Advanced Level of Dental Resins - Material Science & Technology E-Book

Ralf Janda

• Herausgeber: tredition
• Kategorie: Fachliteratur
• Serie: Dental Resins - Science & Technology
• Sprache: Englisch

Seitenzahl: 546

Veröffentlichungsjahr: 2021

Beschreibung

Resin materials are broadly used in dentistry for almost all indications, and they will gain even more importance in the future. Especially, the increasing performance and efficiency of the CAD/CAM technology and 3D-printing open possibilities to use resins not used up to now in dentistry. Besides dentists, dental students or dental technicians, there are many other specialists such as researchers, material scientists, industrial developers or experts of adjoining professional disciplines who are technically engaged in dental resins. The idea of this e-Book series is to present a three-level textbook consisting of "Basic Level", "Advanced Level" and "Expert Level" versions dealing with material science and technology of dental resins. Every level significantly expands the information and knowledge given by the respective preceding version. This book presents the "Advanced Level" version. The "Advanced Level" broadens the information given in the "Basic Level" significantly and mainly addresses teachers of dental universities/schools, postgraduate students, PhD candidates, researchers, material scientists, industrial developers or experts of adjoining professional disciplines. The "Advanced Level" gives a very profound insight into chemistry, physics, testing methods and toxicology of dental resins and their technical application.

Leseprobe

Cover picture: SEM picture enamel-hybrid composite interface

2nd Edition

Imprint

Janda, Ralf: Advanced Level of Dental Resins - Material Science & Technology

Publisher: tredition GmbH, Halenreie 40-44, D-22359 Hamburg

www.tredition.de

Copyright © 2021 by Janda, Ralf

[email protected]

Cover: Janda, Ralf

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means without the written permission of the copyright holder.

ISBN 978-3-347-38223-7 (e-Book)

