TürkçeFacial paralysis (facial palsy) developing after dental treatments is a unilateral loss of movement that occurs when the local anesthetic solution comes into contact with the facial nerve controlling facial expressions during the numbing procedure, or when swelling and bleeding developing in the tissues after difficult surgical interventions place pressure on this nerve. This condition, which generally develops immediately after lower jaw procedures, completely resolves within a few hours without leaving any lasting effects as the pharmacological effect of the medication is eliminated from the body. However, in situations such as injury to the nerve by surgical instruments, severe tissue trauma, or untreated deep infections, the damage may become permanent and require specialized rehabilitation and advanced surgical procedures.
| Definition | Facial paralysis after dental treatments is a rare complication that may develop as a result of the facial nerve (7th cranial nerve), which controls the facial muscles, being affected following dental procedures. It may be temporary or, much more rarely, permanent. |
| Incidence | It is quite rare. It most commonly occurs temporarily after local anesthesia applications. |
| Most Common Causes | Accidental spread of the local anesthetic medication to the facial nerve or its surroundings, conditions related to the injection technique, pressure on the nerve, triggering of existing neurological disorders, or, very rarely, infections. |
| Risk Factors | Nerve blocks applied to the posterior lower jaw region, anatomical variations, repeated injections, existing nerve disorders, and a history of viral infection. |
| Early-Onset Facial Paralysis | It usually occurs immediately after anesthesia is administered. In most cases, it resolves as the anesthetic effect wears off. |
| Delayed-Onset Facial Paralysis | It may develop hours or days after the procedure. It may be associated with mechanisms such as viral reactivation, swelling, or inflammation. |
| Symptoms | Loss of movement on one side of the face, drooping of the corner of the mouth, inability to close the eyelid, asymmetry when smiling, weakness in lip movements, and difficulty speaking or drinking liquids. |
| Eye Findings | Because the eyelid cannot close completely, dry eye, tearing, a stinging sensation, and the risk of corneal damage may develop. |
| Pain | Pain is not always present. Some patients may experience mild pain around the ear or in the jaw region. |
| Diagnosis | Diagnosis is made through the patient’s medical history, the timing of the dental treatment, neurological examination, and, when necessary, neurological evaluation. |
| Differential Diagnosis | Stroke, Bell’s palsy, Ramsay Hunt syndrome, traumatic nerve injury, tumors, and other neurological disorders must be ruled out. |
| Treatment Approach | It varies depending on the cause. Eye protection, monitoring, medication when necessary, and neurological evaluation may be applied. |
| Eye Protection | If the eyelid cannot close, artificial tear drops, protective ointments at night, and covering the eye may be necessary. |
| Recovery Time | In temporary cases related to anesthesia, improvement is expected within hours. In cases caused by other factors, recovery may take weeks or months. |
| Prognosis | The prognosis is good in the vast majority of cases, and complete recovery is observed. Permanent facial paralysis is quite rare. |
| Possible Complications | Dry eye, corneal injury, permanent muscle weakness (rare), facial asymmetry, and psychological effects. |
| When Is Urgent Evaluation Required? | Urgent medical evaluation is required if facial paralysis is accompanied by weakness in an arm or leg, speech impairment, altered consciousness, severe headache, vision loss, or balance problems. |
| What the Patient Should Do | The patient should protect the eye, follow the physician’s recommendations, and be reevaluated if the symptoms do not improve or worsen. |
| Prevention Methods | Proper injection technique, careful evaluation of anatomical structures, and experienced performance of the procedure may reduce the risk. |
| Follow-Up | Depending on the duration and severity of the symptoms, follow-up may be planned by a dentist, neurologist, and, when necessary, an ophthalmologist. |
Why and How Does Facial Paralysis Occur After Dental Procedures?
