Tunnel Attachments Paired with Invisalign® for Orthodontic Leveling and Aligning – A Randomized Controlled Clinical Trial

Abstract

Background: Clear aligner therapy has yet to overcome limitations in achieving certain orthodontic tooth movements, more specifically rotations of conical teeth, vertical movements, correcting angulation and inclination. A novel hybrid approach which incorporates a wire into computer-designed Tunnel Attachments used in conjunction with clear aligners to achieve their predicted goal. Specific Aims: 1) Formally describe the novel computer-generated Tunnel Attachments for the purpose of utilizing archwires in conjunction with clear aligner therapy. 2) Characterize and compare the percent accuracy of predicted over achieved outcome of this approach in overcoming non-tracking tooth movements in predicted Invisalign® outcomes as compared to a traditional Invisalign® refinement as a control. Materials & Methods: 1) A description of the evolvement of the approach while testing its validity to refine the developed software, geometry and size of Tunnel Attachments, transfer method as well as materials and archwires used. 2) A parallel-arm prospective randomized controlled clinical trial. Twenty-six non-tracking segments were included. The amount of predicted tooth movement was superimposed and compared to the amount achieved utilizing Dental Compare SoftwareTM (VisionX, LLC). Types of tooth movement studied were mesial-distal tip, buccal-lingual tip, extrusion, intrusion, and mesial-distal rotation. Results: 1) A case report describing the proposed method on a non-tracking tipped lower second premolar after extraction treatment with Invisalign®. 2) The percent accuracy was higher for Tunnel Attachment group compared to the control group for mesial-distal crown tip (56.5% vs. 42%, p = 0.004), buccal crown tip (62% vs. 52%, p = 0.012), extrusion (59% vs. 42%, p 0.001), intrusion (60% vs. 43%, p 0.001), rotation (59% vs. 47%, p = 0.001), while no difference was found between the two groups in lingual crown tip. Conclusion: Despite the design not allowing the wires to fully express, pairing Tunnel Attachments with clear aligner therapy is effective in improving their achieved outcome. The full potential of this hybrid approach is yet to be explored.