In Memoriam

Queeny, Buffy & Vinny

Welcome

Shawny & Lenny

Contents

Contents

Preface - 2nd Ed. Advanced Level

Preface - 1st Ed. Advanced Level

Preface - Book Series

Literature/Trademarks/Other

Introduction

Abbreviations

Terms and Definitions

1 Chemistry/Polymer Chemistry

2 Radiometry

Resin Materials in Dentistry

1 Introduction

2 Modern Dental Resins

Matrix Resins

1 Introduction

2 Functional Groups and Monomer Links

3 Polyreactions

3.1 Polymerization Reactions

3.1.1 Free Radical Polymerization

3.1.1.1 Oxygen Inhibition

3.1.2 Cationic Polymerization

3.1.3 Anionic Polymerization

3.1.4 Ring-Opening Polymerization

3.1.5 Thiol-Ene Polymerization

3.1.6 Technical Polymerization Processes

3.2 Polycondensation

3.3 Polyaddition

4 Matrix Resins According to Links

4.1 Carbon-Carbon Link

4.1.1 Acrylates and Methacrylates

4.1.2 Other Important C-C-Linked Polymers

4.1.2.1 Polyethylene

4.1.2.2 Polypropylene

4.1.2.3 Polyvinyl chloride

4.1.2.4 Polytetrafluoroethylene

4.1.2.5 Polyvinyl acetate

4.1.2.6 Polystyrene

4.1.2.7 Synthetic Rubbers

4.2 Ester Link

4.2.1 Saturated Polyesters

4.2.2 Unsaturated Polyesters

4.2.3 Polycarbonates

4.3 Amide Link

4.4 Urethane Link

4.5 Ether Link

4.5.1 Polyphenylene oxide (PPO)/Polyphenylene ether (PPE)

4.5.2 Poly(aryl-ether-ether-ketone) (PEEK)

4.5.3 Polyoxymethylene (POM)

4.5.4 Epoxide Polymers (EP)

4.6 Siloxane Link

4.7 Sulfone Link

5 Structures and Properties of Monomers and Oligomers

5.1 Acrylates and Methacrylates

5.2 Other Monomers

5.3 Degree of Conversion (DC)

5.3.1 Degree of Conversion of Methacrylate-Based Composites

5.3.2 Degree of Conversion of Silorane-Based Composites

5.3.3 Degree of Conversion of Anionic Polymerization

5.3.4 Degree of Conversion of Polyaddition and Polycondensation

6 Structures and Properties of Polymers

6.1 Types of Chemical Bonds/Forces

6.2 Primary Polymer Structures

6.3 Secondary Polymer Structures

6.4 Tertiary Polymer Structures

6.5 Thermoplastics

6.6 Elastomers

6.7 Duromers

6.8 Interpenetrating Polymer Networks

6.9 Polymer Blends

7 Chemical Reactions of Polymers

7.1 Grafting

7.2 Cross-Linking of Polymers and Vulcanization

7.3 Layering/Incremental Technique and Repair of Resin Composites

Initiators and Catalysts

1 Introduction

2 Initiators

2.1 Thermal/Heat Initiators

2.2 Redox Initiators

2.2.1 Peroxide/Amine-Based Redox Initiators

2.2.2 Barbituric Acid-Based Redox Initiators

2.2.3 Sulfinic Acid-Based Redox Initiators

2.3 Photoinitiators

2.3.1 Conventional Radical Photoinitiators

2.3.2 Tailor-Made Radical Photoinitiators

2.3.3 Cationic Photoinitiators

2.3.4 Radical/Cationic Hybrid Photoinitiators

3 Synergists

4 Catalysts

Fillers

1 Introduction

2 General Effects of Fillers on Material Properties

3 Effect of Refractive Index on Optical Properties

4 Effect of Filler Shape on Mechanical Properties

5 Particle Reinforcement and Material Properties

6 Fiber Reinforcement and Material Properties

7 Organic Fillers

7.1 Adhesion Organic Filler/Resin Matrix

8 Inorganic Fillers

8.1 Adhesion Inorganic Filler/Resin Matrix

8.1.1 Adhesion of Inorganic Filler/Organic Matrix by Silanization

8.1.2 Other Surface Treatments for Adhesion Inorganic Filler/Organic Matrix

Pigments and Dyes

1 Introduction

2 Pigments

3 Dyes

Additives

1 Introduction

2 Stabilizers

3 Antioxidants

4 UV-Stabilizers

5 Plasticizers

Physical and Chemical Properties of Polymers - General Aspects

1 Introduction

2 Physical Properties

3 Chemical Properties

4 Ageing Processes/Depolymerization

Material Testing/Standards

1 Introduction

2 Parameters of Material Testing

3 Standards

4 Some Standard Tests

4.1 Methods to Test Mechanical Properties

4.1.1 Flexural Strength and Modulus of Elasticity

4.1.2 Tensile/Tear Strength and Modulus of Elasticity

4.1.3 Compressive Strength

4.1.4 Impact Strength

4.1.4.1 Izod Impact Strength

4.1.4.2 Charpey Impact Strength

4.1.5 Hardness Tests

4.1.5.1 Brinell Hardness

4.1.5.2 Knoop Hardness

4.1.5.3 Rockwell Hardness

4.1.5.4 Shore Hardness

4.1.5.5 Vickers Hardness

4.2 Chemical Properties

4.3 Other Physical Properties

4.3.1 Color Stability

4.3.2 X-Ray Opacity

4.4 Adhesion Testing

4.4.1 Micro-Tensile Bond Strength (µTBS) Test

4.4.2 Shear Bond Strength (SBS) Test

4.5 Statistics

Toxicology/Clinics/Standards

1 Introduction

