Tissue Management and Impression Making PDF

TISSUE MANAGEMENT AND IMPRESSION MAKING DR. ADHAM NIYAZI CHAPTER 14 PAGES 431-465 Outline What are impressions? Soft tissue and margins Displacement of gingival tissue Displacement cord Hemorrhage Control with an infuser syringe Displacement paste Electrosurg...

TISSUE MANAGEMENT AND IMPRESSION MAKING DR. ADHAM NIYAZI CHAPTER 14 PAGES 431-465 Outline What are impressions? Soft tissue and margins Displacement of gingival tissue Displacement cord Hemorrhage Control with an infuser syringe Displacement paste Electrosurgery LASER Impression Trays Impression materials Techniques of taking impressions Impressions A negative likeness of the teeth and surrounding structures that are necessary to obtain a xed restoration in the lab fi Impressions An acceptable impression Prepared / unprepared tooth surfaces Margins Surroundings Impressions Impressions should be free of: Air bubble voids Tearing Other imperfections Impressions The challenge Patient communication Moisture control Surrounding tissues Delicate spaces Outline What are impressions? Soft tissue and margins Displacement of gingival tissue Displacement cord Hemorrhage Control with an infuser syringe Displacement paste Electrosurgery LASER Impression Trays Impression materials Techniques of taking impressions Outline What are impressions? Soft tissue and margins Displacement of gingival tissue Displacement cord Hemorrhage Control with an infuser syringe Displacement paste Electrosurgery LASER Impression Trays Impression materials Techniques of taking impressions Impression Trays Requirements Rigid Dimensionally stable Provide even space for impression material Proper extension Retentive for impression material  Impression Trays The trays are in uenced by the type of material Types of trays Stock trays Special trays Water-cooled stock trays, used only with reversible hydrocolloid (Agar- Agar) fl Impression Trays Stock trays Metallic / plastic Time saving Use of material Requires sterilization Impression Trays Special trays Acrylic resin More accurate Use of material Impression Trays Thickness of 2-3 mm 2 mm separation that extends 3-5 mm apical to the gingival margin and 3 mm beyond the most distal tooth Requires tissue stops (usually on non- functioning cusps of unprepared teeth)  Special Trays Di erent materials Autopolymerizing acrylic resin (cold cure) Thermoplastic resin Photo-polymerized resin ff Outline What are impressions? Soft tissue and margins Displacement of gingival tissue Displacement cord Hemorrhage Control with an infuser syringe Displacement paste Electrosurgery LASER Impression Trays Impression materials Techniques of taking impressions Impression Material Easy to mix and handle Fluidity Reasonable working and setting time Non harmful Elasticity Adherence to the tray Stability Easy to pour Acceptable to the patient Multiple pouring  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Hydrocolloids Hydro = water Colloid = gelatin substance Advantages Hydrophilic (displaces moisture, blood, uids) Cheap Disadvantages Dimensionally unstable (synergistic and imbibition) Requires immediate pour fl  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Irreversible Hydrocolloid Alginate is the most widely used impression material Indicated for study models or opposing non prepped dentition  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Reversible Hydrocolloid Agar-Agar, excellent Sol dimensional stability 99oc 50oc Hydrophilic material 3 chamber conditioning Gel unit is used: 1. Liquefy at 100oC for 10 min 2. Store at 65oC 3. Temper at 50oC for 3 min  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Elastomers Rubber like material Classi ed by: Chemistry Condensation polymerization (by-products) Additional polymerization (no by-products) Viscosity Very high High (heavy) Medium (regular, monophase) Low (light) fi  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Polysul de First dental elastomeric impression material 2 pastes, base and catalyst 3 viscosities, heavy, medium, light Hydrophobic Condensation polymerization (byproduct = water) fi Polysul de Advantages Long working time High tear strength High exibility Good ow and detail reproduction fl fl fi  Polysul de Disadvantages Poor dimensional stability Water by-product Pour within 1 hour Single pour Requires special tray Messy Bad odor and taste Stains clothes Long setting time (8-10 min) A ected by temp. and humidity ff fi  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Polyether 2 pastes, base and catalyst with 3 viscosities No by-products Hydrophilic Can be mixed manually, automatically (gun mix or machine dispenser) Additional polymerization Polyether Advantages High accuracy High dimension stability Stock or special tray Good surface details Pour within 1 week (saved dry) Multiple pouring Good wettability Polyether Disadvantages Short working time Highly rigid (undercuts) Low tear strength Absorbs water  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Condensation Silicon Base and catalyst in 4 viscosities Hydrophobic Condensation polymerization (ethyl alcohol = by-product) Condensation Silicon Advantages Better elastic properties Stock or special trays Good working and setting time Condensation Silicon Disadvantages Poor dimensional stability High shrinkage (evaporation of ethanol) Must be poured within 30 min Hydrophobic (poor wettability) Low tear strength  Irreversible (Alginate) Aqueous Hydrocolloids Reversible (Agar) Elastic Impression Material Polysul de Elastromers Polyether Condensation Silicons Additional fi Addition Silicon Base and catalyst with 4 viscosities Addition polymerization No by-products Hydrophobic Addition Silicon Advantages Highly accurate High dimensional stability (pour within 1 week) Stock or special tray Multiple pouring Easy to mix Addition Silicon Disadvantages Surfer inhibit polymerization Latex gloves contain sulfur Short working time Lower tear strength Absorbs water Hydrophobic Comparisons Working time alginatea. silicon>polyether>c. silicon>hydrocolloid greatest ———> least ff fi fi Comparisons Cost alginatehydrocolloid best ———> worst fi fi Comparisons Wettability hydrocolloids>polyether>a. silicon>polysul de>c. silicon best ———> worst Wettability: the degree of spreading of a liquid drop on a solid surface fi No ma er how y feel Get up, s up, ow up and never give up tt dr es ou sh. ,