It is very common to experience difficulty opening your mouth after having your wisdom teeth removed, a condition known medically as trismus or “lockjaw.” This symptom arises because the surgical process directly affects the muscles responsible for chewing and jaw movement. This muscle stiffness is a highly anticipated and temporary side effect of the procedure. Understanding the physiological reasons behind this symptom can help you manage your recovery effectively. This article will explain why your jaw is restricted, what you can do to regain mobility, and when to be concerned about your recovery.
The Physical Causes of Restricted Jaw Movement
The primary reason for restricted jaw movement is trauma and inflammation to the muscles of mastication, the powerful muscles used for chewing. Lower wisdom teeth are positioned very close to two important muscles: the masseter and the medial pterygoid. Any surgical manipulation in this area, especially during the removal of impacted teeth, can cause these muscles to become strained or bruised.
Inflammation and edema (swelling caused by fluid buildup) are natural responses to the surgery and contribute significantly to trismus. As the tissues surrounding the surgical site swell, they compress and irritate the adjacent muscles, causing them to spasm and tighten in a protective reflex known as muscle guarding. This tonic contraction of the chewing muscles limits how wide you can comfortably open your mouth.
The anesthetic injection itself can also be a minor contributing factor to temporary jaw stiffness. The needle used to deliver the local anesthetic to the inferior alveolar nerve—often necessary for lower wisdom tooth removal—passes through or near the medial pterygoid muscle. This can cause localized soreness or a small bruise (hematoma) within the muscle tissue, leading to temporary pain and stiffness at the injection site. A complex extraction requiring the mouth to be held open wide for an extended period can also lead to muscle fatigue and hyperextension.
Managing Stiffness and Improving Mobility
Managing trismus involves a cautious, multi-step approach focused on reducing inflammation and gently re-introducing movement. The initial strategy centers on controlling swelling. For the first 24 to 48 hours following surgery, cold therapy is recommended to minimize edema and pain, which in turn helps limit the severity of muscle tightening.
After the initial two days, the focus shifts from cold therapy to moist heat application. Applying a warm compress or a damp, heated towel to the stiff cheek and jaw area for 15 to 20 minutes every hour can help relax the contracted muscles. Heat increases blood flow to the area, promoting the relaxation of the masseter and medial pterygoid muscles.
Pain management also plays an important role, particularly with medications that reduce inflammation. Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen work to decrease the inflammatory response that directly contributes to muscle spasms and stiffness. Your surgeon may prescribe a muscle relaxant, such as a benzodiazepine, to help stop the jaw muscles from cramping and reduce the tonic contraction.
Once the acute swelling begins to subside, typically around day three, gentle stretching exercises can be introduced, but only after consulting your surgeon. These exercises should always be slow, steady, and performed without causing pain, as forcing the jaw can lead to further trauma.
Gentle Stretching Techniques
A passive stretch involves opening your mouth as wide as is comfortable and holding the position for a few seconds. Another gentle technique involves using your fingers to provide slight, passive pressure to increase the stretch, or moving your jaw slowly side-to-side.
Muscle Massage
Massaging the tender spots and knots in the cheek muscles in a circular motion can also help to loosen the tight tissues. These movements are intended to prevent the muscles from healing in a shortened, stiff position, which could lead to a permanent limitation of mouth opening.
Recovery Timeline and Recognizing Warning Signs
The stiffness associated with trismus is almost always temporary, reflecting the body’s normal healing process after a surgical procedure. Most people will experience the most significant difficulty opening their mouth on the second or third day post-surgery, coinciding with the peak of post-operative swelling. For the majority of patients, a noticeable improvement in jaw mobility occurs within the first week following the extraction.
The condition typically resolves completely within 7 to 10 days, though full resolution of all stiffness may take up to two or three weeks in more complex cases. It is important to continue with the recommended gentle exercises and heat therapy until your mouth opening returns to its normal range.
However, certain symptoms warrant immediate contact with your oral surgeon as they may indicate a complication requiring medical intervention. If the trismus persists or worsens significantly beyond 10 days, this is a sign that the underlying issue is not resolving normally, potentially pointing toward a more involved muscle or joint issue.
Seek prompt medical attention if the limited jaw movement is accompanied by signs of a developing infection, such as severe, increasing pain not relieved by medication, a fever with chills, or the presence of pus or a foul odor coming from the surgical site. These symptoms suggest an infection or an abscess near the muscle, which requires immediate professional assessment and treatment.