The “silver caps” people refer to are Stainless Steel Crowns (SSCs). These pre-formed metal restorations are primarily used in pediatric dentistry for covering and protecting primary, or “baby,” teeth. Made from a durable alloy of stainless steel, nickel, and chromium, these caps provide full coverage for a compromised tooth. They are a common solution for restoring the function of a severely damaged tooth until it is naturally replaced by the permanent tooth.
Clinical Rationale for Stainless Steel Crowns
A dentist chooses an SSC when damage to a primary molar is too extensive for a standard filling to reliably restore the tooth structure. This often occurs when decay has spread across multiple tooth surfaces, compromising the tooth’s structural integrity. A large, multi-surface filling is significantly more likely to fracture or fail under the heavy chewing forces of the back teeth compared to a full-coverage metal crown.
SSCs are also the standard restoration following pulp therapy (a baby root canal), as this procedure weakens the tooth structure. They are also indicated for teeth with congenital developmental defects, such as amelogenesis imperfecta. By capping the tooth, the crown prevents the premature loss of the primary tooth. This maintains the correct space necessary for the permanent tooth to erupt properly until natural exfoliation occurs.
Preparing the Natural Tooth Structure
The procedure begins with the dentist administering a local anesthetic to numb the tooth and surrounding gum tissue. Once the area is numb, any existing decay is thoroughly removed from the tooth structure using a dental drill. This step cleans the tooth and eliminates any ongoing bacterial infection before the crown is placed.
The next step is physically shaping the tooth so the pre-formed metal cap can slide over it securely without interfering with the patient’s bite. This involves reducing the height of the biting surface (occlusal reduction) by approximately 1.0 to 1.5 millimeters. The dentist also slightly reduces the sides (proximal reduction) to break contact with adjacent teeth, creating a clear path for the crown to seat fully. This minimal reduction prepares the tooth to accept the crown while ensuring the final restoration is not bulky.
Fitting and Cementing the Crown
The dentist first selects the smallest pre-formed SSC that covers the prepared tooth, using a sizing gauge to match the tooth’s width. The crown is test-fitted to ensure it extends slightly below the gum line, providing a tight seal around the circumference. If the crown is too long, the dentist trims the edge using specialized scissors until the margin sits about one millimeter below the free gingival margin.
Next, contouring and crimping are performed using specialized pliers. Contouring rolls the crown’s edge inward to mimic the natural bulge of the tooth, while crimping tightens the bottom edge. This adaptation creates a firm, retentive “snap-fit” that prevents food from getting trapped under the margin. The dentist then checks the patient’s bite to confirm the crown does not feel “high” and that the teeth fit together naturally.
The final step is cementing the crown, typically using a luting material like glass ionomer cement. This cement is preferred because it bonds well to the tooth and releases fluoride, offering added protection against secondary decay. The cement is mixed, placed inside the crown, and the cap is seated onto the prepared tooth. Any excess cement that oozes out is immediately removed using an explorer and dental floss to ensure the surrounding gum tissue remains healthy.
Aftercare and Longevity
Immediately after the procedure, the patient may experience numbness from the local anesthetic. Minor gum irritation is common where the crown margin sits, and the crown may feel slightly different to the bite for a few days. Over-the-counter pain relievers are sufficient to manage any discomfort until the surrounding teeth and jaw muscles adapt.
The SSC is designed to remain in place for the entire lifespan of the primary tooth. It will only come out naturally when the underlying permanent tooth erupts and pushes the baby tooth out, with the crown still attached. Proper care involves regular brushing and flossing, treating the crowned tooth like any other natural tooth. Patients should avoid chewing on hard or sticky foods, as these can potentially loosen the crown.