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The increase in orthodontics and the risks that might arise

23 October 2019

With the clear aligner market increasing around the world, dentolegal adviser Dr Simon Parsons looks into the complexity of orthodontics, the potential limitations and the risks that might arise.

The worldwide USD $3bn per annum clear aligner market is forecast to continue growing by around 21% over the five year period of 2018-2023.1

General dentists with limited prior orthodontic training may be drawn to the promise of aligner systems that seem almost to ‘do it all’ and are increasingly offering this treatment to their patients. This opportunity to augment practice revenue, and grow one’s clinical skill set, brings in its wake the increased likelihood of complaints and claims when the treatment outcome is compromised or patient expectations have not been met.

The provision of orthodontic treatment by general dental practitioners can be risky, even when it involves modest tooth movement. The importance of case selection cannot be overstated and unmet expectations can trigger litigation. When cases arise, it is not uncommon for general practitioners to be questioned about the extent and adequacy of their training to undertake orthodontic treatment.

A recent study carried out in the United States investigated the different perceptions of case complexity between orthodontists, GDPs, orthodontic trainees and dental students. The study concluded that orthodontists and orthodontic trainees “…had better judgments for evaluating orthodontic case complexity. The high correlation between orthodontic professionals' perceptions and DI scores suggested that additional orthodontic education and training have an influence on the ability to recognize case complexity”.2

Looking at the limitations

Although clear aligner systems have some clinical advantages and are based on sophisticated technology, they have limitations in the amount and type of tooth movement that can be achieved.3

Furthermore, there is some evidence of unexpected risks with aligner therapy, such as breathing difficulty, swelling of the lips, throat and tongue and even anaphylaxis.4 These risks must be appropriately managed.

As a third party usually provides the initial treatment planning for aligner cases, it may be tempting to delegate the decisions in a patient’s orthodontic management to an unseen party who is relying on supplied photographs, scans and models. Inexperienced dentists may not recognise that targets for tooth movement, derotation and intrusion or extrusion are ambitious. The achievement of a successful aesthetic and functional result may well depend on completing all these actions, and the treating dentist will be responsible for the treatment outcome should it fail to meet patient expectations.

The high costs of orthodontic care, and the patients’ capacity to evaluate the outcome, will go a long way towards the patient’s perception of success. There will undoubtedly be high expectations on the part of the patient and, if these are not met, referral for specialist treatment may be indicated which will incur additional costs. Uncertainty can exist in the minds of general dentists and patients as to who is responsible for any costs associated with corrective treatment, or when a patient transfers to another practitioner prior to completion. So how might dentolegal risk be reduced when general dentists consider offering clear aligner treatment?


Making an accurate diagnosis is the first step in understanding patient suitability for treatment by a general dentist. Poor case selection is frequently the root cause of dissatisfaction down the line. Pre-treatment assessment might include detection of unfavourable facial profiles, marked asymmetries, a deep overjet and overbite or substantial midline discrepancies which may prove difficult to manage with clear aligners alone. It can be tempting to offer patients an improvement in tooth position through aligner therapy while unknowingly ignoring underlying factors that may make success almost impossible to achieve without specialist care.

Appealing as it may be to take on a case, it is always wise to discuss alternatives to clear aligner therapy with a patient, including such options as no treatment and specialist referral. Simply because a patient has attended for a consultation or sought information about clear aligners - sometimes as a result of internal marketing – does not mean that this is the only option that should be considered. The dentist must consider all other viable alternatives in consultation with the patient as part of the consent process.

Understanding the patient’s expectations from the outset is essential to avoid future disappointment. Some patients who seek aligner therapy may present with minor orthodontic needs, but may expect absolute perfection in tooth alignment. Indeed, their expectations may involve other factors which they, themselves, do not fully understand such as the shape of individual teeth or the colour of some or all of their teeth. Any non-compliance with aligner wear or post-treatment retention may compromise the outcome and achievement of ideal results. The clinical presentation, diagnosis, treatment options, risks, benefits and costs, importance of compliance with advice and tempering of unrealistic patient expectations should all be documented in the clinical records together. These entries will be scrutinised in the event of any investigation or inquiry.

During treatment

Problems such as speech concerns, excessive salivation, mouth soreness, aligner breakage and aligner loss may all impact on treatment effectiveness. Patients may dislike attachments placed on teeth, fail to use elastics or other adjuncts to treatment or decline to undergo interproximal tooth reduction. A prospective patient needs to be aware of these issues, before and during treatment, so that there are no surprises and disagreement as treatment progresses.

