Do clear aligners have a greater environmental impact than fixed appliances?

We should all be concerned about the impact of our daily activities on the environment. Recently, the environmental impact of some aspects of medical health care has been investigated. However, very few studies have examined this issue for orthodontic treatment. 

This interesting new paper provides us with initial information on the environmental impact of fixed appliances and aligners. This is particularly relevant because the increasing use of plastics and the release of greenhouse gases are of concern.

A team from Nijmegen, Holland, did the study, and the European Journal of Orthodontics published the paper.

What did they ask?

The aim of this study was to

“Develop an estimate overview of the environmental impact of self-ligating metal brackets treatment compared with clear aligner treatment”

What did they do?

They carried out an analysis based on the treatment of four cases: two were non-extraction and two involved extractions. Each case was treated with either clear aligners or fixed appliances. The team obtained these cases from an experienced orthodontist in both fixed appliance and aligner care.

They obtained information on all environmental aspects of providing this treatment, and from this they constructed environmental indicators. These were

• Carbon footprint, expressed per kilogram of carbon dioxide equivalent. 
• Cumulative Energy Demand. This measures the total energy consumption throughout the life cycle of a treatment.
• ReCiPe 2016. This is a widely used method for evaluating the environmental impact of processes.

The data they used were provided by the manufacturers of the fixed appliances (Damon) and the clear aligners (Spark). They then combined this with data from the individual treated cases. This included the amount of materials, the materials’ life cycle, the impact of transport, and, most importantly, the multiple stages of clear aligner treatment.

What did they find?

They produced a large volume of complex data. I do not have the space to cover all of this in this post. However, the key findings were;

1. The carbon footprint for clear aligner treatment ranged from 20.6 to 24.7 kg of CO₂, while fixed appliance treatment was 0.22 kg CO₂.
2. The CED was in favour of fixed appliance treatment and showed greater energy waste with aligner treatment.
3. Fixed appliances created a lower environmental burden.

Their overall conclusions were:

“Within the limitations of a small sample size and simplified model, fixed appliance treatment showed a lower environmental impact than clear aligners.”

What did I think?

This was a very interesting yet complex paper to interpret. Importantly, the authors noted that the results are exploratory and that more research is certainly needed.

Nevertheless, the findings were logical. For example, there are many stages to aligner treatment. These include: 

• multiple 3D printed models
• thermoforming
• trimming and polishing
• the individual plastic wrapping and 
• international shipping

This is compounded by discarding the aligner after a week or two of wear. This process is repeated 30 to 40 times per patient. It was interesting to note that the author estimated that aligner therapy up to 2020 had already generated approximately 1,875 tonnes of plastic waste. This is certainly concerning.

In contrast, fixed appliances use comparatively small quantities of material and generate far less waste.

The authors made several suggestions to change this situation: 

• The use of recyclable polymers
• Biodegradable materials
• Direct 3D printing aligners
• An improved disposal programme

Final thoughts?

This paper addresses a very serious question that is relevant to us all. While the authors have made several assumptions that may overestimate the impact of aligners, there is a degree of logic to their conclusions. This area requires considerably more detailed investigation. I hope to see this team and others continue working on this over the next few years. We need to become more environmentally aware.

Until then, perhaps we need to consider the environment and sustainability when prescribing different types of treatment. This may influence our and our patients’ treatment choices.