# Anchorage Loss Evaluation during Maximillary Molars
## 4 Discussion  
Although CAT is widely used in orthodontic clinical practice, knowledge about side effects in many types of movements obtained with this technique has not yet been clearly described and supported by scientific evidence. Therefore, the aim of the present investigation is to focus on the maxillary dental distalization treatment through CAT and, in particular, to evaluate the anchorage loss at the level of upper premolars and canines at the end of the upper first molars' distal movement as unwanted effects of this therapy. As we all know, the molar distalization procedure requires an anchoring unit usually represented by the anterior part of the arch. Biomechanically, the posterior force applied on the molars generates an equal and opposite reciprocal force, which is discharged on the anterior teeth, particularly in the area of the incisors, which ultimately leads to their flaring and anchorage loss [27]. The resistance of a tooth to a given force depends on the following factors: root area and shape, bone density and periodontal health, muscular force, facial biotype, oral habits, and type of movement applied. Moreover, each dental element has an anchor value, which depends mainly on its root surface. It is very important to take the anchor value into consideration when planning orthodontic movements, especially during distalization movements. In the literature, many authors [3; 21; 28; 29; 30] described the anchorage loss, analyzing the millimeter and angular variation through cephalometric analysis on lateral cephalograms during distalization treatment with traditional intra-oral fixed appliances, and they highlighted that mutual forces resulted in a loss of anterior anchorage that was responsible for some of the space that appeared. Among them, [PERSON] and [PERSON] [31] found that 24% of the total space opening anterior during maxillary molar distalization was due to the reciprocal anchorage loss of the maxillary premolars with the slightly mesial movement \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variables** & **T1 (\(\mu\) = 49 27F; 22M)** & **T2 (\(\mu\) = 49 27F; 22M)** & **T2–T1** & & & \\ \hline
**Measurements** & **(mm)** & **Mean T1** & **SD** & **Mean T2** & **SD** & **Diff** & **95\% CI** & \(p\) Value** \\ \hline
1.3 CS & 3.0 & 1.02 & 1.5 & 1.03 & \(-\)1.5 & 0.932 to 2.068 & *** (0.0001) \\ \hline
2.3 CS & 2.05 & 1.4 & 0.9 & 1.1 & \(-\)1.15 & 0.366 to 1.934 & *** (0.008) \\ \hline
1.4 PBS & 7.7 & 3.3 & 8.0 & 2.7 & 0.3 & \(-\)1.358 to 0.758 & NS (0.5454) \\ \hline
2.4 PBS & 7.9 & 2.7 & 7.8 & 2.4 & \(-\)0.1 & \(-\)1.317 to 1.483 & NS (0.8981) \\ \hline
1.5 PBS & 14.2 & 3.7 & 14.7 & 3.0 & 0.5 & \(-\)1.396 to 0.329 & NS (0.20) \\ \hline
2.5 PBS & 14.7 & 2.7 & 15.0 & 3.0 & 0.3 & \(-\)1.046 to 0.513 & NS (0.47) \\ \hline
1.6 DBS & 25.2 & 3.7 & 28.2 & 3.2 & 3.0 & \(-\)3.938 to \(-\)2.029 & *** (0.0001) \\ \hline
1.6 MBS & 20.6 & 3.6 & 23.0 & 3.0 & 2.4 & \(-\)3.341 to \(-\)1.492 & *** (0.0001) \\ \hline
2.6 DBS & 25.2 & 3.3 & 27.4 & 3.7 & 2.2 & \(-\)3.258 to \(-\)1.142 & *** (0.0008) \\ \hline
2.6 MBS & 20.5 & 3.2 & 22.9 & 3.2 & 2.4 & \(-\)3.440 to \(-\)1.260 & *** (0.0006) \\ \hline \hline \end{tabular}  
* NS: not significant, **\(p\) < 0.01, *** \(p\) < 0.001. CI: confidence of interval; SD: standard deviation.  
\end{table} 
Table 1: Descriptive statistics and statistical comparison of the T2–T1 changes with _paired t-test_. of the upper incisors, whereas the bodily movement of maxillary first molar contributed to 76%. Additionally, [PERSON] et al. [3], in their study about the comparison between the upper molars distalization obtained with a Distal Jet and other traditional methods, highlighted that at the end of the backward molar movement, 71% of the 4.5 mm of space obtained between the upper first molar and the first premolar was due to the distal movement of the molar crown on each side, while the remaining 29% resulted from the loss of anchorage of the premolars. On the contrary, as described by [PERSON] et al.