2 Toxicology

2.1 Toxic Events

2.2 Toxicity Tests

2.3 Toxicity of Some Raw Materials for Dental Resins

2.3.1 (Meth)acrylic Monomers

2.3.2 (Meth)acrylate-Based Dental Resins - Other Components

2.4 Toxicity of Dental Resins - Evaluation and Summary

2.4.1 (Meth)acrylate-Based Dental Resins

2.4.2 Polysiloxanes and Polyethers

3 Standards for Laboratory Testing

4 Standards for Clinical Testing

Denture Base Resins

1 Introduction

2 Classification and Properties

3 Principal Processing Methods

3.1 Full and Partial Embedment

3.1.1 Pack and Press Technique

3.1.2 Injection Technique

3.1.3 Injection Molding

3.1.4 Pouring/Casting Technique

3.1.5 Melt and Press Technique

3.2 No Embedment

3.2.1 Light-Curing Resins

3.2.2 CAD/CAM Technique

3.3 Insulation of Plaster

4 Polymethyl (meth)acrylates

4.1 Powder/Liquid Products

4.1.1 Powder/Liquid Products - Formulation

4.1.1.1 Heat-Curing Products

4.1.1.2 Self-/Cold-Curing Products

4.1.1.3 Microwave-Curing Products

4.1.2 Powder/Liquid Products - Processing

4.1.2.1 Heat-/Microwave-Curing Products

4.1.2.2 Self-/Cold-Curing Products

4.2 One-Component Products

4.2.1 Polymerizable Products - Formulation and Processing

4.2.1.1 Light-Curing Products - Processing

4.2.1.2 Heat-/Microwave-Curing Products - Processing

4.2.2 Thermoplastic Products - Formulation and Processing

5 Other Denture Base Resins - Formulation and Processing

6 Fit of Dentures

7 Residual Monomer and Denture Intolerance

Resin Teeth

1 Introduction

2 Formulation and Production

3 Properties

4 Processing

Denture Reline Resins

1 Introduction

2 Indications and Requirements

3 Poly(meth)acrylate-Based Reline Materials

4 Polysiloxane-Based Reline Materials

Crown and Bridge Veneer Resins

1 Introduction

2 Classification, Formulation and Processing

2.1 Powder/Liquid Veneer Resins

2.2 One-Component Veneer Resins

3 Properties and Performance of Veneer Resins

3.1 Powder/Liquid Veneer Resins

3.2 One-Component Veneer Resins

Resins for Provisional/Temporary Crowns and Bridges

1 Introduction

2 Formulation and Processing

3 Properties

Resins for Crown Copings and Bridge Frames

Impression Materials

1 Introduction

2 Classification, Processing and Performance

3 Polysulfides

4 Polyethers

5 Polysiloxanes (Silicones)

Resin-Based Filling Composites

1 Introduction

2 Classification

3 Formulation

3.1 General Aspects and Overview

3.2 Microfill Filling Composites

3.3 Hybrid/Micro-Hybrid Filling Composites

3.4 Compomer Filling Composites

3.5 Ormocer Filling Composites

3.6 Nanoparticle Filling Composites

3.7 Silorane Filling Composites

3.8 Bulk-Fill Filling Composites

3.9 Giomer Filling Composites

3.10 Flowable Filling Composites

4 Properties and Performance

4.1 Flexural Strength and Flexural Modulus

4.2 Polymerization Shrinkage and Shrinkage Stress

4.3 Depth of Cure

4.4 Water Sorption, Solubility and Hygroscopic Expansion

4.5 Color Stability

4.6 X-Ray Opacity

4.7 Antibacterial Effects

5 Resins for Prophylaxis

Other Dental Polymers

Light-Curing Devices

1 Introduction

2 Light-Curing Devices for the Dental Practice

3 Light-Curing Devices for the Dental Laboratory

CAD/CAM Technology

1 Introduction

2 Intraoral Scanning

3 Grinding and Milling

4 3D Printing

Adhesion and Adhesives

1 Introduction

2 Theoretical Aspects of Adhesion

2.1 Surface Pretreatment

2.2 Adhesive Bond

2.3 Mechanical Bond

2.4 Chemical Bond

2.5 Geometrical Design of Bonding Surfaces

3 Special Surface Pretreatment Techniques

3.1 Silicatization Processes

3.1.1 Pyrolytic Silicatization

3.1.2 Tribochenical Silicatization

4 Metal/Resin Bond

5 Ceramic/Resin Bond

6 Resin/Resin Bond

7 Hard Tooth Tissues/Resin Bond

7.1 Mechanism of Resin/Enamel-Dentin Bond

7.2 Etchants and Etching Process

7.3 Classification

7.4 Formulation

7.5 Total-Etch Adhesives

7.5.1 3-Step Adhesives

7.5.2 2-Step Adhesives

7.6 Self-Etch Adhesives

7.6.1 2-Step Adhesives

7.6.2 1-Step Adhesives

7.7 Requirements and Properties

7.8 Creation of Dentin Bond - Smear and Hybrid Layer

7.8.1 Total-Etch Technique - Smear Layer Removal

7.8.2 Self-Etch Technique - Smear Layer Fixation and Hybrid Layer Creation

7.8.3 Adverse Effects on the Adhesive/Dentin Bonding Zone

7.9 Biocompatibility

8 Resin-Based Luting Composites

8.1 Conventional Luting Resin Composites

8.2 Self-Etch Luting Resin Composites

