A deep bite, or excessive overbite, is a common vertical misalignment of the teeth where the upper front teeth cover too much of the lower front teeth when the jaw is closed. A deep bite occurs when this vertical coverage is significant, often described as the upper teeth overlapping the lower teeth by more than 4 millimeters. Braces are a highly effective and common method for correcting this condition, working by applying precise, continuous forces to reposition the teeth vertically.
Defining Deep Bite and Addressing Necessity
This condition is not just a cosmetic issue; it can lead to several long-term health problems. When the overlap is too severe, the lower front teeth can prematurely wear down the enamel on the back surface of the upper front teeth, increasing sensitivity and compromising the structure of the tooth over time. Excessive pressure from the lower teeth can also cause irritation and damage to the gum tissue behind the upper front teeth, potentially leading to gum recession or sores on the roof of the mouth. Furthermore, an untreated deep bite may contribute to or worsen issues in the temporomandibular joint (TMJ), which can manifest as jaw discomfort or difficulty chewing properly.
Specific Mechanics Used to Correct Deep Bite
The primary goal of correcting a deep bite with braces is to increase the vertical dimension of the bite, which is achieved through two main mechanical strategies: intrusion and extrusion.
Intrusion Mechanics
Intrusion involves moving the front teeth (incisors) upward into the bone socket, effectively reducing the overlap. This movement is accomplished using auxiliary wires, such as a utility arch or a Connecticut intrusion arch, which are specialized archwires that generate a light, continuous intrusive force on the incisors. The utility arch is a versatile biomechanical tool that connects the incisor brackets to the molar bands, bypassing the intermediate teeth to deliver controlled force.
Extrusion Mechanics
Alternatively, the bite can be opened by the relative extrusion of the back teeth (molars and premolars), allowing them to move downward into the bite plane. This movement is often facilitated by temporary appliances called bite turbos or bite planes. Bite turbos are small, temporary pads bonded to the biting surfaces of the back teeth or the back of the upper front teeth. Their function is to physically prevent the patient from fully closing their teeth, which removes the biting force from the front teeth and allows the back teeth to naturally erupt or move into a more open vertical position. For example, a reverse curve of Spee may be placed in the lower archwire, which exerts an intrusive force on the lower incisors while simultaneously extruding the lower back teeth.
The Patient Experience and Treatment Timeline
Active Treatment and Adjustments
If bite turbos are used, patients may initially experience some difficulty chewing because only a few points of contact exist between the upper and lower teeth. This initial discomfort is temporary, typically resolving within a few days or weeks as the patient adjusts and the bite begins to open. The active correction phase usually takes between 6 to 18 months, though the total treatment time can range from 18 to 30 months depending on the severity of the deep bite and whether other issues also need correction. During this time, the patient will have regular adjustment appointments, typically every four to eight weeks, where the orthodontist activates the archwires or adjusts the intrusion mechanics.
Retention and Stability
Age is a factor, as younger patients with active jaw growth may respond more quickly to treatment than adults, who only experience tooth movement. Once the deep bite is fully corrected and the teeth are properly aligned, the braces are removed, and the retention phase begins. This final phase is essential for maintaining the corrected position, as teeth have a natural tendency to shift back toward their original positions, a phenomenon known as relapse. Retainers, which can be fixed (bonded to the back of the teeth) or removable, must be worn as directed to ensure the stability of the new, healthy bite for years to come.