IPR — Interproximal Reduction UK

IPR should not be painful because enamel has no nerve supply. Patients usually feel vibration, pressure, or cold water spray. If gum tissue is inflamed or the strip contacts soft tissue, it can feel uncomfortable. Tell the clinician immediately if it hurts.

Conservative, properly planned interproximal reduction is a long-established orthodontic technique and should not damage a healthy tooth. Only a fraction of the enamel thickness is removed from the contact point between two teeth, the surface is polished afterwards, and fluoride is usually applied. The risks come from how it is done rather than from the technique itself: taking too much enamel, doing it without measuring or planning, leaving rough unpolished surfaces where plaque collects, or performing it on someone whose oral hygiene is already poor. Enamel does not grow back, so ask what total amount is planned, where, and why, before you consent.

IPR is not needed in every Invisalign or clear aligner case — plenty of treatments are completed without removing any enamel at all. It becomes likely when there is crowding but no room to expand the arch, when the teeth are triangular in shape so that reshaping the contact points reduces the chance of black triangles, or when a tooth needs slimming to rotate into line. Your ClinCheck or equivalent treatment simulation should show exactly which contacts are marked for IPR, how much at each, and at which stage in the sequence. Ask to see it, and ask what the alternatives would be in your case.

You can refuse interproximal reduction — it requires your consent like any other procedure, and no clinician should proceed without explaining it first. What matters is understanding what changes if you decline. Space has to come from somewhere: without IPR the options are widening the arch, tipping the front teeth forward, accepting a less complete result, switching to fixed braces which offer different mechanics, or extracting a tooth in a genuinely crowded case. Extraction removes far more tooth structure than IPR does. Ask your clinician to set out the alternatives and their trade-offs in writing, then decide.

Each contact point typically has 0.1 to 0.5 mm of enamel removed — far less than the total enamel thickness of around 1.5 to 2.5 mm on most teeth. The total planned IPR for a case is documented in the treatment plan and should be disclosed before you consent. Enamel removed by IPR is not replaced, so knowing the total amount helps you make an informed decision.

IPR does not cause black triangles by itself. Black triangles occur when gum tissue does not fill the space between teeth at the gum line — usually because the teeth have a triangular shape with wider contact points near the gum than at the edges. In some cases, IPR performed to reshape triangular contact points actually reduces the risk of black triangles forming after alignment, because slimmer, more rectangular contact points allow the papilla to sit higher and fill the space more completely.