The question of whether an orthodontist keeps the final dental impression, often called a mold, is common for patients who have completed treatment and now rely on a retainer. This impression is an accurate record of the teeth in their perfected state, captured when braces or aligners are removed. Whether this record is retained depends on practice policy, state regulations, and the technology used to capture the impression. The retention of this post-treatment record has significant implications for a patient’s ability to maintain their smile in the years following treatment.
Retention Policies: Physical Molds Versus Digital Scans
The decision to retain a patient’s final dental record is heavily influenced by the format of that record. Historically, final impressions were taken using a putty-like material, such as alginate, to create a negative impression from which a positive plaster model of the teeth was poured. These physical plaster models are bulky, fragile, and require substantial storage space, making long-term retention impractical for many high-volume practices due to costs and logistics.
Modern orthodontic practices increasingly use intraoral digital scanners, which capture a highly precise 3D digital model of the patient’s dentition in minutes. This digital file replaces the need for a physical impression and offers superior accuracy compared to traditional putty molds, which are prone to distortion or human error. Digital scans are stored electronically, making them easily accessible and virtually indefinite, eliminating the space and deterioration concerns associated with plaster models.
While practice policy dictates storage, state dental board regulations establish the minimum time dental records must be kept. These regulations often require patient records—which include the final impression or scan—to be maintained for a specific period, such as seven to ten years after treatment completion. For minors, the retention period is often tied to the age of majority, requiring records to be kept for a set time after the patient turns 18 or 21.
How Retained Records Streamline Retainer Replacement
The most significant practical benefit of a retained final mold or digital scan is the ability to quickly and efficiently replace a lost, broken, or worn-out retainer. Retainers, especially clear plastic types, often need replacement every one to three years due to wear and tear. If the original digital file exists, the orthodontist or lab can fabricate a new retainer immediately, often without the patient needing to schedule an in-office appointment for a new impression.
This streamlined process significantly reduces the time from ordering a replacement to receiving it, which is especially important because teeth can begin to shift rapidly without retainer wear. The cost is also lower because the expense of chair time for a new impression, material costs, and the lab fee for creating a new physical model are eliminated. In some cases, a new retainer can be shipped directly to the patient, saving them the inconvenience and expense of a physical visit. The accuracy of the digital file ensures the replacement retainer fits the patient’s post-treatment alignment exactly, preventing micro-movements of the teeth.
What Happens When the Original Molds Are Unavailable
When a patient requires a replacement retainer but the original physical mold has been discarded or the digital file deleted after the retention period, the process becomes more involved and costly. The orthodontist must first schedule an appointment to take a new impression or perform a new intraoral scan of the patient’s current dental alignment. This step is necessary to ensure the new retainer matches the teeth’s present position, which may have changed slightly since the original treatment was completed.
Taking a new impression adds the cost of the office visit, materials for the mold or digital scanner use, and laboratory fees for fabricating a new model. The turnaround time for the replacement retainer is also extended, as the new data must be sent to the lab, and a physical model must be created before the final appliance can be manufactured. If the teeth have shifted significantly, the orthodontist may advise the patient that a simple replacement retainer is not sufficient and that a short course of minor tooth movement, perhaps with clear aligners, is necessary before a new retainer can be created to prevent further relapse.