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Are Clear Aligners as effective as conventional fixed appliances?

Updated: Dec 1, 2022

A systematic review of clear aligners and older methods of tooth correction.

Malocclusion, in any of its glory, be it tooth crowding, crooked teeth, protruding incisors, or open bites is not a favorable trait. As the obsession with aesthetics continues to intrigue individuals, more and more of the population are seeking orthodontic relief for their malalignments in an attempt to achieve the smile they’ve always wanted.

Clear aligners are increasingly being favored by doctors and patients due to more flexibility, higher comfort and easier treatment - while providing the same accuracy as conventional fixed appliances.

For over a hundred years or so, traditional braces have cemented their role in the orthodontic environment. Being the oldest and the most reliable treatment for misaligned teeth, there have been many studies that support the narrative. However, as time has progressed, there have been new innovations in the market that have catered more to aesthetics in conjunction with efficacy. Clear aligners are one of these highly praised innovations.

In recent years, a good chunk of the population has flocked to the support of clear aligners, mainly due to their characteristic of being virtually invisible to the human eye. Not only that but much evidence-based research has also found that clear aligners facilitate a less painful and more hygienic route of orthodontic tooth movement.

Although clear aligners are becoming increasingly popular in the wake of publicization by celebrities on social media and the general rise of white label clear aligners in Europe, whether they can completely replace traditional braces is still up for debate. This study strives to answer the pounding question - are clear aligners as effective as conventional fixed appliances?

This study was conducted by two authors from Scotland - Shaira K. Kassam and Fleur R. Stoops. It was published by Evidence-Based Dentistry in 2020.

Are clear aligners as effective as conventional fixed appliances?

Kassam SK, Stoops FR(

Evid Based Dent. 2020 Mar;21(1):30-31. doi: 10.1038/s41432-020-0079-5.

What they asked

The authors of this study aimed to evaluate the characteristics of clear aligners and whether they are as effective as conventional fixed appliances in successful orthodontic tooth movement.

What they did

They conducted the study based on the following criteria:

  • Participants: Orthodontic patients undergoing treatment with removable thermoplastic retainers compared with conventional fixed orthodontic appliances of either self-ligating or tip-edge bracket systems. The mean age of patients was between 15 and 33 years.

They conducted an electronic search of six databases namely: Scopus, Web-of-Science, PubMed, Cochrane, Clinical Trials, and Grey Literature. They also searched references in eligible studies with no restriction on language.

Two members of the research team independently selected the articles which fulfilled the inclusion criteria and compared results prior to data collection, while a third-party examiner helped resolve disagreements.

They also had the study analyzed for the presence of bias.

What they found out

Out of a total of 59 studies that were selected, only 55 were eligible when vetted through the inclusion criteria. In the end, only 4 articles were included (3 non-randomized and 1 randomized controlled trial). A total of 96-182 patients were included in the study.

When assessed for bias, they found that out of the 3 non-randomized trials that were evaluated and scored using the Methodological Index for Non-Randomized Studies (MINORS), 3 were found to be at moderate risk of bias, whereas 1 was considered high. The randomized controlled trial, on the other hand, were analyzed using the Cochrane Collaboration Common Scheme for Bias and were deemed to be at low risk of bias.

They concluded that while Clear Aligners was able to provide successful alignment, it did pose difficulties in achieving occlusal contacts, buccolingual inclination, and vertical movement of the teeth. One study even suggested that patients treated with Clear Aligners were prone to relapse as compared to conventional fixed appliances.

Some studies were able to show that aligners, especially OEM clear aligners, could result in a much shorter overall treatment time. However, the final occlusion was not favorable for most. The outcome of the randomized trial showed that aligners can be successful in treating Class I malocclusions in extraction cases.

What we can conclude

The results of this systemic review suggested that there was no significant difference in treatment time with either clear aligners or conventional fixed appliances. Additionally, clear aligners were effective in crowding cases, but had limitations in achieving favorable outcomes in the anterior-posterior position and final occlusion. There was also a certain risk of relapse post-treatment, with removable aligners.

However, aligners can be removed for meals and oral hygiene, and thus offer patients significantly more flexibility and comfort in everyday life than fixed applications. Nevertheless, clear aligners continue to enjoy increasing popularity among patients and doctors alike, as greater investments in large clear aligner manufacturer companies enable continuous improvement and innovation in the field of invisible orthodontics and OEM clear aligners.

What are you waiting for?


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