The canine tooth, often called an eyetooth, is the pointed tooth situated at the corner of the mouth. Humans have four permanent canines, with the upper pair typically erupting between the ages of 11 and 12. A canine tooth is considered “impacted” when it fails to erupt fully into its correct spot in the dental arch by the expected time, remaining stuck either beneath the gum line or embedded in the jawbone. This condition is the second most common form of impaction after wisdom teeth, affecting approximately one to two percent of the general population.
The Immediate and Long-Term Consequences
Leaving an impacted canine tooth untreated can result in serious complications. One severe risk is the potential for external root resorption of adjacent teeth, particularly the lateral incisor. As the impacted canine presses against the root of the neighboring tooth, it can cause the tooth structure to be slowly dissolved. This process can ultimately weaken the adjacent tooth to the point of loss if the damage is extensive.
The pressure exerted by the unerupted tooth can also cause the shifting and misalignment of the surrounding teeth, leading to malocclusion. This shifting can create gaps, crowding, or an incorrect bite relationship, which may introduce discomfort and difficulty with chewing. Furthermore, the presence of the impacted tooth beneath the surface can sometimes lead to localized periodontal issues, promoting bacterial overgrowth, decay, and gum disease if the impaction is partial.
A concerning consequence is the formation of a dentigerous cyst, a fluid-filled sac that develops around the crown of the impacted tooth. These cysts can grow over time, gradually destroying the surrounding jawbone and soft tissues as they expand. In rare but severe cases, this bone destruction can thin the jawbone, making it vulnerable to a pathological fracture even from minor trauma. The formation of such a cyst requires surgical removal of the tissue and often the impacted tooth to prevent further damage to the structural integrity of the jaw.
Identifying the Impaction and Understanding the Causes
The diagnosis of an impacted canine is often made incidentally during routine dental checkups, typically when X-rays are taken around the expected age of eruption in late childhood or early adolescence. A clinical examination may reveal a retained primary canine or a lack of the expected canine bulge in the gum line, prompting further investigation. Diagnostic imaging, such as a panoramic radiograph, is commonly used to screen the entire dental arch and visualize the position of the unerupted tooth.
A cone-beam computed tomography (CBCT) scan may be utilized, offering a detailed three-dimensional view of the tooth’s position and its relationship to the roots of neighboring teeth. Early diagnosis, ideally around eight to ten years of age, is important because it allows for interceptive treatments that can sometimes prevent full impaction and minimize complications.
Several factors contribute to why a canine tooth may become impacted, with a lack of adequate space in the dental arch being a frequent cause. If the jaw is too small or if other teeth are crowded, the canine may be unable to find its correct position. Genetic factors also play a role, as a familial predisposition is often observed, particularly with palatally impacted canines. Other contributing elements include the premature loss or, more commonly, the prolonged retention of the primary baby canine, which blocks the eruption path of the permanent tooth.
Treatment Pathways for Resolution
The treatment strategy for an impacted canine depends heavily on the tooth’s exact position, its angulation, and the patient’s age. The primary goal is usually to preserve the tooth and guide it into its proper place in the dental arch. For less severely impacted teeth in younger patients, an interceptive approach might be attempted, such as the extraction of the retained baby canine to open the eruption path and encourage natural movement.
The most common and preferred treatment for an impacted canine is a combined surgical and orthodontic procedure, often called “surgical exposure and orthodontic alignment.” An oral surgeon first creates a small opening in the gum tissue to expose the crown of the impacted tooth, then attaches a small bracket and chain to it. An orthodontist then uses this attachment with braces to apply gentle, continuous force, gradually pulling the impacted tooth into its correct alignment over a period of months or even years.
In cases where the tooth is severely malpositioned, deeply embedded, or if the patient is older with a reduced chance of successful movement, extraction of the impacted canine may be necessary. Following extraction, the space may be closed orthodontically by moving adjacent teeth, or the missing tooth may be replaced with a prosthetic option like a dental implant. In rare instances, particularly with mild impactions in older, asymptomatic patients, a treatment plan of observation and regular radiographic monitoring may be chosen.