Dental Resins and Polymerization Processes

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Questions and Answers

What is the primary characteristic of heat-cured resin?

Cures by heating over a long period (correct)

Forms by addition reaction without by-products

Requires halogen light for curing

Cures at room temperature

Self-cured resin requires heating to initiate the curing process.

False

Name two types of polymerization processes mentioned.

Condensation Polymerization, Addition Polymerization

In the process of addition polymerization, monomers combine without the formation of any __________.

by-products Signup and view all the answers

Match the following dental resins with their curing process:

Heat-cured Resin = Heated to cure Self-cured Resin = Chemically activated Light-cured Resin = Polymerization by halogen light Addition Polymerization = No by-products formed Signup and view all the answers

Which of the following is NOT a use of dental resins?

Mobile phone cases Signup and view all the answers

Poly (methyl methacrylate) is a type of acrylic resin used in dentistry.

True Signup and view all the answers

What is a required component for addition polymerization?

A double bond and a free radical Signup and view all the answers

Condensation polymerization is also known as __________ growth polymerization.

step Signup and view all the answers

Match the types of dental resins with their characteristics:

Elastomeric Impression Materials = Flexible and adaptable to mouth shape Individual Trays = Custom fit for impressions Denture Base = Supports artificial teeth Soft liners = Comfortable cushioning for denture wearers Signup and view all the answers

Which of the following materials can be categorized as synthetic resin?

Acrylic Signup and view all the answers

Thermoset resins can be reshaped by applying heat.

False Signup and view all the answers

What is polymerization?

The conversion of low molecular weight compounds called monomers to high molecular weight compounds called polymers. Signup and view all the answers

A polymer composed of two or more different monomers is called a __________.

copolymer Signup and view all the answers

Match the following terms to their definitions:

Monomer = One unit Polymer = Many units Free Radical = Molecular fragment with an unpaired electron Plasticize = To soften Signup and view all the answers

Which of the following is NOT a use of synthetic resin?

Metal crowns Signup and view all the answers

Thermoplastic materials become liquid when heated.

True Signup and view all the answers

What type of polymer is formed from a network structure?

Cross-linked polymer Signup and view all the answers

Synthetic resins can be used for __________, temporary sealers, and orthodontic appliances.

restorative materials Signup and view all the answers

What is one characteristic of thermoset resins?

They are infusible and insoluble Signup and view all the answers

What is the duration for the dough to be moldable according to ADA SPEC.#12?

At least 5 minutes Signup and view all the answers

The stiff stage indicates that the dough can still be packed into the mold space.

False Signup and view all the answers

What is the purpose of placing a polyethylene sheet over the resin during the trial closure?

To prevent the adhesion of resin to the lower mold surface. Signup and view all the answers

The assembly is kept in a water bath for __________ hours during the rapid curing process.

1-1.5 Signup and view all the answers

Match the stages of the curing process with their respective descriptions:

Rapid Curing = Water slowly increased until boiling Slow Curing = Assembly placed at around 74°C for 6-8 hours Bench Curing = Flask kept at room temperature for 30-60 minutes Dough Forming Time = Must be attained in at least 20 minutes Signup and view all the answers

During which stage does the dough become completely hardened?

Stage 5: Stiff Stage Signup and view all the answers

What is the function of dibutyl phthalate in synthetic fiber applications?

To act as a plasticizer Signup and view all the answers

Poly (methyl methacrylate) discolors in UV light.

False Signup and view all the answers

What is the role of hydroquinone in the components of liquid monomer?

It is an organic inhibitor that prolongs storage. Signup and view all the answers

The __________ stage is when the resin is packed.

Dough Signup and view all the answers

Match the following types of acrylic resin with their descriptions:

Heat-Cured Resin = Cured with heat to achieve final properties Chemically Cured Resin = Cured by chemical reactions Light-Cured Resin = Cured when exposed to light Signup and view all the answers

Which material is used to prevent cohesion of beads or pearls during storage?

Talc or gelatin Signup and view all the answers

Organic amines act as accelerators to decompose peroxide at high temperatures.

False Signup and view all the answers

What is the main purpose of the double-pressing technique in denture base construction?

To create a mold space for the denture. Signup and view all the answers

_____ is used as a cross-linking agent to resist surface cracks in acrylic resin.

Glycol Dimethacrylate Signup and view all the answers

Which monomer is commonly used in the components of liquid for acrylic resin?

Methyl methacrylate Signup and view all the answers

What is the boiling point of the highly volatile resin mentioned?

100.8°C Signup and view all the answers

The steps in denture base construction include trimming and polishing.

True Signup and view all the answers

What are the two techniques for packing resin into the mold space?

Dough-molding technique and Injection-Molding technique. Signup and view all the answers

The polymer-to-monomer ratio by weight is ______.

2 – 2.5:1 Signup and view all the answers

Match the steps in denture base construction with the correct process:

Preliminary impression = Step 1 Construct the study cast = Step 2 Individual tray for final impression = Step 3 Master/Working cast = Step 4 Signup and view all the answers

During the investment, what is used to ensure retention at the base of the master cast?

