Crowding can be a functional and aesthetic headache for patients, and orthodontic treatment is essential to solve such problems, or prevent them from getting any worse.
For some patients, orthodontics in the mixed or early permanent dentition is necessary and effective. Others may not urgently need orthodontics early in life, but choose to undergo treatment in adulthood. In each case, clinicians may need to create space within the dentition. This is achievable in a number of ways. Clinicians could expand the arches with removable, semi-fixed or fixed appliance, or perhaps even extract teeth in severe cases.[i]
One other solution is interproximal reduction (IPR), which has been hailed as minimally invasive, and is preferred by many clinicians due to decreased treatment times and prevention of interdental gingival retraction.[ii] Dental professionals should become familiar with the approach as acquiring IPR management skills may open up the potential for new and more complex treatments to be provided within the practice, without the need for referral.
Know your limits
IPR is an effective approach to space creation commonly employed in clear aligner orthodontics. By reducing the mesiodistal dimensions of the teeth, clinicians can facilitate movement, but it is an irreversible change to the tissue that requires meticulous planning and execution to carefully balance an effective result with minimal intervention.[iii]
The volume of space that can be created, whilst retaining aesthetics, function and the health of the dentition, is approximately 8mm in each arch when using IPR in lateral segments.iii This figure is debated, and there is no consensus on the maximum volume that can be removed from each tooth. Some researchers in the literature recommend that no more than 0.5mm is removed from the lower incisors and the upper lateral incisorsiii – others limit this further, stating just 0.3mm should be removed from incisors in the upper arch and 0.2 for incisors in the lower.[iv] Clinicians should consult the latest findings and take care considering each case individually.
There must be an awareness of the suspected risks in the workflow. Enamel roughness may promote plaque accumulation, leading to an increased risk of interproximal caries, gingival inflammation, gingival recession and increased sensitivity to extreme temperatures.ii
Whilst clear aligner therapy itself presents a reduced risk of plaque accumulation when compared to conventional fixed orthodontics, patients with susceptibility to periodontal diseases need to pay extra attention to their oral hygiene.[v] Considering the potential risks of IPR, it’s even more important to reinforce consistent oral hygiene habits with these patients.
Chasing predictability
As noted, clinical intervention to reduce enamel from the interproximal spaces requires great care to achieve optimal outcomes with minimally invasive actions. Today, there are a variety of digital solutions that aid the treatment planning process.
Studies in the literature have shown that orthodontists who have carried out IPR can attain predictable results when using mechanical oscillating systems in accordance with digital planning software.[vi] This result shows that, with little margin for error, current digital solutions can provide replicable results in vivo.
However, researchers have also found examples where the IPR planned with digital software has been seen to overestimate the amount of IPR needed. One study[vii] found that the IPR carried out in practice only replicated that of the digital plan was only accurate 44.95% of the time in the upper arch, and 37.02% in the lower arch. In the majority of cases, the performed IPR was lower than planned. This is beneficial for minimally invasive results, but speaks to the need for software that develops predictable results that best informs a treatment plan.
The discrepancies in findings could be due to the IPR method used and the experience of the clinician. No matter the case, it’s important to know that current digital solutions could be used as a guide, but should be subject to change where an optimal outcome can be created without excessive enamel reduction.
Developing skills
Clinicians should seek educational opportunities that allow them to develop the necessary skills to carry out IPR safely and predictably, in order to create space for orthodontic movement. The Clear Aligners (Level 1) course from IAS Academy provides this, with a hands-on session for dental professionals to put theory immediately into practice. The course, led by IAS Academy founder and clinical director Dr Tif Qureshi, is the ideal introduction into clear aligner orthodontics, and equips clinicians with the skills to treat a wide range of cases, and recognise when to refer for more complex treatment.
Carefully and justifiably removing enamel from the interproximal spaces can be an effective method of space creation in orthodontic treatment, but requires accurate treatment planning and a conservative approach. With experience, clinicians can implement this within their workflows, and generate optimal results without drastic treatment measures, such as tooth extraction.
For more information on upcoming IAS Academy training courses, please visit www.iasortho.com or call 01932 336470 (Press 1)
[i] Kulshrestha, R., Parkar, A., Vibhute, P. K., Chetan Patil, U. V., & Chandurkar, K. (2020). Methods of Gaining Space:-A Review. ES J Dent Sci, 1(2), 1012.
[ii] Barcoma, E., Shroff, B., Best, A. M., Shoff, M. C., & Lindauer, S. J. (2015). Interproximal reduction of teeth: differences in perspective between orthodontists and dentists. The Angle Orthodontist, 85(5), 820-825.
[iii] Dahhas, F. Y., Almutairi, N. S., Almutairi, R. S., Alshamrani, H. A., Alshyai, H. S., Almazyad, R. K., … & Gadi, S. A. (2024). The Role of Interproximal Reduction (IPR) in Clear Aligner Therapy: A Critical Analysis of Indications, Techniques, and Outcomes. Cureus, 16(3).
[iv] Frindel, C. (2010). Clear thinking about interproximal stripping. Journal of Dentofacial Anomalies and Orthodontics, 13(2), 187-199.
[v] Verma, S. K., Yadav, P. K., Bais, D. R. S., Singh, S., (2024). Impact of clear aligners on plaque and periodontal health. International Journal of Oral Health Dentistry, 10(1):9-12
[vi] Laganà, G., Malara, A., Lione, R., Danesi, C., Meuli, S., & Cozza, P. (2021). Enamel interproximal reduction during treatment with clear aligners: digital planning versus OrthoCAD analysis. BMC Oral Health, 21, 1-6.
[vii] De Felice, M. E., Nucci, L., Fiori, A., Flores-Mir, C., Perillo, L., & Grassia, V. (2020). Accuracy of interproximal enamel reduction during clear aligner treatment. Progress in orthodontics, 21, 1-7.
