Gingival retraction techniques for implants versus teeth/ cosmetic dentistry training

INDIAN DENTAL ACADEMY
Leader in continuing dental education
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1.Screw retained implant restorations
2. Cement retained implant restorations

Restoration of choice
Cement retained implants
esthetics
Occlusal
stability
Overcoming
angulation
problems
Passively
fitting
restoration

 Several impression techniques are used in
implant dentistry, some requires gingival
displacement while making impressions.
 Others like pick up impression technique do
not require any gingival retraction

 Screw retained implant restorations:
 Most systems use mechanical
components(impression copings)that can be
adapted accurately and directly to fixture
head on the abutment shoulder
 In cement retained prostheses that used
customized abutment this technique cannot
be used owing to unique contour of
abutments

 Hence clinicians must use another technique
such as conventional crown and bridge
impression or optical impression.

 To ensure accuracy with polyvinyl siloxane
impression materials, minimum bulk of 0.2
mm thickness has to be maintained in sulcus
area, that can be achieved by retracting the
gingiva for more than 4 min before making
the impression

 Larger sulcus spaces than necessary for
conventional crown and bridge impression
techniques are neededwhen making digital
CAD/CAM impressions to ensure accurate
recording of finishing lines

 Direct optical impressions are limited to line
of sight, which is facilitated by performing
gingival retraction to expose finish lines.
 Artifacts caused by retraction cord fibres that
remain in sulcus may affect the accuracy of
optical impressions

 Donovan and Chee described a variety of
gingival displacement techniques, but no
articles were found that specifically reviewed
gingival retraction techniques in implant
dentistry.
 Since the architecture of gingival crevice
surrounding natural teeth is different
biologically from that around implants,
authors wanted to know if conventional
retraction techniques could be applied safely
to peri-implant tissue.

 In this article, the advantages and
disadvantages of different gingival retraction
techniques on peri-implant and peridental
tissues are reviewed.

 A literature search for articles about gingival
retraction techniques used when making
impressions of implant restorations.
 It was noted that there was no literature on
this subject, so search was widened to
include soft tissue retraction techniques
applicable to natural teeth.

Peridental tissue Peri-implant tissue
Free gingival margin with buccal
keratinized epithelium
Free gingival margin with buccal
keratinized epithelium
Gingival sulcus apically limited by
junctional epithelium
Gingival sulcus apically limited by
Keratinized epithelium at the base
of gingival sulcus
No keratinized epithelium at base
of gingival sulcus
Junctional epithelium adherent,
less permeable, high regenerative
capacity
Junctional epithelium poorly
adherent, more permeable, low
regenerative capacity
Cementum No cementum
Gingival fibers inserting
perpendicularly in the cementum
Gingival fibers running parallel to
implant collar
Biological width of at least 2.04
mm
Biological width of 2.5mm [+/-]
0.5 mm
Periodontal ligament No periodontal ligament
No direct contact between tooth
and bone
Direct contact of implant to bone

 Rougher implant surface – encourages
attachment of fibrils to implant surface,
affecting orientation of fibers adjacent to
implants at varying angles
 Length of junctional epithelium:
a) Machined implant surface – 2.9 mm
b) Acid etched conditioned surface – 1.4 mm
c) Oxidised surface – 1.6 mm

 When junctional epithelium that surrounds
implant is exposed to trauma (eg : gingival
retraction procedures), it is at greater risk of
experiencing penetration damage than is the
more robust sulcus of natural teeth.
 Another considertaion – natural soft tissue
biotype

 The aim of gingival retraction:
To atraumatically allow access for the
impression material beyond the abutment
margins and to create space so that the
impression material is sufficiently thick so as
to be tear resistant.

 Deformation of gingival tissues during
retraction and impression procedures
involves four forces:
1. Retraction
2. Relapse
3. Displacement
4. Collapse

 Retraction :
• Downward and outward movement of free
gingival margin.
• Caused by retraction material and technique
used
 Relapse :
• Tendecy of the gingival cuff to go back into
its original position
• Elasticity or memory of gingival cuff
• Rebound forces of attached gingiva that
was comprssed during retraction

 Plain mechanical retraction cords – sulci
remain open for less than 1 min after removal
of cord.
 Medicated retraction cords – sulci remain
open longer.
 0.2 mm of sulcular width is necessary - for
sufficient thickness of material at the margins
so they can withstand tearing/distortion on
removal of impression

 Another study showed that in order to
achieve 0.2 mm crevicular width – retraction
cord needed to be in place for 4min before
making impressions.

