A loose dental crown accompanied by a foul odor signals a breakdown in the restoration’s seal. A dental crown is a fixed cap placed over a damaged tooth to restore its shape, strength, and appearance. When the crown feels mobile and produces a bad smell, the protective barrier has failed, exposing the underlying prepared tooth structure. This situation requires immediate attention to prevent further damage to the natural tooth.
The Causes of Crown Failure
The sensation of looseness and the accompanying odor result from the crown’s adhesive bond failing, creating an open margin. The most common cause is the gradual breakdown and dissolution of the dental cement securing the crown to the tooth preparation. This process, often called cement washout, allows saliva and oral bacteria to seep into the microscopic space between the crown and the tooth surface. This loss of mechanical retention causes the crown to feel mobile.
The unpleasant smell, which may manifest as a foul taste, is a symptom of bacterial activity in this compromised area. Bacteria thrive on trapped food debris and decaying organic matter accumulating in the gap. These anaerobic bacteria release foul-smelling volatile sulfur compounds (VSCs) as a byproduct of their metabolism, causing the distinct odor.
A more serious underlying factor is recurrent decay (caries) forming beneath the crown’s margin. The natural tooth structure remains susceptible to decay, typically where the crown meets the gum line. As decay progresses, the supporting tooth structure is weakened and destroyed, compromising the crown’s fit and providing a reservoir for bacteria. Traumatic events, such as a physical blow or chronic stress from teeth grinding (bruxism), can also prematurely fracture the cement seal or the underlying tooth.
Immediate Steps and Potential Complications
The first step upon noticing a loose or foul-smelling crown is to contact your dentist immediately. Do not wait for the crown to fall out completely; the exposed prepared tooth is highly sensitive and vulnerable to rapid decay and fracture. While waiting for your appointment, avoid chewing or applying pressure on the affected side of your mouth to prevent further dislodgement or damage.
If the crown comes off completely, retrieve it, gently clean it with water, and store it safely. If the crown is intact, the dentist may be able to recement it, making preservation a priority. Never use household glues, such as super glue, to reattach the crown, as these products are toxic and will make professional re-cementation impossible.
If you cannot see a dentist right away, you may attempt temporary reattachment using an over-the-counter dental cement kit. Clean the inside of the crown and the tooth surface, apply a small amount of temporary cement inside the crown, and gently seat it back into place. This is a short-term measure to protect the exposed tooth and prevent nearby teeth from shifting. Ignoring a loose crown carries the risk of the crown being swallowed or aspirated (inhaled), which is a serious medical complication.
The exposed tooth structure is at high risk of developing a severe infection, potentially leading to an abscess if bacteria reach the pulp chamber. Rapid decay in the unprotected tooth may lead to significant structural loss, complicating the final repair. Prompt professional care is necessary to protect the remaining tooth structure and prevent the need for more complex treatment.
Fixing the Problem: Dental Solutions
The professional treatment pathway is determined by diagnostic findings, typically involving a visual examination and dental X-rays to assess the underlying tooth condition. If the tooth structure beneath the crown is healthy and the crown is undamaged, the simplest solution is to thoroughly clean both the crown and the tooth, then permanently recement the existing crown. This is the fastest and least invasive treatment option.
If the X-ray reveals recurrent decay, the dentist must first remove all the carious tissue. This process may require a core buildup using a restorative material to re-establish the necessary structure to support a new crown. In these cases, a new crown must be fabricated because the original crown will no longer fit the altered tooth shape.
If decay has progressed significantly, reaching the tooth’s nerve (pulp), a root canal procedure is necessary before a new crown can be placed. This involves removing the infected pulp tissue to save the tooth from extraction. If the remaining natural tooth structure is severely compromised or fractured below the gum line, the tooth may be deemed non-restorable, and extraction becomes the only viable option.