Anterior IPR Bur for Clear Aligners: MR.BUR One Slice IPR Kit Clinical Guide

Abstract

Anterior interproximal reduction is commonly incorporated into clear aligner and fixed orthodontic treatment to create space, relieve crowding, correct tooth-size discrepancies and improve anterior tooth proportions. However, IPR between incisors and canines can be challenging because the contacts are narrow, visibility may be restricted and only a limited amount of enamel should be removed.

The MR.BUR One Slice IPR Kit is a 23-piece friction-grip diamond bur system developed for anterior and posterior interproximal reduction. The complete kit contains seven bur designs: X02, X03W, X04R, X05B, X03SF, XL04 and XL05.

For anterior IPR, the workflow uses X02 for initial contact access, X03W, X04R and X05B for progressive enamel reduction, and X03SF for super-fine finishing. XL04 and XL05 are designed specifically for posterior contacts.

This article explains the design, clinical applications and recommended use of the MR.BUR One Slice IPR burs for anterior teeth during clear aligner, Invisalign and fixed orthodontic treatment.

Keywords: anterior IPR bur, anterior interproximal reduction, One Slice IPR Kit, clear aligner IPR, Invisalign IPR, anterior enamel reduction

Introduction

Interproximal reduction, also called interproximal enamel reduction or orthodontic stripping, involves the controlled removal of a limited amount of enamel from the proximal surfaces of adjacent teeth.

Livas, Jongsma and Ren (2013) described IPR as an established orthodontic technique for creating space and managing tooth-size discrepancies. In the anterior region, it may be used to relieve mild-to-moderate crowding without extraction, improve tooth proportions and support planned orthodontic movement.

Common indications for anterior IPR include:

• Correcting Bolton tooth-size discrepancies
• Reshaping triangular incisors
• Reducing gingival black triangles
• Improving interproximal contact areas
• Supporting anterior tooth retraction
• Creating space during clear aligner or braces treatment

Digital clear aligner planning may prescribe a specific amount of reduction at selected contact points. However, the planned amount may not always be achieved clinically.

De Felice and colleagues (2020) found that the amount of enamel removed during clear aligner treatment was generally lower than the amount prescribed in the digital setup. Restricted access, contact tightness, operator technique, temporary tooth displacement and measurement errors may all influence the result.

Anterior IPR should therefore be performed progressively and verified repeatedly rather than completed through visual estimation alone.

Why Anterior IPR Can Be Difficult

Anterior contacts are generally narrower than posterior contacts, while the amount of enamel prescribed is often relatively small. This creates a limited margin for error.

Manual abrasive strips provide tactile control but may require repeated movements to open a tight contact. Applying excessive pressure may also temporarily compress the periodontal ligament, producing an apparent space that does not represent the actual amount of enamel removed.

Abrasive discs can remove enamel efficiently, but their size may interfere with visibility. Their rotating surfaces also require careful protection of the lips, gingiva and neighbouring teeth.

Some rotary burs intended for posterior IPR may be too thick for the smaller reductions commonly required between incisors and canines.

Har-Zion (2025) highlighted the need for specialised anterior IPR burs that improve access and visibility while allowing the transitional line angles to be restored. Anterior teeth should not be left with excessively flat proximal surfaces or sharp edges.

A controlled anterior IPR system should therefore support four stages:

1. Initial contact access
2. Progressive enamel reduction
3. Anatomical recontouring
4. Surface finishing

MR.BUR One Slice IPR Kit: Complete Bur Configuration

The MR.BUR One Slice IPR Kit contains 23 friction-grip diamond burs for anterior and posterior interproximal reduction. According to the supplied product specifications, the system includes five bur types used in the anterior workflow, two posterior slicing burs and the X02, which may be used for initial contact access in both regions.

According to MR.BUR product specifications, the burs are manufactured from medical-grade stainless steel and feature a three-layer diamond coating. They are intended for use with a friction-grip high-speed handpiece under adequate water cooling.

This article focuses on the five instruments used in the anterior workflow: X02, X03W, X04R, X05B and X03SF. XL04 and XL05 are included in the complete kit for posterior IPR.

X02 for Initial Anterior Contact Access

The X02 has a 0.2-mm head size and a 6.0-mm working length. It is designed for initial access through tight anterior or posterior contacts.

Its narrow profile may help establish a pathway between crowded incisors before a larger bur is introduced. The bur should be inserted under direct visual control using light pressure and a stable finger rest.

The objective is to open the contact progressively rather than force the instrument through it. Excessive pressure may result in uncontrolled cutting, localised grooves or unnecessary enamel removal.

The 0.2-mm head size should not be interpreted as a guarantee that exactly 0.2 mm of space will be created. The final reduction is influenced by bur movement, pressure, angulation, the number of passes and the anatomy of both adjacent teeth.

Progressive Anterior Reduction with X03W, X04R and X05B

The anterior One Slice IPR range includes three burs with a 3.0-mm working length:

• X03W — 0.3 mm
• X04R — 0.4 mm
• X05B — 0.5 mm

The shorter working length is intended to support visibility and hand control around the incisors and canines.

The clinician should begin with the smallest suitable bur based on the planned reduction and the space already created. A larger bur should only be introduced after the contact has been inspected and measured.

A practical sequence is:

X02 access → selected anterior IPR bur → gauge verification → X03SF finishing

Not every bur must be used at every contact. A conservative case may only require X02 followed by X03W. Greater prescribed reduction may require progression to X04R or X05B.

The instrument should be moved gingivo-incisally or inciso-gingivally along the proximal surface. This controlled movement distributes the reduction and reduces the risk of cutting deeply into one isolated area.

The bur should remain generally parallel to the proximal surface. Excessive buccolingual angulation or apical pressure should be avoided.