 Displacement:
• Downward movement of gingival cuff
• Caused by heavy consistency impression
material bearing down on unsupported
retracted gingival tissues.
 Collapse:
• Tendency of the gingival cuff to flatten under
the forces associated with the use of closely
adapted customized impression trays

 Peri-implant fiber structure does not provide
the same level of support for gingival tissues
when the retraction agents are removed .
 Thus, more collapsing forces occur on
retracted tissues of implants as compared to
peridental retracted tissues.
 Particularly true in situations in which depth
of sulcus is greater than average, such as
when implant is placed deeply.

 Purpose designed packing devices should be
used
 Smooth, non serrated circular heads – twisted
cords placed with sliding motion
 Serrated circular heads - braided cords
 Fibers of conventional cords may cause
residual contamination of sulcal wounds
 Healing of sulcus can take 7 – 10 days
 Wetting the cord before removal will help
contain bleeding.

Retraction methods Advantages Disadvantages Use in
implant
dentistry
Mechanical
Cord (twisted,
knitted or
braided)
•Single cord
technique
•Dual cord
technique
•Inexpensive
•Achieve
varying
degrees of
retraction
•Can be used
with chemical
adjuncts
•Painful
•Rapid
collapse of
sulcus after
removal
•Trauma to
epithelial
attachment
•Time
consuming
•Sulcus
contamination
Yes/
No
(metho
d could
be
used
but not
recom
mende
d)

Chemico-
mechancal
Chemicals with cord
Epinephrine •Hemostatic
•Vasoconstrictive
•Systemic effects
“epinephrine
syndrome”
•Rebound
hyperemia
•Risk of tissue
necrosis
No
Synthetic
sympathomimetic
agents
•Hemostatic &
vasoconstrictive
•More effective with
absence of
systemic effects
•Rebound
hyperemia
•Inflammation of
gingival cuff
No
Aluminum sulfate and
aluminum potassium
sulfate
•Hemostasis
•Lest inflammation
of all agents used
with cords
•Little sulcus
collapse after cord
removal
•Offensive taste
•Risk of sulcus
contamination
•Risk of necrosis if
high concentration
Yes / No

Aluminum
chloride
•No systemic
effects
•Lest irritating of
all chemicals
•Hemostasis
•Little sulcus
collapse
•Less vasonstriction
than epinephrine
•Modifies surface detail
reproduction
•Inhibits set of polyvinyl
siloxane and polyether
impression materials
Yes / No
Ferric
sulfate
Hemostasis •Tissue discolouration
•Acidic taste
•Inhibits set of polyvinyl
siloxane and polyether
impression materials
Yes / No

 Absorption of chemical agents at the sulcus
interface depends on patients gingival health.
 Healthy gingiva acts as a barrier.
 Epinephrine syndrome – tachycardia, rapid
respiration, increased blood pressure, anxiety
and postoperative depression.

 Aluminum sulfate and aluminum potassium
sulfate acts by:
1) Precipitating tissue proteins with tissue
contraction,
2) Inhibiting transcapillary movement of
plasma proteins and
3) Arresting capillary bleeding.
 Aluminum chloride :
• Astringent – precipitation of tissue proteins
• Less vasoonstriction than epinephrine

 80 % of orignal sulcus space remains open
after12 min of packing with cord
impregnated with aluminum chloride
 50% of space remains when sulcus is packed
with cord impregnated with epinephrine over
a similar time.
 Ferric sulfate:
• Stains the tissue a yellow brown to black
colour for several days after its use

