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Anna Iliadi: Materials and achieved tooth movement still sub-optimal in clear aligner orthodontics

Tampere University
LocationKalevantie 4, Tampere
City centre campus, Main building, auditorium D11 and remote connection
Date12.4.2024 9.00–13.00
Entrance feeFree of charge
Anna Iliadi seisoo meren rannalla, taustalla on laivoja. Hänellä on yllään vaalea takki.
Photo: Katerina Pappa
In her doctoral dissertation, DDS MSc Dr med dent Anna Iliadi delves into the realm of orthodontic treatment with clear aligners, examining the integration of new materials and clinical implications. Her research encompasses the assessment of the accuracy of tooth movement achieved with clear aligners, the clinical effectiveness of clear aligner treatment and the effects of cleansers and attachments on the surface topography and structure of clear aligners.

The concept of fabricating aligners on setup casts for orthodontic tooth movement dates back to 1945. Clear aligners have gained significant traction in recent years, largely attributed to aggressive marketing campaigns from manufacturers. In 2014, 89% of orthodontic specialists in the USA had treated at least one case with clear aligners, whereas in a recent study published in 2023, aligners were used by 65% of orthodontists members of the American Association of  Orthodontists in Canada and the US. This revolutionary development was driven mainly by the increasing demand for invisible orthodontics and aesthetic considerations, primarily across adult patients.

In recent years, there has been a significant rise in the utilization of orthodontic aligners for treating various malocclusions. However, despite their widespread use, there remains a lack of conclusive evidence regarding several critical aspects.

“Contrary to many medical fields, it is a common place in orthodontics that novel marketed products and treatment approaches are clinically adopted based on advertisement policies, apparently without the appropriate clinical evidence to back any claims by the manufacturers,” says Anna Iliadi.

Despite their increasing popularity, concerns have emerged regarding the effectiveness of aligners compared to traditional fixed orthodontic appliances.

“While aligners offer advantages such as enhanced comfort and improved aesthetics, doubts persist regarding their clinical effectiveness. Additionally, the surface morphology alterations of attachments bonded to teeth during orthodontic treatment with aligners has not been previously studied”, Iliadi states, emphasizing that observations in clinical settings often reveal instances of cracked surfaces and debonding of attachments, prompting concerns about potential health risks if patients swallow such particles.

“The characteristic defects created on the attachments after removal and reseating, highlight the critical role of friction between the aligner and the composite attachment. The release of biological active compounds from attachment surfaces due to this unfavourable outcome has yet to be studied,” says Iliadi.

The findings of the present thesis shed light on the dynamics of orthodontic treatment with aligners. It appears that the thickness of aligners has minimal impact on the initial forces and moments exerted by aligners under specific circumstances. Furthermore, the study unveils inconsistencies in the accuracy of canine rotations and incisor intrusions, implying that over-correcting these movements could potentially minimize the necessity for refinement.

Surprisingly, aligner-based orthodontic treatment may yield less favorable outcomes compared to fixed appliances, as gleaned from current clinical evidence. Moreover, it’s worth noting that the use of cleaners with certain solutions may affect the chemical structure and surface of certain aligner materials. The present thesis also uncovers characteristic abrasion-induced defects created by removal and reseating of the aligners, which may potentially release particles in the oral environment.

Overall, Anna Iliadi’s research highlights the current strengths and limitations surrounding orthodontic treatment with aligners. These limitations underscore the importance of tailoring their usage to meet the specific needs of each patient in order to optimize the treatment outcome.

Public defence on Friday 12 April

The doctoral dissertation of DDS MSc Dr med dent Anna Iliadi in the field of orthodontics titled Materials and clinical aspects of orthodontic treatment with aligners will be publicly examined at the Faculty of Medicine and Health Technology at Tampere University at 12 o’clock on Friday 12.4.2024 at the City centre campus, Main building, auditorium D11 (Kalevantie 4, Tampere). The Opponent will be Professor David Rice University of Helsinki. The Custos will be Professor Timo Peltomäki.

The doctoral dissertation is available online

The public defence can be followed via remote connection