What Is IPR in Invisalign?

What this means for your treatment decision

It is a planned, measured procedure performed only on certain teeth and only by the amount specified in your treatment plan — it is not performed broadly or by estimation in the chair.

Why creating small amounts of space is sometimes necessary

Crowded teeth often need somewhere to go as they straighten, and that space can come from a few different sources: slightly widening the dental arch, moving teeth further back if a gap exists, or removing very small amounts of enamel between select teeth. IPR is generally considered a conservative alternative to extraction in cases involving mild to moderate crowding, since it avoids removing an entire tooth, but it is only appropriate up to a certain amount of needed space; more significant crowding may still require extraction or other approaches.

How much enamel is actually involved

The amount of enamel removed during IPR is intentionally very small, typically measured in fractions of a millimeter per contact point, and planned precisely based on your digital treatment plan rather than performed freehand. Enamel does not regenerate once removed, which is exactly why the planned amount is calculated carefully in advance and why a clinician, not a general estimate, should determine how much space is actually needed and from which specific contact points.

How the procedure is typically performed

• A thin strip, disc, or fine bur is used between two specific teeth to remove enamel in small, controlled increments
• Measurements or spacing gauges are often used to confirm the exact amount removed matches the plan
• The treated surface is polished smooth afterward to leave a comfortable, rounded contact rather than a rough edge
• A fluoride application is sometimes used afterward to support the treated enamel surface

What it feels like during and after

IPR is generally performed without anesthesia because it involves the outer enamel layer, which does not contain nerve endings, so most patients describe the sensation as mild vibration or pressure rather than pain. Afterward, some patients notice brief, mild sensitivity to cold in the treated area for a short period, which typically settles on its own within a short time.

Is removing enamel ever a long-term concern

Because the amount removed during planned IPR is small and limited to between-tooth surfaces rather than the biting or visible outer surface, it is not generally associated with weakening the tooth or increasing long-term decay risk when performed within standard planned limits. That said, it is not reversible, which is why it is used selectively, based on a specific calculated need in your plan, rather than applied broadly as a default strategy.

How IPR fits into the overall aligner sequence

IPR is usually scheduled at specific points within the aligner sequence, often matching the stage where the digital plan anticipated the additional space being needed, rather than all at once at the very beginning. Your clinician will indicate in advance which stages involve IPR so you know what to expect at each visit.

Caring for teeth after IPR

• Continue regular brushing and flossing as usual; IPR does not change your basic hygiene routine
• Expect any mild cold sensitivity to resolve within a short period; mention it at your next visit if it persists or worsens
• Keep wearing aligners as prescribed so the newly created space is used as the plan intended, rather than closing unpredictably on its own

Questions worth asking before IPR is performed

• Which specific teeth and contact points are planned for IPR, and why those specific locations
• Roughly how much space is intended to be created in total across the plan
• Whether IPR will be done in one visit or spread across multiple stages
• What alternatives, such as arch expansion or extraction, were considered for creating the needed space

Questions patients ask