When we examine the anatomical and physiological mechanism, we encounter a highly complex and delicate structure. While sitting in the dentist’s chair, particularly when a filling, root canal treatment, or tooth extraction is to be performed on the lower jaw, the area must be deeply numbed. For this procedure, dentists generally administer an injection called “mandibular anesthesia,” which aims to block the lower jaw nerve. This is an extremely reliable and routine procedure performed millions of times every day worldwide. However, the internal structures of our face resemble a very narrow highway where nerves, vessels, and glands are arranged one after another at millimetric distances.
The facial nerve, which controls our facial expressions, begins at the brainstem and passes through narrow and winding bony canals inside the skull. As soon as it exits the skull, it enters directly into the center of the parotid gland, which is located at the level of the earlobe and is responsible for saliva production. Inside this salivary gland, it divides into five main branches, much like the branches of a tree. These branches extend toward the temples, around the eyes, the cheeks, the corners of the lips, and the neck, transmitting the command to “contract” to all the facial muscles.
When the needle used to numb the lower jaw is directed a few millimeters farther back than the anatomical target or slightly deeper than intended, the local anesthetic solution inside the syringe may leak directly into the capsule of this salivary gland. The fundamental function of local anesthetic medications is to temporarily suspend electrical conduction by blocking the sodium channels on the nerves they contact. When the medication comes into contact with the facial nerve, it not only blocks the sensation of pain but also completely stops the movement commands traveling to the muscles. At the moment this leakage occurs, sudden and complete paralysis develops on the side of the patient’s face where the injection was administered. This is a temporary condition caused by the pharmacological effect of the medication and generally resolves spontaneously within a few hours.
Is Facial Paralysis Caused by Dental Treatments Always Temporary?
Sudden paralysis caused by the spread of local anesthetic medications into the tissues is temporary in most cases. The bloodstream in our body gradually absorbs and metabolizes the medication in that area and removes it from the tissues. As the medication is cleared from around the nerve cell, the sodium channels reopen and nerve conduction returns to its previous healthy state. This recovery process is generally completed within one to five hours. A few hours after leaving the clinic, the patient notices that movement in the face is gradually returning.
However, not every case of facial paralysis is caused solely by the numbing effect of the medication. Different mechanisms may also transform the process into permanent damage requiring long-term treatment. During the injection, the tip of the needle may strike the nerve sheath directly because of anatomical variations, causing physical injury similar to an abrasion. In addition, during surgical procedures such as the extraction of difficult impacted wisdom teeth, removal of large jaw cysts, or orthognathic surgery that changes the position of the jaw, the instruments used may cut superficially located nerve branches or crush them, disrupting tissue integrity. When the nerve trunk physically loses its integrity, the repair process enters a much more difficult and sometimes impossible course.
There are also other situations in which tissue integrity remains intact but the damage may become permanent. Unexpected bleeding may occur in the area after a surgical procedure, leading to the formation of a closed pool of blood within the tissue, known as a hematoma. Similarly, uncontrolled deep gum or tooth-root infections may cause severe swelling in the tissues. These fluids accumulate within enclosed spaces and begin to exert external mechanical pressure on the neighboring facial nerve. Blood flow within the nerve’s own fine vessels is disrupted under continuous pressure. The nerve tissue, unable to receive sufficient blood and oxygen, becomes deprived of nourishment, a condition known as ischemia, and cellular death occurs over time. In damage developing through this mechanism, facial paralysis does not appear immediately in the dental chair but gradually develops several days after the procedure. In addition, dormant herpes viruses in the body may be reactivated by the stress caused by dental treatment and infect the nerve sheath, representing another rare pathway leading to permanent damage.
Which Physiological Symptoms Do Patients Experience When Facial Paralysis Develops?
When the facial nerve is damaged, this is not merely an aesthetic difference that causes the face to appear asymmetrical. It is also a functional loss that profoundly affects all moving functions of the face, as well as the initial points of the digestive and visual systems. When nerve signals are interrupted, the muscles relax completely and sag downward under the influence of gravity. Patients are forced to cope with a severe imbalance between the pulling power of the muscles on the healthy side of the face and the unresponsiveness of the paralyzed side.
