The effect of two bleaching products on microhardness and surface texture of different dental aesthetic restorative materials [Elektronische Ressource] / vorgelegt von Olga Polydorou

De
Aus der Universitätsklinik für Zahn-, Mund-, und Kieferheilkunde der Albert-Ludwigs-Universität Freiburg Abteilung für Zahnerhaltungskunde und Parodontologie (Ärztl. Direktor: Prof. Dr. E. Hellwig) The effect of two bleaching products on microhardness and surface texture of different dental aesthetic restorative materials INAUGURAL-DISSERTATION zur Erlangung des Zahnmedizinischen Doktorgrades Der Medizinischen Fakultät der Albert-Ludwigs-Universität Freiburg Vorgelegt 2004 Von Olga Polydorou Geboren in Nafpaktos, Griechenland Dekan: Prof. Dr. med. J. Zentner 1. Gutachter: Prof. Dr. E. Hellwig 2. Gutachter: Prof. Dr. Dr. R. Schmelzeisen Jahr der Promotion: 2004 To my family Στην οικογένειά µ ου Table of contents: 1 Introduction...................................................................................................................... 1 2 Literature Review............................................................................................................ 3 2.1 Tooth Bleaching.........................................................................................................3 2.1.1 : An Evolving History........................................................................
Publié le : jeudi 1 janvier 2004
Lecture(s) : 33
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Source : FREIDOK.UB.UNI-FREIBURG.DE/FREIDOK/VOLLTEXTE/2004/1433/PDF/DR.PDF
Nombre de pages : 100
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Aus der Universitätsklinik für Zahn-, Mund-, und Kieferheilkunde der
Albert-Ludwigs-Universität Freiburg
Abteilung für Zahnerhaltungskunde und Parodontologie
(Ärztl. Direktor: Prof. Dr. E. Hellwig)


The effect of two bleaching products on microhardness and
surface texture of different dental aesthetic restorative
materials


INAUGURAL-DISSERTATION
zur Erlangung des
Zahnmedizinischen Doktorgrades
Der Medizinischen Fakultät der Albert-Ludwigs-Universität
Freiburg


Vorgelegt 2004
Von
Olga Polydorou
Geboren in Nafpaktos, Griechenland















Dekan: Prof. Dr. med. J. Zentner
1. Gutachter: Prof. Dr. E. Hellwig
2. Gutachter: Prof. Dr. Dr. R. Schmelzeisen
Jahr der Promotion: 2004


























To my family

Στην οικογένειά µ ου



Table of contents:

1 Introduction...................................................................................................................... 1
2 Literature Review............................................................................................................ 3
2.1 Tooth Bleaching.........................................................................................................3
2.1.1 : An Evolving History........................................................................ 3
2.1.2 Chemistry of bleaching ...................................................................................... 4
2.1.3 Bleaching techniques..........................................................................................5
2.1.3.1 In-office bleaching of vital and nonvital teeth ...............................................
2.1.3.2 Waiting room bleaching................................................................................. 6
2.1.3.3 Home bleaching..............................................................................................6
2.1.3.4 Intracoronal bleaching....................................................................................7
2.1.3.5 Over-the-counter bleaching............................................................................7
2.1.4 Hydrogen Peroxide Bleaching ........................................................................... 8
2.1.5 Dental bleaching mechanism ............................................................................. 9
2.1.6 Carbamide peroxide chemistry9
2.1.7 Constituents of the bleaching agents................................................................ 10
2.1.7.1 Carbamide peroxide.....................................................................................10
2.1.7.2 Thickening agents........................................................................................11
2.1.7.3 Urea..............................................................................................................11
2.1.7.4 Vehicle.........................................................................................................12
2.1.7.5 Surfactant and pigment dispersant ............................................................... 12
2.1.7.6 Preservatives.................................................................................................12
2.1.7.7 Flavourings...................................................................................................12
2.2 Aesthetic Restorative Materials ............................................................................... 12
2.2.1 Direct-placement aesthetic restorative materials.............................................. 12
2.2.1.1 Resin restorative materials ........................................................................... 13
2.2.1.2 Indirect-placement aesthetic restorative materials ....................................... 19
2.3 Bleaching: How safe is it?........................................................................................ 20
2.3.1 Effects on enamel ............................................................................................. 20
2.3.2 Effects on dentine 21
2.3.3 Effects on pulp ................................................................................................. 21
2.3.4 Effects on restorative materials........................................................................ 22
2.3.4.1 Composite materials.....................................................................................22
2.3.4.2 Amalgam restorations..................................................................................23
2.3.4.3 Other materials23
2.3.5 Toxicological considerations............................................................................23
2.3.6 Further ......................................................................................24
2.3.6.1 Microhardness..............................................................................................
2.3.6.2 Surface properties.........................................................................................25
2.3.6.3 The release of chemical toxic products ........................................................ 26
2.4 Aim of the study....................................................................................................... 28
3 Materials and methods ................................................................................................. 29
3.1 Materials................................................................................................................... 29
3.1.1 Restorative materials........................................................................................29
®3.1.1.1 TETRIC CERAM (Ivoclar Vivadent AG) .................................................
®3.1.1.2 TETRIC FLOW .................................................... 30
3.1.1.3 ENAMEL PLUS HFO (MICERIUM) ......................................................... 30 ®3.1.1.4 FILTEK SUPREME (3M ESPE)............................................................... 31
®3.1.1.5 DEFINITE (Denstply)................................................................................ 32
® ® ®3.1.1.6 VITABLOCS for CEREC (VITA SYSTEM 3D-MASTER (VITA))... 33
3.1.2 Bleaching Materials..........................................................................................34
® ® TM3.1.2.1 OPALESCENCE XTRA BOOST (ULTRADENT)...........................
®3.1.2.2 OPALESCENCE PF 15% CARBAMIDE PEROXIDE (ULTRADENT) 34
3.1.3 Additional materials.........................................................................................35
3.1.4 Examination machines.....................................................................................
3.1.4.1 Knoop Microhardness tester.........................................................................35
3.1.4.2 Scanning Electron Microscope..................................................................... 36
3.2 METHODS...............................................................................................................37
3.2.1 Construction of the samples .............................................................................
3.2.2 First part of the study ....................................................................................... 38
3.2.3 Second Part of Study........................................................................................ 40
4 RESULTS.........................................................................................................................43
4.1 Microhardness..........................................................................................................43
® ® TM ®4.1.1 Opelescence Xtra Boost / Opalescence carbamide peroxide 15%......... 44
4.1.1.1 Tetric Ceram.................................................................................................45
4.1.1.2 Tetric Flow...................................................................................................47
4.1.1.3 Filtek Supreme.............................................................................................48
4.1.1.4 Enamel Plus HFO......................................................................................... 49
4.1.1.5 Definite.........................................................................................................50
4.1.1.6 Ceramic........................................................................................................52
4.2 Surface texture..........................................................................................................53
® ® TM4.2.1 Opalescence Xtra Boost ............................................................................ 53
4.2.1.1 Tetric Ceram.................................................................................................54
4.2.1.2 Tetric Flow55
4.2.1.3 Filtek Supreme56
4.2.1.4 Enamel Plus..................................................................................................57
4.2.1.5 Definite.........................................................................................................57
4.2.1.6 Ceramic........................................................................................................58
®4.2.2 Opalescence PF Carbamide peroxide 15% .................................................... 59
4.2.2.1 Tetric Ceram60
4.2.2.2 Tetric Flow...................................................................................................60
4.2.2.3 Filtek Supreme.............................................................................................61
4.2.2.4 Enamel Plus HFO......................................................................................... 62
4.2.2.5 Definite.........................................................................................................63
4.2.2.6 Ceramic63
5 Discussion....................................................................................................................... 65
5.1 Discussion of the materials ...................................................................................... 65
5.1.1 Restorative ma........................................................................................65
5.1.2 Bleaching materials..........................................................................................
5.1.3 Storage solution................................................................................................65
5.2 Discussion of the methods 66
5.2.1 Preparation of the specimens............................................................................ 66
5.2.2 Bleaching procedure.........................................................................................66
5.2.3 Microhardness..................................................................................................67
5.2.4 SEM..................................................................................................................
5.3 Discussion of the results........................................................................................... 68 5.3.1 Microhardness..................................................................................................68
5.3.2 Surface texture73
5.4 Conclusions..............................................................................................................77
6 Summary ........................................................................................................................ 78
7 Zusammenfassung ........................................................................................................ 79
8 Literature ........................................................................................................................ 80
9 Curriculum Vitae........................................................................................................... 91
10 Acknowledgments .................................................................................................... 93 1 Introduction 1

1 Introduction
Aesthetics, by definition, is the science of beauty, that particular detail of an animate
or inanimate object that makes appealing to the eye (Arens 1989).
The last three decades have witnessed immense changes in dentistry, beginning with
the profession’s dramatic and unprecedented success in the reduction of caries and
periodontal disease (Goldstein and Lancaster 1984). The subsequent decline in what
had been the primary activities in dentistry caused many dentists to reexamine and
redefine their roles in meeting the dental needs of their patients. Perhaps the most
significant change was contemporary dentistry’s new emphasis on esthetics. There
was a direct result of dentists’ ability to bond predictably to teeth, allowing patients
to keep sound tooth structure while improving their looks (Sheridan and Armbruster
1999).
Attractive teeth have always been the typical patients’ primary concern. In the past,
dentists were often dismayed by a patients’ disappointment in a “perfect
restoration”, painstakingly crafted of the finest gold or other material, with
minimized enamel reduction and long-lasting preservation of function. The patient,
of course, had hoped the restoration would mimic the appearance of the original
teeth. Today, by taking full advantage of new materials and techniques, dentists can
often meet or even exceed such expectations (Arens 1989; Bailey and Swift 1992).
Bleaching is now the single most common esthetic treatment for adults (Anderson
1991). It is estimated that more than a million people have had teeth bleached by
dentists, while perhaps millions more have tried their own hand at bleaching with
over-the-counter products. The popularity of bleaching is easily understood. For the
appropriate patient, with careful diagnosis, case selection, treatment planning, and
attention to technique, bleaching is the simplest, least invasive, least expensive
means available to lighten discolored teeth and diminish or eliminate many stains in
both vital and pulpless teeth (Goldstein 1987). Once considered the province of a few
pioneering specialists in esthetic dentistry, bleaching has now moved into the
mainstream of restorative dentistry.
1 Introduction 2

