Prosthodontics Lecture Reviewer PDF | S.Y. 2025-2026

Prosthodontics 1: Lecture 2nd SEMESTER I S.Y. 2025-2026 MODULE 9 Pontic Fixed Partial Denture ⇒​ an artificial tooth on a fixed partial denture that replaces...

Prosthodontics 1: Lecture 2nd SEMESTER I S.Y. 2025-2026 MODULE 9 Pontic Fixed Partial Denture ⇒​ an artificial tooth on a fixed partial denture that replaces a missing natural tooth, restores its function, and usually restores the space previously occupied by the clinical crown Retainer ⇒​ any type of device used for the stabilization or retention of a prosthesis Connector ⇒​ in fixed prosthodontics, the portion of a fixed partial denture that unites the retainers and pontic(s) Ridge Defects ⇒​ Restorations encompassing the cusps of endodontically ⇒​ 3 components of fpd: retainer, pontic, connector Siebert's Classification: ⇒​ Class I defects: faciolingual loss of tissue width with Introduction to Fixed Prosthodontics normal ridge height ⇒​ Fixed prosthodontics treatment can range from the ⇒​ Class Il defects: loss of ridge height with normal ridge restoration of a single tooth to the rehabilitation of the width entire occlusion. ⇒​ Class III defects: a combination of loss in both ⇒​ Missing teeth can be replaced with fixed prostheses that dimensions will improve patient comfort and masticatory ability, maintain the health and integrity of the dental arches, and, in many instances, elevate the patient's self-image. ⇒​ A FIXED PARTIAL DENTURE (FPD) is a Partial denture that is luted to natural teeth or tooth roots and/or affixed to dental implants that furnish the primary support for theprosthesis. Pontic CLASSIFICATION OF PONTICS I) According to Rosenstiel (Based on mucosal contact): Mucosal Contact ⇒​ Ridge-lap Parts of FPD ⇒​ Modified ridge-lap ⇒​ Ovate| ⇒​ Conical I No Mucosal Contact ⇒​ Sanitary (hygienic) ⇒​ Modified sanitary (hygienic) Il) Based on type of material used: ⇒​ Metal and porcelain- veneered pontic ⇒​ Metal and resin veneered pontic ⇒​ All metal pontic ⇒​ All ceramic pontic III) Based on method of fabrication: ⇒​ Custom made pontic ⇒​ Prefabricated pontic Ovate Pontic - Trupontic - Interchangeable facing - Pin-facing pontic - Modified pin-facing pontic - Reverse pin- facing pontic ⇒​ Prefabricated custom modified pontic Pontic Modified Ovate Pontic ⇒​ Overlaps the residual ridge buccolingually, simulating the contours and emergence profile of the missing tooth on both sides of the residual ridge. ⇒​ Avoided because the concave gingival surface of the ⇒​ Liu described a modified version of the ovate pontic that pontic is not accessible to cleaning with dental floss, expands the clinical indications for the ovate pontic. which leads to plaque accumulation ⇒​ The modified ovate pontic possesses an ovate form with ⇒​ This design deficiency has been shown to result in tissue the apex positioned more facially on the residual ridge, inflammation rather than at the crest of the ridge. ⇒​ This alteration allows the use of the pontic in clinical Modified Ridge Lap Pontic scenarios where horizontal ridge width is insufficient for a conventional ovate pontic. ⇒​ Cleansing of this pontic is also reported to be the easiest of all pontic types. Conical Pontic tip to tip Sanitary Pontic  Modified Sanitary Pontic ⇒​ Its gingival portion is shaped like an archway between the retainers. ⇒​ This geometry allows for increased connector size and a decrease in the stress concentrated in the pontic and connectors. ⇒​ It is also less susceptible to tissue proliferation that can occur when a pontic is too close to the residual ridge Retainers CLASSIFICATION OF RETAINERS IN FPD I) According to degree of tooth coverage Rigid Connectors - Casted ​ Full veneer crowns ⇒​ Connectors to be cast are also waxed on the definitive ​ Partial veneer crowns cast before reflowing and investing of the pattern. ​ Conservative (minimal preparation) retainers ⇒​ The presence of a cast connector makes the process of investing somewhat more awkward: Access to the proximal margin is impeded, and the pattern cannot be held proximally during removal from the die. maryland pontic - makapit II) According to material of fabrication ​ All metal retaieners ​ Metal ceramic retainers ​ All ceramic retainers ​ All acrylic retainers Factors Affecting Choice of Retainers in FPD Rigid Connectors - Soldered Connectors CLASSIFICATION OF CONNECTORS IN FPD I) According to rigidity ​ Rigid connectors - ginagamit madalas ​ Non-rigid connectors - female & male ○​ Tenon-Mortise connectors ○​ Loop connectors ○​ Split pontic connectors ○​ Cross pin and wing connectors  Non-Rigid Connectors: Tenon(male) - Mortise (female) for Pier Abutments Non-Rigid Connectors: Crown Form Loop connector for spacing ⇒​ Some teeth have tapered crown form which interferes with parallelism ⇒​ incisors possessing very thin highly translucent incisal edges Degree of Mutilation ⇒​ Size, number and location of carious lesions or restorations affect whether full or partial coverage retainers are indicated ⇒​ Fractured or carious teeth not restorable should be removed thereby altering design and creating the need for a prosthesis Root Length ⇒​ Roots with parallel sides and developmental depressions Non-Rigid Connectors: are better able to resist additional occlusal forces than Cross Pin and Wing connector for tilted abutments are smooth-sided conical roots ⇒​ Multirooted teeth generally provide greater stability than single-rooted teeth ⇒​ Longer root has better retention than short root Crown-Root Ratio ⇒​ 1:1.5 ratio has been generally acceptable whereas 1:1 Non-Rigid Connectors: ratio is considered minimal and requires consideration of Split pontic connector for pier abutments other factors (ex. # of tooth being replaced, tooth mobility, periodontal health) before it can be used as an abutment ⇒​ 2:3 crown rot ratio Factors Influencing Fixed Bridge Design Crown Length ⇒​ Teeth must have adequate occluso-cervical crown length to achieve sufficient retention  Ante’s Law ⇒​ Periodontal ligament area/pericemental area of the abutment teeth should be equal or greater than the periodontal ligament area/pericemental area of the missing tooth/teeth Periodontal Health ⇒​ Absence of any form of periodontal disease such as bone resorption and gingival recession Arch Form Occlusion Mobility ⇒​ Occlusal forces brought to bear on a prostheses are Miller mobility value related to the following factors: ⇒​ 1º mobility - normal A. Degree of muscular activity ⇒​ 2° mobility - still acceptable provided that you must B. Patients habit know the factor that cause the mobility (patient age, C. # Of tooth being replaced presence of calcular deposit) and consider the # of tooth D. Leverage on the bridge being replaced E. Adequacy of bone support ⇒​ 3º mobility - can not be used as an abutment. Pulpal Health Span Length ⇒​ Abutment/s should not be sensitive to percussion or ⇒​ distance between abutments affects the feasibility of vitality testing (normal response) placing fixed prosthesis ⇒​ Abutments with poor pulpal health should undergo ⇒​ ideal for 1-2 missing tth endodontic treatment prior to tooth preparation ⇒​ loss of 3 adjacent tth requires careful evaluation of other factors (crown-root ratio, root length and form, Alveolar Ridge Form periodontal health, mobility) ⇒​ Not indicate for FPD if there is considerable bone loss Axial Alignment ⇒​ Crowns of proposed abutments must be well aligned ⇒​ Minor alterations in axial alignment (tipped/rotated) often necessitate the use of full coverage crowns to achieve retention or acceptable esthetics Age of Patient ⇒​ not indicated in older patient as well as adolescents when teeth are not fully erupted or with large pulps  Phonetics Wax Pattern ⇒​ patients prefer FPD for good phonation (provides ⇒​ a wax form that is a positive likeness of an object to be sufficient resistance to the flow of air to allow