What is the difference between a final impression and a preliminary impression?
What is the difference between a final impression and a preliminary impression?
Preliminary impressions are accurate reproductions of a patient’s mouth, used for the diagnosis, documentation of dental arches, and visual aid for education. Final impressions have the exact details of the tooth structures and their surrounding tissues.
What is a preliminary impression?
A preliminary impression is a negative likeness made for the purpose of diagnosis, treatment planning, or the fabri- cation of a tray. This is the first impression of the patient’s mouth that is made for diagnosis, treatment planning, and then for mak- ing the custom trays.
What is the best material for a RPD impression?
Low‐quality evidence from another study (144 participants) suggested that complete dentures made with silicone elastomer in a two stage–two step final impression, may be better than those made with alginate, in terms of oral health‐related quality of life, stability of the denture, and chewing efficiency.
What is the difference between primary impression and secondary impression?
The primary impression is a concise statement describing the symptom, problem, or condition that is the reason for a medical encounter. A secondary impression is a second, less severe problem with the patient, which may or may not be directly related to the primary impression.
How long should one wait before removing a model from an impression after pouring?
Dental Lab and Equipment
| Question | Answer |
|---|---|
| In minutes, how long should one wait before removing a model from an impression after pouring? | 45-60 minutes |
| How should the patient bite when positioning the bite-fork during a face-bow registration? | Slowly |
What are the 4 types of final impression material?
The types of final impression materials commonly used in dental practice are polysulfide, polyether, condensation silicone, and addition silicone. Each type of material has different properties and characteristics.
What material is used for final impressions?
There are many materials for the final impression, such as gypsum, zinc oxide and eugenol (ZOE) paste, polysulfide rubber, polyether, polyvinyl siloxane, and alginate. Preferences vary much among dentists. However, there is no evidence that one technique or material produces better long term results than another.
Why it is called wash impression?
“Wash impression” – this is a very thin layer of low viscosity impression material which is used to record fine details. Usually it is the second stage, where the runny impression material is used after an initial impression taken with a more viscous material.
What are primary and secondary problems?
Primary Problems which cause the business pain and must be fixed or secondary problems will occur. Secondary Problems which are the effects (or outcome) of the primary problem and are often viewed as the main problem in crisis management.
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