Chemicals in
injectable
matrix
Aluminum
chloride with
kaolin
•Reduced risk of
inflammation(injecta
ble form)
•Non traumatizing to
•Hydrophilic
•Ease of placement
•Painless
•No adverse effects
•More expensive
•Less effective with
very subgingival
margins
•Inhibits set of
polyvinyl siloxane
and polyether
impression
materials
YES
Inert
matrix
Polyvinyl
siloxane
•No risk of
inflammation or
irritation
•Ease of placement
•Painless
•Nontraumatizing
•Limited capacity for
hemostasis(no
avtive chemistry)
•Less effective with
subgingival margins
YES

 Chemicals in an injectable matrix:
• 15% aluminum chloride in kaolin matrix
• Hydrophillic – can be washed away easily
from gingival crevice.
 An inert matrix:
• Polyvinyl siloxane material
• Works by generating hydrogen, causing
expansion of material against the sulcus walls
during setting.

Surgical
Laser •Excellent
hemostasis - CO₂
laser is safe for
implants as
reflected by metal
•Relatively painless
•Sterilizes sulcus
•Nd-:YAG laser –
Contraindicated for
implants
•Er : YAG laser – refected
by metal but not as good
as CO₂ laser for
hemostasis
•No tactile feedback
Yes
/No
Electrosurgery •Efficient precise
hemostasis
Contraindicated with
implants(risk of arcing)
No
Rotary
curettage
•Fast
•Ablity to reduce
excess tissue
•Ability to
recontour gingival
outline
•Considerable hemorrhage
•Contraindicated with
implants
•High risk of bur
damaging the implant
surface
•Risk of tissue retraction
exposing implant threads
•High risk of traumatizing
epithelial attachment
No

 Nd : YAG laser -1064 nm wavelength
• Good for retraction around natural teeth(less
aggressive)
• Contraindicated near implant surfaces
• Heating up of implant surface and
transmission of heat to bone.
 Er : YAG laser – 2940 nm wavelength
 CO₂ laser – 10, 600 nm wavelength
• Prime chromophore is water.

 Surgical wounds created by lasers heal by
secondary intention, and incision lines show
disorganized fibroblast alignment.
 This reduces tissue shrinkage through
scarring, which helps preserve gingival
margin heights.
 Lasers create a trough around implant
margins rather than dispacing soft tissue.
 Hence , a large defect would result around a
deeply placed implant.

 Use of retraction cords around implant
restorations can lead to ulcerations of
junctional epithelium due to forces used in
cord placement.
 Delayed healing of sulcal epithelium
 Risk of permanent recession and loss of
attachment

 Thus mechanical retraction with cords is
contraindicated except in few situations:
a) Shallow sulcus depths ,
b) Mucosal health impeccable and robust ,
c) Thick periodontal biotype is present.

 Addition of chemical agents to retraction
cords may lead to increased inflammation of
subsulcular tissues.
 Lacerated sulcus provides reduced protection
against the penetration of chemicals into
deeper subepithelial cell layers and systemic
dissemination when the vascular bed is
exposed.
 Little is known about the effects of chemicals
when they are placed into peri-implant
tissues.

 Surgical retraction procedures are destructive
and involve excision of tissues.
 Peri-implant mucosa does not have same
regenerative capacity as peridental mucosa.

 Using an injectable matrix for gingival
retraction offers clinicians the opportunity to
perform an atraumatic procedure.
 No risk of lacerations and damage to
 Thus ,risk of inflammation caused by
chemicals delivered in matrix is reduced
significantly.

At the start of injection, the canula
tip
must be braced on the surface of
the tooth and the diametrically
opposite zone positioned in
immediate proximity to the gingival
edge.
As the injection proceeds,
the gingival edge will lift from the
tooth under the pressure effect of
the product with the axis of the
canula being modified as you inject.
The paste must be injected
in a walled space that may be the:
• surface of the tooth;
• intra-sulcus wall of the marginal
gingiva; or
• cross-section of the canula tip.
http://www.gunz.com.au/articles/160-166.pdf

Angle of cannula tip is
increased

Two handed techniqu

 The literature concerning gingival retraction
for impressions in fixed prosthodontics is
extensive.
 By contrast, little has been published about
the challenges presented by the unique
anatomy surrounding implants.
 As implants become mainstream treatments
for tooth loss this topic will warrant further
research.

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Gingival retraction techniques for implants versus teeth/ cosmetic dentistry training

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