normal fabricated speech sounds to be produced) rather than RPD Inlay Casting Wax ⇒​ Wax that is used for pattern in cast restoration Long-Term Abutment Prognosis ⇒​ A pattern of wax is first constructed that duplicates the ⇒​ Take note of the oral hygiene shape and contour of the desired casting ⇒​ If there is question on the ability of the remaining ⇒​ Used in fabrication of direct patterns supporting structure to accept additional occlusal orces, ⇒​ It is used in indirect techniques for inlays, crowns, and RPD is indicated FPDs ⇒​ Tooth with sufficient loss of periodontal support and questionable prognosis may be best treated with an RPD COMPOSITION rather than an FPD Paraffin ⇒​ main component (40-60%) ⇒​ Have tendency to flake Esthetics ⇒​ Less smooth and glossy ⇒​ Prefer FPD because it resembles natural tooth ⇒​ But RPD may be indicated when the use of a pontic Dammar Resin produces large and unsightly proximal embrasures in a ⇒​ reduces flaking fixed prostheses. ⇒​ Improves smoothness Psychological factors Carnauba or Beeswax ⇒​ raise the melting temperature ⇒​ To most patients an FPD feels more normal than an RPD ⇒​ Decrease flow and more quickly becomes an accepted part of the oral ⇒​ Imparts glossy surface environment ⇒​ Dyes- provide color contrast ⇒​ Patients feels mroe confident and look good wearing FPD then RPD CLASSIFICATION OF WAX ⇒​ Type I - Medium Hardness REPORT ○​ used in the direct technique of fabrication of pattern Laboratory Procedures inside the mouth ⇒​ Define the meaning of Porcelain fused to Metal ⇒​ Type II Softer Wax Crown/FPD ○​ used for indirect fabrication of castings ⇒​ Know different methods and materials used in the Fabrication of jacket crown/ FPD WAX PATTERN TECHNIQUES ⇒​ Know the different factors that lead to laboratory failures ⇒​ Direct technique in fabrication ○​ The pattern is waxed on the prepared tooth in the patient’s mouth ⇒​ The fabrication of fixed partial denture is an indirect ○​ Made with Type I inlay wax laboratory procedure as direct fabrication in mouth is not ○​ Can be adapted for small restorations like inlays possible and posts ○​ Note: INDICATIONS: -​ It is practically impossible to make extracoronal ⇒​ Extensive tooth decay or damage. restorations directly as it is cumbersome, ⇒​ Post root canal treatment. technique sensitive and will take away a lot of ⇒​ Tooth replacement in areas with significant occlusal chairside time. forces. ⇒​ Indirect Technique ⇒​ Patients desiring a balance of esthetics and durability. ○​ Most commonly used method for fabricating fixed partial dentures CONTRAINDICATIONS: ○​ The pattern is fabricated on a die made form an ⇒​ Heavy clenching (bruxism) impression of the prepared tooth ⇒​ Not enough tooth to hold the crown ○​ Made with Type II wax ⇒​ Young patients with big pulp chambers ○​ Advantages: ⇒​ Poor oral hygiene -​ Allows better visualization of the restoration -​ Margins can be accessed and finished better FABRICATION OF METAL -​ Chairside time of clinician is reduced -​ Better standardization in technique as it is WAX PATTERN fabricated in a laboratory ⇒​ A Wax Pattern is essential for making the metal portion of all metal and metal veneered with ceramics or resins 1. Waxing Stage ⇒​ Wax Add-On Technique: This involves building up wax in Dental Waxes layers to create the shape of the final restoration. ⇒​ combination of various types of waxes compounded to ⇒​ Full Anatomic Wax-Up: A detailed wax model replicating provide desired physical property the final shape of the restoration. 2. Wax Cutback for the Pontic and Retainer Units ⇒​ Cellulose should be used to aid in uniform expansion of ⇒​ This step ensures that the waxed-up structure is ready the mold. for casting. The cutback involves reducing the wax ⇒​ Wetting the liner increases the hygroscopic expansion of thickness in certain areas to make space for the the investment. porcelain layer in PFM restorations. ⇒​ The ring liner should be coated on the walls of the ⇒​ Design Considerations: casting ring and kept moist before investing the ring. ○​ Must be well-rounded to ensure smooth transitions. ⇒​ After investing, the investment should be left to bench set ○​ Should have no undercuts, which could make for a minimum of one hour. removal difficult. ○​ Must avoid concavities (hollow areas) that could TYPES OF INVESTMENT MATERIAL weaken the structure. ○​ Should not have sharp corners or angles, as these CLASSIFIED BY BINDER: can cause stress concentrations and lead to A. GYPSUM BONDED INVESTMENTS - used for casting fractures. made from Type II, III, IV gold alloys B. PHOSPHATE BONDED INVESTMENTS - used for metal 3. Final Wax Pattern ceramic framework ⇒​ The wax model must be checked before casting the C. SILICA BONDED INVESTMENTS - used for some high metal core. melting base metal alloys for removable partial denture ⇒​ Requirements for a finished wax pattern: framework ○​ No inner surface defects, ensuring proper fit. ○​ Smooth, polished outer surface to prevent BURNOUT OR WAX ELIMINATION roughness in the final restoration. ⇒​ Burnout is the process of removing wax from the mold using heat. WAX DISTORTION ⇒​ Wax does not melt but sublimates into gases that escape ⇒​ When distortion occurs, the wax is bent and the inner through the pores of the investment. molecules are under compression and the outer ones are ⇒​ After bench setting, the investment is heated to 200°C in tension (400°F) for 30 minutes. ⇒​ Once the stresses are gradually relieved, the wax tends ⇒​ Then, it is heated further to 650°C (1200°F) for 45 to straighten and distort minutes to remove remaining wax traces. ⇒​ Heating influences investment expansion, so HOW TO MINIMIZE DISTORTION? temperatures must be standardized. ⇒​ Wax should be added in melted increments or drops or by dipping in melted wax ⇒​ Margins must be remade just before investing ⇒​ Wax patterns should be invested as soon as it is completed. FRAMEWORK ⇒​ Framework is cast by lost wax technique - elimination of the wax pattern from the mold of a set investment material THE PROCESS CONSISTS OF: ⇒​ Surrounding the wax pattern with a mold of heat resistance investment material ⇒​ Eliminating the wax by heating ⇒​ Introducing molten metal into the mold through a channel called sprue SPRUE - channel through which molten metal alloy passes DIE SPACER - agent applied to a die to provide space for into the mold in an invested ring after the wax has been luting cement. eliminated. INVESTING THE WAX PATTERN SPRUING - process of attaching a sprue former to the wax ⇒​ The wax pattern is placed inside a casting ring for pattern investing. ⇒​ A casting ring helps form a mold where metal will be cast. SPRUE FORMER ⇒​ Investment is mixed as per manufacturer’s instructions ⇒​ Sprue design will vary depending on the type of the and poured into the ring. restoration being casted, the alloy used, and the casting ⇒​ A surfactant is applied to the wax pattern to improve machine. wetting by the investment. ⇒​ attached to provide a channel through which molten alloy ⇒​ Investment type depends on the alloy: can reach the mold ○​ High noble alloys use gypsum-bonded investments. ○​ Base metal alloys use phosphate-bonded TYPES OF SPRUE FORMER investments. Based on materials: ⇒​ Ring liners like asbestos (not used now due to health ○ Wax hazards) ○ Plastic ○ Metallic  ○​ These are highly resistant to corrosion and SPRUE DIAMETER oxidation, easy to cast due to their high densities, ⇒​ It should be larger than the thickest portion of the pattern. and are the most expensive. ⇒​ Reservoir should be provided to prevent localized ○​ Ex. Gold, Palladium and Platinum shrinkage porosity. 2. NOBLE ALLOYS (SEMI-PRECIOUS METALS) ⇒​ Contain at least 25% noble elements, but no requirement RECOMMENDED SPRUE DIAMETERS for gold. ⇒​ 2.5 mm (10 gauge) sprues for molar metal ceramic ⇒​ Composed of 75% base metals. restorations. ⇒​ More affordable than high noble alloys but still offer good ⇒​ 2.0 mm (12 gauge) sprues are preferred for premolar biocompatibility. partial veneer restoration. Ex. Au-Ag alloys, Pd-Ag alloys, Pt-Pd alloys ⇒​ Narrow sprues are sufficient for casting to be done on centrifugal machines. 3. BASE METAL ALLOYS ⇒​ Contain less than 25% noble elements. POSITIONING THE SPRUES ⇒​ Made from more reactive metals that form a protective ⇒​ Sprue should be positioned at a 45° angle near the bulk oxide layer to resist further corrosion. of the wax pattern. ⇒​ Commonly used due to lower cost and higher strength, ⇒​ The sprue should form a 135° angle with the axial walls but may be less biocompatible. to reduce air entrapment. ⇒​ Ex. Ni-Cr Alloys, Co-Cr Alloys, Titanium alloys ⇒​ Flared attachment helps prevent turbulence during metal flow. DESIRABLE PROPERTIES OF DENTAL CASTING ALLOYS ⇒​ Proper positioning prevents suck back porosities after ⇒​ 1. Biocompatibility casting. ⇒​ 2. Tarnish and corrosion resistance ⇒​ Auxiliary sprues or vents allow gases to escape and ⇒​ 3. Favorable thermal properties improve casting quality. ⇒​ 4. Adequate strength ⇒​ 5. Suitability for casting frameworks and prostheses ATTACHING THE SPRUE TO THE CRUCIBLE FORMER ⇒​ 6. Compatibility with porcelain bonding ⇒​ The sprue is attached to a crucible former, usually made ⇒​ 7. Economic feasibility of rubber. ⇒​ A crucible former is a conical base that creates a PICKLING concave space in the investment. ⇒​ is the process of cleansing metallic surfaces of the ⇒​ The sprue's free end must be connected to the tip of the products of oxidation and other impurities by immersing crucible former. in acid ⇒​ The crucible former is removed after the investment hardens SOLUTIONS USED: ⇒​ The wax pattern’s end should be about 6 mm from the ⇒​ 50% Hydrochloric Acid free end of the investment. ⇒​ Hydrofluoric Acid ⇒​ This gap allows air to escape through the investment ⇒​ Phosphoric Acid pores during casting. SANDBLASTING CASTING ⇒​ roughen or clean a surface with a jet of sand driven by ⇒​ formed by the solidification of a fluid that has been compressed air or steam poured or injected into the mold ⇒​ the process of creating a metallic replica of a missing tooth structure by pouring molten alloy into a mold and letting it solidify ALLOY ⇒​ An alloy is a union of two or more metallic elements that are mutually soluble in their molten state. TYPES OF CASTING ALLOYS ACCORDING TO HARDNESS AND STRENGTH 1.​ TYPE I (SOFT) –used in casting simple inlays 2.​ TYPE II (MEDIUM) –used in casting complex inlays 3.​ TYPE III (HARD) –used in casting crowns and FPD 4.​ TYPE IV (EXTRA HARD) –used in casting RPD and pin ledges ACCORDING TO ADA CLASSIFICATION 1.​ HIGH NOBLE ALLOYS (PRECIOUS METALS) ○​ Contain at least 60% noble elements, with a minimum of 40% gold. ○​ The remaining 40% may be base metals. COMMON CASTING FAILURES PORCELAIN BUILD UP DENTAL PORCELAIN PORCELAIN ⇒​ refers to a specific compositional range of ceramic material composed of kaolin, silica and feldspar and fired at high temperature. DENTAL CERAMICS ⇒​ Dental ceramics for metal-ceramic restorations belong to this compositional range and are commonly referred to as dental porcelains DENTAL PORCELAIN (FELDSPATHIC) ⇒​ Glassy ceramics that form from the combination of feldspar, silica and alumina ⇒​ Oldest of the dental ceramics and it is the most used ceramics for esthetic dental restorations ADVANTAGES OF DENTAL PORCELAIN ⇒​ Biocompatible as it is chemically inert ⇒​ Excellent esthetics ⇒​ Thermal properties are similar to those enamel and dentin DISADVANTAGES OF DENTAL PORCELAIN ⇒​ High wear resistance ⇒​ Difficult to adjust and polish ⇒​ Low tensile strength so it is brittle material BASIC COMPOSITION OF DENTAL PORCELAIN 1. FELDSPAR - are mixtures of (K2O. Al2O3. 6SiO2) and (Na2O. Al2O3. 6SiO2), fuses when melts forming a glass matrix 2. QUARTZ (SiO2) - serves as a strengthener, remains unchanged during firing, present as a fine crystalline dispersion through the glassy phase 3. KAOLIN - acts as a binder 4. FLUXES - used to decrease firing temperature 5. METAL OXIDES - provides a wide variety of colors MANUFACTURING ⇒​ Raw materials are mixed together in a refractory crucible and heated to a temperature well above their fusion temperature ⇒​ Glass and crystalline phases are produced ⇒​ Fused mass is quenched in water ⇒​ Shatters into small fragments of glass-fritting ⇒​ Ball milled to achieve powdered material supplied to the dental lab, opacifiers and pigments are added SINTERING OR FIRING ⇒​ Manufacturing completed ⇒​ Sintering is a critical process in the fabrication of porcelain used in PFM crowns. It involves the fusion of PORCELAIN PROCESSING OVER METAL CORE porcelain particles at high temperatures to form a dense, 1. Condensation and Build Up - porcelain powder is mixed cohesive material. This process undergoes three main with water then applied to the surface of the core, form the stages: porcelain to the required shape and remove as much water material to prevent decrease in firing shrinkage 1. Low Bisque Stage ⇒​ This is the first heating phase. Objectives of Condensation: ⇒​ The porcelain particles start to stick together, but it’s still 1. Improve contact between the metal framework and porcelain weak and porous. 2. To decrease bubbles in the porcelain ⇒​ There’s only a little bit of shrinkage. 3. Distance between porcelain particles 4. Cracking and distortion prevented through reduced firing 2. Medium Bisque Stage shrinkage ⇒​ More heat is applied. 5. Breaking of the built up structure prevented by increased ⇒​ Water inside the material evaporates, which helps the strength after drying particles get closer and stick better. ⇒​ The structure is stronger, but there’s still some porosity. Methods of Condensation: ⇒​ Vibration 3. High Bisque Stage ○​ Packs porcelain tightly and removes excess ⇒​ This is the final stage of sintering. moisture ⇒​ The particles are fully fused. ○​ Leads to high density and fewer air bubbles ⇒​ There’s no more shrinkage or porosity. ○​ Best for strong, uniform porcelain structure ⇒​ Brush TYPES OF PORCELAIN BASED ON FUSING ○​ Use a fine brush to apply and shape porcelain TEMPERATURE ○​ Allows for smooth surfaces and fine detail 1. High Fusing Porcelain (1288–1371°C / 2350–2500°F) ○​ Ideal for delicate layers like enamel or special color ⇒​ Primarily used for the production of artificial denture ⇒​ Spatulation teeth. ○​ Uses a spatula to manipulate and shape porcelain ⇒​ Not commonly used in tooth restoration due to its high paste melting point. ○​ Promotes particle contact and remove excess water ○​ Good for building large areas and achieve uniform 2. Medium Fusing Porcelain (1093–1260°C / 2000–2300°F) thickness ⇒​ Used in all-ceramic restorations, such as porcelain jacket crowns. TYPES OF PORCELAIN USED IN BUILD UP: ⇒​ Not used in PFM because the temperature is still too high a. Opaque Porcelain - serves to obscure the color of metal for metal safety. core b. Body Porcelain - makes up the bulk of the restoration and 3. Low Fusing Porcelain (871–1066°C / 1600–1950°F) providing the necessary color of the shade ⇒​ Ideal for fabricating metal-ceramic crowns. c. Incisal Porcelain - provide translucency on the incisal ⇒​ Compatible with metal alloys used in substructures due portion which mimics the natural look of the teeth to its lower firing temperature, which prevents metal distortion. GLAZING ⇒​ is the process for obtaining a smooth surface that simulates a natural tooth. PURPOSE OF GLAZING -​ Is used when specific aesthetic or functional ⇒​ To seal the open pores in the surface of a fired porcelain. requirements necessitate a thicker or more ⇒​ Glazing is done to remove surface cracks and improve controlled glaze layer the flexure strength. COOLING ○​ The last step in the manipulation process. COMPOSITION OF DENTAL GLAZE ⇒​ cooling : bench cooling after refiring ⇒​ Colorless glass powder - to produce glossy surface ⇒​ Cooling is slowly and uniformly, otherwise rapid cooling ⇒​ Do not contain opacifiers leads to uniform shrinkage which causes stresses that ⇒​ Has a low fusion temperature cause cracks and loss of strength. ⇒​ Contains glass modifiers COMMON REASONS FOR FAILURE OF METAL-CERAMIC DISADVANTAGES OF UNGLAZED PORCELAIN RESTORATION ⇒​ Unglazed or trimmed porcelain may lead to inflammation of the soft tissues it contacts. ⇒​ Occlusal contacts between unglazed porcelain and opposing unglazed porcelain or enamel are undesirable because of the high rate of wear of enamel and porcelain. TWO TYPES OF GLAZING ⇒​ Auto glazing or self glazing ⇒​ Add on glazing or over glazing AUTO GLAZING OR SELF GLAZING ⇒​ rapid heating up to the fusion temperature for 1-2 minutes to melt the surface particles. ○​ Process -​ The porcelain restoration is heated rapidly to a temperature that melts the surface particles, creating a smooth, glassy layer. ○​ Advantages: SHADE SELECTION -​ Simplicity: requires less steps and time compared to add-on glazing Introduction -​ Efficiency: can be done in a single firing cycle ○​ Disadvantages -​ Limited control: the laze layer might be thinner Definition: Shade selection: Shade selection refers to the or less uniform compared to add-on glazing process of determining the appropriate color of a tooth or teeth -​ Potential for cracks: rapid heating can for a dental restoration, ensuring it harmonizes with the sometimes cause fine surface cracks, though patient’s natural dentition and delivers an aesthetically pleasing this can be mitigated with proper techniques. result. ○​ Indications -​ Auto glazing is often preferred for its simplicity Uses: Shade selection in prosthodontics involves both visual and efficiency, especially for routine and instrumental methods, considering factors such as lighting restorations conditions, translucency, and individual patient characteristics. Accurate shade matching is essential, as an improperly ADD ON GLAZING OR OVER GLAZING selected shade can lead to noticeable discrepancies, ⇒​ applying a glaze to the surface and re-firing compromising esthetic harmony and potentially affecting the ○​ Process patient's confidence and satisfaction. To achieve optimal -​ A thin layer of transparent glaze material is esthetic outcomes, prosthodontists must have a thorough applied to the surface of the porcelain understanding of color science and human color perception. restoration, followed by a re-firing cycle to fuse the glaze Advantages ○​ Advantages: ⇒​ Enhanced Aesthetics and Natural Appearance -​ Enhanced esthetics: allows for more precise ⇒​ Improved Patient Satisfaction control over the glaze layer and its thickness, ⇒​ Increased Patient Confidence and Self-Esteem leading to better esthetic outcomes. ⇒​ Facilitates Psychological Well-being -​ Functional benefits: can be used to address ⇒​ Optimal Color Integration specific functional needs, such as improving ⇒​ Metamerism Reduction surface smoothness or reducing wear. ⇒​ Harmonious Blending with Adjacent Teeth ○​ Disadvantages ⇒​ Reduced Need for Remakes and Adjustments -​ More complex: requires an extra step and ⇒​ Improved Communication with the Dental Laboratory re-firing cycle ⇒​ Long-Term Aesthetic Stability -​ Potential for delamination (separation of material into layers): if the glaze layer is not Elements of Color properly bonded, it can delaminate over time I. Dimensions of color ○​ Indications:  ⇒​ Understanding color involves grasping its dimensions like -​ These pigments are used to recreate the natural hue, value, chroma, and translucency appearance of enamel and dentin, especially in aesthetic restorations for the front teeth. A. Tridimensional property of color -​ refers to the idea that color has three key components B. Importance of Color in Dentistry or dimensions that work together to create what we -​ Restorative materials have color. perceive as a specific color. These three dimensions -​ Accurate shade matching is essential for aesthetics. are: -​ Understanding color theory helps achieve 1.​ Hue – This is what most people think of as natural-looking restorations. “color” 2.​ Value – This refers to how light or dark a color is. 3.​ Chroma – the saturation or intensity. B. Translucency -​ the gradient between transparent and opaque. Increasing the translucency of a crown lowers its value because less light returns to the eye. The translucency of enamel varies with the: 1.​ Angle of incidence 2.​ Surface texture 3.​ Wavelength C. Additive Principle in Dentistry 4.​ Level of dehydration -​ Used to alter the value (brightness/darkness) of a restoration. II. Spectral colors -​ A3 (orange hue) + Blue stain = lower value A. What is Spectral Colors in Shade selection? -​ B shade (yellow hue) + Violet stain = lower value -​ In dentistry, shade selection is the process of -​ Note: Adding gray stain makes the restoration look selecting a restoration color (such as crowns, dull. veneers, or fillings) that matches the patient's natural tooth color. CHALLENGES -​ It further ensures the aesthetic harmony between I. Elements affecting Color Perception natural and restored teeth. A.​ Light in the Dental Office ​ Fluorescent: Bluish/cool tone B. Importance in Dentistry ​ Incandescent: Warm/yellowish tone -​ Essential for accurate shade matching ​ Natural daylight (midday): Balanced and -​ Impacts crowns, veneers, and composites most accurate. -​ Color depends on light-tooth interaction ​ Use color-corrected bulbs for consistency. -​ Affects both aesthetics and patient satisfaction B.​ Metamerism -​ Guides material selection for natural appearance ​ Shade matches under one light, appears -​ different under another. C. What are the factors that affect the Shade selection? - ​ Cross-check using: -​ Lighting conditions (Type of light source, Color ○​ Natural light temperature) ○​ Operatory light -​ Light and Material Reflection (Teeth reflect specific (fluorescent/incandescent) wavelengths Determines perceived shade) ​ Use shade-matching photographs or digital -​ Tooth condition (Surface texture, tooth hydration, age tools. of tooth) C.​ The Tooth Itself -​ Patient factors ​ Enamel: Translucent -​ Material of Restoration ​ Dentin: Opaque; provides most of the tooth’s color. -​ Background and Surroundings ​ Surface texture: Affects light reflection (smooth vs rough). D. Wavelengths of Electromagnetic energy - - ​ Stains/discoloration -​ Red, orange, yellow, green, blue, indigo, and violet; ​ Dry teeth: Appear lighter also known as ROY G BIV. -​ Prism splits light into separate hues D.​ Environment & Background Colors ​ Visual illusions caused by reflections from: E. Wavelengths of Visible light - - ○​ Lipstick, clothing, colored bibs, operatory -​ Range: ~400–700 µm walls. -​ Each color tied to specific frequency ​ Use neutral backgrounds: Gray or beige gloves, curtains, and walls. III. Pigment colors A. What are Pigment Colors in Dentistry? E.​ Patient Position -​ In dentistry, pigment colors refer to the artificial colors ​ The patient should be upright, not reclined. added to restorative materials like ceramics, ​ Tooth at clinician’s eye level, perpendicular to light. composites, and acrylic resins to match the natural shade of a patient’s teeth. F.​ The Human Eye and its limitations  ​ Influenced by: D.​ Shade - X ○​ Retinal fatigue: Staring too long at shades. -​ compact ○​ Binocular differences: Slight perception -​ Cordless ‘‘spot measurement’’ spectrophotometer differences between eyes. with 3 mm probe diameter ○​ Poor color memory: Hard to recall exact -​ Shade-X have two databases to match the color of shades. the dentin (more opaque) and the incisal tooth regions ○​ Aging & color blindness: Natural limitations. (more translucent). G.​ Clinician Factors E.​ SpectroShade Micro ​ Gender: Women tend to have better color perception. -​ An imaging spectrophotometer. ​ Experience: Trained eyes make more accurate -​ It uses a digital camera/LED spectrophotometer judgments. combination. ​ Color blindness/visual impairments: May hinder shade -​ It has an internal computer with analytical software. accuracy. The tooth positioning guidance system, shown on the LCD touchscreen, is used during color measurement. II. Solutions Images and spectral data can be saved on the ​ Use neutral environments (gray tones). internal memory and transferred to a computer ​ Take visual breaks between assessments. ​ Use shade guides, digital tools, and photos. F.​ Colorimeters -​ Measure tristimulus values and filter light in red, green GUIDELINES AND TYPES OF SHADE SELECTION and blue areas of the visible spectrum I. Use of Color measuring instruments -​ Disadvantages A.​ Spectrophotometers 1.​ Colorimeters are not registering spectral -​ A spectrophotometer contains a source of optical reflectance and can be less accurate than radiation, a means of dispersing light, an optical spectrophotometers (aging of the filters can system for measuring, a detector and a means of additionally affect accuracy converting light obtained to a signal that can be 2.​ There is no significant difference in the analyzed. accuracy of shade selection between -​ It measures and records the amount of visible radiant conventional visual assessment and energy reflected or transmitted by an object at 1–25 colorimetric instrument (Kuzmanovic and nm interval, capturing precise data across the entire Lyons) visible spectrum for each hue, value, and chroma. 3.​ Colorimeters are significantly less reliable -​ Compared with observations by the human eye, or that spectrophotometer and digital camera conventional techniques, it was found that spectrophotometers offered a 33% increase in G.​ ShadeVision accuracy and a more objective match in 93.3% of -​ an imaging colorimeter. cases. -​ Complete tooth image is provided through the use of B.​ Crystaleye three separate databases: -​ Combines the benefits of a traditional a.​ Gingival third spectrophotometer with digital photography. b.​ Middle third -​ Virtual shade tabs in the computers database can be c.​ incisal third cross-referenced and superimposed visually onto the -​ Virtual try-in feature enables virtual testing of color natural tooth image to be matched giving the reproduction during fabrication technician the ability to visualize the correct shade tabs. H.​ Digital Cameras and Imaging System -​ The digital image produced by the Crystaleye uses a a.​ Digital Cameras 7-band LED light source, which results in a more -​ Digital cameras represent the most basic approach to precise depiction of color than the conventional electronic shade taking, still requiring a certain degree systems used with digital cameras of subjective shade selection with the human eye -​ Disadvantage: The image produced by the b.​ ClearMatch Crystaleye is taken from inside the oral cavity and -​ A software system that uses high-resolution digital consequently is devoid of the external light that can images and compares shades over the entire tooth cause discrepancies with known reference shades. C.​ Vita Easyshade Compact -​ Similar to the software associated with color -​ Cordless measuring devices, ClearMatch contains the color -​ Small portable database of industry-standard shade guides -​ Cost efficient -​ Battery operated CONVENTIONAL METHOD -​ Contact-type I.​ Visual Shade Guides in Dentistry -​ Different measurement modes ​ Most common and convenient method 1.​ single mode ​ Based on visual comparison to color tabs 2.​ Tooth are mode (cervical, middle and incisal ​ Relies on human eye perception shades) ​ Used for ceramic and composite restorations 3.​ Restoration color verification (includes ​ Common types: lightness, chroma and hue comparison) -​ Vita Classical 4.​ Shade tab mode (practice/training mode) -​ Vita 3D-Master -​ Chromascop  -​ Custom shade guides Step 2 (Chroma Selection) A.​ Vita Classical Shade Guide 1. Gradations: B1, B2, B3, B4 -​ First shade guide introduced by Vita Zahnfabrik 2. Make multiple comparisons to avoid retinal fatigue -​ 16 tabs based on hue 3. Rest eyes between comparisons (blue-gray) -​ Groups: A (reddish-brown), B (reddish-yellow), C (grey), D (reddish-grey) Step 1 (Hue Selection) -​ Within each group: increasing chroma 1. Four hue categories: -​ Easy to use, cost-effective, and commonly available a. A: Yellow-red b. B: Yellow B.​ Vita 3D-Master Shade Guide c. C: Gray -​ 26 tabs arranged by value (lightness) d. D: Red-yellow-gray -​ Five groups (1–5): increasing darkness 2. Select the closest hue to the natural tooth -​ Chroma levels: 1 to 3 3. Use the area of the too -​ Bleaching shades: 0M1, 0M2, 0M3 -​ More precise and systematic than Vita Classical C. Matching Technique Compare shade tab to middle third of tooth C.​ Vita Classical vs. Vita 3D-Master Limit observation to 5–7 seconds -​ Vita Classical: hue-based View from multiple angles -​ Vita 3D-Master: value-based Choose lighter shade if uncertai -​ 3D-Master offers better lightness range and color distribution D. Documentation and Communication -​ Improved grouping and wider chroma/hue range Record selected shade (e.g., A2, B1) Take photo with shade tab next to the tooth D.​ Chromascop Shade Guide Note features like translucency or staining -​ Uses a numeric system Send complete info to lab -​ Hue groups: ​ 100 = white GINGIVAL MANAGEMENT ​ 200 = yellow ​ 300 = orange GINGIVAL RETRACTION ​ 400 = gray is the deflection of the marginal gingiva to expose tooth ​ 500 = brown margins during impression making. It is -​ Chroma increases from 10 to 40 essential for accurately capturing the finish line, ensuring proper fit and function of the final E.​ Custom Shade Guides restoration. -​ Standard guides cover ~85% of cases -​ Custom tabs needed for complex shade matching Need for Gingival Retraction: -​ Materials: composite, ceramic, or acrylic Proper contour of the future restoration -​ Modified using colorants, abrasion, or markers Patient comfort Efficiency of impression material II. Disadvantages of Shade Guides Operator’s access and visibility Shade systems vary by manufacturer Porcelain used in guides ≠ porcelain in restorations Retraction is when the edge of the gum (free gingival margin) Shade guides cannot guide fabrication is gently moved downward and Limited and non-logical color organization outward to expose more of the tooth. Tabs differ in material and thickness from restorations Relapse is when the gum starts to move back to its original Light transmission differs from actual crown position after being retracted. Displacement happens when thick impression material III. STEPS: Conventional Shade Selection Using VITA pushes down on the gum, causing it to Classical Shade Guide move further downward. A. Preparing the Environment: Collapse is when the gum flattens or gets pushed down due to Use natural or 5500K color-corrected light pressure from a tightly fitted Neutral background (gray bib or drape) custom impression tray. Remove makeup, lipstick, or bright clothing Ensure teeth are clean and moist Gingival retraction is important in three phases: Preparatory phase (Tooth Preparation): Plan the position B. Shade Selection Steps: of the finish line relative to Step 1 (Value Selection) the gingiva and displace the gingiva for a clear view of the 1. Use a value-oriented shade guide for value selection cervical area. 2. Suggested order of values: Working phase (Impression Making): Retract the gingiva a. B1, A1, B2, D2, A2, C1, C2, D4, A3, D3, B3, A3.5, B4, C3, apically and laterally to allow A4, C4 access to the finish line and provide space for impression 3. Value best determined by squinting, with comparisons at material. arm’s length Maintenance phase (Cementation): Displace the gingiva to 4. Diminish cone sensitivity, increase rod sensitivity for value check the marginal fit and selection remove excess cement after cementation. 5. Lower values show more fading Gingival sulcus Disadvantages: Shallow crevice or space around the teeth -​ full arch models cannot be made. V- shaped -​ severe cervical extension preparations. Probing depth ( 2-3mm) Limitations: Biological width -Should not be used with polyvinyl siloxane impression About 2.04mm ---- 1.07 con. tissue & 0.97 epithelial material because the rubber dam will inhibit its polymerization. attachment -Cannot be used to record subgingival preparation. Placement of restoration should not encroach this space. COPPER BAND Evaluation of Biological Width - The copper band is a small metal ring placed around the -​ Biological Width: Distance between bone and tooth. It helps push the gums a little to see more of the tooth restorative margin. and holds the impression material in place to get a good copy -​ Clinical Evaluation: Probe used to measure under of the tooth shape. anesthetized tissue. -​ Violation: When the biological width is < 2mm, a Disadvantage violation occurs, which can affect tissue health. Sometimes, it can hurt the gums or cause small cuts if not used carefully. Margin Placement Options 1. Supragingival Technique: 2. Equigingival Selection of copper band: 3. Subgingival -​ A copper band is chosen because it can be easily shaped to fit the tooth. Margin Placement Guidelines One surface of the band may be perforated: -​ Sulcus Depth ≤ 1.5 mm: Preparation should extend -​ A small hole is made in one part of the band to help 0.5mm below the crest. with fitting and molding the material inside. -​ Sulcus Depth > 1.5 mm: Preparation should extend Cervical end of the band may be trimmed in accordance with to 1/5th of the sulcus depth. the finish line: -​ > 2mm Depth: Perform gingivectomy. -​ The bottom edge of the band is trimmed to match the -​ Deeper Sulcus increases the risk of gingival tooth's edge, so it fits well. recession. The band is filled with soft wax and seated on the tooth: -​ Key: Place margin within the sulcus, not within the -​ Soft wax is put inside the band, and the band is attachment area. placed around the tooth to capture its shape. -​ The wax is chilled and the impression is removed: Gingival Retraction Methods (Shillingburg) -​ After the wax is in place, it is cooled to harden, and I. Mechanical method then the impression is taken out. 1. Rubber dam The impression indicates overextension of the band: 2. Wooden wedges -​ The impression may show that the band went too far 3. Rolled cotton twills over the tooth or didn't fit correctly. 4. Cotton twills impregnated with ZnOE Adjustments, if required, may be made and a second trial 5. Copper bands impression is made: 6. Aluminum shell -​ If there’s a problem with the first impression, the band 7. Temporary acrylic resin copings is adjusted, and another impression is taken to check 8. Gingival cords if it fits better. The wax is melted and modeling compound is introduced: II. Chemico-Mechanical method -​ The wax inside the band is melted to make room for 1. Vasoconstrictors the modeling compound. The modeling compound, a 2. Astringents material that can harden, is then added into the band 3. Tissue coagulants to capture the shape of the tooth. Incisal or occlusal end, gingival end: III. Surgical Method -​ This refers to positioning the band correctly on the 1. Gingivectomy and Gingivoplasty tooth. The "incisal" or "occlusal" end is the top part of 2. Periodontal flap procedures the tooth, and the "gingival" end is the bottom, near 3. Electrosurgery the gum line. The band should cover both ends 4. Rotary Gingival Curettage properly. Seat the band securely into its position: MECHANICAL METHODS -​ The band is placed around the tooth and gently pressed into place to ensure it fits securely and Rubber Dam (Introduced by S.C. Barnum, 1864) - comfortably, capturing the exact shape of the tooth. -​ How it works: Compresses tissues to provide Pressure is applied on the compound directly: retraction. -​ After the band is in place, pressure is applied to the -​ Best for: Limited preparations in one quadrant. modeling compound inside the band. This helps the compound to mold more accurately to the tooth’s Advantages: surface and creates a detailed impression. -​ control of seepage and hemorrhage. Chill the impression: -​ ease of application. -​ After the compound has been shaped, it is cooled -​ down to harden it. The cooling process helps to keep  the impression solid and ensures the shape is WHY DO WE USE THIS? preserved. We use this technique because it helps create a stable and A towel clamp may be used to remove the impression: secure packing material for dental procedures. The cotton -​ Once the compound is hardened, a towel clamp can twills and ZOE cement work together to protect the tooth and be used to gently remove the impression from the surrounding tissue. The soft pressure and compacting make tooth, ensuring it doesn’t break or get damaged sure the cotton twills stay in place, and the fast-setting ZOE during removal. cement quickly holds everything in position. This method is useful for packing material during restorative treatments, like EXPLANATION: crowns or fillings, ensuring that everything stays secure and The process begins by melting the wax inside the copper comfortable while the procedure is being done. It also helps band, creating space for a modeling compound to be prevent the material from sticking to the instruments, making introduced. The modeling compound is then placed inside the the process smoother and easier to handle. band to capture the shape of the tooth. The band is positioned carefully around the tooth, ensuring it covers both the top GINGIVAL CORD TECHNIQUE (incisal or occlusal end) and bottom (gingival end) portions of the tooth. Once the band is in place, gentle pressure is applied Physically pushes the gingiva away from the finish line: to the modeling compound to help it mold accurately to the The gingival cord is placed around the tooth to push the gums tooth’s contours. After the compound is shaped, the impression away from the edge (finish line), creating space for dental work is chilled to allow it to harden, thus preserving the exact shape like crowns. of the tooth. Finally, a towel clamp is used to gently remove the impression from the tooth without damaging it. This method Its effectiveness is limited because pressure alone will not ensures that a precise and secure mold of the tooth is created, control sulcular hemorrhage: which is essential for making accurate dental restorations such While the cord pushes the gums away, it doesn’t stop bleeding as crowns or inlays. from the gum tissue (sulcular hemorrhage), so additional methods may be needed to control bleeding. COTTON TWILLS W/ ZNOE CEMENT Employs gentle pressure over a period of time: SIMPLE: -​ You apply soft, steady pressure on the cotton twills for The gingival cord technique is used to push the gums (gingiva) a little while. This helps the cotton twills stay in place away from the edge of the tooth, known as the finish line. This without hurting the gums or tissues. helps to create more space for dental restorations, like crowns, ZnoE mixed into creamy consistency, Cotton twills are rolled by making sure the gums don't get in the way. However, its into this mass and then on a towel to gain compactness: effectiveness is limited because just applying pressure with the -​ The ZOE cement is mixed to a smooth, creamy cord doesn’t stop bleeding from the gums (sulcular texture. Then, the cotton twills are rolled into this hemorrhage), which can still happen during the procedure. cement, and afterward, you roll them on a towel to make them more firm and tight. This makes them DEPENDING ON THE CONFIGURATION: easier to handle. Plain: This prevents sticking of pack to the instruments and gives -​ These cords are simple and straight, with no twists or ease in handling: braids, making them easy to handle and place around -​ By rolling the cotton twills on a towel, it stops the the tooth. cement from sticking to your tools, making it easier to Twisted: work with. -​ These cords have a spiral twist, which makes them Should reflect the tissue laterally: more durable and able to provide better pressure -​ When you place the cotton twills, they should follow when placed around the gums. the shape of the tooth and gums. This means the Braided or Knitted: twills should fit around the tooth and show the same -​ These cords are made by braiding or knitting multiple direction as the surrounding tissue. threads together, providing a strong, flexible, and Pack held in place with fast-setting ZnOE cement: more supportive structure for packing around the -​ Once the cotton twills are in place, you use the tooth. fast-setting ZOE cement to keep them there. The cement hardens quickly, so the pack stays where you DEPENDING ON THE SURFACE FINISH: want it without moving. Waxed: -​ These cords have a wax coating, which makes them SIMPLE EXPLANATIONS: smoother and easier to handle, reducing friction First, we apply gentle pressure on the cotton twills over some during placement. time to make sure they stay in place without harming the gums. Unwaxed: Then, we mix Zinc Oxide Eugenol (ZOE) cement to a creamy -​ These cords do not have a wax coating, making them consistency and roll the cotton twills in this cement. After that, rougher and a bit harder to handle but sometimes we roll the twills on a towel to make them firmer and more preferred for certain applications where extra grip is compact, which helps prevent the cement from sticking to our needed. instruments and makes the process easier. When placing the -​ cotton twills, we make sure they fit around the tooth and reflect DEPENDING ON THE CHEMICAL TREATMENT: the tissue correctly. Finally, we hold the cotton twills in place Plain: with fast-setting ZOE cement, which quickly hardens and -​ These cords are untreated, meaning they are just the keeps everything secure. basic material without any additional chemicals. Impregnated:  -​ These cords are treated with chemicals like One of the main advantages of cotton is its absorption hemostatic agents or other substances to help control capacity—it has the highest absorption bleeding and provide better tissue displacement ability among all materials used for gingival retraction. This during the procedure. property makes cotton ideal for managing any fluids (like blood or saliva) that might interfere DEPENDING ON THE NUMBER OF STRANDS with the procedure. Single: -​ This cord is made from a single thread or strand, Diameter of Cords: making it thinner and easier to work with in smaller The diameter of plain cords used in gingival retraction typically spaces or when less pressure is needed. ranges from 0.58 mm to 1.17 mm Double: -​ This cord is made from two strands twisted together, The choice of diameter depends on the specific clinical providing more strength and pressure for better tissue situation, including the size of the sulcus (the groove between displacement, especially in larger spaces or when the tooth and gum) and the amount of retraction needed. more force is needed. Smaller cords might be used for more delicate or narrow sulci, while larger cords might be necessary for thicker or more DEPENDING ON THE THICKNESS: resilient gum tissue. Black 000: -​ This is the thinnest cord, typically used for delicate Summary: procedures where minimal tissue displacement is In short, materials like nylon, polyester, and cotton are used for required. the plain cord gingival retraction technique. Each material has Yellow 00: its own strengths, with cotton being especially useful due to its -​ Slightly thicker than black, used when a bit more high absorption capacity. The choice of cord diameter depends displacement is needed but still in delicate areas. on the specific needs of the patient's gingival tissue. Purple 0: -​ This cord is medium-thick, providing a good balance SIMPLE TERMS between flexibility and pressure, often used for routine In simple terms, plain cord dental work. -​ is used in dental procedures to push the gum away Blue 1: from the tooth, creating space for better access. -​ Thicker than purple, used for more substantial tissue displacement in areas with more space. MATERIALS USED FOR PLAIN CORD TECHNIQUE Green 2: Nylon and Polyester: -​ This is a thicker cord, often used when more pressure -​ These are strong, durable materials used to push the is needed for larger tissue areas. gum back. They stay intact during the procedure and Red 3: are good at keeping the gum away from the tooth. -​ The thickest cord, used when strong displacement is Cotton: required, such as in cases of more extensive gum -​ is often used with nylon or polyester. It can absorb tissue and in restorative procedures needing fluids like saliva or blood better than the other significant space for the final restoration. materials. It helps keep the area clean and dry. Fischer's Cord Packers In the context of gingival retraction techniques, -​ are tools used in dental procedures to help place Plain cord gingival retraction cords. These tools are designed to -​ is often used to temporarily displace the gingiva (gum gently push the cords into the gum tissue, creating tissue) away from the tooth, creating a space that space for better access during treatments like crown allows for better access to the area during dental preparations or impressions. procedures like crown preparations, impressions, and restorations. Types of Fischer's Cord Packers: #170 and #171 (45° to handle): OTHER MATERIALS USED FOR PLAIN CORD TECHNIQUE -​ These packers have a 45° angle to the handle, Nylon and Polyester: allowing for a more angled approach when placing the -​ are synthetic materials commonly used in the plain cord. This can be helpful for working in areas where cord technique. They are durable, resistant to you need to reach the gum more easily from a side breaking, and can effectively displace the gingival angle. tissue without causing damage. These materials are #172 and #174 (90° and parallel to handle): often chosen for their strength and ability to maintain -​ These packers have a 90° angle to the handle, which their integrity during the procedure. makes the working end parallel to the handle. This design is great for areas that require a direct These synthetic cords can be used alone or in combination approach to pack the cord without bending the tool. with other materials to create optimal retraction. Serrated Cord Packer: -​ This type of packer has serrations (teeth) on the Cotton: working end. The serrated design helps grip the cord -​ is another material that can be used in gingival better, making it easier to push the cord into the gum retraction. While it is not as durable as synthetic without slipping. cords, it can be very effective when combined with Non-serrated Cord Packer: nylon or polyester. -​ This type of packer has a smooth surface on the working end, which is better for pushing the cord gently into the gum without gripping it too tightly.  Insert the cord: Summary: Gently push the cord into the space between the tooth and #170 & #171: 45°:angled to the handle. the gum, starting on the #172 & #174: 90°: angled, parallel to the handle. mesial (front) side of the tooth. Serrated: Has teeth to grip the cord better. Continue packing: Non-serrated: Smooth surface for gentle packing. Keep packing the cord around the tooth on the lingual (inner), distal (back), and buccal This explanation is about the force needed when placing a (outer) sides. gingival retraction cord into the space between the gum and Leave extra cord: tooth (called the gingival sulcus) during dental procedures. Leave 2 mm of extra cord sticking out from the gum. Wait: Epithelial Attachment Resistance: Keep the cord in place for about 10 minutes to allow the -​ The epithelial attachment refers to the connection gums to retract. between the gum tissue and the tooth. It takes about Summary: 1 N/mm of force to resist the separation of this The Single Cord Technique is used for healthy gums and is attachment. ideal for 1 to 3 prepared teeth. It’s a gentle method that Pressure During Periodontal Probing: involves placing a cord soaked in astringent around the tooth, -​ When the dentist uses a probe to measure the depth letting it sit for 10 minutes to create space for the procedure. of the gum around the tooth (periodontal probing), the force applied is typically between 1.31 - 2.41 N/mm. WHY USE ASTRINGENT? This pressure is used to assess how tight or loose the An astringent is used in the Single Cord Technique for these gum is around the tooth. main reasons: Pressure to Insert the Cord: Shrink the gums: -​ To insert the gingival retraction cord into the gum, it -​ It makes the gums shrink and move away from the requires more pressure than probing—around 2.5 - 5 tooth, giving more space for the dental procedure. N/mm. This force is necessary to push the cord into Control bleeding: the gingival sulcus to temporarily move the gum -​ It helps stop minor bleeding by tightening the blood tissue away from the tooth. vessels in the gums. Pressure for a 0.5 mm Gingival Opening: Clearer view: -​ If the goal is to create a 0.5 mm opening in the gum (a -​ It helps the dentist see the tooth better by making the small gap around the tooth), it will require about 0.1 gums tighter and less swollen. N/mm of pressure to achieve this. In short, the astringent helps shrink the gums, reduce bleeding, and make the area easier to work on. Summary: It takes 1 N/mm of force to resist the attachment of the gum to Double Cord Technique - Simple Explanation the tooth. The Double Cord Technique Probing the gum requires 1.31 - 2.41 N/mm. -​ is used in cases where the gums are inflamed or To insert the retraction cord, 2.5 - 5 N/mm of pressure is there's excessive bleeding. It's a two-step method that needed. helps create more space around the tooth for better For a small 0.5 mm opening in the gum, only about 0.1 N/mm dental impressions or work. of pressure is required. Indication (When to Use It): TECHNIQUE FOR PLACEMENT OF CORD INTO THE Gingival inflammation (swollen or irritated gums). GINGIVAL SULCUS Increased bleeding (hemorrhage) during the procedure. The Single Cord Technique Disadvantage: -​ is a simple and gentle method used to manage the The healing and re-attachment of the gums can be gums (gingiva) during dental procedures like unpredictable, meaning it might not always return to its original impressions. It’s one of the least traumatic position smoothly. techniques, meaning it causes minimal stress or harm Procedure: to the gum tissue. First Cord (Thin cord): A very thin cord (like size #00 with 0.3 mm diameter) Indications (When to Use It): -​ is placed 0.5 mm below the tooth's finish line (the Healthy gums that don’t bleed. edge where the crown or restoration will sit) for 5 For 1 to 3 teeth that have been prepared for a dental minutes. This helps push the gum away slightly. procedure (like a crown). Second Cord (Larger cord): A larger, impregnated cord (soaked in an astringent) Procedure: -​ is placed on top of the first one for 8-10 minutes. This Isolate the quadrant: step helps stop bleeding (hemostasis) and further The area of work is isolated to keep it dry and free from pushes the gum back. saliva. Remove Second Cord: Select the right cord: The second, larger cord is removed just before taking the Choose a cord that is the right length and diameter for the impression. This ensures the area is clean and the gum tissue job. is in the correct position. Prepare the cord: Remove First Cord: Dip the cord in an astringent solution (a substance that helps After temporization and cementation (placing temporary shrink the tissue) and then squeeze out the excess liquid using restorations and cementing them), the first cord is removed to gauze. clear any remaining impression material from the sulcus (the Sometimes, if the gums are inflamed or unhealthy, they might space between the gum and the tooth). bleed when the cords are placed. This can mess up the Summary: impression because blood or fluids might get into the mold, The Double Cord Technique uses two cords: - making it less accurate. -one thin and one larger. Risk of Irreversible Gingival Retraction: -The thin cord is placed first to move the gums slightly, and the If the dentist is too rough with the cords or leaves them in too larger cord is placed to stop bleeding and push the gums back long, it could cause the gums to recede permanently. This more. could expose more of the tooth than desired, which might -After a few minutes, the larger cord is removed before taking affect the look and function of the crown later. the impression, and the thin cord is removed later after the In Simple Terms: temporary restoration is placed. The double cord technique is useful because it gives a clear -This technique is good for managing inflamed gums and impression of the tooth, but it can be a little uncomfortable and bleeding, but the gum healing afterward can be unpredictable. requires careful technique. If done poorly, it can hurt the gums, cause bleeding, or even lead to long-term gum problems. But if DIFFERENCE BETWEEN SINGLE AND DOUBLE? done well, it helps get a very accurate mold for things like Single Cord: crowns -​ One cord, used for healthy gums, less bleeding. Double Cord: CHEMICO-MECHANICAL TECHNIQUE & MODERN -​ Two cords, used for inflamed gums or heavy bleeding, CHEMICALS USED WITH CORD provides more retraction This technique combines chemical agents with the mechanical pressure of a retraction cord to manage the BOTH USED ASTRINGENT SOLUTION FOR? gingival tissues during restorative orprosthodontic procedures. cord contains an astringent solution that helps stop bleeding The purpose of this technique is to enlarge the gingival sulcus by constricting blood vessels in the gum tissue. This is and to control fluids like blood and crevicular seepage during especially helpful when there is increased hemorrhage or if the procedures. gums are inflamed. 1. Hemostatic agents First Cord: A. Ferric sulphate - controls bleeding effectively The first (larger) cord 2. Astringent -​ is placed into the gingival sulcus around the tooth. It is A. Aluminium chloride designed to gently push the gingiva away from the B. Aluminium sulphate tooth, creating space for the impression material. 3. Vasoconstrictor Second Cord: A. Epinephrine The second (smaller) cord - -​ is then placed on top of the first one, often deeper into EPINEPHRINE: the sulcus. This second cord further compresses the Advantages: gingiva to create a wider space. Excellent tissue displacement Hemostasis Advantages of the Double Cord Technique: No long-term tissue damage Accurate and Precise Impression: This method helps the dentist get a very clear and detailed Contraindications: impression of your tooth. It makes sure the edge of the tooth Heart disease, Hypertension, Diabetes, Hyperthyroidism, (where the crown will fit) is visible, so the mold is as precise as Drug interactions possible. No Chemical Substances Added to the Sulcus: GELCORD & STAT GEL Unlike other methods, the double cord technique doesn’t These products works for the purpose; for hemostasis and always use chemicals around the gum line (like special tissue retraction medicines to stop bleeding or control swelling). This can be a GelCord: 25% aluminium sulphate good thing for people who might react to these chemicals, Stat Gel: 15% ferric sulphate avoiding any irritation. Infusion Technique: