Tzortzopoulou E*, Bairami V. (Department of Prosthodontics, University of Athens)
In the present investigation the thermomechanical behaviour of two different types of cements was studied and the results were compared and analysed both qualitatively and quantitatively.
Methods and materials: Two Dental cements were used (Glass Ionomer Fuji I.G.C. Coporation and Resin cement, Dual.Vivadent). The experimental was performed by means of thermomechanical Analyser (TMA). Specimens of dimension with diameter 2 cm and thickness 2,5 mm were manufactured and tested under controlled heating rate 5°C/min between 30°C up to 60°C. The parameters studied were the thermal expansion coefficient and the glass transition temperature.
Results: Five specimens from each cement were analysed and was found that the glass-ionomer cement had a lower thermal expansion coefficient ( a= 9 x 10-6 C-1) when compared to the perspective co-efficient of the resin type cement ( a= 20 x 10-6 C-1),while Tg was the same for both types of cements.
Conclusion: It shows that glass-ionomer cement is more resistant from resin cement as far as the thermal behaviour is considered . This type of behaviour is attributed to the different structural characteristics of cements under consideration.