What is the Difference Between Addition Silicone and Condensation Silicone?

The main difference between addition silicone and condensation silicone lies in their curing processes and the resulting properties. Here are the key differences between the two:

Curing Process: Addition silicone forms from an addition chemical reaction, while condensation silicone forms from a condensation chemical reaction.
Curing Time: Condensation silicones react when a liquid or paste activator is added, and the reactions involved occur at ambient temperature. This means that the curing time is directly proportional to the ambient temperature. Addition silicones, on the other hand, use a platinum-based catalyst for curing, which offers shorter curing times.
Shrinkage: Condensation silicone molds cure with a slight degree of shrinkage, while addition silicone cures with virtually no shrinkage.
Strength and Durability: Addition silicones are generally more pliable and tough than condensation silicones. Condensation silicone molds tend to weaken or tear after a year or two, depending on the amount of use.
Heat Resistance: Addition silicones offer exceptional heat resistance and work better in high temperatures.
Cost: Condensation silicones are more economical and are typically preferred for general mold making, while addition silicones are often used in high-temperature applications.

Both types of silicone are used in various applications, such as removable metal dentures, indirect cast restorations, and matrices for indirect restorations. The choice between addition and condensation silicone depends on the specific requirements of the application, such as curing time, shrinkage, strength, durability, heat resistance, and cost.

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What is the Difference Between Addition Silicone and Condensation Silicone?

Comparative Table: Addition Silicone vs Condensation Silicone

The main difference between addition silicone and condensation silicone lies in their chemical reactions and dimensional stability. Here is a comparison table of their properties:

Property	Addition Silicone	Condensation Silicone
Chemical Reaction	Forms from an addition reaction of silicone elastomer	Forms from a condensation chemical reaction
Dimensional Stability	Greater dimensional stability due to the lack of by-products	Lower dimensional stability due to the release of volatile by-products during the condensation reaction
Shrinkage	Virtually no shrinkage	A slight degree of shrinkage
Catalyst	Vulcanization process triggered by the addition of a catalyst	Tin(ii) octoate is the most common activator
Mixing and Working	Simple and easy to mix	More complex and needs to be mixed manually using a metallic spatula
Reaction Time	Faster in warm rooms and slower in cold rooms	Setting usually occurs at room temperature

Both addition and condensation silicones are used in dentistry for making impressions, but addition silicones have become more popular due to their greater dimensional stability and easier handling.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.