J Korean Acad Prosthodont.  1997 Jun;35(2):417-430.

A STUDY ON FRACTURE STRENGTH OF CONVENTIONAL AND COPY-MILLED IN-CERAM CROWNS

• Hwang JW
• Yang JH
• Lee SH
• Chung HY

Abstract

The purpose of this study was to compare the fracture resistance of copy-milled and conventional In-Ceram crown. Four groups of ten uniform sized all-ceramic crowns were fabricated. In-Ceram Spinell and In-Ceram Alumina crowns were fabricated as control group, Celay In-Ceram Spinell and Celay In-Ceram Alumina crowns were fabricated as test group. All specimen were cemented on stainless steel master die with resin cement, and stored in 37degrees C water for 1 day prior to loading in Instron testing machine. Using a steel ball at a crosshead speed of 0.5mm/min, the crowns were loaded at 30degree angle until catastrophic failure occurred. The results obtained were as follows : 1. With the value of 984.8N+/-103.67N, the strength of Celay In-Ceram Alumina crowns had a significantly higher fracture strength than conventional In-Ceram Alumina crowns(876.2N+/-92.20N) (P<0.05). 2. The fracture strength of Celay In-Ceram Spinell crowns(706.3+/-70.59N) was greater than that of conventional In-Ceram Spinell crowns(687.4+/-90.26N), but there was no significant difference(P>0.05). 3. The In-Ceram Alumina crowns had a significantly higher fracture strength than In-Ceram Spinell crowns in both methods(P<0.05). 4. Ther order of fracture strength was as followed : Celay In-Ceram Alumina, In-Ceram Alumina, Celay In-Ceram Spinell and In-Ceram Spinell crowns

MeSH Terms

Aluminum Oxide
Crowns*
Resin Cements
Stainless Steel
Steel
Water
Aluminum Oxide
Resin Cements
Stainless Steel
Steel
Water