Interproximal reduction (IPR) has been used for decades as a means to recover space and decrease the need for dental extractions during orthodontic treatment. However, far too often, IPR is performed only where dental crowding is present, without taking into account the golden ratio between the upper and lower dental arches identified by the Bolton Index. This can lead to iatrogenic interarch disharmony and therefore unsatisfactory finalization of orthodontic treatment. On the contrary, once a Bolton Index alteration has been diagnosed, IPR is the only method capable of bringing it back to ideal values, allowing the orthodontist to fully respect Andrews' six keys of the occlusion. Another element of extreme importance for the aesthetics of the smile, which is often underestimated by orthodontists, is the research and respect for the golden proportion existing between the height and the mesio-distal diameter of the dental elements and between the mesio-distal width of the six teeth of the upper frontal sector: in the case of disproportionate dental elements, IPR is, once again, the only tool for the orthodontist to re-estabilish the optimal proportions of the teeth. Hence, IPR is a very powerful and too often underestimated tool in the hands of the mindful orthodontist, and in many cases it must be used even in the absence of dental crowding! Aligner therapy is particularly synergistic with IPR, because the digital setup provides data related to the Bolton Index and the size of dental elements, allowing the orthodontist an extremely precise planning of IPR.


Learning Objectives
After this lecture, you will be able to know the advantages of interproximal reduction as a means to recover arch space
After this lecture, you will be able to understand the importance of the Bolton Index
After this lecture, you will be able to plan interproximal reduction in order to improve dental proportions