Efficacy of conventional cord versus cordless techniques for gingival displacement: A systematic review and meta-analysis

Felipe V. Martins, DDS, MS, Ronaldo B. Santana, DDS, MS, PhD, and Edgard
M. Fonseca, DDS, MS, PhD

DR. AWANI GUPTA

2ND YEAR PG
 CONTENTS
 INTRODUCTION
 NEED FOR GINGIVAL RETRACTION
 TECHNIQUES
 RETRACTION CORDS
 RECENT ADVANCEMENTS
 DISCUSSION
 RESULT OF THE STUDIES
 CRITICAL ANALYSIS
 REFERENCES
 INTRODUCTION
 Marginal integrity is one of the important factors, which contribute to the success of
cast restorations. The restoration can survive in the biological environment of the
oral cavity, only if the margins are closely adapted to the finish line of the
preparation . The gingiva must be displaced to make a complete impression and
sometimes even to permit completion of the preparation and cementation of the
restoration.
DEFINITION
The procedure to expose the sub-gingival finish lines of
preparation may be termed as gingival displacement,
also referred as gingival retraction, gingival deflection and
gingival tissue deflection.
the combined width of connective tissue and junctional
epithelial attachment formed adjacent to a tooth and
superior to the crestal bone is referred as biological
width.
 Need for the gingival retraction
 1. To widen the gingival sulcus in order to  5. During cementation it helps in easy removal
provide access for impression material to reach of cement without tissue damage.
the subgingival margins and to record  6. It helps the dentist in visually assessing the
adequately the finish line. marginal fit and any caries if present.
 2. Helps in obtaining the perfect die with  7. In situations when it is necessary to extend
accurate margins, which helps in margin the restoration below the gingival margin to
placement and contouring of the restoration. enhance retention.
 3. Helps in blending of the restoration with the  8. To enhance access and to prevent damage to
unprepared tooth surface.
the soft tissue during cavity preparation
 4. Helps in placement and finishing of the procedure, it may be desirable to carry out some
margins on the prepared tooth. degree of gingival retraction prior to
commencement of preparation.

Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical Dental Science. 2011 Mar 5;2(1)..
 Categories of biological Width

Normal‑crest patients

High‑crest patients

Low‑crest patients

(a) The normal crest, (b) the high crest, (c) the low crest, and (d) the Low crest, stable or unstable
subclassifications of the low crest
Sampath P, Varma L, Varma M, Shabu A. Recent advances on gingival tissue management in restorative dentistry. Indian Journal of Dental
Sciences. 2019 Oct 1;11(4):185
 Gingival Displacement Techniques

Mechanical Technique Chemico-Mechanical Technique

1. Copper band 1. 8% racemic epinephrine

2. Rubber dam 2. Aluminium chloride
3. Displacement cords 3. Alum (aluminium potassium sulphate)
4. Aluminium sulphate
5. Ferric sulphate

Rotary curettage
Surgical Technique Electrosurgical method
LASER

Singh D, Gupta P, Bhatnagar A. Gingival displacements options in prosthodontics: a critical review on recent
advances. J Adv Res Dent Oral Health. 2016;1:13-21.
Impression material filled copper band/tube
VARIOUS IMPRESSION MATERIALS USED:
elastomeric material, Gutta-percha or auto polymerizing resin.

DISADVANTAGES: ADVANTAGE:
• Incisional injuries to the • Good method to
gingival tissues
confirm gingival
• Excess pressure tends to margins e.g. in
stipple the tissue from the multiple abutments
tooth

Singh D, Gupta P, Bhatnagar A. Gingival displacements options in prosthodontics: a critical review on recent
advances. J Adv Res Dent Oral Health. 2016;1:13-21.
RUBBER DAM
ADVANTAGES
• Asset during tooth preparation as it exposes
the finish line.
• Excellent impressions are obtained due to
fluid control
DISADVANTAGES
• Useful only when limited number of teeth in
one quadrant are being restored.
• Used in simple preparations with minimal
Sub-gingival preparations.
RETRACTION CORD
DESIGNS
• Twisted,
• Knitted
• Braided
– does not separate when
inserted into the sulcus and
much easy to use.
– larger sizes should be avoided
as they tend to double up and
leads to traumatic placement
RETRACTION CORD DIAMETER
The cord that can be atraumatically placed into the
sulcus should be used.
• SMALL- to be used in anterior teeth, where thin
firm tissue is present
• MEDIUM- indicated where greater bulk is
encountered e.g. posterior teeth
• LARGE- should be used with caution as can
produce soft tissue trauma
TIME OF PLACEMENT OF RETRACTION
CORDS