Deep scratches Signup and view all the answers

The metal flask used in the investing process consists of three parts.

False Signup and view all the answers

What is the purpose of applying colorgard while packing resin?

To prevent penetration of monomer into the investing medium. Signup and view all the answers

To soften the wax, place the assembly in _____.

boiling water Signup and view all the answers

How long should the wax assembly be soaked in boiling water?

5-10 minutes Signup and view all the answers

Study Notes

Heat-Cured Resin

Heat-cured resin needs heat to start the curing process.

Polymerization Processes

Addition polymerization monomers combine without forming byproducts.
Condensation polymerization monomers combine, releasing small molecules like water.

Dental Resins and Curing Processes

Heat-cured resin uses heat for curing.
Self-cured resin cures at room temperature.
Light-cured resin uses UV light for curing.

Uses of Dental Resins

Dental resins are NOT used for dental implants.
Poly (methyl methacrylate) acrylic resin is used in dentistry for dentures, crowns, and fillings.

Requirements for Addition Polymerization

Initiator molecule is needed for addition polymerization.

Condensation Polymerization

Condensation polymerization is also known as step-growth polymerization.

Types of Dental Resins and Characteristics

Heat-cured resin has good strength and durability.
Self-cured resin cures quickly but may have lower strength.
Light-cured resin is used for fillings due to its ease of application and control.

Synthetic Resins

Synthetic resin can be categorized as a thermoplastic or thermoset material.
Thermoset resin cannot be reshaped by applying heat.

Polymerization Definition

Polymerization is the process of joining monomers to form long chains called polymers.

Polymer Types

Copolymers are polymers made of two or more different monomers.

Terms and Definitions

Monomer is a small molecule that can join with other monomers to form a polymer.
Polymer is a large molecule made up of repeating units called monomers.

Uses of Synthetic Resin

Synthetic resin is NOT used for construction materials.
Synthetic resins are used for dentures, temporary sealers, and orthodontic appliances.

Thermoset Resin Characteristics

Thermoset resins permanently harden and cannot be reshaped.

ADA SPEC.#12 for Dental Resin

Dough needs to be moldable for 1.5 hours according to ADA SPEC.#12.

Curing Stages and Techniques

Stiff Stage

Stiff stage allows the dough to be packed into the mold space.

Polyethylene Sheet

Polyethylene sheet is used over the resin during the trial closure to prevent sticking to the mold.

Rapid Curing Process

Rapid curing process involves soaking the assembly in a water bath for 8 hours.

Curing Stages

Dough stage is when the resin is mixed and is moldable.
Stiff stage is when the resin can be packed into the mold.
Hard stage is when the resin is fully cured and hardened.

Dibutyl Phthalate

Dibutyl phthalate is used in synthetic fiber applications to make the fibers soft and pliable.

Poly (methyl methacrylate) Discoloration

Poly (methyl methacrylate) can discolor in UV light.

Hydroquinone in Liquid Monomer

Hydroquinone is used in liquid monomer to inhibit polymerization during storage.

Packing Stage

Packing stage is when the resin is packed into the mold.

Acrylic Resin Types

Heat-cured acrylic resin is processed using heat.
Self-cured acrylic resin is processed at room temperature.
Light-cured acrylic resin is processed using UV light.

Cohesion Prevention

Silicone oil is used to prevent cohesion of beads or pearls during storage.

Organic Amines

Organic amines act as accelerators to decompose peroxide at high temperatures.

Double-Pressing Technique

Double-pressing technique in denture base construction is used to improve the fit and accuracy of the denture.

Cross-linking Agent

Methyl methacrylate is used as a cross-linking agent to resist surface cracks in acrylic resin.

Liquid Monomer Component

Methyl methacrylate is commonly used in the components of liquid for acrylic resin.

Volatile Resin Boiling Point

Methyl methacrylate is a highly volatile resin with a boiling point of 100.5°C.

Denture Base Construction Steps

Denture base construction includes trimming and polishing.

Packing Resin Techniques

Hand packing and injection molding are two techniques for packing resin into the mold space.

Polymer-to-Monomer Ratio

The polymer-to-monomer ratio by weight is 3:1.

Denture Base Construction Steps

Investing involves placing the master cast in a flask with investment material.
Packing involves filling the flask with resin dough.
Curing involves hardening the resin through controlled heat application.

Retention in Investing

Retention in the base of the master cast during investing is ensured using a retention groove.

Metal Flask Components

The metal flask used in the investing process consists of three parts: bottom, ring, and lid.

Colorgard Application

Colorgard is applied while packing resin to improve the aesthetic appearance of the denture.

Wax Assembly Softening

Boiling water is used to soften the wax assembly.

Wax Assembly Soaking Time

The wax assembly should be soaked in boiling water for 10 minutes.

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Description

This quiz explores key concepts related to dental resins, including their curing processes and types of polymerization. Test your knowledge on the characteristics, uses, and definitions associated with various resins in dentistry. Perfect for dental students and professionals!