Because the forehead muscles in the upper part of the face do not function, the person cannot make a surprised expression, and the forehead on that side becomes completely smooth. Moving downward, the characteristic fold between the nose and the corner of the mouth disappears. Since the muscles around the mouth become nonfunctional, the lips shift toward the healthy side while smiling. This asymmetrical appearance may create such a severe psychological burden that the individual withdraws socially, avoids making eye contact with others, and refrains from eating in public.
The prominent complaints that make daily life difficult for patients in physiological and functional terms are quite clear. The main problems that occur when facial paralysis develops include:
- Complete smoothing of forehead wrinkles
- Inability to raise the eyebrow on the affected side
- Inability to close the eyelid completely
- Corneal dryness on the eye surface
- Uncontrolled overflow of tears
- Deviation of the corner of the mouth while smiling
- Inability to whistle
- Slurred speech due to inability to close the lips
- Leakage of liquids from the corner of the mouth while eating
- Reduced ability to taste at the tip of the tongue
- Intolerance to loud sounds
What Are the Degrees of Facial Paralysis and Early Treatment Methods During Recovery?
The severity of nerve damage is the most important factor determining how long recovery will take and whether the face can return to its previous condition. We can think of the nervous system as a massive electrical cable containing thousands of fine copper wires and insulated on the outside with thick plastic. If the damage consists only of mild compression of the cable, there is no anatomical disruption. Conduction has only stopped temporarily. This is called first-degree injury, and it heals completely on its own within a few days without leaving any lasting effects.
If the outer sheath remains intact but the small conducting wires inside are severed, this is called second-degree injury. The nerve fibers begin to regrow and repair themselves at an extremely slow rate of approximately one or two millimeters per day. It may take months for the muscles to begin receiving signals, but because the sheath remains intact, the nerve finds the correct pathway and satisfactory improvement is observed over time. In third-degree injury, the most severe scenario, both the nerve fibers and the guiding sheath are completely severed. In this case, the nerve cannot find its own pathway and reach the muscles, the muscles gradually begin to waste away, and permanent paralysis becomes established. Supporting the process and keeping the facial muscles viable during the early period is of great importance.
Protective and supportive approaches that may be used during this early period include:
- Warm wet compress applications
- Use of prescribed painkillers
- Muscle relaxant medications
- Special jaw-opening exercises
- Acupuncture sessions
- Neural therapy applications
- Use of cornea-protective drops
- Massage to increase circulation in the facial muscles
When Is Surgery Considered in Permanent Facial Paralysis That Does Not Improve Despite All Treatments?
The body needs time to repair nerve damage. In facial paralysis developing after dental treatment, if no movement has begun despite months passing and despite all medication treatments, physical therapy sessions, and supportive methods, the process takes a different direction. In medical protocols, the period between six months and one year is considered the observation and waiting period. If there is not even the slightest twitch in the patient’s facial muscles at the end of one year, the condition is then regarded as permanent facial paralysis.
Why does the approach change completely after one year? Because facial muscles that receive no neural command and cannot be moved enter an irreversible wasting process due to disuse, known as atrophy. Muscle tissue loses its volume and is replaced by nonfunctional fatty and connective tissue. After this point, finding and suturing or repairing the severed nerve provides no benefit because the muscle that the nerve would stimulate has already lost its vitality. At this stage, advanced plastic and reconstructive surgery protocols are introduced to restore movement to the area and reconstruct facial symmetry both at rest and during facial expressions.
Which Plastic Surgery Techniques Are Used in Permanent Facial Paralysis?
When muscle tissue has completely lost its vitality in adult patients, a new muscle group must be transferred from another part of the body to the face together with its own blood vessels and nerve. This series of procedures, called dynamic reanimation, aims to enable the patient to smile voluntarily again. In this highly complex process requiring considerable expertise, the tissues are joined together with extremely fine sutures under an operating microscope.
