# Microbiological Changes during Orthodontic Aligner Therapy: A Prospective Clinical Trial
## 3 Results
### Microbiological Tests  
As shown in Tables 4 and 5 and Figures 2 and 3, no significant inter- or intra-group differences were shown for the bacteria tested (\(p>0.05\)), considering neither the copies/microlitre nor for the relative percentages. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variable** & **Group** & **Mean** & **SD** & **Min** & **Median** & **Max** & **Significance \({}^{*}\)** \\ \hline \multirow{4}{*}{PPD} & Control T\({}_{0}\) & 2.26 & 0.40 & 1.53 & 2.42 & 2.61 & \\  & Control T\({}_{1}\) & 2.12 & 0.35 & 1.78 & 2.06 & 2.78 & \\  & Trial T\({}_{0}\) & 1.89 & 0.46 & 1.17 & 1.81 & 3.00 & \(p>0.05\) \\  & Trial T\({}_{1}\) & 1.99 & 0.51 & 0.64 & 2.17 & 2.47 & \\ \hline \multirow{4}{*}{BOP (\%)} & Control T\({}_{0}\) & 5.98 & 10.53 & 0.00 & 1.00 & 38.91 & \\  & Control T\({}_{1}\) & 7.57 & 10.50 & 0.00 & 4.92 & 36.10 & \\  & Trial T\({}_{0}\) & 4.55 & 5.00 & 0.00 & 2.52 & 15.00 & \(p>0.05\) \\  & Trial T\({}_{1}\) & 4.08 & 5.50 & 0.00 & 1.80 & 15.00 & \\ \hline \multirow{4}{*}{PI (0–4)} & Control T\({}_{0}\) & 0.50 & 0.46 & 0.00 & 0.38 & 1.58 & \\  & Control T\({}_{1}\) & 0.57 & 0.54 & 0.00 & 0.46 & 1.78 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 0.39 & 0.22 & 0.00 & 0.36 & 0.78 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 0.30 & 0.23 & 0.00 & 0.25 & 0.65 & \\ \hline \hline \end{tabular} Legend: T\({}_{0}\): baseline; T\({}_{1}\): after 2 months; \({}^{*}p>0.05\) means that there is no significant difference.  
\end{table} 
Table 3: Descriptive statistics of periodontal clinical indexes. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Bacteria Type** & **Group** & **Mean** & **SD** & **Min** & **Median** & **Max** & **Significance \({}^{*}\)** \\ \hline \multirow{4}{*}{_Aggregatihacter actinomycetemomitans_} & Control T\({}_{0}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \multirow{4}{*}{_p_ \(>\) 0.05} \\  & 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 & \\  & Trial T\({}_{1}\) & 0.00 & 0.00 & 0.00 & 0.00 & 0.00 & \\ \hline \multirow{4}{*}{_Porphyomonas_} & Control T\({}_{0}\) & 26.63 & 61.50 & 0.00 & 0.00 & 223.00 & \multirow{4}{*}{_p_ \(>\) 0.05} \\  & Control T\({}_{1}\) & 29.47 & 65.88 & 0.00 & 0.00 & 223.00 & \\  & Trial T\({}_{0}\) & 12.15 & 31.76 & 0.00 & 0.00 & 102.00 & \\  & Trial T\({}_{1}\) & 23.15 & 61.75 & 0.00 & 0.00 & 199.00 & \\ \hline \multirow{4}{*}{_Tannerella forsythia_} & Control T\({}_{0}\) & 520.00 & 1034.57 & 0.00 & 0.00 & 2470.00 & \multirow{4}{*}{_p_ \(>\) 0.05} \\  & Control T\({}_{1}\) & 178.74 & 157.84 & 0.00 & 158.00 & 351.00 & \\  & Trial T\({}_{0}\) & 641.00 & 1487.69 & 0.00 & 0.00 & 4720.00 & \\  & Trial T\({}_{1}\) & 874.60 & 2280.12 & 0.00 & 0.00 & 7480.00 & \\ \hline \multirow{4}{*}{_Treponema donticola_} & Control T\({}_{0}\) & 0.00 & 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}{*}{_Prevotella internedia_} & Control T\({}_{0}\) & 459.16 & 901.71 & 0.00 & 0.00 & 2650.00 & \multirow{4}{*}{_p_ \(>\) 0.05} \\  & Control T\({}_{1}\) & 586.84 & 1562.15 & 0.00 & 0.00 & 6600.00 & \\  & Trial T\({}_{0}\) & 150.00 & 461.69 & 0.00 & 0.00 & 1500.00 & \\  & Trial T\({}_{1}\) & 294.40 & 901.37 & 0.00 & 0.00 & 2930.00 & \\ \hline \multirow{4}{*}{_Fusobacterium_} & Control T\({}_{0}\) & 125.21 & 238.97 & 0.00 & 0.00 & 712.00 & \multirow{4}{*}{_p_ \(>\) 0.05} \\  & Control T\({}_{1}\) & 107.58 & 223.23 & 0.00 & 0.00 & 766.00 & \\ \cline{1-1}  & Trial T\({}_{0}\) & 38.45 & 97.81 & 0.00 & 0.00 & 305.00 & \\ \cline{1-1}  & Trial T\({}_{1}\) & 220.85 & 797.48 & 0.00 & 0.00 & 3590.00 & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Descriptive statistics of each bacterial count expressed as copies/micolitre.