Orthodontic braces are specialized medical devices used to correct the alignment of teeth and jaws using constant, gentle force. They guide teeth into healthier positions, which creates a straight smile and improves overall oral function. Treatment addresses bite issues, making it easier to chew, speak, and maintain proper hygiene. This transformation involves mechanical engineering and biological adaptation within the patient’s mouth.
The Starting Point: Understanding Misalignment
The need for braces begins with malocclusion, an improper alignment between the upper and lower teeth. This “bad bite” manifests as dental crowding, where insufficient space causes teeth to overlap or rotate. Conversely, significant spacing, or diastema, results from a mismatch between jaw and tooth size.
The relationship between the upper and lower jaws is a frequent concern. Issues include an overbite, where the upper front teeth extend too far over the lower teeth. An underbite occurs when the lower teeth protrude in front of the upper teeth, while a crossbite involves upper teeth biting on the inside of the lower teeth. The severity of these malocclusions dictates the specific mechanics and duration of the treatment plan.
The Science of Tooth Movement
Braces apply a continuous, controlled force using brackets, an archwire, and ligatures or elastics. The bracket is a small component bonded to the tooth surface, acting as an anchor point. The archwire is the active element, providing the steady, gentle pressure necessary to drive the tooth’s movement.
This mechanical force initiates a biological response within the periodontal ligament (PDL), a specialized tissue connecting the tooth root to the jawbone. When pressure is applied, the PDL is compressed on one side and stretched on the opposite side. The body responds to compression by activating osteoclasts, which break down adjacent jawbone tissue to create space for the tooth to move.
Simultaneously, the tension side of the PDL stimulates osteoblasts, cells responsible for depositing new bone material. This coordinated process of bone resorption and deposition is known as bone remodeling. Bone remodeling allows the tooth to gradually migrate through the jawbone. The movement requires constant, low-level force to prevent damage to the tooth root or surrounding structures.
The Treatment Phases and Adjustments
The patient’s journey begins with the initial bonding appointment, where brackets are affixed and the first, most flexible archwire is placed. This initial wire is often heat-activated, exerting a consistent light force to begin alignment and leveling. Routine adjustment appointments follow every four to eight weeks, where the orthodontist changes the archwire or makes necessary modifications.
The treatment progresses through distinct phases. The first phase involves leveling and aligning the teeth to correct rotations and vertical discrepancies. Next, the working phase focuses on correcting the bite relationship and closing remaining spaces. This stage frequently involves the patient wearing small elastic bands to apply specific forces between the upper and lower jaws for proper bite correction. The final phase, known as finishing, involves fine-tuning tooth positions before the braces are removed.
Achieving and Maintaining the Results
When braces are removed, teeth are in their desired positions, but surrounding bone and soft tissues have not fully stabilized. The periodontal ligament, reformed during movement, has a “memory” and attempts to pull the teeth back toward their original positions, known as relapse. This tendency is greatest immediately following appliance removal.
To counteract relapse and allow the jawbone to solidify around the newly positioned teeth, a retention phase is necessary for long-term success. The patient is prescribed retainers, which may be removable or fixed. Removable retainers are worn full-time initially and then transitioned to nighttime use. Fixed retainers are thin wires permanently bonded to the back surfaces of the teeth. Consistent use of the retainer is the most important factor in maintaining the final result.