tissue management & impression techniques

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Tissue Management & Impression Techniques for Fixed Prosthodontics

Khaled Q Al HamadBDS MSc MRD RCSEd

Assistant Professor, Faculty of DentistryJordan University Of Science & Technology

8 April 09 Tissue Management and Impression Techniques for Fixed Prosthodontics

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Tissue management

Impression techniques


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Part I: tissue management

Tissue management Aims and principles Techniques

Mechanical Chemo mechanical Surgical Combination

Haemostatic agents New cordless techniques


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The impression should provide a precise and clear model of the prepared tooth and the surrounding tissues for the technician to fabricate an accurate dies and to produce a biologically, functionally and esthetically satisfactory fit restoration

The impression should provide a precise and clear model of the prepared tooth and the surrounding tissues for the technician to fabricate an accurate dies and to produce a biologically, functionally and esthetically satisfactory fit restoration

Donovan & Chee 2004 Donovan & Chee 2004


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Impressions not accurately recording Impressions not accurately recording the gingival finish lines the gingival finish lines

Impressions not accurately recording Impressions not accurately recording the gingival finish lines the gingival finish lines

Not reproducible finish line Not reproducible finish line

Inflamed gingival Inflamed gingival inflammation and/or inflammation and/or

recessionrecession

Inflamed gingival Inflamed gingival inflammation and/or inflammation and/or

recessionrecession

Inadequate restorationsInadequate restorationsInadequate restorationsInadequate restorations

Open marginsOpen marginsOpen marginsOpen margins OverhangsOverhangsOverhangsOverhangs

Loss of CALLoss of CALLoss of CALLoss of CALIncreased PDIncreased PDIncreased PDIncreased PD Bone resorptionBone resorptionBone resorptionBone resorption


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Tissue DisplacementTissue Displacement

Academy of Prosthodontics. Academy of Prosthodontics. Glossary of Prosthodontic Terms Glossary of Prosthodontic Terms

20052005

Academy of Prosthodontics. Academy of Prosthodontics. Glossary of Prosthodontic Terms Glossary of Prosthodontic Terms

20052005

““The deflection of the The deflection of the marginal gingiva away from marginal gingiva away from

the tooth” the tooth”

““The deflection of the The deflection of the marginal gingiva away from marginal gingiva away from

the tooth” the tooth”


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Tissue Displacement Tissue Displacement PurposesPurposes

Tissue Displacement Tissue Displacement PurposesPurposes

Create sufficient lateral and vertical Create sufficient lateral and vertical space between the gingival finish line space between the gingival finish line and the gingival tissueand the gingival tissue

Create sufficient lateral and vertical Create sufficient lateral and vertical space between the gingival finish line space between the gingival finish line and the gingival tissueand the gingival tissue

Nemetz et al 1984 Nemetz et al 1984 Nemetz et al 1984 Nemetz et al 1984

Provide absolute control of gingival Provide absolute control of gingival fluid seepage and hemorrhagefluid seepage and hemorrhageProvide absolute control of gingival Provide absolute control of gingival

fluid seepage and hemorrhagefluid seepage and hemorrhage


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Ideal Retraction Material CharacteristicsIdeal Retraction Material Characteristics

Should not cause significant and Should not cause significant and irreversible tissue damageirreversible tissue damage

Should not cause significant and Should not cause significant and irreversible tissue damageirreversible tissue damage

Effective for its intended useEffective for its intended use Effective for its intended useEffective for its intended use

Should not produce potentially Should not produce potentially harmful systemic effectsharmful systemic effects

Should not produce potentially Should not produce potentially harmful systemic effectsharmful systemic effects

Donovan et al Donovan et al 19851985

Donovan et al Donovan et al 19851985


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Tissue management Aims, purposes and principles Techniques




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Techniques Techniques

Mechanical Mechanical MethodsMethods

Retraction cordsRetraction cords

Mechanical Mechanical MethodsMethods

Retraction cordsRetraction cordsChemomechanical MethodsChemomechanical MethodsRetraction cord+ Haemostatic agents Retraction cord+ Haemostatic agents

Chemomechanical MethodsChemomechanical MethodsRetraction cord+ Haemostatic agents Retraction cord+ Haemostatic agents

Surgical Methods Surgical Methods Electro surgeryElectro surgeryRotary gingival curettageRotary gingival curettage

Surgical Methods Surgical Methods Electro surgeryElectro surgeryRotary gingival curettageRotary gingival curettage

Combination of theseCombination of theseCombination of theseCombination of these


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Retraction cordsRetraction cords

