Introduction
Ankylosis of the teeth, also known as submergence and infra-occlusion, is a condition where the teeth are located below the occlusal plane. The terms infra-occlusion and submergence are often used interchangeably with ankylosis in literature and studies. While ankylosed teeth are found in many cases, they are not very common, with a frequency ranging from 1.2 % to 39.5 %. The most commonly affected teeth are the mandibular first primary molars, followed by the second mandibular molars and maxillary primary molars. The primary cause of ankylosis is still unknown, but several theories have been proposed by researchers, including familial patterns, traumatic injury to Hertwig's epithelial root sheath, deficiency in bone growth, problems in local metabolism and inflammation, localized infection, and exposure to thermal or chemical irritants. Diagnosing ankylosed teeth is not difficult and relies on radiographic findings and clinical signs. Clinically, ankylosed teeth produce sharp, solid sounds on percussion tests, which differ from the cushion sound of normal teeth.
What Is Primary Molar Ankylosis?
Primary molar ankylosis refers to the condition where primary molars erupt with submergence or infra-occlusion below the occlusal plane. Ankylosed primary molars generally exhibit mild to moderate progressive infra-occlusion. It is recommended to monitor ankylosed primary molars and consider extraction if the permanent successor's eruption is compromised. Extraction may also be considered when the ankylosed primary molar is significantly infra-occluded, leading to the tilting of adjacent teeth and hindering successor eruption. There are various ways to manage and treat ankylosed teeth.
What Is Known as Ankylosis of Teeth?
Ankylosis of the tooth is elaborated as a state of the root of the tooth that gets permanently connected to the jaw. The tooth becomes immobile as the tooth no longer has the supportive periodontal ligament around it. The root of the tooth hence gets permanently attached to the jaw bone. An ankylosed tooth looks no different from a normal regular tooth, except it can sometimes be lower or higher to the occlusal plane. At the time of the developmental phase of the tooth, the growing tooth can get ankylosed even before it grows out of the gingiva. So, when this happens, the tooth usually stays shorter due to its hampered growth midway. The ankylosis of the teeth is also referred to as submergence or infra-occlusion. A person may have a single ankylosed tooth or may also have multiple ankylosed teeth. The dental practitioner may be able to detect the presence of ankylosis while the dental examination. Ankylosis is divided into a few types, such as slight, moderate, or severe, according to the position or level of the submerged or infra-occluded tooth. If the infra-occlusion is less than 2 millimeters, then it comes in the category of slight ankylosis. The category of moderate submergence has an ankylosed tooth that has the occlusal surface to the contact area. In severe ankylosis, the infra-occlusion below the contact area of the adjacent teeth can be seen.
What Is the Etiology of Ankylosis of the Teeth?
Ankylosis of the teeth is a serious condition elaborated as the process where the fusion between the dentin or the cementum of the root and the alveolar bone, and the deducting periodontal ligament eventually gets replaced by the bone tissue. Dental ankylosis is an eruptive disorder characterized by the fusion of the dentin or the cementum of the root to the surrounding bone, where the obliteration of the periodontal ligament will occur, and the periodontal ligament will be progressively replaced by bone tissue. It may appear at any tooth eruption stage, either before the primary retention (complete eruption) in the oral cavity or after the secondary retention (the tooth has reached the occlusal plane). For many years, a few theories have been proposed to explain the etiology of the ankylosis of the teeth. One theory states that local factors are the main cause behind the condition, and the other theory supports that genetic factors are responsible for the condition. However, until now, none of them have been declared as the main cause.
One of the proposed theories identifies that any disruption in the uniformity of the periodontal ligament caused by the trauma can initiate degenerative processes that can lead to the fusion of the tooth and the bone. When the periodontal ligament is completely destroyed and does not have healing capacity, a gradual replacement of the root with bone and progressive tooth ankylosis can be seen. Some other theory proposes that local factors, such as the disturbances in the local metabolism which can initiate the degeneration of the periodontal ligament, are responsible for the fusion of the root surface and the bone.
Ankylosis of primary molars has the potential to cause severe clinical consequences in children that includes tooth infra-occlusion and vertical bone defect, loss of arch space due to the tipping of adjacent teeth in the area of infra-occlusion, asymmetrical dentition, deviated midline, impacted ankylosed tooth and its successors, supra-eruption of the opposing teeth and the eruption path gets deflected off the successors. An extensive bony ankylosed primary molars are known to interfere with the exfoliation and the eruption of the permanent teeth successors.
How to Treat Ankylosed Tooth?
Many people are unaware that they have ankylosed teeth until the dental practitioner makes a diagnosis during a routine exam. The problem with the tooth can be suspected with visual appearance and eventually confirmed by taking a dental X-ray. After the confirmation of the condition, the treatment plan is finalized. The primary intention of the treatment plan is to remove or extract the ankylosed tooth to facilitate the proper growth of the permanent tooth. Sometimes, a space maintainer can also be placed in order to maintain the space between the two adjacent teeth of the extracted tooth until the permanent tooth erupts at the vacant position. Some dental practitioners may also place a restorative material to increase the level of the tooth in accordance with the occlusal plane. An orthodontist can also be involved in the treatment plan so as to correct skeletal issues and bite-related problems. An oral surgeon can also be included in the treatment plan if oral surgery is recommended to expose and reposition the adult successor tooth. Teeth implants can be used when no successor is present, or the ankylosed tooth is permanent. It is better to detect the ankylosed condition of the tooth as soon as possible as it may limit future complications with the treatment.
Conclusion
Ankylosis of the primary molar or any other teeth in the dentition can be prevented as there are many theories supporting the cause of this condition, and none is yet declared as the primary cause. Primary molar ankylosis can be managed with proper care and can be treated by dental practitioners also. The central part of the treatment plan is to extract the ankylosed primary molar in time and facilitate the growth of its successor. Early detection of the condition may prevent various dental problems and complicated dental treatments. One should always get dental examinations done regularly as this can be the only way to detect the ankylosis of any tooth, and one also should take care of dental hygiene. The dental practitioner can help the person with problems related to ankylosed teeth.
