The goal of orthodontic treatment is to achieve optimal dental alignment and good occlusion. Fixed braces have traditionally been the main treatment option for correcting malpositioned teeth. However, patients now have a different choice that provides better aesthetic appeal and convenience because to the development of clear aligner therapy(CAT).

Clear aligners are custom-made, removable trays that gradually move the teeth into their desired positions by exerting gentle forces on the teeth through a series of aligners that are worn sequentially to correct the malocclusion.In fixed orthodontics the bracket and wire interact to bring about the desired tooth movement while in aligners desired tooth movement occurs as a consequence of predefined mismatch between the tooth and aligner coinciding with desired tooth movement . Aligners without any auxilaries have a number of limitations as they move the teeth into the available space away from centre of resistance.  Attachments are tooth-colored structures made of composite resin bonded to teeth increasing the area of contact and locating the point of force application closer to the centre of resistance allowing more bodily tooth   movement. As the use of aligners is limited, attachments are designed to improve the retention and movement of teeth.  

Attachment designs differ in their shape, size and placement to accommodate specific tooth movement³.  Despite the apparent improvements associated with attachment shapes, the absence of comprehensive research makes it 窗体底端

Attachment designs differ in their shape, size and placement to accommodate specific tooth movement.  Despite the apparent improvements associated with attachment shapes, the absence of comprehensive research makes it challenging to determine their relative efficacy for specific tooth movements.

 Aligners with attachments are used to carry out various tooth movements. Numerous studies and clinical assessments have examined the efficiency of attachments in carrying out different tooth movements. The efficiency of aligner is influenced by morphology of tooth due the interaction between the aligner and the teeth.  

                   Rotation correction of round shaped tooth is one of the least predictable movements in aligners and rotation correction of premolars is the least accurate . Derotation is carried by two methods: (1) Bonding attachments or other auxilaries to the buccal and palatal surfaces of the rotated tooth to create a couple  of force to correct it (2)using optimized  rotational attachments to derotate canines and premolars. These attachments are designed depending upon the force needed to derotate the tooth.  Additional aspects needed to be considered during derotation are overall amount of derotation, staging (degree of derotation per aligner), interproximal reduction [IPR], and the use of buttons with elastics.

One of the most common side effects of CAT is the unintended intrusion of the displaced tooth. This is known as ‘watermelon seed effect’ a phenomenon connected with aligners is used to measure intrusive force. These intrusive forces can be explained by local deformation of appliance’s inclined inner surface and decreased fit during increasing axial rotation which tends to raise the anterior surface, deforming the appliance like a bow.

As there are few evidence based studies carried out to evaluate the predictability of rotation with attachments in aligners as achieving the desired tooth movement is still a challenge. This study aims to compare the correction of  maxillary premolar derotation with double attachment on one side and single attachment on the opposite side with clear aligner therapy with a follow up of 7 days.The aligner changing protocol for all the patients will be one week, and they will be instructed to wear the aligners for 22 hours per day