Traditionally been the most popular Traditionally been the most popular methodmethodTraditionally been the most popular Traditionally been the most popular methodmethod

98% of respondents 98% of respondents used gingival used gingival

retraction cords, with retraction cords, with 44% of them using a 44% of them using a

plain cordplain cord

98% of respondents 98% of respondents used gingival used gingival

retraction cords, with retraction cords, with 44% of them using a 44% of them using a

plain cordplain cord

Hansen et 1999Hansen et 1999Hansen et 1999Hansen et 1999

SafeSafeSafeSafe

EasyEasyEasyEasy

QuickQuickQuickQuick

Effective Effective

InexpensivInexpensivee

InexpensivInexpensivee

Poss 2007 Poss 2007 Ferencz 1991 Ferencz 1991

Poss 2007 Poss 2007 Ferencz 1991 Ferencz 1991


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““Gingival Gingival retraction retraction cord may cord may

damage the damage the periodontal periodontal

tissues”tissues”

““Gingival Gingival retraction retraction cord may cord may

damage the damage the periodontal periodontal

tissues”tissues”Liu et al 2004Liu et al 2004 Liu et al 2004Liu et al 2004

““Tissue Tissue damage may damage may occur, with occur, with friable thin friable thin

gingival tissue gingival tissue particularly particularly

susceptible and susceptible and subject to subject to tearing”tearing”

““Tissue Tissue damage may damage may occur, with occur, with friable thin friable thin

gingival tissue gingival tissue particularly particularly

susceptible and susceptible and subject to subject to tearing”tearing”Poss 2007Poss 2007Poss 2007Poss 2007


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Factors Affecting DamageFactors Affecting DamageFactors Affecting DamageFactors Affecting Damage

Ferencz 1991Ferencz 1991Ferencz 1991Ferencz 1991Goodacre 1990 Goodacre 1990 Goodacre 1990 Goodacre 1990

Force Force used in packing the cordused in packing the cordForce Force used in packing the cordused in packing the cord

SizeSize or or NumberNumber of retraction cords of retraction cordsSizeSize or or NumberNumber of retraction cords of retraction cords

Length of Length of timetime the cord is left in the cord is left in place within the sulcusplace within the sulcusLength of Length of timetime the cord is left in the cord is left in place within the sulcusplace within the sulcus

ChemicalChemical agent with which the agent with which the cord has been impregnatedcord has been impregnatedChemicalChemical agent with which the agent with which the cord has been impregnatedcord has been impregnated


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If the gingiva is healthy initially, healing If the gingiva is healthy initially, healing will occur will occur rapidlyrapidlyIf the gingiva is healthy initially, healing If the gingiva is healthy initially, healing will occur will occur rapidlyrapidly

Took about Took about 8 days8 days to heal, but with average to heal, but with average postoperative gingival recession of about 0.2 postoperative gingival recession of about 0.2 - 0.1 mm- 0.1 mm

Took about Took about 8 days8 days to heal, but with average to heal, but with average postoperative gingival recession of about 0.2 postoperative gingival recession of about 0.2 - 0.1 mm- 0.1 mm

Ruel et alRuel et al. . 19801980Ruel et alRuel et al. . 19801980

The damage healed clinically within The damage healed clinically within two two weeksweeks as was indicated by the GI as was indicated by the GIThe damage healed clinically within The damage healed clinically within two two weeksweeks as was indicated by the GI as was indicated by the GI

Feng et alFeng et al. . 20062006 Feng et alFeng et al. . 20062006

Yap & Ong Yap & Ong 19941994

Yap & Ong Yap & Ong 19941994

Healing occurred histologically in Healing occurred histologically in 7 to 10 days7 to 10 daysHealing occurred histologically in Healing occurred histologically in 7 to 10 days7 to 10 days

Goodacre 1990Goodacre 1990Goodacre 1990Goodacre 1990


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Haemostatic Agent

-epinephrine-potassium aluminum sulfate (ALUM)-aluminum chloride (Hemodent)-ferric sulfate-zinc chloride-tetrahydrozoline