Preserving Natural Anterior Tooth Anatomy

Anterior IPR should create the required space without making the teeth appear unnaturally narrow, flat or angular.

Particular attention should be given to the facial and lingual transitional line angles. Excessive reduction in these areas may alter the apparent width and shape of the crown.

As discussed by Har-Zion (2025), recontouring the transitional line angles is an important part of anterior IPR. Simply cutting through the contact may leave flat surfaces or sharp edges that require further refinement.

The proximal anatomy should be evaluated from both the facial and lingual aspects. Natural convexity should be maintained where possible.

Triangular incisors may require a different reduction pattern from rectangular incisors. When IPR is used to manage black triangles, enamel may be redistributed to broaden the contact area and allow orthodontic movement to reposition the contact more gingivally.

The treatment objective should determine where enamel is removed rather than applying the same reduction pattern to every tooth.

Clinical Workflow for Anterior IPR

1. Confirm the treatment plan

Before performing anterior interproximal reduction, confirm:

• The teeth selected for IPR
• The prescribed amount at each contact
• Whether reduction is divided between both adjacent teeth
• Crown shape and proximal anatomy
• Existing restorations
• Periodontal condition
• Enamel defects or sensitivity
• Caries risk and oral hygiene

Kailasam, Rangarajan, Easwaran and Muthu (2021) reported that proximal enamel thickness varies between permanent teeth and individuals. A bur size should therefore not be considered universally suitable for every contact.

2. Protect the soft tissues

The lips, tongue and gingiva should be protected throughout the procedure. A wedge, matrix, protective guard or another suitable method may be used when required.

The operating field should be well illuminated, and a stable finger rest should be maintained.

3. Use adequate water cooling

High-speed diamond burs should be operated with sufficient water cooling. Cooling helps control heat generation, remove enamel debris and maintain visibility.

The bur should remain in controlled motion rather than being held against one area for an extended period.

4. Open the contact conservatively

The X02 may be used first when the contact is tight. It should be advanced using gentle pressure and direct visual control.

After initial access has been established, the clinician may select X03W, X04R or X05B according to the prescribed reduction.

5. Measure repeatedly

An IPR gauge should be used throughout the procedure.

A practical sequence is:

Reduce → Irrigate → Measure → Inspect → Continue only when necessary

The gauge should pass through the contact without excessive force. Forcing it between the teeth may temporarily displace them and produce an inaccurate measurement.

The space created should not be assessed only by the bur selected. A 0.4-mm bur does not automatically produce exactly 0.4 mm of clinical space.

6. Finish the reduced enamel

After the planned reduction has been achieved, inspect the contact for:

• Sharp edges
• Deep scratches
• Uneven reduction
• Flat proximal contours
• Residual ledges
• Surface roughness

The X03SF super-fine bur may be used to refine and smooth the enamel surface. Fine abrasive strips may be added when further polishing is required.

Gómez-Aguirre and colleagues (2022) reported that the final surface condition after IPR is influenced by both the reduction instrument and the polishing method. Finishing should therefore be treated as an essential part of anterior IPR.

Clinical Applications

The anterior MR.BUR One Slice IPR burs may be considered for professionally planned cases involving:

• Clear aligner treatment
• Invisalign treatment
• Fixed orthodontic braces
• Mild anterior crowding
• Bolton tooth-size discrepancy
• Triangular incisor reshaping
• Gingival black triangle management
• Anterior retraction
• Improvement of proximal contact form

Additional caution may be required in patients with active caries, poor oral hygiene, enamel hypoplasia, extensive proximal restorations, periodontal disease or limited proximal enamel thickness.

Discussion

The objective of anterior IPR is to create controlled space while preserving enamel, tooth shape and proximal surface quality.

The complete MR.BUR One Slice IPR Kit contains seven bur designs and 23 instruments. Within the anterior workflow, X02 supports initial contact access, X03W, X04R and X05B provide progressive reduction options, and X03SF supports finishing. XL04 and XL05 extend the system to posterior contacts.

However, the One Slice IPR system is not self-measuring. The final amount of enamel removed depends on bur angulation, operating pressure, movement, enamel anatomy, contact tightness and the number of passes.

Repeated gauge verification remains necessary even when size-specific burs are used.

The work of Livas, De Felice, Kailasam, Gómez-Aguirre, Zachrisson and Har-Zion supports the general principles of conservative reduction, accurate measurement, anatomical recontouring and surface finishing. These researchers did not independently test or endorse the MR.BUR One Slice IPR Kit.

Product-specific clinical studies would be required to compare its accuracy, cutting time, enamel surface quality and patient experience with manual strips, discs and reciprocating IPR systems.

Conclusion

Anterior interproximal reduction requires precision because only a limited amount of enamel is normally removed between incisors and canines.

The MR.BUR One Slice IPR Kit  is a complete 23-piece system containing seven bur types for anterior and posterior IPR. For anterior teeth, the clinical sequence may include:

• X02, 0.2 mm for initial contact access
• X03W, 0.3 mm for conservative anterior reduction
• X04R, 0.4 mm for moderate anterior reduction
• X05B, 0.5 mm for greater planned anterior reduction
• X03SF, 0.3 mm for super-fine finishing

The complete kit also includes XL04, 0.45 mm, and XL05, 0.5 mm, for posterior interproximal reduction.

Successful anterior IPR depends on appropriate diagnosis, conservative bur selection, soft-tissue protection, adequate water cooling, stable hand control, repeated gauge measurement and careful polishing.

When selected according to individual tooth anatomy and orthodontic treatment planning, the MR.BUR One Slice IPR burs provide a structured instrument system for anterior interproximal reduction during clear aligner, Invisalign and fixed orthodontic treatment.

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