8.3 Self-Adhesive Luting Resin Composites

9 Bacterial Adhesion to Resins

Curriculum Vitae

Literature

Index

Preface - 2nd Ed. Advanced Level

Many mistakes and errors were corrected and some chapters reorganized or a little bit extended. Figures and tables were improved. Links were corrected or repaired.

Best regards

Ralf

November 2021

Preface - 1st Ed. Advanced Level

The “Advanced Level” is the second book of the series “Dental Resins - Material Science & Technology”. It comprises around 670 manuscript pages, 253 figures and 57 tables. The Advanced Level presents a very comprehensive and detailed insight into the material science and technology of dental resin polymers and their application and thus enormously extended the knowledge base of the Basic Level. It mainly addresses very interested dentists, teachers of dental universities/schools, postgraduate students, PhD candidates, researchers, material scientists, industrial developers or experts of adjoining professional disciplines.

Many thanks for your interest and best regards

Ralf

January 2021

Preface - Book Series

Resin materials are broadly used in dentistry for almost all indications and they will gain even more importance in future. Especially the increasing performance and efficiency of CAD/CAM technology and 3D-printing open possibilities to use resins not used up to now for dental applications. Besides of dentists, dental technicians, dental students, teachers of dental universities/schools, postgraduate students and PhD candidates there are many other specialists such as researchers, material scientists, industrial developers or experts of adjoining professional disciplines who are technically engaged in dental resins. Mainly two reasons are responsible for this interest: a) many persons dealing with dentistry feel a large desire for deeper knowledge in dental resins, b) the knowledge of many different specialists is requested to develop, to investigate, to test and to evaluate dental resins; c) dental resins offer very sophisticated highly developed properties so that they are also used in other disciplines for other purposes or are the base to develop tailor-made products for other very special non-dental applications.

The idea of this e-Book is to present a three-level textbook dealing with material science and technology of dental resins:

a) The Basic Level addresses students, dental technicians, teachers or all those interested in dental resins. The Basic Level gives a comprehensive insight into chemistry, physics and toxicology of dental resins and their technical application.

b) The Advanced Level broadens the information of the Basic Level significantly and mainly addresses teachers of dental universities/schools, postgraduate students, PhD candidates, researchers, material scientists, industrial developers or experts of adjoining professional disciplines.

c) The Expert Level gives a very deep insight into the science of dental resins and mainly addresses scientists doing research on dental resins, industrial developers or scientists of adjoining professional disciplines who are very strongly interested to become also specialists in dental resin material science. The Expert Level describes also the industrial processes that are used to manufacture dental resins. Furthermore, some exact formulations for some dental products are given; this includes know-how that has never been published before as far as the author knows.

Contrarily to print books, it is the great advantage of e-Books that improvements, corrections, additions or enhancements can be done swiftly so that new improved editions can be produced and distributed rapidly and cheaply. Therefore, the e-Book is the ideal format to update the content immediately whenever errors or mistakes must be eliminated or the scientific progress makes it necessary. It is the desired and planned scenario that the content of this e-Book will not become obsolete as fast as it usually happens with conventional print books but will be refreshed in shorter periods of time.

Illustrations and tables will increase in number with each level. The information they give is - hopefully - clear and understandable but certainly they will not become prettier or colored. This is a low-cost book and everything is done keeping costs to a minimum.

