An IRM filling, or Intermediate Restorative Material, is a common temporary solution in dentistry. It provides protection and stability to a tooth when a permanent restoration cannot be immediately placed. This material acts as a provisional barrier, allowing for a period of observation or serving as a placeholder until a more definitive treatment can be completed.
What is an IRM Filling?
An IRM filling is primarily composed of a reinforced zinc oxide-eugenol cement, often with added polymers like polymethyl methacrylate to enhance its strength and durability. This combination gives the material distinct characteristics, including a mild sedative effect on the dental pulp due to the eugenol content. The material is designed for ease of placement and removal, offering good sealing properties to protect the tooth from bacterial leakage and sensitivity. While stronger than basic zinc oxide-eugenol (ZOE) cements, IRM is a temporary material.
When is an IRM Filling Used?
IRM fillings are utilized when an immediate permanent restoration is not feasible or desirable. They commonly serve as temporary fillings for cavities, particularly in emergency dental situations to alleviate pain or protect exposed tooth structure. In pediatric dentistry, IRM is frequently used for temporary restorations in primary (baby) teeth, especially when permanent teeth are expected to erupt within two years or less.
This material also functions as a base or liner under other permanent restorations, providing pulpal protection before the final filling or crown is placed. After root canal treatment, IRM is often applied to temporarily seal access cavities between appointments, preventing bacterial contamination until a permanent restoration can be completed. For fractured teeth where a full restoration is not immediately possible, IRM offers temporary structural support.
Caring for and Replacing an IRM Filling
Caring for an IRM filling involves several precautions to ensure its temporary integrity. Patients should avoid chewing hard or sticky foods on the filled tooth to prevent dislodgement or fracture. Maintaining diligent oral hygiene, including regular brushing and gentle flossing around the area, is also important to keep the tooth clean and prevent further issues.
An IRM filling can remain in place for up to one year, though its duration varies based on the tooth’s location and the forces it endures. It is not a permanent solution and will eventually need to be removed and replaced with a definitive restoration, such as a permanent filling, crown, or onlay. The replacement process involves the dentist carefully removing the IRM material before preparing the tooth for the final restoration.