# Anchorage Loss Evaluation during Maximillary Molars
## 4 Discussion
[32], distal tipping of the first premolar of \(-1.7^{\circ}\) was observed during distalization treatment performed with a pendulum. Thus, there is no consensus on the direction in which premolars tip during the movement of molar distalization with these popular appliances. Furthermore, Class II elastics are frequently used in conventional fixed-multibracket therapy for anchorage support and sagittal correction during maxillary molar distalization. Although widely employed, some researchers have found that the unwanted effects of Class II elastics are very habitual, increasing the facial height, owing to the rotation of the mandible and the consequent worsening of smile aesthetics [33]. In recent years, CAT has become an alternative to conventional fixed appliances, and therefore, they are also used for molars distalization with a specific protocol, defined as the standardized 50% sequential distalization protocol. This strategy is particularly advantageous because it does not involve the movement of more than two teeth at the same time. In this way, the arch is divided into two units, in which the support one has more dental anchoring mass than the active segment that performs the movement. This standardized 50% sequential distalization protocol makes the movements of the teeth in the posterior part of the arch more predictable, which have a higher anchoring value than the single-rooted elements of the anterior sector. Recent studies [18; 34] evaluated the accuracy of upper-molar bodily distal movement with aligners. [PERSON] and [PERSON] [34], in their systematic review, reported a significant amount of distalization of nearly 2-3 mm in all the selected studies and suggested this complex movement could be performed using CAT with good control over vertical craniofacial parameters, mesio-distal angulation of molars, and anchorage loss. Other studies analyzed the anchorage loss obtained during the upper-molar distalization movement with CAT. [PERSON] et al. [17] and [PERSON] et al. [1] observed no anchorage loss at the end of the therapy on upper incisors during distalization movements performed with aligners, sequential movement protocol, and early Class II elastics. On the contrary, [PERSON] et al. [23], using three-dimensional finite element models, found a worsening of anterior anchorage during first molar distalization, with a mesial palatal relapse tendency of the second molar. However, they reported that the use of Class II elastics was effectively able to reinforce the anchorage of both anterior teeth and molars. The configuration of the precision cuts for elastics also deserves particular attention. There are no clinical guidelines for the selection of an application for Class II elastics, including the bonding of buttons directly onto the tooth surface and the precise cutting of clear aligners [23]. In our protocol, in the upper arch, the intra-oral elastic hooked directly to the aligner (on canines or first premolars) exerts a distal force on the entire arch reducing the overjet. This principle is also applicable during the sequential distalization mechanics to better express the posterior movement, especially where it is necessary to correct a Class II malocclusion with proclined maxillary incisors. Also in the lower arch, according to our protocol, it is suitable to use precision cuts (on first molars) in order to work by associating all the dental elements and generating a homogeneous force on the entire arch, which thus functions as a passive anchoring segment. Moreover, the application of a precision button cut on the lower molars causes a direct force to be applied to the tooth. Since our protocol provides for the use of full-time elastics, the clinical preference of a precision cut avoids the expression of any extrusive force vectors and, thus, causes a clockwise movement of the mandible. CAT has also been used to improve vertical dimension control, rendering this a superior alternative for the treatment of patients with hyperdivergent or open bites [1].