30 Questions
What is the difference between a true solution and a suspension?
Particle size of the dispersed phase is large in a true solution.
How are reversible hydrocolloids different from irreversible hydrocolloids?
Irreversible hydrocolloids involve primary bond formation.
Which type of colloid involves a liquid dispersed phase instead of a solid?
Emulsion
What defines hydrocolloids?
The particle size of the dispersed phase is smaller than in suspensions.
What causes agglomeration in hydrocolloids leading to gelation?
Decrease in temperature
In what state are hydrocolloids inserted in the mouth to record details?
Sol
What is the role of Sodium triphosphate in alginate?
Delays gel formation
Which type of alginate has a shorter working time?
Fast set
In the setting reaction of alginate, what is formed when Calcium sulfate reacts with Sodium triphosphate?
Calcium phosphate + Sodium sulfate
Which compound is involved in forming the set gel during the setting reaction of alginate?
Calcium alginate
What equipment is NOT typically used during the manipulation of alginate?
Plaster spatula
Which additive is commonly used in alginate for disinfection purposes?
Chlorhexidine
What is the clinical importance of removing the impression from the mouth with a snap removal?
To increase tear strength
Why should the impression be removed suddenly from the mouth?
To reduce permanent deformation
What is the primary difference between irreversible and reversible hydrocolloids in terms of gelation?
Irreversible hydrocolloids undergo gelation through a chemical reaction, while reversible hydrocolloids undergo gelation through a physical reaction.
How does the water content of impressions affect gypsum materials?
Inhibits setting and results in a soft surface
What are the advantages of alginate impression material?
Inexpensive, easy to use, hydrophilic, no need for custom trays
What is the mode of setting for alginate impression material inside the patient's mouth?
Faster at tissue side then tray wise
Which component serves as the main reaction ingredient in Na alginate or K alginate to form gel in irreversible hydrocolloids?
CaSO4.2H2O
Why are irreversible hydrocolloids not suitable for crown and bridge, inlays, or onlays?
They do not produce fine details required for such procedures.
What is the primary reason for preferring individual sealed packets over bulk containers for irreversible hydrocolloids like Alginate impression materials?
Less chance for contamination during storage.
What role does CaSO4.2H2O play in the gelation process of irreversible hydrocolloids?
It is the main reaction ingredient that forms the gel.
What are the disadvantages of alginate impression material?
Tears easily, incompatible with gypsum materials
Why is tempering done in the manipulation of agar impression material?
To avoid burning the patient's oral tissues
What is the purpose of adding potassium sulfate to gypsum cast material?
To accelerate the setting of the material
At what temperature does the 'sol' state of agar impression material change to 'gel'?
37-45°C
What is the function of a conditioning unit in the manipulation of agar impression material?
To control and adjust the temperature of the material
What is the primary function of Na alginate or K alginate in irreversible hydrocolloids?
To form a sol with water that later reacts with calcium to form gel.
What happens to the 'gel' state of agar impression material when heated?
It changes back to 'sol'
What transformation does agar impression material undergo when cooling from 'sol' state?
It changes from 'sol' to 'gel'
Test your knowledge on Alginate impressions and its components such as Sodium triphosphate, Ca2+, and retarder. Learn about the classification of alginate based on working time and understand the use of additives like K Ti fluoride, gypsum accelerator, and hardener.
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