Dentaltown August 2018 - 84

Fig. 1: A patient presents with a large amalgam Class II
failure in the mandibular first molar with a fractured
distobuccal cusp. While an onlay or crown is probably the
restoration of choice, a direct resin was chosen because
of the patient's time constraints.

Fig. 2: The one-time-use Max pin latch type came in
a sealed plastic container. Place the pin into a low-speed
handpiece.

Fig. 3: All-Bond Universal primer from Bisco (10 micros)
is applied to the Max pin.

AUGUST 2018 // dentaltown.com

Early investigations on the durability of resin-dentin
adhesion found decline over time. Tooth-resin adhesion
may degrade by chemical and physical stress.14 However, the
mechanism of the decrease in bond strength was unknown
until it was published in 2004. As a result of long-term
exposure in a humid environment, the hybrid layer degrades,
and the dentin-adhesive resin bonds weaken.15 If there is a
presence of sclerotic dentin, the bond strength significantly
decreases.16
A fabricated indirect restoration laboratory (onlay
or crown) is considered the treatment of choice when a
cusp is lost.17 CAD/CAM technology can also be applied
for inlays and onlays.18 Both alternatives offer advantages
and disadvantages, and both are complex and expensive
treatments. Crowns are highly invasive, and can be pricey
as well. The full-coverage crown should always be the
last treatment option, because it is the most invasive and
traumatic restorative procedure.19
Many crowned teeth could have been restored with less
aggressive restorations.20 Direct options such as composite
or amalgam restorations are acceptable, with both being a
single-appointment procedure and having a similar prevalence
in cusp fracture.21 Amalgam has long history of use with
clinical success, and has been an effective restorative material
for Class I and Class II preparations. However, its use has
declined because patients and clinicians preferred aesthetic,
adhesive, mercury-free restorative materials.22
Data supports that glass fiber-reinforced composite
increases the fracture resistance of weakened marginal ridges
in molar teeth.23 Fibers also increase the damage tolerance
of a tooth; they can be used to provide additional support to
weakened cusps and to span cracks.24 In applications such as
cuspid reconstruction, multidirectional reinforcement can
arrest cracks and prevent their propagation in the cervical
direction.25 As shown in literature, dentin pins increase shear
resistance of extensive composite restorations.26
Composite restorations may be the optimal choice
because of their conservative preparation and aesthetics.
Using pins and high-strength polyethylene fibers is another
alternative. They offer an efficient load distribution and also
make its structure extremely impact-resistant. This results
in a successful aesthetic integration of the restoration.
In the late 1950s, the introduction of practical instrumentation use for stainless steel pins resulted in their extensive
use in dentistry.27 Pins in dentistry are indicated as additional
aids of retention in badly broken-down or mutilated teeth.
They are especially needed when one or more cusps need

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Table of Contents for the Digital Edition of Dentaltown August 2018