What are Invisalign refinements, and why might I need another set of aligners?

Why the first series can fall short of the plan

Your orthodontist sets the target positions in the aligner software, and teeth do not always reach them with the first series. Two AJODO studies that measured planned against achieved movement, by Kravitz and colleagues in 2009 and Haouili and colleagues in 2020, found achieved movement fell short of the plan on average, with relatively the same strengths and weaknesses in both. Some movements lag more than others: extrusion was the least accurate in the 2009 study, and incisor intrusion and canine rotation the most inaccurate in the 2018 Charalampakis study.

The American Association of Orthodontists (AAO) names the wider pressures on any plan: moving teeth is “a complex biological process”, inconsistent wear can extend treatment or compromise the results, and aligners “may not work as predictably” for severe malocclusions, significant tooth rotations and large gaps. Kravitz and colleagues wrote that a better understanding of the Invisalign system “might help” reduce the need for case refinement, and Patterson and colleagues (AJODO, 2021) say refinements may be necessary to address problems created during treatment.

What your orthodontist does with a new scan

A refinement is planned from where your teeth are, not from where the first plan expected them. In the research, the refinement stage starts from new intraoral scans: Castroflorio and colleagues, writing in Progress in Orthodontics in 2023, treated the refinement-stage scans as the actual outcome of the first set of aligners. Your orthodontist plans the further series from that outcome, and whether a plan needs one, and when, is your orthodontist's call.

Tracking has its own definition in the practice's guide to Invisalign treatment time: “how well your teeth are following the aligners.” Questions about cost go to the cost of Invisalign page and to your consultation.

Your part at home

Wearing each aligner as prescribed is the part of the plan you control. In the AAO's comparison of aligners and braces, “The key responsibility is wearing them as prescribed”, so wear each aligner as many hours a day as your orthodontist prescribes and change trays on the schedule your orthodontist sets, the rule the Invisalign treatment page gives. The practice's own advice adds seating each aligner fully when you put it in; what Invisalign chewies do for seating is covered separately.

Changes worth a call between check-ins

Call the office when something changes between check-ins: a tray that stops seating fully, a lost or damaged aligner, or an attachment that comes off. The AAO says to contact your orthodontist immediately for advice if an aligner is lost or damaged, and the FAQ on the Invisalign in Marlborough page covers a lost tray. A loose attachment has its own page, what to do when an attachment falls off, and a tray that stops fitting raises the question of whether your orthodontist can tell aligner wear.