Comparison of various clinically orientated techniques to increase surface hardness of a glass ionomer restorative cement
van Zyl, Luzaan
Rossouw, Shaun N.
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The aim of this study was to compare various clinically orientated techniques that could potentially increase surface hardness of a glass ionomer restorative cement. Six methods were assessed to determine the extent of surface hardness improvement. The methods were: standard set as the control, pressure, high frequency, low frequency, heat and high frequency/heat. Surface microhardness was tested with a Vickers hardness tester (Zwick-Roell durometer, ZHV1/2 Micro-Vickers, Italy) at HV0.5 (500gf) load with a dwell time of 10 seconds. The glass ionomer used to assess the six methods was Chemfil Rock (DeTrey, Dentsply, Konstanz, Germany). The average Vickers hardness for the control was 49.5. No statistical difference was demonstrated by employing the pressure (49.2) and the low frequency (48.49) in comparison with control. The high frequency (54.21) and the heat (57.5) had an increase hardness compared to the control, pressure, low frequency, high frequency & heat. Only the heat technique had a higher surface hardness that was statistically significant from the control, pressure, low frequency and the high frequency/heat (p < 0.001). The clinician can use high frequency, low frequency to induce the command set of the glass ionomer Chemfill Rock in 15 seconds. Although heat does not induce command set in less than 90 seconds, the surface hardness is improved with Chemfill Rock (DeTrey, Dentsply) compared to standard set (STS).