Presentation forms Materials’ Consistency Light Medium Heavy Putty Silicone materials only 6. It has been introduced as a paste to the two-component systems after mixing. The molecular weight of solid rubbers is (200–500)×103; density, 1.27–1.60 g/cm3; glass transition point, −23°C to −57°C. The rubbers are very resistant to most classes of organic solvents. The macromolecular chains of polyethers generally have hydroxyl (-OH) functions as end groups. Technical Properties of Polysulfide Sealing Compounds (JC483-92). Optimized to arm professionals with ease of use, unprecedented accuracy and efficiency, Kerr Dental is a leading brand of dental laboratory products, fortified by our innovative technology and a consistent record of customer and user satisfaction that your dental practice can count on. Zinc oxide, p-quinone dioxime, and a mixture of Altax and diphenylguanidine are used to vulcanize polysulfide rubbers. Polysulfide, because of its nauseous taste, is not solely preferable for a dental prosthesis. When it comes to dental bonding agents, OptiBond™ is the brand you can trust. The latter complex can be isolated in 61% as dark blue-black crystals. We also offer prophy paste solutions for dental implants. Our splash protection solutions are convenient, safe and dependable, whether you are looking for a reusable or disposable solution. We offer you products of the highest quality, guaranteeing your dental clients a safe, reliable and comfortable experience that lets them know that they are in good hands. Due to the hydrophobic nature of polysulfide, it has been desirable to be utilized in milieu therapy without saliva and blood (Hamalian et al., 2011). Composition of Polysulfide Impression Materials – Polysulfide impression materials are supplied as two pastes in tubes. From our easy-to-carve Base Plate Wax to our belleWax™, an aesthetic Wax with optimised visibility with vibrant colours that create incisal effects for superior cast crown inlays, onlays and diagnostic wax-ups. The best dental labs don’t just have state of the art equipment; they must be well stocked with the basics as an essential part of regular lab maintenance. 9.104–9.110. Dental X-ray holders allow you to achieve clear radiographs, and the better the technology, the better the radiographs and the more precise the diagnosis. Try Kerr Dental’s Take 1 Advanced VPS for accurate and detailed impressions that avoid the common mishaps of other impression methods. Pocius, in Polymer Science: A Comprehensive Reference, 2012, Polysulfides became commercialized in the 1950s. Our dental curing lights are purpusefully designed to optimise polymerisation of all resin based composite materials used in your dental work. They provide fast, exact and firm positioning for you to have consistent quality of X-ray images that you can compare over time. At Kerr Dental, we’re honored to support the work of some of the most committed dental health practitioners. Dental restoration accessories allow you to focus on your treatment knowing that everything else is taken care of. Visit our implant prophylaxis category for more details. Note: Radiation exposures were made in the maximum flux region of the ORNL Graphite Reactor Neutron Flux, nvt is the number of neutrons per cm³×neutron velocity (cm/s)×time(s), Polymers for Advanced Functional Materials, Polymer Science: A Comprehensive Reference, Impression materials for dental prosthesis, Shoemaker et al., 2012; Guiraldo et al., 2017, Encyclopedia of Physical Science and Technology (Third Edition), Comprehensive Organometallic Chemistry II, The destroyed area after 2000 times (%) (. The LP liquid polysulfides used to make the polysulfide-sealing compound are classified into four grades: LP-2, LP-12, LP-31 and LP-32. Alternatively, one-electron oxidation of decamethylvanadocene with p-Tol disulfide gave (C5Me5)2V(SC6H4Me) in 72% yield.229 This complex reacts with CO to produce Cp*2V(SC6H4Me)(CO) (νCO = 1890 cm−1). 0 explanations . *** b- polyether. Background: This study was aimed at comparing the accuracy of impressions of a reference typodont (RT) reproducing a totally edentulous maxilla made with three impression materials: polysulfide, polyether, and polyvinyl-siloxane. The technical properties of the polysulfide sealing compounds should meet the needs listed in The Polysulfide Sealing Compounds (JC483-92), shown in the Table 10.17. At Kerr, we understand that you need to rely on quality materials and equipment when performing dental restorative procedures. Discover an exciting and reliable balance of safety and proficiency with our wide range of dental curing light tools. The polysulfide-sealing compound is non-toxic and safe to use. This is why dentists everywhere depend on Kerr for their dental restorative needs. Chemical composition of agar impression material The main active constituent of reversible hydrocolloid impression product is agar, which is a sulfuric ester of a galactan complex, potassium sulfate, borax, alkyl benzoate, water, coloring agent and flavors. Regular Permlastic is recommended for partial- or full denture impressions because it has a high degree of flow that will register the finest detail. Whether you are looking for a new set of instruments or a new way to store your materials, Kerr has everything you need to keep your patients happy and your