The AI Dentist - Classic Papers

The 1992 Review That Opened the Door to Modern All-Ceramic Crowns

THE CONTEXT

Published in Current Opinion in Dentistry in 1992, this comprehensive review by Lehner and Schärer examined the state of all-ceramic crown systems at a pivotal moment in restorative dentistry. While citation counts weren’t tracked as extensively then, this paper became a foundational reference during dentistry’s transition away from metal-ceramic restorations. In 1992, porcelain-fused-to-metal crowns dominated, but patients increasingly demanded metal-free alternatives for aesthetic reasons.

THE CONTRIBUTION

The authors provided the first systematic analysis of all-ceramic systems’ strengths and limitations, acknowledging that “failures are still of considerable concern because of some limited properties common to all-ceramic crown systems.” Importantly, they introduced the dental community to IPS-Empress, a new leucite-reinforced glass-ceramic that could be fabricated using a simple press-molding technique. This marked a turning point from earlier, more fragile all-ceramic systems.

THE LEGACY

This paper legitimized all-ceramic restorations as viable alternatives to metal-ceramic crowns, despite their limitations. The authors’ balanced assessment - praising aesthetic qualities while honestly discussing fracture risks - helped establish clinical protocols that made all-ceramic crowns practical. Their emphasis on “long-term clinical trials” to validate new systems became the gold standard for evaluating ceramic materials.

The introduction of IPS-Empress in this review launched the modern era of pressed ceramics. Today’s lithium disilicate systems like IPS e.max directly evolved from this early leucite-reinforced technology.

MODERN RELEVANCE

Every all-ceramic crown placed today builds on the foundation laid by this 1992 analysis. The authors’ core insight - that ceramic systems must balance aesthetics with mechanical properties - remains central to material selection. While we now have zirconia and advanced lithium disilicates that far exceed 1992’s strength limitations, the systematic approach to evaluating ceramic systems established here continues to guide clinical decision-making.

The paper’s call for rigorous clinical validation also shaped how we evaluate new materials, ensuring evidence-based adoption rather than marketing-driven enthusiasm.

https://pubmed.ncbi.nlm.nih.gov/1325848/

The AI Dentist - Classic Papers