Adhesive-free bonding of metal buttons to clear aligners

Dental Tribune International

Wed. 20. August 2025

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HANOI, Vietnam: Conventional methods for bonding auxiliary buttons in aligner therapy detract from their substantial clinical benefits for elastic traction in cases requiring heavier or more complex forces. Drawbacks include occasional debonding, increased chair time and decreased aligner translucency when resin margins are visible. A recent technical report outlines a novel thermal embedding technique that aims to eliminate these limitations.

The report, by Dr Viet Anh Nguyen, a researcher in the Faculty of Dentistry at Phenikaa University in Hanoi, presents a clinical protocol that employs thermal softening and mechanical engagement to embed auxiliaries directly into aligners rather than the more usual method of attaching buttons to teeth. By conducting heat into the aligner polymer through the stainless steel buttons, localised softening permits the button flange to partially sink into the polymer. The polymer, upon cooling, resolidifies around and mechanically interlocks with the auxiliary, achieving an adhesiveless bond.

Dr Nguyen writes that clinical observations have confirmed mechanical engagement without debonding under standard forces, indicating that the desired bond strength is achieved. The main indications for the technique are cases requiring immediate elastic traction, including treatment of Class III malocclusion and exposure of impacted canines, as well as a backup for situations where precision cuts are unavailable. It is not recommended for use with materials with low thermal resistance.

The report concludes that, although further studies are needed to validate the technique, its mechanical efficacy has been demonstrated. Dr Nguyen explained to Dental Tribune International: “In day-to-day orthodontics, retention has been reliable over the typical aligner wear interval. Because most trays are changed every one to two weeks, the attachment only needs to last a short period. Even in cases where a single button must remain on the same tray for many weeks, such as on retainers, we have found the method to perform well.”

He further explained the technique’s benefits for clinical efficiency and the aesthetic advantages to aligner therapy. “Clinically, adhesiveless bonding streamlines the visit: there is no primer or polymerisation, so the set-up is faster. It also reduces costs because clinicians do not need to stock bonding primers and adhesives. After straightforward training, a trained dental assistant can perform the procedure under appropriate supervision—subject to local regulations—which helps standardise the workflow and free up dentist time.”

The report, titled, “Adhesiveless bonding of metal buttons to clear aligners: A technical report”, was published online on 28 July 2025 in the Cureus Journal of Medical Science.