Despite the best efforts of both the patient and the clinician, sometimes treatment does not progress as well as expected. Dentolegal risk can be reduced through regular patient reviews in surgery rather than an ‘arm’s length’ approach of minimal treatment supervision. Early detection of problems enables prompt correction where possible and helps to avoid escalation of problems and further patient dissatisfaction. Our experience is that it is wise to refer patients to specialist providers promptly whenever the efficacy of aligner treatment seems to be in doubt. This can mitigate the risk of further complications while also optimising the chance of a favourable overall treatment outcome.

Post treatment

While all orthodontic treatment carries risk, some risks may persist upon treatment completion. Patients may be unhappy with the overall treatment outcome and request refinement, retreatment or referral. The general dentist will need to evaluate with the patient how closely the result matches with the pre-treatment projection and the individual patient’s long term expectations. Retreatment or referral may carry financial implications for both parties and is best understood before treatment commences (through an explanation) rather than after treatment has finished (via an excuse). Devitalised teeth, relapse, or – particularly with aligners – a failure to achieve adequate occlusal contacts may also occur. Effective retention is essential if relapse is to be avoided. 

Case assessment

To manage risk with clear aligner cases, careful case assessment is key. Some aligner systems allow prediction of the final outcome and alteration of the treatment parameters to suit the objectives of the patient and the clinician. These are preferred over a ‘one size fits all’ approach. Dental Protection recommends any treatment proposal be thoroughly checked prior to finalisation of the treatment plan by the treating clinician to ensure that proposed tooth movements are within a predictably reliable range.

General practitioners have the advantage of coordinating a patient’s total dental care, and this provides scope for considering preventive and restorative needs within the overall plan. The general practitioner is well placed to consider any pre-existing limitations to effective tooth movement, such as implants and bridgework, while also understanding how to manage restoration fracture or loss during aligner treatment. Are you able to deal with complications if they arise? Do you have the knowledge and skill necessary to identify and manage likely complications that might occur during the treatment phase?

As with any treatment that incurs significant financial and time costs, it is always prudent to approach clear aligner therapy alongside other necessary treatment rather than as a standalone treatment. Despite a patient’s understandable desire to get on with the cosmetic component first, it is often wise to schedule orthodontic treatment towards the latter stages of any treatment plan. Ensuring all periodontal, endodontic and restorative issues have been addressed first means that the patient is more likely to be a suitable candidate for orthodontic treatment.

Learning points

  • Take models/scans, radiographs and photographs as part of a preoperative assessment and evaluate these thoroughly before discussing the feasibility of aligner therapy with your patient.
  • Clearly outline the costs of care, including the costs of replacement aligners and retainers. Ensure patients understand when payments are due.
  • Carefully explain the process, including composite resin attachments if required, and the importance of compliance. Explain that, occasionally, a specialist referral may be necessary if things do not go to plan. Establish who will be responsible for the costs of such a referral.
  • Be on your guard towards patients with unrealistically high expectations or those who seem in a hurry to commence treatment without due consideration to their other treatment needs (such as caries or periodontal issues).
  • If in any doubt as to the likelihood of success, consider referral of a patient to a more experienced colleague or specialist.
  • If you are not a specialist orthodontist, make sure that the patient is aware of this and offer a referral to a specialist as one of the options for treatment.


1. (2019). Clear Aligners Market 2018 Global Trends, Key Vendors Analysis, Industry Growth, Import - Reuters.

2. Heath EM, English JD, Johnson CD, Swearingen EB, Akyalcin S, Perceptions of orthodontic case complexity among orthodontists, general practitioners, orthodontic residents, and dental students, Am J Orthod Dentofacial Orthop. 2017 Feb;151(2):335-341. doi: 10.1016/j.ajodo.2016.06.045.

3. Ke Y, Zhu Y, Zhu M, A comparison of treatment effectiveness between clear aligner and fixed appliance therapies. BMC oral health 19(1), 24. doi:10.1186/s12903-018-0695-z (2019)

4. Allareddy, Veerasathpurush et al. (2017). Adverse clinical events reported during Invisalign treatment: Analysis of the MAUDE database. American Journal of Orthodontics and Dentofacial Orthopedics, Volume 152, Issue 5, 706 - 710