 0.41 & 0.00 & 0.00 & 1.00 & \\ \cline{1-1}  & Control T\({}_{1}\) & 0.32 & 0.65 & 0.00 & 0.00 & 1.59 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.19 & 0.49 & 0.00 & 0.00 & 1.59 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 0.24 & 0.37 & 0.00 & 0.00 & 0.87 & \\ \hline \multirow{4}{*}{_Treponema donticola_} & Control T\({}_{0}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ \cline{1-1}  & Control T\({}_{1}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ \hline \multirow{4}{*}{_Prevotella internedia_} & Control T\({}_{0}\) & 0.30 & 0.98 & 0.00 & 0.00 & 4.00 & \\ \cline{1-1}  & Control T\({}_{1}\) & 0.45 & 1.61 & 0.00 & 0.00 & 7.00 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.10 & 0.31 & 0.00 & 0.00 & 1.00 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 0.20 & 0.53 & 0.00 & 0.00 & 1.73 & \\ \hline \multirow{4}{*}{_Fusobacterium_} & Control T\({}_{0}\) & 0.05 & 0.22 & 0.00 & 0.00 & 1.00 & \\ \cline{1-1}  & Control T\({}_{1}\) & 0.30 & 0.92 & 0.00 & 0.00 & 4.00 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.10 & 0.31 & 0.00 & 0.00 & 1.00 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 0.22 & 0.61 & 0.00 & 0.00 & 2.00 & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Descriptive statistics of each bacterial count expressed as percentage. Neither _Aggregatibacter actinomycetemontians_ nor _Treponema denticola_ were detected in the groups at any time. Considering the expression of the bacterial count as copies/microlitre, _Porphyromonas gigivalis_ and _Prevotella Intermedia_ increased in both groups from T\({}_{0}\) to T\({}_{1}\). Conversely, _Tannerella foryththia_ and _Fusobacterium nucleatum_ increased in the trial group but decreased in the control one. However, none of all these variations were shown to be statistically significant. Figure 3: Percentage of the bacteria tested in the study (this figure shows the data reported in Table 5). Figure 2: Number of copies/microlitre for the bacteria tested in the study (this figure shows the data reported in Table 4). The table shows that the copies/microlitre of each bacterium tested did not significantly change, neither in the control group (no treatment) nor in the trial group (clear aligner treatment) from the beginning to the end of the study. As regards the percentage expression of the bacteria detected (thus excluding _Aggregat-ibacter actinomycetencomitans_ and _Treponema denticola_), this value increased in both groups for _Tannerella forysthia_, _Prevotella intermediia_ and _Fusobacterium nucleatum_. Conversely, the percentage of Porphyomonas gingivalis increased in the control group but decreased in the trial one. However, none of all these variations were shown to be statistically significant. The table shows that the percentage of each bacterium tested did not significantly change, neither in the control group (no treatment) nor in the trial group (clear aligner treatment) from the beginning to the end of the study. For both the control and the trial group, the total bacteria count was significantly increased compared to the values, respectively, assessed at T\({}_{0}\) and at T\({}_{1}\) (intragroup differences), as shown in Table 6 and Figure 4 (\(p<0.05\)). No significant intergroup differences were assessed.