Sep 284 min read

Considerations when utilizing IPR in clear aligner treatments

Interproximal reduction (IPR) has become a staple in modern orthodontics, especially within clear aligner therapy. This technique, which involves the reduction of enamel between adjacent teeth, is integral to achieving optimal alignment and aesthetic outcomes.

However, its irreversible nature requires careful consideration and precise execution. Here, we delve into key considerations general dentists should be aware of when incorporating IPR into their clear aligner treatments.

Spark clear aligner setup illustrating planned IPR

Understanding clear aligner IPR: A Brief Overview

IPR, sometimes referred to as enamel stripping or selective reduction, is employed to create space within the dental arch. It is particularly useful in clear aligner therapy for addressing crowding, resolving tooth size discrepancies, and improving overall aesthetics. Since IPR alters the tooth structure permanently, accurate planning and execution are paramount.

Key Considerations for Effective IPR

Indications for IPR
- Space Creation: IPR is often used to alleviate crowding, especially in the anterior segment where space is needed to align misaligned teeth. For minor to moderate crowding, IPR offers a non-extraction alternative that reduces the overall distance teeth need to move.
- Tooth Size Discrepancies: The Bolton ratio, which compares the size of the anterior and posterior teeth, often necessitates IPR to correct discrepancies. This helps in achieving the desired overbite and overjet.
- Tooth Shape Adjustments: Reshaping teeth through IPR can improve aesthetics and facilitate better alignment. However, it is crucial to avoid excessive enamel removal, which can lead to structural issues and increased sensitivity.
Techniques and Tools
- Instruments: Various tools are available for performing IPR, including abrasive metal strips, diamond discs, and burs. Each tool has its advantages and disadvantages. Manual adjustments should only be cosidered .when very small changes (0,1-0,2 mm) are to be performed on onse side of a tooth in order to change the morphology. With bigger changes it takes too long, the precision is reduced and too much enamel will be removed from one tooth. In these isntances use the Dentatus IPR set instead.
- Technique: The procedure should be done conservatively. It is often recommended to perform IPR gradually and to monitor the process carefully to avoid over-reduction. We prefer correct planning in combination with a calibrated IPR system. Polishing post-IPR is essential to smoothen the surface and reduce enamel roughness.
Patient Considerations
- Tooth Sensitivity and Pulp Health: IPR can elevate tooth temperature and potentially cause sensitivity if rotating instruments are used. Utilizing coolant during these kind of procedures and monitoring pulp health are crucial to mitigate these effects. Alternatively use a slower occiliating system.
- Oral Hygiene: Patients must maintain excellent oral hygiene to prevent caries and periodontal issues, especially since IPR can alter the surface texture of teeth.
Contraindications
- Enamel Thickness and Tooth Shape: IPR is not advisable if the enamel is too thin or if the tooth shape is not conducive to reduction. For instance, rectangular or square-shaped teeth may not be ideal candidates for extensive IPR.
- Existing Conditions: Avoid performing IPR in patients with active periodontal disease, poor oral hygiene, or enamel hypoplasia. Additionally, be cautious with patients who have large pulp chambers or significant crowding that impedes access to the contact areas.
- Blind trust in the digital setup: Clear aligner technicians or the artificial intelligens creating the initial digital setups will sometimes plan agressive IPR in cases that will lead to severe malocclusions if their suggestions are followed.
Impact on Treatment Outcomes
- Aesthetic and Functional Results: IPR can improve aesthetic outcomes by correcting tooth alignment and enhancing gingival contours. However, it is essential to assess the potential for creating black triangles or other aesthetic issues post-treatment.
- Long-term Stability: IPR should be used thoughtfully to ensure that it contributes positively to long-term treatment stability. Research suggests that well-executed IPR can help maintain arch width and improve stability when combined with other orthodontic techniques.
Precision and Planning
- Digital Planning: With advancements in digital orthodontics, precise planning for IPR is now possible. This planning helps in predicting the amount of enamel to be reduced and ensures that the procedure aligns with the overall treatment goals.
- Monitoring Progress: Regularly check the actual amount of enamel removed versus the planned reduction. Discrepancies should be addressed promptly to avoid deviations from the intended treatment outcome.

Conclusion

IPR or Interproximal reduction is a powerful tool in clear aligner therapy, offering significant benefits in space creation, tooth alignment, and aesthetic enhancement. However, its success hinges on careful planning, precise execution, and ongoing patient management. By understanding the indications, techniques, and potential impacts of IPR, general dentists can navigate this procedure effectively, ensuring optimal outcomes for their patients.

For more detailed guidance on IPR and its applications in clear aligner therapy, consult the latest literature and consider collaborating with dentists or orthodontic specialists with lots of clear aligner expereince to refine your approach.

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