Orthodontic rubber bands are a common component of braces treatment used to correct jaw alignment and position teeth. These small bands apply controlled mechanical energy, guiding teeth and jaws into the desired location. The lifespan of these bands varies significantly, depending entirely on their specific function and type within the mouth.
Ligatures vs. Elastics: Defining the Two Types
The term “rubber bands” in orthodontics refers to two distinct items: ligatures and intermaxillary elastics. Ligatures are the tiny, often colorful, bands that fit directly around each bracket to secure the archwire in place. Their primary function is to hold the main wire within the bracket slot, allowing the wire to exert continuous pressure.
Intermaxillary elastics, commonly called rubber bands, are larger and worn between the upper and lower jaws. These elastics connect hooks on brackets in different arches to generate an active force for bite correction. They address issues like overbites, underbites, and crossbites by encouraging the jaws to align correctly. Unlike ligatures, elastics actively move entire groups of teeth or the jaw relationship itself.
Expected Duration and Replacement Schedule
The two types of bands follow entirely different replacement schedules. Ligatures are designed to remain in place, securing the archwire until the next scheduled appointment, typically every four to eight weeks. While they may lose some tension, their primary role as a fastener is maintained. The orthodontist replaces all ligatures at each visit, often because they can discolor or due to hygienic concerns.
Intermaxillary elastics, however, must be replaced by the patient frequently. These bands are active force generators, and their material experiences rapid force decay when stretched. Within just a few hours of wear, the elastic can lose a significant percentage of its intended force, rendering it ineffective for tooth movement. Consequently, patients are instructed to change these elastics every 12 to 24 hours to ensure a consistent, active force is applied to the bite.
Consistent replacement is necessary because an old, stretched-out elastic will not effectively guide the jaw or teeth. Wearing a fresh band ensures the continuous pressure needed to facilitate biological changes. Following the prescribed daily replacement schedule is a patient responsibility that directly impacts the overall success and timeline of the bite correction phase.
Factors That Affect Elasticity and Cause Breakage
The effectiveness of orthodontic elastics is compromised by both mechanical stress and environmental factors within the mouth. The most common failure mode is the loss of elasticity, which occurs rapidly as the rubber polymers are constantly stretched and exposed to the oral environment. Exposure to saliva and the constant temperature of the mouth can accelerate the degradation of the elastic material over time.
Mechanical stress, such as excessive stretching or opening the mouth too far, can cause premature breakage. Certain foods and beverages, especially those that are acidic or very hot, can also weaken the elastic material. While ligatures are more durable, excessive force from chewing sticky or hard foods can cause them to snap or pop off the bracket.
Should an intermaxillary elastic break, the patient must immediately replace it with a fresh one to maintain the prescribed force. If a ligature pops off the bracket, the patient should contact their orthodontist, as this can allow the archwire to move out of position, potentially reversing progress. Regular replacement and avoiding activities that overly stress the bands are the best ways to prevent unexpected failures and ensure treatment stays on track.