How do orthodontic treatments work together with IPR (interproximal reduction) to address dental crowding problems?

Firstly, interproximal reduction (IPR) is known as teeth stripping or shaving. The overall goal is to narrow the teeth by trimming off a small thickness of tooth enamel [1]. Often, the dentist will recommend this when the patient has:

• Proclined incisors
• Overjet correction
• Tooth crowding
• Discrepancies in tooth sizes

Orthodontic treatments like Invisalign is often paired together with an interproximal reduction [2]. In the past, IPR is done first at the beginning of the treatment process.

However, things have changed. With the advances with Invisalign, a process known as ‘staging’ can be used [3]. Tooth trimming will be done at a delayed stage where your dentist has better access to the surfaces that need to be adjusted. Meanwhile, for traditional braces, tooth stripping can be done at any point during the treatment process.

Interproximal stripping is done with all forms of orthodontic treatments to

1. Create space to correct mild crowding,
2. Proclination of teeth, where the upper and lower incisor teeth are being inclined forward,
3. Alter the shape of the teeth to minimise interdental spaces (black triangular spaces) to improve the smile aesthetics. It is not something new created with aligner treatment.

When patients have good facial profiles and minimal space is required to achieve aesthetic results, where extraction will create too much space, sometimes interdental spaces are done in these cases

References:

1. INTERPROXIMAL REDUCTION PATIENT INFORMATION LEAFLET BRITISH ORTHODONTIC SOCIETY. Accessed December 11, 2019.

2. Hellak A, Schmidt N, Schauseil M, Stein S, Drechsler T, Korbmacher-Steiner HM. Influence of Invisalign treatment with interproximal enamel reduction (IER) on bone volume for adult crowding: a retrospective three-dimensional cone beam computed tomography study. BMC Oral Health. 2016;16(1). doi:10.1186/s12903-016-0281-1

3. Boyd RL. Esthetic orthodontic treatment using the invisalign appliance for moderate to complex malocclusions. Journal of dental education. 2008;72(8):948-967. Accessed December 11, 2019.