Indirect and Direct Restorative Protocols - Caulk

››Principles & Practices
Predictable
Tissue Retraction:
Methods and Techniques
››Abstract:
Accurate data transfer
between the clinician and
ceramist is critical for any
indirect restorative procedure.
A precise retraction technique
is necessary to allow for
reliable information transfer
during impression making.
Since different surfaces
(eg, gingival tissues, dentin,
enamels, and metals) have
such varied moisture content,
friction resistance, and surface
tensions, clinicians should also
use a reliable methodology
in which each surface can be
predictably optimized prior to
impressing for the best
possible results.
S
uccessful placement of a fixed
dental prosthesis requires the
clinician to accurately communicate
the details of the patient’s
intraoral environment to
the laboratory technician. To capture this
information, the practitioner must first
control systemic factors (eg, periodontal
health, crevicular fluid, inflammation) at
the restorative site, create a proper margin
design, and then make an impression of
the required preparation. Additionally, he
or she must displace or remove the gingival
tissues that prevent the subsequently
applied impression material from gaining
access to a subgingival finish line.
Care should, therefore, be taken to utilize
proper methods of exposing subgingival
finish line and to select a retraction cord
that is resistant to fraying or tearing and that
will not adhere to the dental tissues or the
impression material. Although some cords
are available in a pre-impregnated format to
assist in hemostasis, it is generally advisable
to utilize a hemostatic agent in order to limit
the presence of fluids during impression
capture and to ensure a clear, detailed margin
(Figure 1). Localized anesthesia may be
indicated for patients who require it, and
can be applied to one or several periodontal
pockets in a needle-free application.
Retraction Cords and Pastes
When employing retraction devices, the
primary concern is maintenance of clear
finish lines and margins in order to ensure
their capture and transfer to a detailed impression.
Whether using a cord or paste retraction
material (Table), proper packing
also allows the impression material to flow
subgingivally, which enables the soft tissue
topography and prepared hard tissues
to be properly recorded (Figure 2). When
using retraction cord techniques, the clinician
should:
■■
Create a lateral space of >0.5 mm;
■■ Take care when using a heavy/rigid
tray material to avoid locking an
impression in undercuts;
■■ Delay the impression procedure if
adequate hemostasis cannot be
achieved; and
■■ Maintain proper moisture control
subgingivally.
Figure 1. The retraction cord should be placed carefully to avoid soft
tissue trauma and ensure precise marginal detail in the impression.
Figure 2. Correct positioning of the retraction cord should be verified
prior to impression making.
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