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epi (0.1%-0.8%): -creates local vasoconstriction -a 1 inch of cord with 1.0mg of epi contains 2.5x the max dose for healthy patients and 12x the dose recommended for cardiac patients -contraindications for epi use in cord: hx of cardiovascular disease, hyperthyroidism, allergy to epi -signs of epi syndrome: tachycardia, increase in respirations, nervousness, increase in B.P., post op. depression---these symptoms will appear after the cord has been in place for a few minutes or shortly after it is removed. -ALUM (potassium aluminum sulfate): -only slightly less effective than epi at shrinking tissues -Hemodent (aluminum chloride):5-10%: -conc in excess of 10% will cause local tissue destruction -there are no major contraindications and minimal systemic effects -Ferric sulfate (13.3%): -astringent -very good for hemostasis -does not noticeably traumatize tissues and heal more rapidly than hemodent -temporarily discolors tissues for 1-2 days -provides tissue displacement for at least 30min -Zinc chloride (Bitartrate):8% & 40%: -tissue displacement equal to epi -* tissue necrosis is high -NOT RECOMMENDED FOR USE -Tetrahydrozoline (visine, afrin, murine plus, neosynephrine) -a sympathomimetic amine that produces vasoconstriction with minimal side effects


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Cordless TechniquesCordless TechniquesCordless TechniquesCordless Techniques

Expasyl®Expasyl®

Magic Foam Magic Foam Cord®Cord®


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ExpasylExpasylExpasylExpasyl

Viscous paste acts as a chemo-Viscous paste acts as a chemo-mechanical haemostatic and retraction mechanical haemostatic and retraction agentagent

ComponentComponentOrganic, clay material (kaolin)

Aluminum chloride (15%)

Additional ingredients include colorants, water, and essential oil of lemon

Viscous paste acts as a chemo-Viscous paste acts as a chemo-mechanical haemostatic and retraction mechanical haemostatic and retraction agentagent

ComponentComponentOrganic, clay material (kaolin)

Aluminum chloride (15%)

Additional ingredients include colorants, water, and essential oil of lemon

Soll 2001Soll 2001

((Kerr cooperation, Orange, Kerr cooperation, Orange, CACA) ) ((Kerr cooperation, Orange, Kerr cooperation, Orange, CACA) )

Easy and quick tissue displacementEasy and quick tissue displacementEasy and quick tissue displacementEasy and quick tissue displacement

Hemostatic agentHemostatic agent


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ExpasylExpasylExpasylExpasyl

Cartridge Form Cartridge Form

Stainless Steel Dispenser Stainless Steel Dispenser

Disposable TipsDisposable Tips

Cartridge Form Cartridge Form

Stainless Steel Dispenser Stainless Steel Dispenser

Disposable TipsDisposable Tips


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Technique PrincipleTechnique Principle

Lesage 2002Lesage 2002Lesage 2002Lesage 2002

The strength of the epithelial attachment The strength of the epithelial attachment is is 1 N/ mm21 N/ mm2

Injured by the application of a pressure of Injured by the application of a pressure of 2.5 N/ mm22.5 N/ mm2

Pressure of Pressure of 0.1 N/mm20.1 N/mm2 enable sulcus enable sulcus opening of opening of 1.5 mm1.5 mm & a delayed recovery up & a delayed recovery up to to 2 minutes per 0.5 mm2 minutes per 0.5 mm opening opening

The strength of the epithelial attachment The strength of the epithelial attachment is is 1 N/ mm21 N/ mm2

Injured by the application of a pressure of Injured by the application of a pressure of 2.5 N/ mm22.5 N/ mm2

Pressure of Pressure of 0.1 N/mm20.1 N/mm2 enable sulcus enable sulcus opening of opening of 1.5 mm1.5 mm & a delayed recovery up & a delayed recovery up to to 2 minutes per 0.5 mm2 minutes per 0.5 mm opening opening

Sufficient to obtain Sufficient to obtain sulcus openingsulcus openingSufficient to obtain Sufficient to obtain sulcus openingsulcus openingToo low to damageToo low to damageToo low to damageToo low to damage


23Donovan & Chee 2004Donovan & Chee 2004Donovan & Chee 2004Donovan & Chee 2004

EfficacyEfficacyEfficacyEfficacyhas yet to be establishedhas yet to be establishedhas yet to be establishedhas yet to be established


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Magic Foam CordMagic Foam CordMagic Foam CordMagic Foam CordColtène/Whaledent Coltène/Whaledent Coltène/Whaledent Coltène/Whaledent

The first expanding PVS The first expanding PVS material designed for easy material designed for easy and fast retraction of the and fast retraction of the

sulcussulcus

The first expanding PVS The first expanding PVS material designed for easy material designed for easy and fast retraction of the and fast retraction of the

sulcussulcus


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Cartridge similar to the regular Cartridge similar to the regular impression materialsimpression materials

Disposable tipsDisposable tips

Cotton cap (Comprecap)Cotton cap (Comprecap)

