Dental Impressions Overview

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Questions and Answers

What is a primary purpose of making a preliminary impression?

To diagnose systemic health issues

To create a master cast for denture fabrication

To determine the conditions of the mouth (correct)

To enhance food retention beneath the denture

What is the main advantage of a mucostatic impression technique?

High retention from mechanical locking

Minimal pressure to maintain tissue health (correct)

Ease of achieving a detailed reproduction

Preservation of oral tissues under pressure

Which type of impression uses selective pressure on readily displaceable tissues?

Selective pressure impression (correct)

Mucostatic impression

Final impression

Custom tray impression

What does the use of an individual tray during the final impression provide?

An accurate impression and master cast Signup and view all the answers

What is a disadvantage of short flanges in impression making?

They can lead to lesser stability of function Signup and view all the answers

In which condition are impressions particularly helpful due to flabby, sharp, and thin ridges?

Flabby and unstable tissues Signup and view all the answers

What method combines principles of mucostatic and mucocompressive techniques?

Selective pressure impression Signup and view all the answers

What is the retention mechanism primarily relied upon in mucostatic impressions?

Interfacial surface tension Signup and view all the answers

What is the primary purpose of the closed mouth method in impression making?

To utilize trays without handles for functional impressions Signup and view all the answers

Which impression technique relies on recording tissues under functional pressure for better denture support?

Functional impression technique Signup and view all the answers

Which of the following is NOT a component of the procedure for making a functional impression?

Use of a handle on the impression tray Signup and view all the answers

In the functional impression technique, what does 'border molding' refer to?

Manipulation of soft tissues to define the peripheral borders Signup and view all the answers

What is a significant disadvantage of impressions taken under high pressure?

Retention is usually short-lived Signup and view all the answers

What is the primary purpose of study or diagnostic casts?

For treatment planning and study Signup and view all the answers

Which method emphasizes changes in muscle movement for the operator's observation?

Open mouth method Signup and view all the answers

What distinguishes refractory casts from other types of casts?

They are made from materials that withstand high temperatures Signup and view all the answers

What is a key characteristic of the impressions made using the closed mouth method?

They lead to improved denture stability during function Signup and view all the answers

What is the role of the border molding in the impression making process?

To enhance retention and support of the denture Signup and view all the answers

What type of material is typically used for the primary impression in functional impression techniques?

Impression compound Signup and view all the answers

What is the posterior palatal seal created by?

Pressure on the soft tissues and hard palate Signup and view all the answers

What is a master or working cast primarily used for?

For mounting on an articulator Signup and view all the answers

Which aspect is NOT part of the posterior palatal seal creation process?

Creating an investment cast Signup and view all the answers

In the context of impression making, what does 'wax block out' refer to?

Blocking out undercuts in the impression Signup and view all the answers

What characterizes a study cast compared to other casts?

It is a life-size representation for study and planning Signup and view all the answers

What is the primary purpose of creating tentative blueprints in denture construction?

To assist in determining various parameters during the construction process Signup and view all the answers

What is meant by the term 'High Lip Line' in denture construction?

The highest position a lip can assume while smiling Signup and view all the answers

Which aspect does the OCR specifically help to determine during denture construction?

The arch form and occlusal plane level Signup and view all the answers

What does the 'Neutral Zone' concept refer to in the context of denture construction?

The equilibrium zone where natural teeth stabilize Signup and view all the answers

What is the main purpose of marking the corners of the mouth on the occlusion rims?

To provide anterior landmarks for the height of the 1st premolars Signup and view all the answers

What role does 'lip and cheek support' play in denture aesthetics?

It helps to establish the natural contours of the face Signup and view all the answers

How does the preliminary registration of jaw relations benefit denture construction?

It ensures proper alignment and occlusion of the denture Signup and view all the answers

Where does bone reduction typically occur in the maxillary residual ridge?

On the labial and buccal areas Signup and view all the answers

Which statement best describes Wilfred Fish's contribution to denture construction?

He introduced the concept of the Neutral Zone Signup and view all the answers

Which anatomical structure is referred to as the "meeting place" of eight muscles?

Modiolus Signup and view all the answers

What is the usual position of maxillary teeth when placed in the neutral zone?

Labial and buccal to the edentulous ridge Signup and view all the answers

What factor does NOT affect the selection of the size of teeth in denture construction?

The materials used for denture base Signup and view all the answers

Which line should the occlusion rim be parallel to anteriorly?

Interpupillary line Signup and view all the answers

What is the primary factor in establishing the vertical dimension of occlusion (VDO)?

Presence of healthy natural dentition Signup and view all the answers

What happens during the contraction of the buccinator muscle in relation to the modiolus?

It fixes the modiolus in place Signup and view all the answers

How might the occlusion rims need to be adjusted after determining the preferred vertical dimension of occlusion?

They might have to be slightly augmented or reduced Signup and view all the answers

Study Notes

Impression Making

Reduced lip support can happen due to short flanges.
Preliminary Impression is made for diagnostic purposes and to create a study cast/diagnostic cast.
Final Impression is made using a custom tray which provides a detailed reproduction of the jaw.
Mucostatic Impression is made with minimal pressure and uses free-flowing material to preserve tissue health.
Functional Impression is made with pressure and aims for stability during function.
Selective Pressure Impression combines principles of both mucostatic and mucocompressive techniques.

Impression Types

Mucostatic Impression emphasizes tissue preservation.
Mucocompressive Impression aims for better support and retention during function.

Impression Techniques

Open mouth method is used with trays that have handles.
Closed mouth method is used with trays that do not have handles.

Border Molding

Hand manipulation uses the dentist's hands to manipulate the lips and cheeks.

Laboratory Samples

Study/Diagnostic Cast is a life-size replica for study and treatment planning.
Master/Working Cast is used for mounting dentures on an articulator.
Refractory Cast is used in denture fabrication and can withstand high temperatures.

Posterior Palatal Seal

Created at the posterior periphery of the denture.
Provides retention and stability for the upper denture.

Occlusion Rim

Used to determine the arch form, occlusal plane, and jaw relations.
Contributes to esthetics and lip support.

Neutral Zone

Concept by Wilfred Fish.
Describes the stable position of natural teeth.
Aims to place artificial teeth in the same location as natural teeth.
Maxillary teeth should be labial and buccal to the edentulous ridge.

Occlusal Plane

The surface where food is triturated.
Usually parallel to the interpupillary line anteriorly and Camper's line posteriorly.
Mandibular molars are usually at the level of the 2/3rds of the retromolar pad.

VDO (Vertical Dimension of Occlusion)

Established in the presence of healthy natural dentition.
Simulates tooth length and lip support.

Lip Support

Important for esthetics and function.
Maxillary occlusion rim should be contoured to provide proper lip support. I

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Description

This quiz covers the fundamental concepts of dental impressions, including types, techniques, and the importance of tissue preservation. Understand the differences between mucostatic, mucocompressive, and functional impressions, along with the methods used in border molding.