PDM 2016
Adhesive Dentistry Symposium
a Cornerstone of PDM 2016
By Alan M. Atlas, DMD
Adhesive Dentistry has become the
cornerstone of all restorative dentistry
by being the key element to minimally
invasive and esthetic dental restorations.
Adhesion to tooth structure has major influences on most
clinical procedures including anterior and posterior composites,
endodontic obturation and tooth reconstruction, CAD-CAM
ceramic cementation and other dental specialties. Yet, there is
an extreme diversity of opinion on how to accomplish each
procedure correctly and successfully. This article summarizes
key aspects and guidelines for clinical success with adhesive
dentistry and summarizes evidenced-based information
presented by selected academic clinicians at the Pennsylvania’s
Dental Meeting Symposium on Adhesive Dentistry.
Dr. John Burgess, a world-renowned dental material researcher
who is the Assistant Dean for Clinical Research at the University
of Alabama, started the session with an evidenced based review
of clinical materials related to adhesive bonding agents. Current
adhesive systems are divided into two strategies: total-etch or
etch-and-rinse and self-etch. Etch-and-rinse systems comprise
two or three steps utilizing phosphoric acid pretreatment of the
dentin with subsequent development of a demineralized zone
of collagen. Self-etch systems offer one or two-steps comprised
of different pH levels that interact with dentin via functional
acidic monomers without phosphoric acid. Dr. Burgess pointed
out the advantages and disadvantages of each strategy.
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With total etch technique, the exposed collagen fibrils may
suffer hydrolytic degradation and enzymatic degradation by
matrix metalloproteinases (MMPs). Application of chlorhexidine
after application of phosphoric acid may prevent degradation,
but not for an extended period of time. Self-etch adhesives are
not affected by MMPs to the same degree, due in part to the
fact that collagen is demineralized to a lesser extent. However,
self etch adhesives, demonstrated through clinical, do not etch
enamel sufficiently to establish a durable bond. Therefore,
Dr. Burgess suggested careful selective enamel etching when
using self etch adhesives in order to create an optimum seal
and minimize discoloration and deterioration of the restoration,
which is named “ring around the restoration.” He demonstrated
critical clinical technique emphasizing agitation of the etch on
enamel and primer/bond on both dentin and enamel. Dr. Burgess
also presented on bulk fill composites and demonstrated several
materials that did well in recent clinical trials including many of
his own studies. The take home message was initial data is
good on many of these composites but long term wear and
degradation at the occlusal surface is still relatively unknown
and further clinical studies are necessary.