The author is aware that there will be errors, inaccuracies and ambiguousness but hopefully no incorrect or even misleading information in the text despite of all the care taken. The honorable readership is kindly asked for understanding and the author will be very grateful for any hints and proposals to improve the content of the book or the book at all. Therefore, every type of constructive criticism will be highly appreciated.

Having said all this, I hope you will enjoy the book and you will get the information that is helpful and valuable for you and your work.

Many thanks and best regards

Ralf

Literature/Trademarks/Other

Not all the literature used to write this book is specifically cited. Common dental, chemical or material science knowledge taken from textbooks is not specifically cited in the text. Such textbooks are

- dentistry and dental materials [1-20]

- chemistry [21-46]

- adhesives and adhesive technology [47-50]

- material science [50-52]

Also information, figures or tables taken from the author’s sole publications are not specifically cited; these are [53-79].

Information (terms, definitions, etc.) deriving from scientific organizations is not always specifically cited; these organizations are [80-83].

Specific information given is specifically cited.

Product names are not specifically marked as registered even if they are so. Principally brand names are only used when they are important in connection with the described subjects. This might be the case when only one product of a specific product category is available. Apart from that representatives of product categories presented in tables or graphics are anonymized.

Introduction

Besides of metals, alloys and ceramics plastics and composite resins have become to one of the most important material categories in all areas of daily life such as engineering, electronics, building and construction industry, car industry and many other industries as well as in medicine and dentistry. In 1922 Hermann Staudinger discovered these high molecular compounds and called them macromolecules [84]. This was the start of a new until then unknown chemistry called polymer chemistry. The development of numerous polymeric materials and combinations thereof with other organic or inorganic substances or materials gave birth to a huge number of advanced materials with exceptional properties.

In the early years plastics were considered to be cheap and inferior materials but today composite resins and high-performance plastics are very valuable and indispensable in all industries. The most important aspect for the resin materials’ breakthrough is certainly the fact that for nearly every usage custom-made, often also called tailor-made, products can be developed and finally provided. For sure, more and more new, until now unknown, resins or resin composites will be tailor-made for further or today even unknown applications in future.

Resin materials (plastics, composite plastics, composite resins, resin composites) are high molecular mass products (polymers). They are manufactured by transformation of naturally occurring or by synthesis from low molecular mass substances (monomers). These low molecular mass substances (monomers) are the smallest multiple recurring units building the high molecular mass substances (polymers). The properties of each of the resulting polymers depend on how the monomers are linked, on their chemical structure as well as on the spatial configuration of the formed macromolecules. Polymers or macromolecules do not have an exact but an average molecular mass because the single chains building the polymer/macromolecule are growing randomly and not in a well-defined manner.

Resin Materials in Dentistry

1 Introduction

Resin materials are of high interest and importance in dentistry. They are used for numerous applications such as dentures, partial dentures, relining of dentures, artificial teeth, fillings, inlays, crowns, bridges, temporary restorations, sealants, luting purposes, adhesives, impressions etc.

Charles Goodyear ran the vulcanization of natural rubber the first time in 1839 and as a result the first resin material was born [64, 91-93]. This process served to manufacture denture bases in the following period of time. Although the natural rubber used for this purpose was pink-colored the esthetic appearance of the denture was very poor because of the rubber’s high opacity. Yet, this process was used till the thirties of the 20th century. Since approx. 1870 celluloid, synthesized from nitrocellulose and camphor, was used for denture bases aside from rubber. Celluloid denture base materials entered the market in the USA under the trademarks Hecolite and Coralite [91, 94, 95]. Around 1900 phenolic resins, developed by Baekeland and, therefore, often called bakelite, with the trademarks Aldenol and Walkerit were also used as denture base materials [53, 64, 91, 95-97].

In 1934 Pierre Castan synthesized the first epoxy polymer resin (trademark: Epoxolon) in the laboratories of DeTrey Fréres Co. (today: DeTrey/Dentsply GmbH, Germany) in Switzerland while he was searching for an improved denture base material and obtained a patent in 1940 [53, 64, 91, 98]. Although they were never used for dentures since then epoxy polymers were used for products of highest quality demands. Other plastics like benzyl cellulose (trademark: Pertax), polyamides (trademark: Protenyl), polystyrenes (trademark: Polystein), polyvinyl chloride (trademark: Hekodent, Hewodent) or polyolefins (trademark: Odenta) had similar destinies. They were only used for a short period of time as denture base materials [39, 53, 64, 91, 95-97].