• Untreated string/cord is safe for placement for

periods from 5-30 min, when bleeding and seepage
not a problem.>30 mins, causes permanent soft
tissue changes.
• Strings saturated with chemicals are recommended
for use from 5 – 10 min , <20 min.
• After 30 min, impregnated cords caused injury to the
sulcular epithelium, these healed with in 10 days.
 MECHANICO-CHEMICAL METHODS
CHEMICALLY IMPREGNATED
• The Mechanical aspect involves CORDS
placement of a string into the • The cords are used to keep
gingival sulcus to displace the tissues. the chemicals in contact with
the tissue and confine them
• The Chemical aspect involves to the application site.
treatment of the string with one or • By combining chemical
more number of chemical
compounds that will induce action with pressure
i) Temporary shrinkage of the tissues
packing, enlargement of
& the gingival sulcus as well
as fluid control is more
ii) Control the hemorrhage & fluid
seepage
readily accomplished.
EPINEPHRINE ALUM (POTASSIUM
ALUMINUM SULFATE)
Advantages
Advantages Disadvantages
•Vasoconstrictive
•Hemostatic • Hemostasis
• Least inflammation of • Offensive taste
all agents used with • Risk of necrosis if in
Disadvantages
cords high concentration
• Little sulcus collapse
• Systemic effects: after cord removal
epinephrine syndrome
• Risk of inflammation of
gingival cuff
• Rebound hyperemia
• Risk of tissue necrosis
 Ferric sulfate Aluminum chloride

Advantages Advantages

• No systemic effects
Hemostasis • Least irritating of all Disadvantages
chemicals
• Hemostasis
Disadvantages • Less vasoconstriction than
• Little sulcus collapse
epinephrine
after cord removal
• Risk of sulcus contamination
• Tissue discoloration • Modifies surface detail
• Acidic taste reproduction
• Risk of sulcus contamination • Inhibits set of polyvinyl
• Inhibits set of polyvinyl siloxane and siloxane and polyether
polyether impressions impressions
 TECHNIQUES FOR GINGIVAL DISPLACEMENT
USING RETRACTION CORDS
1. Single cord technique
2. Double cord technique
3. Infusion technique of gingival displacement
SINGLE CORD TECHNIQUE
1. Loop of retraction
cord is Formed around the
tooth and held with the
thumb and forefinger

2. Placement of the cord is begun By

pushing it in the sulcus on the
mesial surface of the tooth (A)
it should also be tacked into the
distal
crevice to hold the cord in place (B)
3. As the cord is placed subgingivally
the instrument must be pushed slightly
towards the area already tucked into
place (A)
if the force is directed away from the
area previously packed the cord
will be pulled out (B)

4. It may be needed to hold the cord

with another instrument.

5.The instrument should be slightly

angled towards the root to
facilitate subgingival placement.
6. Excess cord is cut at the mesial
Interproximal area.

7. Placement of the distal end

of the cord is continued till
it overlaps the mesial.
• CORD PACKING INSTRUMENTS:

Fischer’s ULTRAPAK
Packers

PASCAL Cord Packing

Instrument
Circlet®

Standard
Packing

Packing
Plain

Plain
 THE DOUBLE CORD TECHNIQUE

Indications:

-impression of multiple
prepared Teeth.
-when tissue health is
compromised.
-excess gingival fluid
exudates.
-can be used
 1. A smaller diameter cord is
placed in sulcus.

2. A second cord (largest diameter

that can be placed) is placed
above the first.

3.After waiting for 8-10 min it is

soaked in water and removed,
dried,and impression is made
with the first cord in place
THE INFUSION TECHNIQUE
Steps:
1.After preparation of the margins,
hemorrhage is controlled Using a special
dental Infusor with Ferric sulfate
medicament 15% 0r 20%.

2.The infusor is used with a burnishing

Action, 360 deg. Around the sulcus.

3.Recommended time 1-3 mins.

4.Cord is removed
and impression
made.
ROTARY GINGIVAL CURETTAGE
• Also called as ‘Gingettage’ and
‘Troughing’ SUITABILITY OF THE GINGIVA FOR
• A technique of using rotary GINGETTAGE
diamond instruments to enlarge
the sulcus. It involves preparation • Absence of bleeding
of the tooth sub-gingivally while from probing.
simultaneously curetting the inner • Sulcus depth less than 3
lining of the gingival sulcus. mm.
• The goal is to eliminate the • Presence of adequate
trauma from pressure packing keratinized gingiva.
and the need for electrosurgical
procedures
RECENT ADVANCEMENT
Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical Dental Science. 2011 Mar 5;2(1)..
 Crown preparation
prior to retraction

have the patient

Pre-fit one Comprecap bite and maintain
Apply Magic FoamCord
per crown pressure
preparation

Remove Result is open wide sulcus multiple preparations

after 5 minutes
 • Comprecap / Comprecap anatomic

Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical Dental Science. 2011 Mar 5;2(1)..
  GingiTrac™

2) Dispense
GingiTrac
into the
matrix
1) Make Matrix

4) Ready for impression

in less than 5 minutes
3) Bite down & wait
Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical Dental Science. 2011 Mar 5;2(1)..
 MEROCEL (Merocel Co.,
Mystic)

Synthetic material that is

specifically
chemically extracted from a biocompatible
polymer (Hydroxylate polyvinyl
acetate)

Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical Dental Science. 2011 Mar 5;2(1)..
• Stay-put

Stay-put is so pliable that

it stays where you put it.
Stay-put is a unique combination
of softly braided retraction cord
and an ultra fine copper filament

• GINGI-LOOPS
 LASER:
• DIODE AND ND:YAG LASER channels
laser through a fiber optic light bundle
which incises and cauterizes tissue
simultaneously creating haemostasisas well
as a retracted field.

