When is it most advantageous to use alginate impressions for RPD master impressions?

Using alginate impressions for RPD master impressions is particularly advantageous when dealing with mobile teeth, long clinical crowns, and large embrasures. This is due to several key factors that make alginate a suitable material for capturing the necessary details in these specific scenarios.

In cases with mobile teeth, alginate can help document the relationship between the teeth and the surrounding soft tissues more accurately. The flexibility of alginate allows it to conform well around areas where teeth may not be stable, capturing better details of the remaining dentition and ensuring that the impression reflects the true intraoral conditions.

When there are long clinical crowns, alginate's ability to flow and capture undercuts becomes beneficial, as it can accommodate the height of the crowns while accurately recording their contours. This characteristic is vital for ensuring that the frameworks of RPDs fit snugly and adequately engage with the teeth.

Moreover, large embrasures are also well accommodated by alginate impressions because the material can capture the open spaces between the teeth effectively. This is crucial for ensuring that the resulting RPD framework can properly interface with the existing dentition and provide adequate support and retention.

Overall, the combination of flexibility, the ability to capture detailed anatomical relationships, and a more accurate representation in cases of mobile teeth