Which of the following can negatively impact orthodontic treatment stability?

Inconsistent use of retainers after orthodontic treatment is a significant factor that can negatively impact the stability of the treatment results. Retainers are used to maintain the new position of the teeth after braces or other orthodontic appliances have been removed. During the first few months or even years after treatment, teeth are particularly prone to relapse—that is, they may drift back toward their original positions. A consistent retainer routine helps to counteract the natural tendencies of the teeth to shift. When patients are inconsistent in wearing their retainers, they increase the likelihood of experiencing movement of the teeth, which can lead to a compromise in the treatment's stability and the aesthetic outcomes achieved.

Conversely, factors such as excellent oral hygiene and regular follow-up appointments typically contribute positively to the treatment process, ensuring optimal conditions for dental health and providing opportunities to address any issues that may arise. Age-related changes in patients can influence treatment outcomes but are generally less controllable compared to the direct impact of retainer wear on tooth position maintenance. Thus, consistent retainer use stands out as a crucial practice for preserving the results of orthodontic treatment.