EVALUATION OF THE CEMENT SAMPLES ENDURANCE UNDER THE CYCLIC COMPRESSION

Abstract

The method and results of cement samples evaluation under the cyclic compression are presented in the paper. The study included 6 cements for permanent fixation of non-removable dentures, namely, 2 zinc phosphate cements – Viscine and Adhessor, 2 polycarboxylate cements – Belokor and Durelon and 2 glass ionomer cements – Stion-F and Restocem-PL. The sample corresponded to a tooth with the crown which was fixed with cement. For testing, 6 batches of samples were manufactured (3 samples per batch). The special test bench was used in the process of investigation which made it possible to test the samples applying the cyclic compression with the load frequency of 5.4 Hz or 324 cycles per minute and the increase in the cyclic compression from 10 to 100 kgf. Three levels of maximum compression efforts were chosen: 25 +1,40 +1.60 +1 kgf at which the cyclic endurance of the samples was determined. Endurance was evaluated by the number of cycles which the sample withstood before destruction at chosen load levels. The loss of cement retaining property was accepted as sample destruction which was distinguished in the insignificant crown displacement in relation to tooth with the application of weak static force (~ 2–3 kg) for crown separation from tooth. The comparative analysis of the mechanical compressive properties of dental cements for permanent fixation has determined that the resulting deformation curves were significantly different for various cements used in the experiment. All studied cements have fairly significant strength parameters, but the presence of plastic deformation in individual materials suggests that polycarboxylate cements should have higher functional properties. Considering the fact that the load on dental bridges is greater than on individual crowns, the zinc phosphate and glass ionomer cements are advisable to use while fixing them. The research results of the physical and mechanical properties of cements have determined that zinc phosphate cement Viscine and glass ionomer cements Stion-F and Restocem-PL have the most advisable complex of properties. This fact is the most clearly confirmed while studying the cement samples endurance under the cyclic compression which simulates the real conditions.

Keywords

• dental cements
• dental crowns
• fixation
• cyclic compression