40 Questions
At what temperature should type I waxes be heated to before carving, burnishing, and polishing?
37°C
What is the importance of a wax having a uniform consistency when softened?
To prevent granules on the surface and hard spots within the surface.
Why is it necessary to add modifiers to paraffin wax?
To minimize flakiness.
What should happen to the wax pattern when it is removed from the cavity in case of an undercut?
It should fracture rather than deform.
What are the three methods of wax pattern construction mentioned in the text?
Addition method, Dipping Method, and CAD/CAM System.
What is the advantage of using CAD/CAM and 3D printing in wax pattern construction?
They are faster, more precise, and accurate.
What is the role of digital impression or scanning of the cast in the CAD/CAM and 3D printing process?
It provides the basis for digital designing of the wax pattern.
How does a 3D printer create a wax pattern?
By expelling microdroplets of wax, developing a wax pattern in a layer-by-layer manner.
What is the primary material used in the construction of wax patterns in the lost wax technique?
Paraffin
What is the purpose of adding natural resins, such as Dammar resin, to the inlay casting wax?
To reduce flaking and increase toughness
What is the consequence of trimming paraffin wax?
It is likely to flake
What is the primary purpose of using wax in the lost wax technique?
It can be conveniently manipulated and precisely shaped, and it can be completely eliminated from the mold after investing
What is the difference between Type I and Type II inlay casting wax?
Type I is a medium-hardness wax, while Type II is a softer wax
What is the purpose of adding dyes to the inlay casting wax?
To provide color contrasts
What are the two main requirements for inlay casting wax?
Adequate flow at typical forming temperatures and moderate hardness
What is the ultimate goal of the lost wax technique in fabricating metal or pressed-ceramic fixed prostheses?
To create a precise and accurate pattern for casting
What is the primary purpose of correcting defects in wax before metal casting?
To prevent defects from appearing in the metal casting, as they are difficult to correct once the metal casting is formed.
What is the common method used to block out small defects on the die?
Glass ionomer cement (GIC) intraorally or zinc phosphate cement/autopolymerizing resin on the die.
Why is die trimming important in wax patterning?
To accentuate the finish line and produce a smooth area gingival to the finish line.
What is the purpose of ditching in wax patterning?
To facilitate the establishment of good margin and accentuate the finish line.
Why is marking the margins important in wax carving?
To locate the margins during wax carving.
What is the consequence of over-trimming during die trimming?
It results in an over-contoured restoration.
Why are molten press and injection methods used for industrial purposes?
Because they are suitable for industrial purposes.
What is the importance of understanding that every defect or void in the wax will appear in the casting?
It emphasizes the need to correct defects in wax before metal casting.
What is the typical shape of the tooth surface adjacent to the gingival soft tissues, and what is its significance in oral health?
The tooth surface is usually flat or concave, and this shape facilitates bacterial plaque removal and prevents inflammatory and hyperplastic changes in the marginal gingiva.
Why should nonfunctional cusps be shaped to overlap vertically and horizontally?
To prevent accidental biting of the cheek or tongue, and to keep food on the occlusal surface.
What is the importance of the anteroposterior curve and the mediolateral curve in cusp positioning?
The cusps should follow these curves to ensure proper alignment and even contact with the opposing teeth.
What is the significance of evaluating occlusal contacts in excursive movements?
To ensure proper alignment and even contact between teeth during different movements, preventing oral health problems.
Why should adjacent marginal ridges be of the same height?
To ensure even contact and proper alignment between teeth.
What happens when a shelf or ledge is created in the emergence profile?
It makes bacterial plaque removal more difficult and causes inflammatory and hyperplastic changes in the marginal gingiva.
What is the purpose of shaping the cusps and ridges of the occlusal surfaces?
To allow even contact with the opposing teeth while the teeth are stabilized and forces are directed along their long axes.
What is the role of the emergence profile in maintaining oral health?
It facilitates bacterial plaque removal and prevents inflammatory and hyperplastic changes in the marginal gingiva.
Where are the contact areas usually located between maxillary premolars and molars?
Toward the buccal surface
What shape should the proximal contact area in a restoration never be?
Concave
What can be a consequence of abnormally large proximal contact areas?
Plaque control becomes more difficult, leading to periodontal disease
What can very small proximal contacts (point contacts) lead to?
Instability and tooth drifting
What is a potential issue with deficient proximal contacts?
Food impaction
What shape do natural teeth proximal surfaces tend to be, from the contact area to the cementoenamel junction?
Flat or slightly concave
What should the cervical contour of a restoration be?
Continuous with the contour of the unprepared tooth structure
Where is the height of contour usually located on most teeth?
In the gingival third
Learn about the lost wax technique and pressing technique in the fabrication of metal or pressed-ceramic fixed prostheses. Understand the steps involved in wax casting and the properties of dental waxes.
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