The main dynamic and static procedures used in the repair of permanent facial paralysis include:
- Free gracilis muscle transfer
- Cross-face nerve grafting
- Masseteric nerve transfer
- Temporalis muscle transposition
- Fascial suspension
- Placement of a gold plate in the upper eyelid
- Procedure to narrow the outer corner of the eye
- Facelift operations to correct asymmetry
How Are Nerve and Muscle Repair Performed with Microsurgery in Facial Paralysis Treatment?
When muscle transfer is required, plastic surgeons generally prefer the gracilis muscle located on the inner thigh, whose absence is not noticed in basic functions such as walking. Because of its shape and contraction strength, this muscle is highly suitable for imitating the facial expression muscles. During surgery, a small section of this muscle is removed from the body as a whole together with the artery supplying it, the vein draining its blood, and the motor nerve enabling it to contract. To ensure that this new muscle, placed in a prepared pocket beneath the cheek skin on the paralyzed side of the face, continues to survive, its vessels are sutured under a microscope to suitable vessels in the neck or facial region, immediately restoring blood flow.
After ensuring the survival of the muscle, a neural conduction pathway is required to tell it when to contract. If a natural, spontaneous smile is desired, “cross-face nerve grafting” is performed. A thin sensory nerve taken from the back of the leg is passed like an extension cable through a tunnel beneath the upper lip from the nonparalyzed side of the face to the paralyzed side. Small branches from the facial nerve on the healthy side are connected to this cable. Thus, when the person smiles, the signal from the brain activates the healthy side and simultaneously travels through this cable to the new muscle on the opposite side, creating a bilateral and synchronized facial expression. When a faster and stronger contraction is desired, the masseteric nerve responsible for chewing is redirected to the facial muscle. Since the chewing nerve is not affected by the paralysis, a short time after surgery, when the patient lightly clenches the teeth, the transferred muscle contracts strongly and lifts the corner of the mouth. Over the following months, the brain adapts to this new arrangement, and the patient becomes able to smile without consciously thinking about clenching the teeth.
Which Procedures Are Applied in Facial Paralysis Patients Who Are Not Suitable for Microsurgery?
In some cases, the patient’s general health condition, advanced age, or existing systemic diseases may prevent them from undergoing microsurgical operations lasting many hours. Sometimes waiting for nerve recovery that may take months can also be psychologically exhausting for the patient. In scenarios involving such limitations, instead of bringing tissue from a distant part of the body, muscles located close to the paralyzed area and unaffected by the paralysis are redirected to restore movement to the face.
The temporalis muscle in the temple region is most commonly used for this purpose. The temporalis muscle spreads over the temporal bone like a fan and attaches to the lower jaw, helping close the mouth. Because this muscle is controlled not by the facial nerve but by a separate nerve network, it continues to function normally in patients with facial paralysis. The surgeon detaches part of this muscle from the bone, rotates it downward through the inside of the cheek, and sutures it to the corner of the mouth and sometimes to the eyelids. After the procedure, when the patient makes a biting movement, the temporal muscle contracts and pulls the attached corner of the mouth upward, creating a mechanical smile. To improve the success of such operations and ensure that the muscle tissue remains in the correct position during healing, special supporting sutures are placed inside the cheek to statically suspend the facial skin upward.
How Is Eye Health Protected in the Treatment of Permanent Facial Paralysis?
In facial paralysis treatment, there is a much more urgent and critical step than achieving an attractive smile: protecting eye health. While the muscles that close the eye on the paralyzed side lose their function, the muscles that keep the eye open continue to function because they are controlled by a different nerve. The inability of the eyelids to meet and the failure of the eye to close completely cause the cornea to dry rapidly. An eye that remains open even during sleep is exposed to airborne dust and dryness, creating conditions for corneal wounds and, if left untreated, severe damage that may progress to blindness.
To permanently resolve this condition, a small, thin plate is placed in the invisible inner part of the upper eyelid. Gold or platinum, which are generally fully biologically compatible with the body and cause no reaction, are used. The weight of these plates is precisely calculated according to the patient’s eye structure, and with the help of gravity they allow the upper eyelid to descend gently and the eye to close completely. In cases where the lower eyelid sags severely and tears overflow outward, a small suturing procedure is performed at the outer junction of the eyelids to narrow the area that remains open. In this way, rapid evaporation of tears is prevented and the eye surface is protected by a natural moisture barrier.
How Is Botox Used for Involuntary Facial Movements (Synkinesis) After Facial Paralysis?
During the long months in which nerve damage partially heals, the nerve fibers do not always find the correct pathway as they regrow. Signals that move the face may travel into the wrong pathways. For example, fibers carrying the command to smile may lose their way and connect to the muscles around the eye. When this occurs, the patient involuntarily closes the eye tightly every time they smile or begin speaking. Tears may flow involuntarily while eating or chewing, or painful tightening may occur in the neck muscles. This neurological condition in which one muscle group contracts involuntarily while another facial expression is being performed is called “synkinesis.”
When synkinesis becomes established, one of the most effective ways to manage the asymmetry and involuntary spasms experienced by patients is the use of botulinum toxin, commonly known as Botox. Botox temporarily interrupts electrical conduction from the nerve to the muscle in the area where it is injected, relaxing and weakening that muscle. In facial paralysis treatment, this procedure is used not merely for aesthetic purposes but to establish a completely functional balance. Because there is no opposing muscle group resisting it, the healthy side of the face works much more strongly than normal and pulls the mouth toward the healthy side. To slow this excessive contraction on the healthy side and stop incorrect contractions on the paralyzed side, Botox is injected into strategic points in very small doses.
The main conditions that may be managed with Botox include:
- Slowing excessive muscle movements on the healthy side
- Relaxing the eye muscles that close involuntarily while smiling
- Softening the firm bands that appear in the neck while speaking
- Preventing uncontrolled dimpling that develops at the tip of the chin
- Suppressing involuntary facial movements that increase during chewing
- Restoring facial symmetry at rest
- Relieving facial pain caused by muscle spasms
Although facial paralysis is a frightening complication, patients can regain their former expressions, symmetrical appearance, and social confidence thanks to the body’s own repair capacity, advanced microsurgical techniques, and supportive medical approaches.
Frequently Asked Questions
He completed his medical education at Ankara University Faculty of Medicine in 1996 and his specialty training between 1996–2002 at Hacettepe University Faculty of Medicine, Department of Plastic, Reconstructive and Aesthetic Surgery.
Between 2002–2009, he worked at Süleyman Demirel University Faculty of Medicine, Department of Plastic, Reconstructive and Aesthetic Surgery.
Since 2009, he has been working at Hacettepe University Faculty of Medicine, Department of Plastic, Reconstructive and Aesthetic Surgery. He received the title of Associate Professor in 2011. Dr. Nasır became a Professor in 2019 and continues to work as a faculty member in this position.
Between 2006–2008, he conducted studies on composite tissue transplantation at the Cleveland Clinic in Ohio, USA, together with Dr. Siemionow, who performed the first face transplant in the United States and the second in the world.
In 2012, he successfully performed Turkey’s second face transplant, which was the third among full face transplants in the world and the 22nd overall. Simultaneously with this face transplant, the world’s first quadruple limb transplant was carried out at Hacettepe University by a large team under his leadership.
He won second-place awards in the experimental and clinical specialist competitions at the 31st and 32nd National Plastic, Reconstructive and Aesthetic Surgery Congresses. In 2023, he completed his doctorate in Hand Surgery at Hacettepe University Faculty of Medicine.
He is a member of the American Society of Reconstructive Microsurgery, Plastic Surgery Research Council, Turkish Society of Plastic, Reconstructive and Aesthetic Surgery, Reconstructive Microsurgery Association, and Turkish Society for Surgery of the Hand and Upper Extremity.
