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Mini-tubes appliance as an elective non-compliant auxiliary in case of aligners loss of tracking
*Corresponding author: Andrea Rombolà, Department of Orthodontics, Private Practice, Rome, Italy. andrearombola@icloud.com
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Received: ,
Accepted: ,
How to cite this article: Greco MA, Poerio MG, Rombolà A. Mini-tubes appliance as an elective non-compliant auxiliary in case of aligners loss of tracking. APOS Trends Orthod. doi: 10.25259/APOS_321_2025
Abstract
One common negative aspect of clear aligner treatment is represented by the loss of fitting when complex movements such as extrusion, rotations, and generic root movements are planned. In case of loss of tracking during aligner treatment, clinicians could use auxiliaries such as buttons and elastics or elastic chains in combination with aligners to recover the proper position of teeth. This approach is useful to avoid treatment time increase due to a new scan and a consequent new set of aligners, but this procedure increases patient’s compliance requests, leaving the correction of misfitting to the cooperation. For this reason, fixed conventional appliances can represent a solution, but it is difficult to combine brackets and wires with aligners because of the dimensions of the fixed appliance and the poor esthetics. An alternative, effective, smart, and non-compliant solution could be represented by a mini-tube appliance, in combination with aligners.
Keywords
Clear aligners
Mini-tubes
Tracking
INTRODUCTION
The loss of tracking during clear aligner therapy is usually expressed as a discrepancy between planned and achieved tooth movements [Figure 1]. This discrepancy is often due to complex movements such as real extrusion, rotations, or root movements, planned but not properly clinically realized.[1] For example a common problem is represented by IPR not perfectly exerted and power ridge placed in short clinical crowns: Both conditions lead to an undesired intrusion because in case of lack of proper space (insufficient IPR) the force expressed by the aligner can only produce intrusive resultant vector and in case of short clinical crowns power ridge pressure cannot produce torque movements but only a consequent intrusion. As described by Bowman et al.[2] in case of poor tracking, clinicians have several solutions to recover the fitting, such as aligners, chewies, bootstrap elastics that are attached to bonded buttons on the buccal and lingual surfaces of the lagging tooth at the gingival margin, or also triangular inter-arches elastics. These solutions require increased patient compliance to recover from the misfit, and for this reason, fixed mini tubes could be an ideal solution. The mini-tubes appliance (MTA, Osstem Korea) is constituted by 0.18” stainless steel silver-coated tubes covered by an external white resin part that makes the tubes poorly visible. Their mesiodistal width is 3 mm, so they can perfectly fit a cutout and do not require excessive plastic removal. In case of misfitting of one or more teeth, they can be bonded directly on the buccal or palatal surface of the teeth, not following the movement, and on the proximal teeth to create the proper anchorage. Since the tube slot is 0.018”, a 0.012” or 0.014” NiTi or CuNiTi wire can perfectly fit the tube and generate the extrusive force.
- Loss of tracking of the upper right central and lateral incisors due to extrusion planned but not achieved. (a) Loss of tracking of the upper right central and lateral incisors due to extrusion planned but not achieved. (b) close up highlighting the loss of tracking of the upper right central and lateral incisors.
Technique
To bond MTA, a few simple passages are necessary [Figure 2]:
- Four mini-tubes appliances have been bonded from the upper right canine to the left central incisor. A 0.012 NiTi thermal wire has been inserted while the plastic of the aligners has been properly cut palatally and the treatment has been slowed down to 10-day changes.
After etching, a small layer of a bulk composite on the buccal or lingual surfaces of the lagging tooth should be applied without curing (polymerization).
At this point, the mini tube can be placed in the middle of the first composite layer, paying attention to avoid the resin from flowing inside the tubes, and only after can it be cured. A useful tip can be represented by taking the tube by means of a tweezer that covers the mesial and distal ends of the MTA.
A second layer of composite is now necessary to cover the tube, taking care to avoid slot closure (obstruction). A micro brush can be gently used to distribute the second composite layer.
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This procedure can be repeated on adjacent teeth; The MTA is placed accordingly to the need for extrusion of the right central and lateral incisors, with a more gingival position on the teeth to be extruded and more occlusal on the anchorage teeth. The low friction exerted by the system allows the central and lateral incisors to extrude, while the reaction forces that tend to intrude the adjacent teeth can be managed by the plastic of the aligners covering the buccal and occlusal enamel surface [Figure 3].
Figure 3:- Right lateral loss of tracking recovered. The same 0.012 NiTi thermal wire has been reactivated by a direct bonding of the wire in a more gingival position to favor central incisor extrusion.
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Finally, a NiTi or CuNiTi wire can be inserted into the tubes using a small tip Weingart plier and allow it to work until the position of the tooth inside the aligner is recovered [Figure 4].
Figure 4:- Central and lateral incisor misfitting fully recovered in 3 months and ready to replace the attachment and follow the digital setup.
To avoid MTA debonding and to control the vertical movement , the aligner should be properly cut at the tube level to ensure a correct fit on the rest of the arch.
CONCLUSION
The use of Mini Tubes can represent a valid alternative troubleshooting solution compliance free in case of loss of tracking condition that may present when complex movement for aligners (such as extrusion) are planned. Their reduced dimension, their esthetics and the physical properties of low friction make the mini tubes appliance the ideal matching auxiliary to combine with aligners both in troubleshooting both in case of too complex movement planned for aligners. They can be used only for few months to achieve the desired movement, correcting the tracking loss and then removed to continue the aligner treatment avoiding the need for additional aligner phase.
Ethical approval:
Institutional review board approval is not required.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.
Financial support and sponsorship: Nil.
References
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