Dental crowns are a common restorative solution used to cap a damaged or weakened tooth, such as one that is severely decayed, fractured, or has had a root canal. A crown returns the tooth’s function, strength, and appearance while providing necessary protection. The choice for patients typically comes down to two main methods of fabrication: the traditional multi-visit crown crafted by an external dental laboratory, or the single-visit restoration created using in-office computer-aided design and manufacturing (CAD/CAM) technology. This comparison addresses whether the convenience of same-day technology compromises the quality or longevity often associated with the traditional, lab-crafted restoration.
Understanding the Fabrication Process
The process for a traditional, lab-fabricated crown begins with the dentist preparing the tooth and taking a detailed impression, which can be a physical mold or a digital scan. This impression is then sent to an off-site commercial dental laboratory, where specialized technicians spend one to three weeks crafting the final restoration. During this waiting period, the patient wears a temporary acrylic crown to protect the prepared tooth. The second appointment is required for the dentist to remove the temporary, check the fit and shade of the permanent crown, and cement it into place.
In contrast, the same-day crown relies entirely on digital technology to condense this timeline into a single appointment, often lasting only a couple of hours. After the tooth is prepared, an intraoral scanner captures a precise three-dimensional image of the area, eliminating the need for a physical impression. Computer software is then used to design the crown, and the data is sent directly to an in-office milling unit that carves the restoration from a solid ceramic block.
Material Composition and Aesthetic Outcomes
Same-day crowns are typically milled from solid ceramic materials, such as lithium disilicate or glass ceramics. These monolithic materials are strong, durable, and offer a natural, tooth-colored appearance. However, the limitation of the milling process is that the restoration is cut from a single block of uniform color and translucency, which can sometimes result in a crown that appears slightly opaque or monochrome.
Lab-fabricated crowns offer a wider palette of material choices, including porcelain-fused-to-metal (PFM), high-strength zirconia, and layered porcelain. For restorations on highly visible front teeth, the lab process provides a distinct aesthetic advantage. Skilled dental technicians can manually layer different shades of porcelain powder and apply custom stains and glazes, creating depth and natural translucency that closely mimics the subtle characteristics of surrounding natural teeth.
Comparison of Fit and Longevity
The long-term success of any crown depends significantly on its marginal fit, which is the precision of the seal where the crown meets the prepared tooth structure at the gumline. A poor fit can lead to cement washout, microleakage, and increased risk of secondary decay. Modern digital scanning technology, now utilized in both processes, has improved the accuracy of the initial impression for both crown types.
Clinical studies comparing the two methods often demonstrate that CAD/CAM-fabricated crowns achieve a marginal fit that is either superior or comparable to conventionally crafted crowns. For instance, research has shown the mean marginal gap for CAD/CAM crowns to be significantly smaller than conventional crowns, with both typically falling well below the clinically acceptable threshold of 120 micrometers. This suggests that the automated precision of the milling unit can often be more reliable than the manual steps involved in traditional wax-and-casting techniques.
Both same-day and lab-fabricated crowns are highly durable and designed to last for a similar timeframe, typically between 10 and 15 years with proper care. For teeth under extremely heavy biting forces, such as back molars, a lab-fabricated crown utilizing materials like PFM or specialized, multilayered zirconia may still be recommended due to their proven performance in high-stress areas.
Financial and Time Commitments
The most notable difference between the two approaches is the time investment required from the patient. Same-day crowns offer the convenience of a single appointment, eliminating the need to manage a temporary crown for several weeks and avoiding dietary restrictions. This is a major advantage for patients with tight schedules or those who experience anxiety about multiple dental procedures.
While the patient cost for both crown types is generally similar, the elimination of a temporary crown and a second appointment provides indirect savings with same-day crowns. Although same-day procedures remove the external lab fee, the cost of the in-office CAD/CAM technology often balances the patient’s final price. Insurance coverage for both methods is typically the same, as policies cover the restoration regardless of the fabrication technique. The choice often comes down to prioritizing either maximum aesthetic customization for a front tooth or maximum time efficiency for a back tooth.