Used with the same gun of the Used with the same gun of the regular addition silicone impression regular addition silicone impression materialmaterial

Cartridge similar to the regular Cartridge similar to the regular impression materialsimpression materials

Disposable tipsDisposable tips

Cotton cap (Comprecap)Cotton cap (Comprecap)

Used with the same gun of the Used with the same gun of the regular addition silicone impression regular addition silicone impression materialmaterial

Magic Foam CordMagic Foam CordMagic Foam CordMagic Foam CordColtène/Whaledent Coltène/Whaledent Coltène/Whaledent Coltène/Whaledent


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Silicone foam expands in the Silicone foam expands in the sulcus and its mass becomes sulcus and its mass becomes

larger precisely to achieve the larger precisely to achieve the retraction we requireretraction we require

Silicone foam expands in the Silicone foam expands in the sulcus and its mass becomes sulcus and its mass becomes

larger precisely to achieve the larger precisely to achieve the retraction we requireretraction we require

Principle of Principle of WorkWork

Principle of Principle of WorkWork


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Effect on gingival health Effect on gingival health

Efficiency in gingival Efficiency in gingival retractionretraction

Effect on gingival health Effect on gingival health

Efficiency in gingival Efficiency in gingival retractionretraction


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A clinical study on the effects of cordless and conventional retraction techniques on the gingival and periodontal health.

Al Hamad et al., J Clin Periodontol 2008; 35: 1053–1058.

Principal findings: all retraction techniques caused a temporary inflammation, measured through the gingival index.The recovery at 7 days was slower for Expasyl. Bleeding during or after retraction was only encountered with the use of conventional retraction cords.

Practical implications: This study showed that none of the techniques tested seems to harm the tissues in the long term; however, clinicians should be aware that Expasyl use is less friendly to the gingival tissues. Cordless techniques do not require haemostatic agents to control bleeding


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Lecture Outline

Tissue management

Impression techniques


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Part II: Impression Techniques

Classifications Available materials

Polysulphide Polyether Silicones

Condensation-type Addition-type

Comparisons

Packaging & Techniques Disinfection


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Classification: Elasticity


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Viscosity


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Comparisons



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Polysulphide Base:

Short chain Thiokol polymer. Used extensively in building industry where it is supplied as

a one pack and setting takes place under atmospheric oxygen (weeks).

In dentistry, setting is brought about by oxidizing agent (lead dioxide)

Molecule of water is produced for every link that is made. (condensation)

Objectionable odor Long setting time High shrinkage High tear resistance High permanent deformation


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Comparisons

Packaging & Techniques Disnfection


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Polyether Base

Polyether polymer with imine group Plasticizer & Inert filler

Activator Aromatic Sulphonate Plasticizer & Inert filler

Short working time Less permanent deformation than polysulfide but not as

low as silicones. Stiff The least dimensional change except the addition type

silicone. Absorb water.


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Comparisons



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Silicone Rubber

Condensation Type Base:

Hydroxyl terminated Dimethyl siloxane (reactive OH). Catalyst:

Alkyl silicate. Different viscosities produced by different MW of Dimethyl

siloxane and the concentration of the filler. Condensation reaction producing alcohol. Resulting in

dimensional change occuring mainly during the first 24 h. Addition Type

Prepolymer of polydimethyl siloxane in which some of the methyl groups are replaced by vinyl groups in one paste and with hydrogen in the other paste.

Catalyst: Platinum containing compound (chloroplatinic acid). Addition reaction producing no by products. Increase in Temperature and Moisture increases the reaction. Early when they first introduced(1950’s) gaseous hydrogen

was produced as a result of the cross linking reaction. Mechanism is unclear !(side reaction of the hydroxil group ? Or a reaction of the catalyst with moisture??)


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Comparisons



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Comparison of elastomers

Setting time - Polysulfides > Silicones > Polyethers

Tear strength - Polysulfides > Silicones > Polyethers

Stiffness - Polyethers > Silicones > Polysulfides

Dimensional Change - Cond Silicone > Polysulfides > Polyethers > Addition Silicone


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Comparisons



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Materials

Polyvinylsiloxane impression material


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Trays

Stainless steel perforated trays(metal)Polytrays (Polycarbonate/Yellow)Orthodontic impression trays(red)


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Comparisons



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Disinfection DISINFECTANTS FOR IMPRESSION

MATERIALS: Glutaraldehyde: - Indicated for all impression materials

except hydrocolloids Phenols: - Indicated for polysulfide rubber base

only Iodophors and NaOCl: - Indicated for all impression materials


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Clinical Case

tissue management & impression techniques

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