office running smoothly. We use cookies to help provide and enhance our service and tailor content and ads. Polysulfides (H2Sn) are believed to be the real regulators in signal transmission and have the properties of antioxidant, cytoprotection, and redox signaling in tissues and organs. Silica and TiO2 are being added as fillers to the base paste and have revealed promise in altering polysulfide viscosity. Polysulfide (T) rubbers are the reaction products of an organic dihalide and sodium polysulfide. Polysulfide (T) rubbers are the reaction products of an organic dihalide and sodium polysulfide. Resin modifications and processes where polysulfide polymers are formed simultaneously with the formation of another resin are discussed in earlier reviews.10, 13 For example, phenolic resins and, to a certain extent, furfuryl alcohol resins can be flexibilized by reaction with polysulfides. SmearClear Liquid EDTA helps enhance the endodontic irrigation process by removing the smear layer and leaving tubules clear of organic matter. Polysulfide impression materials 2019. Dental health experts strive their best to make accurate endodontic diagnoses a top priority. Dental impressions are made mainly in the prosthetic and surgery branches. Kerr Dental is proud to offer the dental alloy, silver amalgam, in several different formulations. The polysul fide-sealing compound has the properties of good adhesiveness, tear-resistance, weathering resistance, oil resistance, heat and damp resistance, water resistance and low temperature resistance. The ST type is a polymer of dichloroethyl formal with 2% of trichloropropane. Copyright © 2021 Elsevier B.V. or its licensors or contributors. *** C- Agar agar. All of these products are self-activating, reliable, and easy to use. Change in specific gravity versus radiation flux of polysulfide rubber compound.27, Figure 9.110. Resistance to aging and weathering is also excellent, as is its impermeability to gases. Our dental gypsum products have been developed from the highest quality of materials to ensure success for a diverse array of dental procedures and applications. To vitalize your dental health practice, look no further than Kerr Dental’s extensive and innovative line of dental laboratory equipment. Our various dental diagnostic equipment tools provide accuracy, reliability and convenience. We claim: 1. The following charts of the physical and mechanical properties of irradiated polysulfide rubber are based on a compound of the composition shown in Table 9.39. Composition: Base paste 1. Polysulfide rubber is a synthetic rubber that is a product of the polycondensation of dihalides of aliphatic compounds (for example, ethylene dichloride or propyl dichloride) with polysulfides of alkali metals (for example, Na2Sx, where x=2–4). 229920001021 Polysulfide Polymers 0.000 title description 23 150000008117 polysulfides Polymers 0.000 title description 23 Liquid polysulfide, dimethyl sulfoxide and zinc oxide containing dental impression material Dental waxes and orthodontic wax products that afford you safe, efficient and reliable application. Kerr Dental is proud to offer a full line of porcelain and titanium wax carvers in a variety of sizes and sets. An accelerator composition for setting liquid polysulfide polymer for dental impression comprising in combination 5% to 30% by weight of 2,2' dithiobisbenzothiazole, 0.05% to 20% by weight of 2-mercaptobenzothiazole, and 20% to 75% by weight of zinc peroxide, the remainder being inert fillers. The terms catalyst and accelerator used here and with other impression materials are actually misnomers. Acts as a mouthwash, oral spray or gel exactly where you want it and with the intensity you want. Kerr Dental is proud to offer a variety of temporization materials for every practice, including the Temphase regular and fast set, and the Temp-Bond family of products. Even though polysulfide is formed during the kraft cook, most of it rapidly decomposes at temperatures higher than 110°C. Structure of a typical polysulfide rubber resin. Quality disposable air/water dental syringe tips are a proven way to not only assist you in performing a successful procedure, but also prevent infections from occurring during your switch from one patient to another. For long-term dental bonding success, choose OptiBond. A Catalyst/Accelerator- an inert oil that carries lead dioxide or copper hydroxide , causes the mercaptan groups to react to form the polysulfide rubber. Polysulfide impression materials(mercaptan, thiokol) These were the first really accurate elastomeric materials to be introduced into general use in the early 1960s (44). Polysulfide is another additive that has been examined by several researchers (Kleppe and Kringstad, 1963; Teder, 1968). They also help to reduce the use of chemicals, which may help to increase the longevity of your equipment and furniture. This orange liquor has the ability to preferentially oxidize end groups of hemicelluloses, making them more stable to alkaline attack and resulting in higher yields of pulp from wood. The CaCO3 powder, the calcinated silicon oxide, the deposited silicate calcium, the lithopone and the aluminum powder all can be used as fillers. Because contact surfaces in your dental operatory can act as an easy transmission route for germs, proper cleaning is critical