Because odontoma has typical radiographic features, mainly presenting as irregular, unorganized radiopaque mass, usually surrounded by a clear thin radiographic halo, it is easy to make a definite diagnosis in the clinic [4, 5]. However, once the dent-like tissue within the odontoma erupts out of the mouth, although this is very rare, it is difficult to establish a correct clinical diagnosis [6]. This article reports a rare case of atypical odontoma with the above characteristics. At the patient's first visit to our clinic, intraoral examination and imaging findings revealed multiple teeth with abnormal morphology located above the crown of the unerupted teeth 24. However, one month after the removal of the excess teeth, a rapidly growing mass appeared in the alveolar bone, with typical odontoma characteristics. Eruption of impacted teeth will not occur until the second operation, after the obstruction has been removed according to odontoma surgical standards. For this rare case, we will analyze from several aspects, including how to make a correct diagnosis, the cause of rapid tumor growth, and the standard treatment of impacted teeth, in order to provide some references for the diagnosis and treatment of this rare odontoma with teeth eruption.
How to make a correct diagnosis of odontoma with teeth eruption?
The odontoma was mostly enclosed in the alveolar bone, most of the affected parts of the gingiva and alveolar bone showed no obvious abnormality or only slight eminence during clinical oral examination. However, because odontomas show distinct features on imaging, a correct diagnosis can usually be made by routine X-ray or CT examination [7, 8]. Not everything is normal, there will always be accidents. If the odontoma is atypical and does not show typical odontoma features in oral and imaging examinations, how we can make a correct diagnosis is the focus of this paper [9]. For the cases reported in this paper, we took it for granted that they were supernumerary teeth due to the presence of multiple malformed teeth and no obvious odontoma structure on oral and radiographic examination.
We reflect on mistakes made in early diagnosis. First, there are cognitive deficits. Our understanding of odontomas rests on images of the typical odontoma form, the fibrous capsule wall surrounding the dentate tissue. Once the odontoma appears in an atypical form, we cannot make a correct diagnosis. Therefore, this is also the original intention of our case report. We hope that the reflection on this case can expand the clinician's cognition of atypical odontoma, so as to make better diagnosis and treatment for patients. Second, careless observation deprives us of the opportunity to correct the erroneous diagnosis. When we re-examined the earlier CBCT images, we found that on the crown of the un-erupted tooth, apart from several teeth with abnormal morphology that were removed, we could also see some other occluded image coverage. In addition, the post-operative periapical radiography examination after the first extraction of the redundant tooth also showed mixed radio-opaque and radiolucent lesion above the crown of un-erupted tooth. Although preoperative and postoperative imaging does not show the typical characteristics of odontoma, if we look closely, we will find that there is still unremoved tissue after the removal of the redundant tooth. Had we been aware of this at the time and consulted a more experienced professional, a second operation might have been avoided.
Why does the odontoma grow rapidly one month after the removal of abnormal teeth?
In this misdiagnosed case, we stumbled upon a meaningful phenomenon. One month after the removal of the exposed odontoid tissue, the odontoma developed rapidly and presented a typical odontoma-like appearance on imaging. On this issue, we conducted a literature review and reached the following conclusions.
First of all, we need to analyze the etiology of odontoma. Odontomas are developmental abnormalities caused by the interaction of epithelial cells and mesenchymal tissue, which appear as regular or irregular masses of hard tissue surrounded by a fibrous tissue envelope [10, 11]. The specific causes of odontoma still unclear, and there are several theories, including primary dentition trauma, infection, family history, genetic mutations, and overactivity of odontoblast cells [12]. For the cases reported in this paper, we speculated that it may be the trauma during the first extraction of redundant teeth, or the postoperative infection stimulated the odontoma capsule wall, which aggravated the abnormal epithelial and mesenchymal response and stimulated the rapid growth of odontoma lesions. In addition, at the second surgical resection, we found that even after the odontoma had been removed, there were many smaller fibrous capsule walls hidden around the alveolar bone wall. This is similar to the recurrence of myxocysts caused by incomplete cleaning of vesicles after excision [13]. These potential fibrous capsule walls are also important factors for the recurrence of odontoma. Another point that cannot be ignored, the external stimulation during the first operation and the postoperative infection accelerated its growth rate, making it grow into a larger odontoma in just one month. All this reminds us that when performing odontoma removal, thorough detoxification should be carried out to remove all exposed fibrocystic walls, and gentle movements should be performed to reduce adverse intraoperative and postoperative irritation, so as to reduce the possibility of odontoma recurrence.
What do we need to do about unerupted tooth due to odontoma?
Odontoma is more common in young patients, and the reason for visiting the doctor is that the permanent teeth do not erupt normally [14, 15]. Therefore, for these patients, the normal eruption of permanent teeth is their focus. We know that the most common clinical tooth eruption disorder is mechanical impaction except for the unexplained primary eruption disorder, and odontoma is an important cause. For tooth eruption obstacles caused by mechanical impact, most of the clinical treatment is to remove the mechanical obstacles, teeth can normally erupt without special treatment [16].
In the case reported here, the patient came to the clinic because tooth 24 failed to erupt normally. Since clear obstacles can be seen above the crown of the un-erupted tooth, we first take the way to observe the eruption of the tooth after removing the obstacles. However, due to the wrong diagnosis at the first visit, we only removed the abnormal tooth above the un-erupted crown, and failed to completely remove the obstacle on the crown side, resulting in the impacted tooth still unable to erupt.
After fully analyzing the cause and communicating with the patient and her parents, we carried out the second operation very carefully. During the second operation procedure, we considered in detail the factors that might affect the eruption of permanent teeth. In addition to the condition of not damaging the normal development of permanent tooth embryo, the surrounding fiber capsule wall is removed as far as possible. At the same time, a more gentle approach is taken during the operation to prevent recurrence caused by mechanical trauma to the hidden cyst wall and postoperative infection. The results of the second surgery were satisfactory. The un-erupted teeth had erupted normally, and the crown and root development were not abnormal. This case is further described that young permanent teeth affected by odontoma can grow back normally without further treatment as long as the coronary odontoma is removed [17]. Of course, further orthodontic treatment may be required in the future if the dentition is to be made neat and aesthetically pleasing.