Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            ides, but still higher than 
hydrocolloids and causes no clinical problem. 
42
Manipulation:
1.Types of silicones; light, regular and heavy bodied are 
usually supplied as two paste system.
2. Mixing is done in the same manner as with polysulphide 
materials.
3. The mix is collected and used to fill a syringe or a tray 
depending on the type of silicone. Because of the large 
dimensional changes of condensation silicones, they are 
supplied in putty-wash (very thin viscosity0 combination.
4. Putty is very stiff that are dispensed with a scoop. 
Depressions are made in surface of putty and appropriate 
number of drops or length of accelerator is added.
5. A stiff spatula is used to mix putty and accelerator. Once 
they are well incorporated, mixing is continued by hands 
for 30 sec.
6. Initial mixing by hands is inadvisable, since a high 
concentration of accelerator is harmful and could possibly 
cause allergy 
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7. The putty mix is placed in perforated stock tray or an 
adhesive treated non-perforated tray. The impression is 
made before tooth preparation and the impression is 
rocked to provide 1-2mm space for wash material and 
the putty is allowed to set.
8. After tooth preparation, wash material is mixed and 
injected into the impression area or sometimes into 
putty impression. The tray with the putty is inserted 
again and hold firmly until wash material sets.
9. Putty wash system ↑ accuracy of impressions since 
putty has lower dimensional change than wash 
material.
10. Also the dimensional change of putty has little effect 
and it is partially compensated as it occurs before the 
final impression with wash is taken and wash has small 
dimensional changes. 
44
c. Polyether rubber impression material:
Composition and setting reaction:
1. The material is supplied as a base and catalyst 
system.
2. The base is moderately low MW polyether, 
containing ethylene amine terminal groups.
3. These groups react together by the action of an 
aromatic sulphuric acid ester catalyst to form a 
cross linked high-molecular weight rubber.
Manipulation:
The material is supplied as two tubes: base and 
catalyst. Equal lengths are extruded onto a mixing 
pad. Mixing is carried out as with the other rubber 
impression materials.
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Properties:
1. It has the shortest working time of the rubber 
impression materials.
2. Permanent deformation of polyether is less than that 
of polysulphide but more than silicone.
3. It has low flexibility which may cause problems when 
removed from mouth and so a 4mm rather than 2mm 
thickness of rubber material in the tray is 
recommended.
4. Dimensional change of polyether is less than that of 
the other rubber impression materials.
5. The material absorbs water and change dimensions if 
stored in contact with water.
6. The catalyst can cause skin irritation and so direct 
contact should be avoided. Thorough mixing of the 
catalyst with the base is important to avoid oral tissues 
irritation.
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47
Adapted from Philips’ Scien

            Quiz: