L19-YI-Impressions Lecture-Advanced Prosth 2023.txt

Anna Yi, BDSc, MSD, DMSc, FACP Impression Concepts, Principles & Procedures Removable Complete & Partial Dentures Advanced Prosthodontics 2023 Anna Yi, BDSc, MSD, DMSc, FACP Clinical Assistant Professor Department of Prosthodontics Rm 631-S [email protected] Adapted from Dr. A. Soni’s lecture...

Anna Yi, BDSc, MSD, DMSc, FACP Impression Concepts, Principles & Procedures Removable Complete & Partial Dentures Advanced Prosthodontics 2023 Anna Yi, BDSc, MSD, DMSc, FACP Clinical Assistant Professor Department of Prosthodontics Rm 631-S [email protected] Adapted from Dr. A. Soni’s lecture Anna Yi, BDSc, MSD, DMSc, FACP Any questions ➡ please email me and I will collate and organize the answers to be shared during our panel discussion Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Impressions “impression -prĕsh΄an: a negative likeness or copy in reverse of the surface of an object; an imprint of the teeth and adjacent structures for use in dentistry” Glossary of Prosthodontic Terms, Ninth Edition, J Prosthet Dent 2017;117(5S) Anna Yi, BDSc, MSD, DMSc, FACP Impression Taking for Complete Dentures • Anatomy • Techniques & Materials • Preliminary impressions • Final impressions Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Maxilla Anna Yi, BDSc, MSD, DMSc, FACP Anna Yi, BDSc, MSD, DMSc, FACP Anna Yi, BDSc, MSD, DMSc, FACP Maxillary Anatomy and how it relates to Denture Standring, Susan. Gray’s Anatomy, 40th Edition. Elsevier Health Sciences, 2012-09-26. VitalBook file Anna Yi, BDSc, MSD, DMSc, FACP Maxillary Anatomy and how it relates to Denture Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Maxilla • Check visually the maxillary anatomy • Palpate to check sharp bony spicules • Enlarged Tuberosity Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Maxilla • Primary stress bearing area • Firm Tuberosities • Hard Palate • Secondary stress bearing area • Alveolar Ridge • Rugae Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Maxilla • Primary stress bearing area • Firm Tuberosities • Hard Palate • Secondary stress bearing area • Alveolar Ridge • Rugae Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible Anna Yi, BDSc, MSD, DMSc, FACP Mandibular Anatomy and how it relates to Denture Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible • Epulis fissuratum • Overgrowth of intraoral tissue resulting from chronic irritation Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible • Primary stress bearing area • Buccal Shelf • Secondary stress bearing area • Alveolar Ridge Anna Yi, BDSc, MSD, DMSc, FACP Anatomy: Mandible • Primary stress bearing area • Buccal Shelf • Secondary stress bearing area • Alveolar Ridge Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impressions for Complete and Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impressions A negative likeness made for the purpose of diagnosis, treatment planning, and/or the fabrication of a custom impression tray Glossary of Prosthodontic Terms, Ninth Edition, J Prosthet Dent 2017;117(5S) Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Trays • Selection of tray • Modifications • Optimum extension • Optimum adaptation • Borders in resilient tissues • Add or shorten trays for proper extension • Modify handle • Relieve areas for labial, buccal and lingual frenum Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Tray Selection and Modification for Complete and Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Trays Selection and Modifications Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Trays Selection and Modifications Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Trays Selection and Modifications Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Impression Materials Anna Yi, BDSc, MSD, DMSc, FACP Impression Materials Elastic impression material Can spring out from undercuts without deformation • Irreversible hydrocolloids ➡ Powder/Liquid components Pour within 30 minutes; 2nd pour not advocated • Alginate-alternative impression cartridge Stability ➡ pour when you want ➡ repour within 14 days • Polysulfide Mercaptan rubber-base Hydrophilic; pour within 1 hour; repour not advised • Polyether rubber impression Hydrophilic; pour within 1 week; repour possible • Silicone /PVS – Addition silicone: NO Latex gloves (Sulfur) Hydrophobic/Hydrophyllic (Addition of Surfactants - hydrophilized addition silicone) Pour within 1 Week; repour possible Anna Yi, BDSc, MSD, DMSc, FACP Impression Materials Rigid impression material • Impression plaster • Zinc Oxide Impression material Does not spring out from undercuts Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impressions Alginate irreversible hydrocolloid Pointers • Syneresis ➡ Evaporation of water from surface causing shrinkage • Pour as soon as possible or keep it moist • Imbibition ➡ If exposed to water for long will absorb water, swell and distort • Hydrophilic ➡ Can be used in presence of moisture • Impression should be removed with a quick motion • Removing slowly may distort and tear the impression • Impression must be disinfected Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impressions Infection Control • Wash all materials used intraorally under running water to remove visible blood and saliva • Pat dry • Spray thoroughly with Cavicide • Alginate/Alginate Alternative impression ➡ Place immediately in plastic head rest cover for 10 minutes • NOTE: PVS Impression material ➡ place in plastic head rest cover for 3 minutes • Rinse off excess surface disinfectant • Pat dry • Pour impression Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Completed Preliminary Impressions for Complete and Partial Dentures Dentures Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Selection of Impression material • Alginate is the impression material of choice for making primary or preliminary impressions for both Complete and Partial Dentures • Comes in power form in containers or pre-packaged • Follow manufacture instructions for powder:water ratio • Thin mix will be very runny and difficult to control and will tear readily • Thick mix will not record details • Setting time can be altered by temperature of water; warmer water increases the setting rate, and cooler water slows the setting reaction Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impressions Anna Yi, BDSc, MSD, DMSc, FACP Preliminary Impression Pour Impression and fabrication of Preliminary Cast This procedure applies for both Partial and Complete Dentures Students pour the preliminary impressions Mix plaster with correct water powder ratio and vibrate the mass to avoid bubbles Add small increments of mixed plaster from one end of the impression Vibrate to settle the plaster in the impression Continue until the impression is completely filled and allow the plaster to set Anna Yi, BDSc, MSD, DMSc, FACP Final Impressions for Complete and Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Final Impressions The impression that represents the completion of the registration of the surface or object Glossary of Prosthodontic Terms, Ninth Edition, J Prosthet Dent 2017;117(5S) Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Complete Dentures Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Complete Dentures Please listen carefully to this slide Triad material used to fabricate the trays Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Partial Dentures Place two sheets of baseplate wax on the teeth One sheet of baseplate wax on the tissue for spacing Occlusal stops should be incorporated by cutting 2mm squares through the wax Minimum of three stops should be provided One in the anterior and two on the posterior In maxilla posterior stops on either side of ridge and anterior on non abutment tooth In mandible posterior stop on buccal shelf and anterior on non abutment tooth Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Fabrication of custom trays Complete and Partial Dentures We have the custom trays ready for making the final impressions So what’s the next step? Anna Yi, BDSc, MSD, DMSc, FACP Final Impression: Border Molding for Complete and Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Final Impression: Border Molding for Complete and Partial Dentures Dentures Please listen carefully to this slide • Impression compounds are thermoplastic materials and are softened to their working consistency by immersion in hot water or by warming over a flame • When heated over a flame they rapidly soften • Do not overheat to prevent components from evaporating • Soften at 140°F (60°C) • Working Temperature Green Sticks 122-124°F (50-51°C) • Temper in water bath 113°F (45°C) before inserting in patients mouth to prevent tissue burns Anna Yi, BDSc, MSD, DMSc, FACP Final Impression: Border Molding for Complete and Partial Dentures Dentures • Check trays in mouth for fit and border clearance • Maxillary tray should be 4 mm beyond the vibrating line • Add compound to tray in sections for border molding (refer to image) • Must be adequately softened/tempered 1 4 • Preshaped to proper contour with fingers 2 • Must be tempered in a water bath 3 • Chilled after removal from mouth 4 6 • Rounded contours 5 • Make a hole in the center of the palate area • Don’t forget Posterior Palatal Seal 1 5 2 3 7 8 Anna Yi, BDSc, MSD, DMSc, FACP Checking tray for fit clearance and border molding Anna Yi, BDSc, MSD, DMSc, FACP Jaw and Border movements for Border Molding Anna Yi, BDSc, MSD, DMSc, FACP Jaw and Border movements for Border Molding Maxillary Arch • Labial Frenum: Move lip down to clear the labial frenum • Buccal Frenum: Pull cheek down and move back and forth to activate the buccinator and orbicularis oris muscles • Coronoid Process: Move mandible side to side to determines the thickness of the disto buccal flange of maxillary denture Anna Yi, BDSc, MSD, DMSc, FACP Jaw and Border movements for Border Molding Mandibular Arch Please listen carefully to this slide • Labial Frenum: Move lip up to clear the labial frenum • Buccal Frenum: Pull cheek and move back and forth to activate the buccinator and orbicularis oris muscles • Anterior Lingual: Protrude tongue forward to capture length of lingual flange • Anterior Lingual 1/3: Move tip of tongue side to side to corners of the mouth • Lingual Middle 1/3: Move tip of tongue side to side to middle of cheek • Posterior 1/3: Push the handle of the tray forward with tip of tongue Anna Yi, BDSc, MSD, DMSc, FACP Completed Impressions for Complete Dentures Anna Yi, BDSc, MSD, DMSc, FACP Final Impressions- Complete Dentures Please listen carefully to this slide Anna Yi, BDSc, MSD, DMSc, FACP Impressions for Special Conditions Anna Yi, BDSc, MSD, DMSc, FACP Flabby Ridges Flabby ridges due to excessive bone loss Anna Yi, BDSc, MSD, DMSc, FACP Flabby Ridges Anna Yi, BDSc, MSD, DMSc, FACP Final Impressions for Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Anatomic Impression Tooth borne partial dentures SINGLE STAGE IMPRESSION • Anatomic impression records tissue shape without distortion • Tooth borne RPD can be fabricated on as master cast made from a single impression that records the teeth and soft tissues in their anatomic form Anna Yi, BDSc, MSD, DMSc, FACP Functionally Loaded Impression Tooth-tissue borne partial dentures SINGLE STAGE IMPRESSION • The Functionally Loaded impression technique is indicated for mandibular distal extension applications because only a limited ridge area can be used as a stress bearing site Anna Yi, BDSc, MSD, DMSc, FACP Functionally Loaded Impression • Modeling compound sticks used for loading the basal seat • Load the tissue areas for capturing basal seat • Add compound to tray in sections for border molding • Must be adequately softened/tempered • Preshaped to proper contour with fingers • Must be tempered in a water bath • Chilled after removal from mouth • Rounded contours Anna Yi, BDSc, MSD, DMSc, FACP Functionally Loaded Impression • Remove excess modeling compound from tray • Relieve soft tissue undercuts • Apply adhesive • Make the impression • Mandible: keep tongue protruded while impression material is setting Anna Yi, BDSc, MSD, DMSc, FACP Completed Impressions for Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Final Impressions - Partial Dentures Anna Yi, BDSc, MSD, DMSc, FACP Altered Cast Impression altered cast removable partial denture impression ΄terd kast pär΄shal dĕn΄cher ĭm-prĕsh΄an: a negative likeness of a portion or portions of the edentulous denture bearing area made independent of and after the initial impression of the natural teeth; this technique uses an impression tray(s) attached to the framework of the removable partial denture, or its likeness Glossary of Prosthodontic Terms, Ninth Edition, J Prosthet Dent 2017;117(5S) Anna Yi, BDSc, MSD, DMSc, FACP Altered Cast Impression • Applegate fluid wax impression technique is used in mandibular distal extension ridges • Altered cast technique is indicated for mandibular distal extensions ridges • The RPD framework should be made before the cast is altered • The framework should be tried and fitted in the patient’s mouth • Adapt the impression tray on the RPD framework for making a dual impression • Wax is melted in a container in a water bath (125-130°F) • Wax is painted on the framework tray and is then inserted in the mouth • The framework should be held in place by applying finger pressure on the rests • No pressure should be exerted on the impression bases • The impression is left in the mouth to flow under pressure to record the denture bearing area Anna Yi, BDSc, MSD, DMSc, FACP Altered Cast Impression Disadvantages • Time consuming • Wax can be easily distorted if not handled carefully • Use Reprosil PVS material to overcome the disadvantages of the original wax technique Anna Yi, BDSc, MSD, DMSc, FACP Lecture Objectives Given the impression concepts, principles and procedures guidelines for different clinical situations in Complete and Partial Dentures , the students should be able to describe accurately: • The important anatomical landmarks that need to be captured with the impression • The selection of appropriate materials for making an impression of the edentulous and partially edentulous mouth • The clinical principles of impression making • A method for impression making that produces an accurate result • Retain the satisfactory and discard the inadequate result of impression making • The relationship of the secondary impression to expectation of retention Anna Yi, BDSc, MSD, DMSc, FACP Good Job & Thank You :)