Orthodontic clear aligners have revolutionized the field of orthodontics. The ability to provide patients with a discreet and convenient option for straightening their teeth has made clear aligners increasingly popular. However, a new study has highlighted the potential issues associated with directly printed aligners (DPAs) when it comes to their surface quality after intraoral usage. DPAs, which are directly printed, demonstrated increased surface roughness and porosity after only one week of intraoral usage.

This study was published in American Journal Of Orthodontics and Dentofacial Orthopaedics by Sara Eslami and colleagues. The study investigated the effects of one week of intraoral usage on the surface roughness of DPAs and compared them with commercially produced Invisalign aligners.
The research consisted of four groups, with 34 samples in each group. Two groups represented unused control aligners (DP-Ctr and INV-Ctr), while the other two groups included patients currently using DPAs (DP-Clin) and Invisalign aligners (INV-Clin). After one week of intraoral usage, samples were taken from the buccal surface of the maxillary right central incisor on each aligner.
The analysis of the samples revealed significant differences between DPAs and Invisalign aligners. One week of intraoral usage led to a noteworthy increase in surface roughness and porosity of DPAs. This may raise concerns as increased surface roughness and porosity can potentially promote bacterial adhesion and biofilm formation within the aligners.
In contrast, Invisalign aligners showed a significant reduction in surface roughness and porosity parameters after intraoral use, which is generally considered a positive outcome, as smoother surfaces are less conducive to bacterial adhesion.
This study has important implications for orthodontic treatment, particularly regarding the choice of clear aligners. This could potentially lead to an elevated risk of bacterial adhesion and biofilm formation within the aligners, which is a significant concern for patients' oral health. In contrast, commercially produced Invisalign aligners showed improved surface quality following intraoral service, which may be seen as a more favorable outcome.
Orthodontists and patients may need to consider these findings when selecting the type of clear aligners to use in their treatment plans. Ensuring the best possible surface quality and minimizing bacterial adhesion should be a priority in orthodontic care.
Reference:
Eslami, S., Kopp, S., Goteni, M., Dahmer, I., & Sayahpour, B. Alterations in the surface roughness and porosity parameters of directly printed and Invisalign aligners after 1 week of intraoral usage: An in vivo prospective investigation. American Journal of Orthodontics and Dentofacial Orthopedics: Official Publication of the American Association of Orthodontists, Its Constituent Societies, and the American Board of Orthodontics,2023. https://doi.org/10.1016/j.ajodo.2023.07.013