Dentistry, more appropriately "dental medicine", is the art and science of prevention, diagnosis, and treatment of conditions, diseases, and disorders of the oral cavity, the maxillofacial region, and its associated structures as it relates to human beings. While the work of dentists is often surgical in nature, dentists can and do treat many diseases of the oral cavity and face chemotherapeutically (i.e. with prescribed medicines).
A dentist is a doctor, qualified to practice dentistry after graduating with a degree of either Doctor of Dental Surgery (DDS), Doctor of Dental Medicine (DMD), Bachelor of Dentistry (BDent), Bachelor of Dental Science (BDSc), or Bachelor of Dental Surgery (BDS) or (B.Ch.D). In most western countries, to become a qualified dentist one must usually complete at least 4 years of postgraduate study. Generally, 2 years of clinical experience working with patients in an educational setting are required.
The first dental school, the Baltimore College of Dental Surgery, opened in Baltimore, Maryland in 1840. Harvard Dental School was the first dental school to affiliate with a university in 1867 (renamed Harvard School of Dental Medicine in 1940.)
Bond Strengths Between Restorative Materials and Tooth Structures
Adhesion of restorative materials to tooth structures has been studied since 1955. The bond strength is the load required to fracture the bond divided by the cross-sectional area of the bond. Bond strengths are measured either in shear or tension. Many factors, including the dentine substrate, the storage conditions and the test method, affect the bond strength values.
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Shear bond strength
Substrate Adhesive Adherend (psi x 1000) (MPa) Ref.
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Dentin Dentin bonding Composite 3.2-5.1 22-35 238
system
Dentin No smear layer Light-cured
hybrid
glass-ionomer 1.5-1.7 10-12 238
Enamel Enamel bonding Composite 2.6-3.2 18-22 238
system
Enamel Amalgam Composite 1.5-1.7 10-12 238
bonding system
Enamel Amalgam Amalgam 0.3-0.9 2- 6 238
bonding system
Enamel No smear layer Traditional
glass ionomer 1.2-1.7 8-12 238
Enamel Enamel bonding Orthodontic
system bracket 2.6-2.9 18-20 238
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Tensile bond strength
Substrate Adhesive Adherend (psi x 1000) (MPa) Ref.
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Dentin Polyurethane Composite 0.1-0.9 1- 6 147
Dentin Polyacrylic
acid Composite 0.3-0.6 2- 4 147
Dentin Organic
phosphonates Composite 0.4-1.4 3-10 147
Dentin 4-META* Composite 0.4-1.0 3- 7 147
Dentin HEMA + GA# Composite 1.6-2.4 11-17 147
Dentin NPG-GMA/PMDM$ Composite 0.6-1.8 4-12 147
Dentin Glass ionomer 0.6 4 147
Dentin Zinc
polycarboxylate 0.4-0.6 3- 4 147
Dentin Adhesive resin
cement 0.6 4.1 147
Dentin Conventional
resin cement 0.0 0.0 147
Etched enamel Fine composite 2.4-2.8 17-20 147
Etched enamel Microfine
composite 1.4 10 147
Enamel Glass ionomer 0.7 5 147
Etched enamel Adhesive resin
cement 2.2 15 147
Etched enamel Conventional
resin cement 1.5 10 147
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* 4-META-4-methyloxyethyl-trimellitic anhydride
# HEMA - hydroxyethyl methacrylate
GA - glutaraldehyde
$ NPG-GMA - N-phenyl glycine - glycidyl methacrylate
PMDM - pyromellitic acid diethylmethacrylate |
