CEfJect of Worce[ain Sftades on the cnewee of Wo[ eriEation and Surface Cffardness of CDifJerent 9?ftoto-Cured %fing Cements

Abstract

Dental ceramic materials are known for their unsurpased natural resemblance to natural human teeth. Their excellent optical properties is also decided advantage. The understanding of colour concept and optical phenomena increase the ability to produce a final restoration similar to natural tooth• appearance. The recent increased popularity of the ceramic restorations has led to the introduction of several luting cements and techniques.

This study was designed in order to study the effect of different porcelain shades of the hydrothermal ceramic material on the degree of conversion and surface hardness of different types of luting cement n1aterials. The cements were a visible light-cured composite resin cement and the other one was a dual-cured modified glass ionomer cement.

A total of eighty porcelain satnples were constructed in the form of discs (10 mm in diameter and 2 mm in thickness). Eight shades were selected (A1, A4, B1 , B4, c1, C4, D2 and D4) to match

the porcelain vita-lumin shade guide.

A copper mould was especially designedconstructed and used for producing a refractory mould into which the porcelain was condensed and later fired according to manufac-ture's instructions. The porcelain discs were separated by using a sandblasting machine, the samples were adjusted and glazed to the required thickness.