Final answer:
Over trituration of dental amalgam will decrease both the working time and the setting time due to an accelerated mercury-alloy reaction. It can also increase the setting contraction, potentially creating gaps at the margins of restorations which can lead to dental complications.
Step-by-step explanation:
Over trituration of dental amalgam affects its properties significantly. Working time, which is the time span during which the amalgam can be manipulated in the mouth, will be reduced if the amalgam is over triturated. This is because over trituration generates excess heat and accelerates the rate of the mercury-alloy reaction.
Similarly, the setting time, which is the duration for the amalgam to harden sufficiently, will also be decreased. Over triturating leads to an increased rate of hardening which can result in a shorter window for the dentist to work with the material.
The setting contraction, or the minimal shrinkage that occurs as the amalgam hardens, can potentially be increased by over trituration. This can cause gaps at the margins of the restoration which can lead to issues such as microleakage or secondary decay.