Effects of Composite Attachments on Orthodontic Clear Aligners Therapy: A Systematic Review

Abstract

This systematic review aims to highlight the differences between different clear aligner therapies that differ in the presence of attachments or in attachment configuration. Eight electronic databases were searched up to March 2020. Two authors independently proceeded to study selection, data extraction, and risk of bias assessment. The analysis of the results was carried out examining six groups of movements (mesio-distal tipping/bodily movement; anterior bucco-lingual tipping/root torque; posterior bucco-lingual tipping/expansion; intrusion; extrusion; rotation). Five clinical trials were selected and all of them showed a medium risk of bias. Literature showed that attachments mostly increase the effectiveness of orthodontic treatment with clear aligners, improving anterior root torque, rotation, and mesio-distal (M-D) movement; they are also important to increase posterior anchorage. However, some articles showed contradictory or not statistically significant results. Attachments also seem to improve intrusion, but the evidence about this movement, as well as extrusion, is lacking. No studies evaluated posterior bucco-lingual tipping/expansion. Further clinical trials are strongly suggested to clarify the influence of attachments and their number, size, shape, and position on each orthodontic movement.

Different biomechanical effects of clear aligners in bimaxillary space closure under two strong anchorages: finite element analysis

“…However, bodily movements are usually the desired movement patterns in extraction cases. To achieve this, multiple strategies are used to compensate for the control deficiency, such as distal tipping of the posterior teeth before space closure, adding attachments to the teeth, and designing specialized root control attachments [ 12 , 23 ]. To further facilitate orthodontists in accurately compensating for the control deficiencies of CAs, we analyzed the effect of different anchorages on the rotation center of the tooth.…”

“…Nowadays, to manage malocclusion and facial esthetics, the proportion of extraction cases has reached 30% [ 11 ]. To allow these patients to benefit from CA treatment, multiple strategies have been adopted to compensate for the mechanical and retention deficiencies, for instance, adding extra overcorrection to the target position, designing specific attachments to enhance retentive performance, and using a long power arm to retract the anterior teeth [ 9 , 12 – 14 ]. Notably, all these orthodontic strategies should be based on established anchorage control plans.…”

Effectiveness of the attachment position in molar intrusion with clear aligners: a finite element study

“…The attachment position is essential for intrusion. However, no studies have evaluated the effects of different attachment positions on the intrusion movement of the maxillary molars [11].…”

Force delivery modification of removable thermoplastic appliances using Hilliard precision thermopliers for tipping an upper central incisor

“…Consequently, the dimensioning of the bumps or power ridges must be taken into account in the current aligner technology to avoid exceeding the physiological limits of tooth movement. Although the majority of the current literature reports lower root resorptions under aligner therapy [ 30 ], special modifications, such as bumps or power ridges, are almost not differentiated in these analyses [ 31 , 32 ]. However, it is a fact that the root resorptions observed in aligner therapy are generally concentrated in the maxillary incisors [ 33 ], i.e., where additional forces for complex movements are most frequently needed.…”