Crown Restorations

A crown restoration is a fabricated cap that covers the entire clinical portion of a tooth (or an implant abutment), restoring its shape, function, and appearance when the tooth is too broken down, weakened, or root-treated to be restored with a direct filling. Crowns may be made of metal alloy, metal-ceramic, or all-ceramic materials and are cemented or bonded onto a prepared tooth.

Definition

A crown (also called a dental crown or single crown) is a fixed, full-coverage restoration that encases the prepared coronal surface of a tooth or implant abutment and is retained by cementation or adhesive bonding.

Scope

This topic covers the single crown as a unit of fixed prosthodontics: when full coverage is indicated, the main material categories, how crowns are retained, and the survival and complication patterns reported for them. It is a reference-educational overview, not a description of how to prepare or place a crown clinically.

Core questions

• When is a full-coverage crown preferred over a direct or partial-coverage restoration?
• How do all-ceramic, metal-ceramic, and metal crowns differ in survival and complications?
• What technical and biological complications affect single crowns over time?

Key concepts

• Full-coverage (complete-coverage) restoration
• Metal-ceramic crown (porcelain-fused-to-metal)
• All-ceramic and monolithic crowns
• Tooth preparation and crown retention
• Cementation versus adhesive bonding
• Biological versus technical complications
• Cumulative survival rate

Mechanisms

A crown restores a compromised tooth by replacing its outer contour with a rigid shell that distributes occlusal load over the underlying prepared structure and protects it from further fracture. Retention depends on the geometry of the preparation and on the luting cement or adhesive that bonds crown to tooth (Manso & Carvalho, 2017). Material choice trades esthetics against strength: metal-ceramic crowns combine a metal substructure with porcelain veneering, while all-ceramic and monolithic ceramic crowns offer greater translucency but differing fracture behaviour (Sailer et al., 2015).

Clinical relevance

Single crowns are among the most common fixed restorations, and pooled survival and complication data describe how their evidence is summarised — including ceramic chipping or fracture, loss of retention, and biological events such as caries or pulpal change at the margin (Sailer et al., 2015; Pjetursson et al., 2007; Goodacre et al., 2003). This entry explains how crown outcomes are reported and is not guidance for treating an individual tooth.

Epidemiology

Systematic reviews report high cumulative survival for single crowns over observation periods of several years, with metal-ceramic and various all-ceramic systems showing broadly favourable but materially distinct survival and complication profiles; technical complications such as veneering-ceramic fracture and loss of retention are commonly tabulated alongside biological complications (Sailer et al., 2015; Pjetursson et al., 2007; Goodacre et al., 2003).

Evidence & guidelines

The principal evidence base is a series of systematic reviews and meta-analyses pooling survival and complication rates of tooth-supported single crowns by material type (Sailer et al., 2015; Pjetursson et al., 2007), complemented by a structured synthesis of clinical complications across fixed prosthodontics (Goodacre et al., 2003).

Debates

All-ceramic versus metal-ceramic crowns

Reviews compare the survival and complication rates of all-ceramic systems against the long-standing metal-ceramic standard; differences in fracture behaviour, esthetics, and material-specific complications mean no single material is uniformly superior across indications.

Seminal works

• pjetursson-2007-sc
• sailer-2015-sc
• goodacre-2003

Frequently asked questions

What is the difference between a filling and a crown?

A filling rebuilds part of a tooth from within, while a crown is a separately fabricated cap that covers the whole prepared tooth — used when too little sound structure remains for a filling to be reliable.

Are ceramic crowns as durable as metal-ceramic ones?

Systematic reviews report that several all-ceramic systems achieve survival broadly comparable to metal-ceramic crowns, but their complication patterns differ; the comparison depends on the specific ceramic and clinical situation, and this entry does not recommend one for a given patient.