The appearance of a second row of teeth, commonly called “shark teeth,” can be alarming for parents, but this dental event is common during childhood development. This phenomenon describes a situation where the permanent tooth begins to emerge behind a baby tooth that has not yet fallen out, creating a temporary double row. This process is a normal variation of the shedding pattern, rarely causes serious concern, and often resolves with minimal intervention.
Understanding the Causes of Retained Baby Teeth
Tooth replacement relies on the permanent tooth dissolving the root of the baby tooth, a process called root resorption. As the permanent tooth pushes upward, it gradually breaks down the primary tooth’s root structure, causing the baby tooth to loosen and fall out. Shark teeth occur when the permanent tooth erupts slightly off-track, missing the baby tooth’s root entirely.
The most frequent scenario involves the permanent tooth emerging on the tongue side (lingually), leaving the baby tooth’s root intact and firmly anchored. This misalignment keeps the baby tooth securely in place even as its successor emerges. This commonly affects the lower front teeth around ages six to eight, and sometimes the upper back molars around age 11 or 12.
The Immediate Fix and Action Steps
The initial fix depends entirely on the stability of the baby tooth.
If the Tooth is Loose
If the primary tooth is already loose, encourage the child to wiggle it consistently with their finger or tongue. The mechanical force of wiggling helps break down any remaining root tissue and encourages natural exfoliation. This simple act can often resolve the double-row issue within a few weeks.
If the Tooth is Firm
If the baby tooth is firm and the permanent tooth has erupted significantly, professional intervention is necessary to prevent long-term alignment problems. A dental visit is recommended within four to eight weeks of noticing the permanent tooth if the baby tooth remains tightly fixed. The fix is a straightforward, quick extraction of the retained baby tooth performed by a pediatric dentist, often using local anesthesia. Removing the obstruction immediately allows the tongue and cheek muscles to act on the newly emerged permanent tooth.
Post-Treatment Movement and Alignment
After the baby tooth is removed, parents often worry whether the permanent tooth will naturally move forward into the correct position. In the majority of cases, once the primary tooth is extracted, the pressure from the child’s tongue acts as a natural and continuous orthodontic force. This gentle pressure pushes the permanent tooth forward into the newly created space. This process of self-correction usually takes several weeks to a few months.
While most cases resolve after extraction, a small number may require continued monitoring. If the permanent tooth is severely displaced or if there is underlying crowding due to inadequate space in the jaw, the tooth may not fully align on its own. The dentist will monitor the eruption process through regular check-ups. An early referral to an orthodontist may be necessary to address a significant lack of space or severe misalignment.