But bleaching is not a simple yes-or-no treatment opinion, especially as a larger
number and wider range of patients expect and ask for brighter teeth. More
significantly, some patients’ only problem is tooth discoloration, while others have
periodontal problems, tooth misalignment, and caries requiring preliminary
attention.
In combination with other esthetic procedures, such as microabrasion, lightening a
stained tooth before veneering, or crowning to improve the color of adjacent teeth,
bleaching expands the scope of esthetic dentistry. In the 1980s and 1990s, new
partnerships and referral patterns have given bleaching a new role as an adjunct to
orthodontics, orthognathic surgery, endodontics, and restorative dental treatments,
as well as to treatments in dermatology, plastic and reconstructive surgery, and other
fields (Anderson 1991).
A plethora of bleaching products is currently available. Unfortunately, these
products have not been well documented in vitro or clinical research. Little is known
about their effects on soft tissue, tooth structure, or restorative materials. Further
research is necessary.
2 Literature Review 3

2 Literature Review

2.1 Tooth Bleaching
2.1.1 Bleaching: An Evolving History
Bleaching is not new! The earliest agent reportedly used was oxalic acid, described
by Chappel 1877 (Zaragoza 1984; Goldstein 1997). Following experiments with
various forms of chlorine, Harlan described in 1884 what is believed to be the first
use of hydrogen peroxide, which he called hydrogen dioxide (Zaragoza 1984;
Goldstein 1997).
Bleaching nonvital or pulpless teeth changed less rapidly. The first reported instance
of bleaching nonvital teeth was in 1895, when a dentist named Gatterson applied
chloride to the tooth surface (Sakaguchi et al. 1991). The results were not inspiring,
and there were few followers. In 1958 Pearson realized the dentist could take
advantage of the nonvital tooth’s lack of a pulp. He packed the same hydrogen
peroxide agent being used for bleaching of vital teeth, Superoxol, in the pulp
chamber for 3 days. By the late 1960s the standard method was established by
Nutting and Poe, who sealed a mixture of 30% hydrogen peroxide and sodium
perborate in the pulp chamber for up to a week (Nutting and Poe 1967; Haywood
1992).
How well bleaching works depends upon the cause of the stain; where, how deeply,
and how long the stain has permeated the structure of the tooth; and how well the
bleaching agent can permeate to the source of the discoloration and remain there
long enough to release deep stains (Goldstein 1997).
In the decade since home bleaching materials were introduced, there have been
numerous changes to the materials. The first-generation materials were in a liquid
form. These materials did not remain in the trays for long and needed more
replenishment over time. The second-generation materials that are currently
available are more viscous and in gel form. This is to stop the materials leaching out
of the tray and causing soft tissue irritation. The second-generation materials also
2 Literature Review 4

contain differing concentrations of active ingredients. The third-generation materials
differ in their vehicle and color. In general, quality control by the manufactures and
dental companies has improved, together with changes in the packaging and patient
instruction, to make them more patient-friendly (Fasanaro 1992; Blankenau et al.
1999).

2.1.2 Chemistry of bleaching
Bleaching is a chemical process for whitening materials, which is widely used in
dentistry (Sheridan and Armbruster 1999). In dentistry, bleaching usually refers to
products containing some form of hydrogen peroxide (Anderson 1991).
The three most prominent commercial bleaching processes are peroxide, chlorine,
and chloride, in that order (Trotman 1987). Peroxide bleaching requires the least time
and is most commonly used. The strength is designated most frequently by volume
rather than by percentage of peroxide. Thus, although they are interrelated
proportionately, 27,5% hydrogen peroxide is termed 100 volume, 35% is 130 volume,
and 50% is 200 volume, volume indicating the volume of oxygen released by one
volume of the designed hydrogen peroxide (Marshall et al. 1995).
Although bleaching processes are complex, the vast majority works by oxidation, the
chemical process by which organic materials are eventually converted into carbon
dioxide and water.
Wood burning in a fireplace is a common example of oxidation. The differences
between the oxidation that occurs with bleaching and that of burning wood are the
rate of each reaction and the number of intermediate products produced. Burning
rapidly transforms a substance into carbon dioxide, water and heat. In comparison,
bleaching slowly transforms an organic substance into chemical intermediates that
are lighter in color than the original. Corrosion of metal is an example of a slow
oxidation process. If allowed to progress long enough, however, both burning and
bleaching will result in the conversion of organic materials into carbon dioxide and
water (Goldstein and Garber 1995).

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