PULSED ND: YAG LASER IRRADIATION.

The present histological findings revealed that
with the application of PULSED ND: YAG
LASER the gingival tissues showed faster
healing with less hemorrhage and less
inflammatory reaction in comparison with
the Ferric sulphate (13.3%).
 Gingival Displacement in Implants

The mechanical retraction of gingival tissues by

using cords around implant restorations can lead
to ulceration of the junctional epithelium. Retraction cords
were developed for application around natural teeth where the
junctional epithelium is healthy. Thus, the use of mechanical
retraction with cords may be contraindicated
around implants

Using an injectable matrix for gingival retraction offers

clinicians the opportunity to perform
Comparison of periodontal biological width and peri- an atraumatic procedure. There is no risk of laceration when
implant biological width. clinicians introduce materials such
as 15 percent aluminium chloride in a kaolin
matrix into the sulcus surrounding natural teeth
 Gingival Displacement in Digital Impressions

A major restraint of direct optical impressions is their

limitation to line of sight. A clean sulcus is a
requirement of paramount importance while making
digital computer-aided design/ computer-added
manufacturing (CAD/ CAM) impressions. Retraction
cord fibers that remain in the sulcus may affect the
accuracy of gingival retraction and may result in
artifact-generated errors. Indirect capture of digitalized
information is considered more accurate by clinicians.
 DISCUSSION
Gingival displacement (GD) is a procedure that aims to dry and allow access of the impression material to the gingival sulcus
by moving the adjacent tissues laterally from the prepared tooth. The goal is to obtain a sulcular width greater than 0.2 mm,
making it possible for the impression material, or scanner, to copy the tooth structure and provide adequate thickness of the
impression material to resist distortion or tearing. Therefore, the choice of an appropriate displacement method is a critical
step.
Studies included for META - ANALYSIS
GD with cords is still considered the gold-standard technique. In this meta-analysis, displacement cord resulted in increased
GD when compared with the cordless technique. Taken together, the current evidence supports the general superiority of the
cord technique for increased gingival displacement. Although a goal of GD is to provide a dry gingival sulcus, the use of a dry
cord leads to rupture and desquamation of the sulcular and junctional epithelium, leading to increased fluid flow.

Despite the increased GD with cords observed in this meta-analysis, the pressure applied during
the insertion of cords can cause lesions to the epithelial attachment and induce bleeding during
removal. This damage tends to be clinically and histologically reversible within 2 Weeks. For this
reason, alternative displacement materials have been developed.
Among the materials used in the cordless methods, Expasyl paste (Satelec) is formulated as a
viscous paste to be injected and maintained for about 2 minutes into the gingival sulcus in a
mechanochemical technique.
 CONCLUSION

Within the limitations imposed on this systematic review and meta-analysis, the following
conclusions were drawn:
 1. The cord technique resulted in increased displacement when compared with the cordless
technique.
 2. Expasyl paste was the most effective cordless material.
 3. Evaluation of the sulcular width with a digital microscope image obtained from a
sectioned gypsum cast is an adequate and versatile experimental methodology for
measuring displacement.
 4. Evaluation of the sulcular width directly on the impression material is a limited
methodology for measuring displacement.
CRITICAL
ANALYSIS
 No pictures given in the article
 Procedure for gingival displacement not explained
 Laser technology was not included in the study
 References

 Prasad KD, Hegde C, Agrawal G, Shetty M. Gingival displacement in prosthodontics: A critical

review of existing methods. Journal of interdisciplinary dentistry. 2011 Jul 1;1(2):80.
 Acar Ö, Erkut S, Özçelik TB, Ozdemır E, Akçil M. A clinical comparison of cordless and
conventional displacement systems regarding clinical performance and impression quality. The
Journal of prosthetic dentistry. 2014 May 1;111(5):388-94.
 Singh D, Gupta P, Bhatnagar A. Gingival displacements options in prosthodontics: a critical
review on recent advances. J Adv Res Dent Oral Health. 2016;1:13-21.
 Sampath P, Varma L, Varma M, Shabu A. Recent advances on gingival tissue management in
restorative dentistry. Indian Journal of Dental Sciences. 2019 Oct 1;11(4):185
 Kamath R, DL S, Baid GC. Advances in gingival retraction. International Journal of Clinical
Dental Science. 2011 Mar 5;2(1)..
 Bennani V, Schwass D, Chandler N. Gingival retraction techniques for implants versus teeth:
current status. The Journal of the American Dental Association. 2008 Oct 1;139(10):1354-63.