Getting new braces is often followed by acute, throbbing discomfort that can be surprising in its intensity. This initial soreness is a predictable physiological response to the mechanical forces now at work in the mouth. Understanding the science behind this temporary pain, which typically peaks within the first 24 to 48 hours, helps reframe the experience as a normal part of the process. This explains the biological and mechanical reasons why the first day with braces is uncomfortable.
The Immediate Biomechanical Pressure
The process begins the moment the orthodontist installs the archwire into the brackets, which immediately applies a continuous, gentle force to the teeth. Each tooth is anchored to the jawbone by the periodontal ligament (PDL), a thin layer of connective tissue rich in blood vessels and nerve fibers. As the archwire begins to move the teeth, it compresses the PDL on the side of the tooth facing the direction of movement, while the opposite side is placed under tension.
The compression side is where the initial pain is generated. This mechanical pressure is strong enough to squeeze the delicate blood vessels running through the PDL, leading to reduced blood flow, known as localized ischemia. The lack of oxygen in the compressed tissue is the direct physical trigger that signals the body to initiate a biological response, resulting in the deep ache patients feel.
The Cellular Response: Inflammation and Pain Signaling
The body’s reaction to the localized lack of blood flow is an acute inflammatory response in the periodontium, designed to begin the tissue remodeling process. The cells in the compressed area of the periodontal ligament begin to release a cascade of chemical mediators as a distress signal. Among these are specific signaling molecules, including prostaglandins, such as Prostaglandin E2 (PGE2), and various cytokines, like Interleukin-1 (IL-1).
These chemical messengers serve two purposes: they promote the activity of bone-resorbing cells (osteoclasts) to allow the tooth to move, and they sensitize the local nerve endings. This sensitization lowers the threshold for pain, meaning that even a slight pressure on the tooth, such as biting down, is interpreted as significant pain. This chemical activity translates the physical pressure from the braces into a persistent, dull, aching sensation that can last for several days.
Two Types of Discomfort: Tooth Movement vs. Soft Tissue Irritation
The discomfort experienced on the first day is a combination of two distinct types of pain. The first is the deep, widespread ache originating from the periodontal ligament and the inflammatory response described above. This internal pain is a necessary byproduct of the teeth shifting within the jawbone. It is usually described as a dull, constant soreness that makes biting and chewing difficult.
The second type of discomfort is a sharp, localized pain caused by the hardware rubbing against the delicate mucosal tissues of the mouth. The brackets, wires, and other components of the new appliance present an abrasive surface to the inner cheeks, lips, and tongue. This external irritation can lead to small sores or ulcers and is purely mechanical, independent of the biological process of tooth movement.
Immediate Relief Strategies
Managing the initial discomfort involves targeting both the internal aching pain and the external surface irritation. For the deep ache, over-the-counter pain relievers are highly effective, especially those that target the inflammatory response. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen work by inhibiting the production of prostaglandins, which are the key pain-sensitizing mediators. An alternative is acetaminophen, which provides pain relief without interfering with the inflammatory pathway that facilitates tooth movement.
For the sharp, localized irritation from the hardware, orthodontic wax provides a simple, physical barrier. A small piece of wax can be pressed directly onto the bracket or wire causing the friction, creating a smooth surface that protects the soft tissues. Additionally, rinsing the mouth with a warm saltwater solution several times a day can help soothe any irritated or broken skin by reducing inflammation and promoting healing. This acute phase of soreness typically peaks within 48 hours, with significant relief usually felt after three to five days as the mouth adjusts.