Dr. Gordon Christensen The Dangers of - Glidewell Dental Labs

Monolithic Versus
Bilayered Restorations:
A Closer
– ARTICLE and CLINICAL PHOTOS by
Gregg Helvey, DDS, MAGD
Abstract
The all-ceramic crown was developed in the early 20th century when Charles H. Land patented the allporcelain
“jacket” crown to improve esthetics. This procedure consisted of rebuilding the missing tooth
with a porcelain covering, or “jacket” as Land called it. To solve the product’s strength problems, Abraham
Weinstein in the late 1950s introduced a metal core to which porcelain was fused, thus creating the
ceramo-metal crown. Throughout the years, the metal has been substituted with different materials to
achieve a more esthetic result. Problems have been reported with the fusion between the ceramic and the
core, which have resulted in debonding of the veneered ceramic. Further investigations in dental material
science have produced tremendous advances in unveiling aspects that have been taken for granted, such
as the bond strength between different materials that comprise the crown restoration. Recently, a lithium
disilicate material that was once used solely as a core material was introduced as an all-ceramic alternative.
This article discusses the strength factors that comprise a monolithic and bilayered ceramic restoration.
Monolithic Versus Bilayered Restorations21