A tooth can be pushed back into the gums, a severe form of dental trauma termed dental intrusion. This injury involves the tooth being forcibly displaced deeper into its bony socket, or alveolus, along the tooth’s long axis. Intrusion is a type of luxation injury and is considered one of the most severe forms of dental trauma due to the extensive damage it causes to the supporting structures. It commonly affects the upper front teeth and requires immediate professional attention for a favorable outcome.
Defining Dental Intrusion
Dental intrusion is the apical displacement of the tooth, where the crown is driven toward the jawbone, often resulting in a shortened or completely hidden visible tooth. This forceful impact compresses and tears the periodontal ligament (PDL), the tissue that acts as a natural shock absorber between the root and the bone. The neurovascular bundle, which supplies the tooth’s pulp, is also severed or crushed, leading to a high likelihood of pulp death.
The force involved in intrusion is often strong enough to fracture or comminute the surrounding alveolar bone. Unlike avulsion, where the tooth is knocked out entirely, intrusion locks the root deeper into the bone. Common causes include falls, especially in young children, high-velocity sports injuries, and motor vehicle accidents. The pliable nature of a child’s jawbone makes primary teeth particularly susceptible.
Immediate Steps Following Injury
The proper initial response to a suspected dental intrusion is important for the tooth’s prognosis. The priority is to remain calm and immediately assess the extent of the injury, checking for any other head or facial trauma. It is important to control any bleeding from the soft tissues by applying gentle pressure with a clean cloth or gauze.
A cold compress applied to the outside of the mouth can help reduce swelling and pain immediately following the injury. Never attempt to pull the tooth back down or reposition it yourself, as this causes further damage to the root and surrounding bone. Urgent dental care is required, ideally within the hour, because the viability of the tooth decreases rapidly once the PDL is damaged.
Treatment Approaches for Permanent Teeth
The treatment strategy for an intruded permanent tooth depends on the severity of the intrusion, measured in millimeters, and whether the tooth’s root apex is fully formed. For a mild intrusion, generally less than 3 millimeters, the dentist may recommend a passive repositioning approach. This involves monitoring the tooth and allowing it to spontaneously re-erupt into its correct position over several weeks.
If the intrusion is moderate (3 to 6 millimeters) or if no spontaneous movement occurs within two to three weeks, active repositioning is necessary. The preferred method is often orthodontic repositioning, where a bracket is bonded to the tooth. Light, continuous forces are then applied via wires or elastics to slowly pull the tooth back into the arch over several months. This slow movement is intended to preserve the surrounding tissues and encourage healing.
For severe intrusions, typically greater than 6 millimeters, or when the tooth is completely submerged, surgical repositioning is often used. This procedure involves gently moving the tooth back into its proper position using forceps and then stabilizing it with a flexible splint for one to two weeks. Regardless of the repositioning method, root canal treatment (endodontic therapy) is frequently required soon after the trauma. This is due to the high chance of pulp necrosis in fully developed permanent teeth following severe intrusion.
Special Considerations for Primary Teeth
The management of intruded primary teeth differs significantly from permanent teeth because the primary concern is protecting the developing permanent tooth bud underneath. Since the root of the intruded primary tooth can be pushed into the successor tooth, treatment aims to minimize potential damage to the permanent tooth. The pliable nature of a child’s alveolar bone means that intrusion is the most common luxation injury in primary teeth.
In most cases where the intruded primary tooth is not interfering with the bite, the tooth is left to re-erupt spontaneously, which can occur within six months. Extraction is the treatment of choice if the primary tooth is severely intruded and its root apex is displaced toward the permanent tooth germ, or if the tooth shows signs of infection. Active repositioning methods like orthodontics or surgery are generally avoided for primary teeth due to the high risk of harming the underlying permanent tooth bud.
Long-Term Outcomes and Potential Complications
Despite immediate and appropriate treatment, dental intrusion carries a guarded long-term prognosis due to the severity of the initial injury. The most common and serious complication is pulp necrosis, the death of the tooth’s internal tissue. This often requires endodontic treatment to prevent infection from spreading to the surrounding bone.
Another significant risk is root resorption, where the body’s cells begin to dissolve the tooth root, potentially leading to tooth loss. Ankylosis, or replacement resorption, is a complication where the tooth root fuses directly to the jawbone, preventing normal movement. This can cause the tooth to become permanently stuck or submerged relative to the adjacent teeth. Long-term follow-up appointments, often spanning multiple years, are necessary to monitor for these complications and manage them early.