The crucial ascent of polymer chemistry started in the thirties of the 20th century with Otto Röhm’s development of methyl methacrylate (also called: methacrylic acid methyl ester or MMA) from which he synthesized via polymerization polymethyl methacrylate (also called: polymethacrylic acid methyl ester or PMMA) [91, 99]. PPMA has the well-known trademark Plexiglas. In 1936 PMMA determined the great breakthrough in dental materials. The dental technician Gottfried Roth mixed milled PMMA with its monomer MMA and stirred the mixture until it becomes dough-like. Then he processed it the same way as it was commonly done to manufacture rubber dentures. He pressed the dough between two halves of a plaster mold representing the denture and boiled the whole assembly in a water bath until the dough was hardened [91]. This was the first time esthetically satisfying dentures were obtained and the method as well as the materials were patented in 1936 [91, 100]. This process was improved and optimized in the following years and decades and it is broadly used to manufacture dentures up to now. Later developments substituted MMA by numerous newly synthesized methacrylates, dimethacrylates or multifunctional methacrylates with sometimes very high molecular masses. This led to totally new high-performance composite resins that can be used for nearly almost all indications in the oral cavity.

Later MMA/PMMA composites [101-103] and newly developed high molecular mass methacrylates [104-106] were the base of modern resin-based filling materials and adhesives. R. L. Bowen laid the foundation stone for modern resin composite filling materials by his crucial research work and inventions and thus revolutionized restorative dentistry [104-111].

It was and it is still tried to use other polymers such as polycarbonates or polyacetals (also called polyoxymethylene or POM) to manufacture dentures. These products are processed via injection molding technique but they did not succeed on the market and are only occasionally used.

POM and polyaryletheretherketone (PEEK) processed via CAD/CAM are used today to manufacture denture bases or suprastructures which are usually made from metal. Very likely other polymers will be used for dental purposes in future due to the upcoming innovative processing techniques like CAD/CAM grinding or milling or 3D-printing.

Since 1955 the elastomeric polymers, the polysulfides, and in 1958 [112] the polysiloxanes (also called silicones) entered the dental market and were predominantly applied in the oral cavity for performing impressions. Today, the polysiloxanes dominate this segment. Since 1966 the polyether impression materials also took a great part of this segment [113, 114]. But polysiloxanes are also used in the dental laboratory for duplicating or embedding purposes.

2 Modern Dental Resins

Today, a very broad variety of polymeric materials and composite polymers are used in dentistry. Polymethacrylates, polyacrylates, epoxies and polysiloxanes cover the largest areas of application. It is most certain that newly developed monomers and polymers will be used to develop dental materials in future.

Still, what ever kind of resin or composite resin it is or will be they all have or will have the general composition schematically illustrated in figure 1b. Composite resins consist of very many different ingredients. The respective monomer or monomer blend, also called resin matrix, forms different polymers with different chemical and physical properties. The resin matrix is the central ingredient which contains or may contain different types of fillers, pigments, dies, stabilizers or other various additives and if necessary initiators or catalysts to create a finished product that fulfills the objectives.

The chemical and physical properties of polymers are determined by the

- type of monomers

- type of monomeric links

- alignment of the monomers (primary structure)

- spatial alignment of the monomers in the polymeric chains (secondary structure)

- spatial alignment of the chains’ secondary structures against each other (tertiary structure)

There are numerous different monomers available to create the resin matrix. Depending on the type of monomer different resins with different chemical and physical properties emerge. The chosen monomers determine the type of link by the functional groups reacting with each other and thus also the type of polyreaction as well. The type of link determines the name of the polymer. The next chapter presents various polymers, also called matrix resins, their links and the respective polyreaction.

Fig. 1b: Principal composition of composite resins.