Traumatic Bone Cysts of the Jaw

What Is a Traumatic Bone Cyst?

This “pseudocyst” of the jaws that is usually asymptomatic in young adolescents and patients between 10 to 20 years of age may cause several complications, including the delayed eruption of permanent teeth, pain, numbness, and facial swelling, and is not neoplastic or cancerous. This pseudocyst of the jaws, yet a non-epithelial form of a cyst caused by trauma, is capable of causing great discomfiture to the young patients and children.

The lesion is certainly not neoplastic or cancerous and is detected usually by the dental surgeon in patients between 10 to 20 years. It is not very uncommon. It is known in dental literature by a wide variety of other names (usually specifying the origin or based on the location, but the pathogenesis of the cyst remains the same) like a solitary bone cyst, unicameral bone cyst, extravasation cyst, hemorrhagic cyst, or a cyst that has a progressive bone cavity.

This traumatic bone cyst may be quite asymptomatic in adolescents and young adults and, in fact, may only be discovered during a routine radiographic examination at the dental office. Also, unlike other cystic lesions that may cause tooth displacement or tooth resorption adjacent to such a cystic lesion, traumatic bone cysts do not cause any such issues dentally except recurring pain or numbness in the affected area. The exact pathogenesis of this cyst remains elusive in research. A traumatic impact is directly or indirectly responsible for its formation; hence the name was given to it. This cyst has a slightly more male predilection than the female population, as per the etiology.

Why Is Traumatic Bone Cyst Not a True Cyst?

Traumatic bone cysts are a distinct clinical entity given that they are distinguished from true cysts mainly because of the lack of epithelial lining the cyst cavity. A true cyst of dental origin is defined as the pathologically lined epithelial cavity containing fluid drawn into its cavity because of hydrostatic pressure. Hence traumatic bone cyst is definitely a pseudocyst as commonly termed. However, as per research, most theories also focus on the potential link between local bone defects, localized infections of the jaws, or a combination of bone necrosis, a disorder or a disease of calcium metabolism in the affected individual.

Only a detailed medical history of the patient can trace these underlying causes, if any.

What Is the Pathogenesis of Traumatic Bone Cysts?

Though not exactly elaborated in literature, widely accepted theories by dental surgeons are that a traumatic force or impact that is often disorganized in nature tends to cause a rise in osteoclastic activity (increase in the number of osteoclast or bone-resorbing cells) that is in turn because of a hematoma formation or a solid tissue blood clot.

Location: Most traumatic bone cysts are located along the mandibular body, especially in between the areas of canine teeth to the third molar tooth segments. Some case reports have also been reported at the mandibular symphysis region. In the maxillary region, though traumatic bone cysts are much less predominant, case reports of occurrence in the anterior maxillary segment are not rare.

What Are the Clinical Features of Traumatic Bone Cysts?

The main clinical features of this bone cyst in symptomatic patients are:

1. Pain in the affected area of the mandible (lower jaw) or might be in the maxilla (upper jaw region anterior segment) if the cyst is present in the maxilla.

2. Tooth sensitivity or associated pain in the surrounding region of the cyst.

3. Delayed eruption of permanent teeth [which usually prompts the dental surgeon to visualize the child’s tooth in two-dimensional or three-dimensional scanning, OPG (orthopantomography), CBCT (cone-bone computed tomography) scanning, radiographic imaging to detect any abnormal cysts or pathologies obstructing the eruption of child’s permanent tooth]. A traumatic bone cyst in a child may hence be detected this way during a routine examination this way.

4. Displacement of the inferior alveolar nerve canal of the mandible can lead to both pain and sometimes paresthesia or numbness in the region.

5. Presence of oral fistulas (abnormal communications with the skin from the oral cavity due to long-standing or chronic infections of dental origin).

6. Though this symptom may be rare, and as the cyst is often asymptomatic initially when it expands beyond a certain size, there would be intraoral or extraoral swelling on the affected side of the face (jaw bone/facial swelling).

7. Radiologic Diagnosis: This is a definitive indicator of the traumatic bone cyst. It presents in the patient unilocular as a well-defined radiolucent outlined lesion with a characteristic scalloping effect of the cystic lesion seen between the two tooth roots that are affected as well. As mentioned earlier, if the cystic lesion is of moderate to large size, the expansion of the cortical plate is observed clearly radiologically. The margins of the cyst may appear irregular.

How Can Traumatic Bone Cysts of the Jaw Be Treated?

On surgical resection of this cyst, the bone cavity is found to be empty, in other words, non-epithelialized, and only fibrous tissue is observable along with blood that is curetted out almost completely by the surgeon. In fact, the dental surgeon or maxillofacial surgeon produces characteristic bleeding within the cavity of the cyst for draining it effectively by surgically maneuvering or exploring the bony walls of the cystic lesion. No epithelial content is found by the surgeon in this cyst, and hence complete curettage alongside all the bony walls of the cyst produces an effective result to prevent the relapse or possible recurrence of this traumatic cyst.

This cyst also does not exhibit any varying histopathologic features as in other major cystic lesions. The histologic examination is not an accurate diagnostic feature for traumatic cyst as this depends more on obtaining the cause or pathogenesis from patients medical history and more so histologically, areas of great vascularity are observed along with giant cells, fibrin, or red blood cells, which may be a common finding in so many other oral lesions and hence histopathologic feature is not used as a standard for diagnosis.

Conclusion:

Traumatic bone cysts are usually due to long-standing infection or traumatic impact; hence, the dental surgeon's early detection, intervention, and diagnosis will be beneficial to the young patients.