Denture Bases and Resins in Dentistry

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Questions and Answers

What is the primary material used to fabricate denture bases since the mid-1940s?

Polyurethane

Polyvinylacetate-ethylene

Poly(methyl methacrylate) resins (PMMA) (correct)

Phenol formaldehyde

Who developed Poly(methyl methacrylate) polymers in 1937?

Charles Goodyear Jr

Walter Wright (correct)

Powers

Craig

What material was used for denture bases before the development of acrylic resins?

Vulcanite

Nitrocellulose

Phenol formaldehyde

All of the above (correct)

What is the term for materials that can be moulded or shaped when heated and then retain their shape when cooled?

Thermoplastics Signup and view all the answers

What is the purpose of Material Safety Data Sheets (MSDS)?

To provide information on the safe handling and use of dental materials Signup and view all the answers

What is the primary cause of porosity in an acrylic denture base?

Inadequate mixing of the resin Signup and view all the answers

What type of resin is commonly used for soft denture liners?

Hydrophilic polyacrylate Signup and view all the answers

What is the term for dental devices used to close a hole in the palate or to separate the nasal and oral cavities?

Obturators Signup and view all the answers

What is a characteristic of PMMA that makes it suitable for dental applications?

Relative ease of processing Signup and view all the answers

What is the primary component of the powder in a PMMA denture base material?

PMMA resin in the form of micro-sized beads Signup and view all the answers

What type of energy can be used to polymerize PMMA?

Chemical, heat, and light Signup and view all the answers

What is one application of CAD-CAM technologies in dentistry?

3-D printing using methacrylate-based monomers Signup and view all the answers

What type of material is used for anterior aesthetic restorations?

Polymeric matrix with a ceramic filler Signup and view all the answers

What is one use of acrylic polymers in dental technology?

Creating complete dentures Signup and view all the answers

What is one application of acrylic polymers in clinic?

Impression materials Signup and view all the answers

What is a temporary restoration material used in dentistry?

Temporary crowns Signup and view all the answers

What is the consistency of the mixture at the beginning of the process?

Coarse or grainy Signup and view all the answers

What happens to the polymer chains during the stringy stage?

They uncoil Signup and view all the answers

What is the ideal consistency for compression molding?

Doughlike Signup and view all the answers

Why does the mixture become stiff after standing for an extended period?

Due to the evaporation of unreacted monomer Signup and view all the answers

What happens to the monomer during the rubbery stage?

It penetrates further into remaining polymer beads Signup and view all the answers

What is the term for the time required for the resin mixture to reach a doughlike stage?

Dough-forming time Signup and view all the answers

How would you describe the mixture during the doughlike stage?

Pliable and moldable Signup and view all the answers

What happens to the mixture during the rubbery stage?

It becomes elastic Signup and view all the answers

What is a disadvantage of Acrylic Soft-liner?

Losse plactiser in time Signup and view all the answers

What is an advantage of Silicone - Room Temperature Vulcanising (RTV) Soft-liner?

Resilience Signup and view all the answers

What is a disadvantage of Silicone - Heat Cured (Molloplast B) Soft-liner?

Low tear strength Signup and view all the answers

Which Soft-liner has a high rupture strength?

Acrylic Soft-liner Signup and view all the answers

What is an advantage of Acrylic Soft-liner?

High peel strength to acrylic denture base Signup and view all the answers

What is a disadvantage of Silicone - RTV Soft-liner?

Low tear strength Signup and view all the answers

Which Soft-liner has a more resistance to aqueous environment?

Silicone - Heat Cured Soft-liner Signup and view all the answers

What is an advantage of Silicone - Heat Cured (Molloplast B) Soft-liner?

Adequate bond strength to acrylic Signup and view all the answers

What is the name of the biomaterial emerging for oral implants and dental prostheses?

PEKK Signup and view all the answers

Which of the following authors discussed prosthetic polymers and resins?

Shen Signup and view all the answers

What is the name of the journal that published an article on Polyetherketoneketone (PEKK) in 2021?

Journal of Advanced Research Signup and view all the answers

Which of the following materials is used for CAD-CAM dentistry?

PEEK Signup and view all the answers

Who reviewed the properties and use of PEEK polymer in prosthodontics?

Skirbutis et al. Signup and view all the answers

Which of the following is NOT a characteristic of PEEK?

Conductivity Signup and view all the answers

What is the purpose of the reference cited from the website 'panadent.co.uk'?

To review the use of PEEK in dentistry Signup and view all the answers

Which of the following authors discussed dental materials and their selection?

O'Brien Signup and view all the answers

Study Notes

Types of Denture Bases

Available types of denture bases include: heat activated resins, chemically activated resins (cold or self-cured), light activated resins, soft denture liners, acrylic resin teeth, and obturators for cleft palates/maxillofacial prosthetic devices.

History of Denture Bases

Earlier materials used for denture bases include: Vulcanite (1839), nitrocellulose, phenol formaldehyde, vinyl plastics, and porcelain.
In 1937, Poly(methyl methacrylate) (PMMA) polymers were introduced by Walter Wright.
By 1946, 95-98% of dentures were constructed from PMMA or copolymers.
Other polymers developed during the Thermoplastic development period (1910-1950) include: vinyl acrylic, polystyrene, epoxy, nylon, vinyl styrene, polycarbonate, polysulfone, polyurethane, polyvinylacetate-ethylene, hydrophilic polyacrylate, silicones, and light activated urethane dimethacrylate.

Acrylic Resins

Since the mid-1940s, the majority of denture bases have been fabricated using PMMA resins.
PMMA is a colorless, transparent solid that can be tinted with pigments, dyes, fillers, and fibers to provide various colors, shades, and degrees of translucency.
The color, optical characteristics, and dimensional properties of PMMA remain stable under normal intraoral conditions.
Acrylic resins are commonly supplied as a powder-liquid system, which can be mixed in the proper proportions to form a workable mass.
Polymerization can be activated by chemical, heat, and light energy, as well as microwave energy.

Stages of Acrylic Resin Polymerization

The mixture enters a stringy stage when the monomer attacks the surfaces of individual polymer beads and is absorbed into the beads, causing swelling of the beads and dissolution of non-crosslinked polymer chains into the liquid monomer.
The mass enters a doughlike stage when an increased number of polymer chains enter the solution, making it behave as a pliable dough.
The mixture enters a rubbery or elastic stage when some monomer is dissipated by evaporation, and some penetrates further into remaining polymer beads.
The mixture becomes stiff and resistant to mechanical deformation when it reaches the final stage.

Soft Lining Materials

Acrylic soft liner (Vertex) has high peel strength to acrylic denture base, high rupture strength, and some can be polished or cooled.
Silicone soft liners (RTV and Heat Cured) have resilience, but low tear strength and low bond strength to denture base.

PEEK

PEEK is a material used for CAD-CAM dentistry, introduced by Whitty in 2013.
It has properties suitable for dental applications, including strength, durability, and aesthetics.

References

List of references cited in the text, including Alqurashiab et al. (2021), Aunsavice (2003), Shen (2022), Powers and Wataha (2017), Craig and Powers (2002), Skirbutis et al. (2017), Van Noort (2002), and O'Brien (2002).

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Description

This quiz covers different types of denture bases, including heat, chemically, and light activated resins, as well as soft denture liners and acrylic resin teeth. It also touches on obturators for cleft palates and maxillofacial defects.