Orthodontic treatment frequently requires the use of small rubber bands, known as orthodontic elastics. These elastics serve as an active component of the treatment, applying controlled forces to guide the teeth into their ideal positions. The forces they generate are aimed at correcting the relationship between the upper and lower dental arches to achieve a proper bite. When patients wear these bands, a common question arises regarding their effect on the underlying bone structure: Do these rubber bands actually move the jaw itself? This question touches upon the distinction between dental and skeletal correction, which is central to understanding how these tools contribute to the overall alignment process.
Dentoalveolar Changes Versus Skeletal Movement
The direct answer is that orthodontic elastics primarily cause dentoalveolar movement, meaning they move the teeth within the sockets of the jawbone. The force applied by the elastics acts on the individual teeth, causing them to shift position and rotationally align within the existing bone structure of the maxilla (upper jaw) and mandible (lower jaw).
True skeletal movement, or changing the physical size and position of the jawbones themselves, is generally reserved for other treatments. In younger patients, specialized orthopedic appliances may be used to modify jaw growth, while adults typically require orthognathic surgery for substantial jaw correction. While elastics correct the bite relationship, the change is accomplished by repositioning the teeth to mask minor skeletal imbalances, rather than physically shifting the jawbones.
The Mechanics of Inter-Arch Force Application
Orthodontic elastics function through inter-arch force application, meaning they create a pull between the upper and lower arches to correct a misalignment. The specific placement of the bands determines the direction and type of force, allowing for highly targeted bite correction. The force levels of these bands are carefully calibrated, with typical forces for Class II or Class III elastics ranging from 113 to 170 grams.
A common application is the use of Class II elastics, which typically stretch from a hook on an upper tooth down and back to a lower molar. This diagonal vector of force serves to pull the upper teeth backward and the lower teeth forward, correcting an overbite. Conversely, Class III elastics are deployed to address an underbite, running from a hook on a lower tooth up and back to an upper molar.
The size and strength of the elastics, labeled by their diameter and force rating, are selected to exert continuous, light pressure that safely guides the teeth. The consistent tension provided by the bands works to remodel the bone surrounding the tooth roots, allowing the teeth to move along the wire and into their prescribed positions. This system of opposing forces is fundamental to correcting the anteroposterior relationship between the two arches.
Maximizing Results Through Patient Compliance
The effectiveness of inter-arch elastics depends almost entirely on the patient’s consistent use of the bands. Orthodontists typically recommend wearing the elastics for 20 to 22 hours per day, removing them only for eating and brushing. Wearing the bands for a shorter period, such as only at night, is insufficient to generate the necessary continuous force for effective tooth movement.
Non-compliance has a direct and detrimental effect on the treatment timeline and final outcome. Inconsistent wear can prolong the overall treatment by several months or result in an incomplete correction of the bite relationship. Since elastics lose their stretch and effectiveness over time, they must be changed frequently, usually three to four times daily, to ensure the application of the prescribed force. Patients should always carry replacement elastics so that a broken or lost band can be replaced immediately.