THE JOURNAL OF - Dentsply

Dental Adhesives …. How it All Started and Later Evolved
Karl-Johan M. Söderholm a
Abstract: This article describes how dental adhesives evolved from the cements developed by the Mayan Indians into
today’s modern dental adhesives. Particular attention is paid to Oskar Hagger, a chemist who worked for DeTrey/Amalgamated
Dental Company, and already in 1949 developed an adhesive product called Sevriton Cavity Seal. That adhesive
was acidic and interacted with the tooth surface on a molecular level. His ground-breaking concept makes him the
true “Father of Modern Dental Adhesives.” Hagger’s concept was soon adopted by other investigators, and different generations
of dental adhesives evolved thereafter. Today, after many years of accepting that the key to the success of dental
adhesives is the micromechanical retention resulting from acid etching of dentin and enamel, we still return to Dr.
Hagger’s original concept that bonding can be achieved via molecular interactions between adhesives and tooth surfaces.
That concept is obvious in the development of newer generations of dentin adhesives. These adhesives, like Sevriton
Cavity Seal, rely on acidic monomers capable of etching and interacting on a molecular level with tooth surfaces in
order to form physical/chemical bonds between the restoration and the tooth. Whether Hagger’s concept will become
the norm in the future is still an open question, but one thing is certain: Hagger’s idea is still very much alive.
Keywords: review, generations, clinical evaluations.
J Adhes Dent 2007; 9: 227-230. Submitted for publication: 15.12.06; accepted for publication: 4.1.07.
a Professor, Department of Dental Biomaterials, College of Dentistry, University
of Florida, Gainesville, FL, USA.
Paper presented at Satellite Symposium on Dental Adhesives, Dublin,
September 13th, 2006.
Reprint requests: Prof. Karl-Johan M. Söderholm, Department of Dental Biomaterials,
College of Dentistry, College of Dentistry, 1600 SW Archer Road,
Gainesville, FL 32610-0446, USA. Tel: +1-352-392-0575, Fax: +1-352-392-7808.
e-mail: ksoderholm@dental.ufl.edu
In 1955, Buonocore published a paper entitled “A simple
method of increasing the adhesion of acrylic filling materials
to enamel surfaces”. 15 That paper is often regarded as
the foundation of adhesive dentistry, and today that paper
is the 17th most cited paper published in the Journal of Dental
Research since March of 1919.
Buonocore’s paper 15 clearly outlined different approaches
to obtain bonding between filling materials and tooth
structure. These approaches included: (a) the development
of new materials which have adhesive properties, (b) modification
of present materials to make them adhesive, (c) the
use of coatings as adhesive interface materials between filling
and tooth, and (d) the alteration of the tooth surface by
chemical treatment to produce a new surface to which present
materials might adhere.
In the 1955 paper, Buonocore focused on the (d) alternative
by targeting enamel bonding. He believed that treatment
of intact enamel surfaces would have only limited application
to the broader problems of restorative dentistry. He
focused on enamel etching because he had found that phosphoric
acid or preparations containing phosphoric acid had
been used to treat metal surfaces in order to obtain better
adhesion of paint and different resin coatings.
Obviously, Buonocore used knowledge from other disciplines
and transferred that knowledge to dentistry. What
Buonocore did not seem to consider was that the Mayan Indians
in pre-Columbian times had used acidic cements to attach
their semi-precious stone inlays. 20 He also forgot to
consider that several acidic cements had been used by dentists
more than a hundred years before he invented acid
etching, 27 and that a common zinc phosphate cement was
a mixture of zinc oxide and phosphoric acid. 37 It was well
known that during setting, these cements remained
acidic. 40 What Buonocore forgot was that these cements
were also able to etch tooth surfaces and increase the surface
roughness. During setting, formed setting compounds
grew into the surface roughnesses created by the acidic cement.
Because of mechanical interlocking between tooth,
cement, and crown, retention of the cemented restoration
could be achieved. Considering that the Maya were the first
to use acidic cements, a legitimate question is whether
Buonocore really was the one who invented acid etching or
if that honor shouldn’t go to the Maya. Buonocore’s true contribution
was that he opened our eyes to make us aware of
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