The question involves understanding why addition silicone impression materials might not set properly when handled with latex gloves. Various statements are provided, and we need to identify which one correctly explains the observed issue. Let’s evaluate the options given:
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Hydroxyl ions which are released retard the reaction:
The idea of hydroxyl ions affecting the setting of addition silicone is irrelevant as hydroxyl ions are not commonly released from latex gloves. Therefore, this statement is incorrect.
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Sulfur released from gloves acts as poison to platinum, slowing the reaction:
Addition silicones (polyvinyl siloxanes) often use platinum-based catalysts for setting. Sulfur compounds, which can be present in latex gloves, can indeed inhibit the setting of silicone by poisoning the platinum catalyst, leading to an incomplete polymerization. This directly explains the observed phenomenon and is the correct statement.
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Water powder ratio is incorrect:
This option does not apply to addition silicones because they are not mixed with water and powder; they are typically mixed as a putty or paste. Therefore, this option is irrelevant and incorrect.
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Alcohol is released which changes the setting time:
Alcohol is not released from latex gloves, nor does it have any effect on the setting of addition silicones in the context of this question. Hence, this statement is incorrect.
The correct answer is: Sulfur released from gloves acts as poison to platinum, slowing the reaction. This is because the sulfur in the latex gloves interacts with the platinum catalyst in the silicone material, inhibiting the setting process.
Tip: To avoid such issues, it is advisable to use nitrile gloves instead of latex when handling silicone materials, as nitrile gloves do not release sulfur compounds.