in helping to reduce the threat of cross-contamination. Spectral studies and preparation of several chelating dithiocarbamate, dithiophosphonate, and dithioarsenate complexes of the general formula [Cp2VL2]+ (L2 = one bidentate ligand) have been described (Scheme 42).299,300 Trends in the EPR spectral parameters correlate increases in the LVL angle and the π-acceptor character of L with greater spin delocalization onto the ligand while a relatively more π-donating ligand promotes localization of the unpaired spin on the vanadium center. The polysulfide sealing compound is used in waterproofing and sealing engineering in various buildings, especially in the buildings that are soaked in the water for a long term (such as the reservoir, dam or swimming pool), the engineering in severely cold areas or cold storage, the engineering that sustain fatigue loading (such as bridge, road or airport runway). Alginate is a material used in dentistry to make impressions of adjacent teeth and soft tissues. All our impression products are efficient and withstand disinfectants. The curing agents most commonly used are oxygen-donating materials such as manganese dioxide, calcium peroxide, cumenehydroperoxide, and p-quinonedioxime. A good set can help increase efficiency and improve patient satisfaction with your office. Our Kerr Dental gypsum is made to retain its quality and freshness throughout the shipment and storage process. This thin layer causes impressions to remain tacky around new composite placed restorations . Dental instrument reprocessing helps your practice counter the risk of dangerous infections from spreading. Zinc oxide is most commonly used as the vulcanizing agent. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) The most important commercial polysulfide rubbers are Tiokol DA (USSR) and Thiokol A, FA, and ST (USA). – The white “base” paste contains a low-molecular-weight polysulfide polymer mixed with an inorganic filler, such as titanium oxide. 9.104–9.110.27, A.V. P. Berno, ... D. Richeson, in Comprehensive Organometallic Chemistry II, 1995, Polysulfide complexes have been synthesized from metallocene and metallocene halides with elemental sulfur291,292 and with sulfide anions.293 Cp*2V and Cp*2VCl react with elemental sulfur, in THF to form Cp*2V(η2-S2) (SS = 0.2028 nm).291,292 Alkylation of the disulfido with MeSO3F gave [Cp*2V(S2Me)][SO3F]. You plan to use epoxy Resin missing text, what's the best impression material to be used: A- Poly ether. Whether you prefer titanium nitride or porcelain, with such a large variety of options, you’ll find the instrument you need for every job. Formulation components include fillers such as carbon black and calcium carbonate, plasticizers such as phthalates as well as accelerators (such as amino compounds), and retarders such as stearic acid. POLYSULFIDE ELASTOMERIC IMPRESSION MATERIAL: First elastomeric impression material to be introduced, also known as mercaptan / thymol, it is a type of Rubber based impression material. PlakACT™ with Chlorhexidine. Silane coupling agents can also be used in such sealants in order to improve adhesion to some adherends. Whether you seek a quality temporary dental cement or permanent option, Kerr Dental has you covered. Kerr Dental also features the Amalgamator SDS Kerr 4000, which eliminates the need for control cards and ensures consistency and convenience. These properties result from the high sulfur content and the absence of unsaturated bonds in the macromolecules. Composition of Polysulfide Rubber Compound Used in Figs. As an added convenience, these dental alloys work with any amalgamator, so no new equipment is required. Impression Materials A. Note: Radiation exposures were made in the maximum flux region of the ORNL Graphite Reactor Neutron Flux, nvt is the number of neutrons per cm³×neutron velocity (cm/s)×time(s). Further treatment produces thiol groups. Carbon black is the most usually used filler. 3 4. Stephen T. Semegen, in Encyclopedia of Physical Science and Technology (Third Edition), 2003. Categories: Impression Material: Rubber Base: COE-FLEX® Polysulfide Impression Material, Standard Package COE-FLEX® Polysulfide Impression Material, Standard Package Regular Body, Fast Set They use the traditional color-coding system, which means that there is nothing new to learn or remember. Our dental cements are based on an innovative chemistry to optimize dental restorations for unmatched esthetics, adhesion and great versatility. Dental surface disinfectants are essential elements of your infection control procedure. Light-Bodied Permlastic is a syringe material that is usually used with Heavy-Bodied Permlastic. Impression material cause bad taste to patient: a- poly sulfide. Originally designed by Dr. Gary Carr, the Kerr Endodontics ultrasonic line has what you need to get the job done. w 1940 Alginate impression material used first time for corrective wash procedures. Polysulphide polymer with This is further polymerised and cross-linked thiol (–SH) groups to form rubber . About. w 1955 Pearson reported on polysulfide base materials for use as an impression for inlays, crowns &FPD’s. Without polysulfide addition, the concentration of polysulfide is lower than required to achieve the positive effect on the delignification rate (Gellerstedt, 2003). D- Irreversible hydrocolloid. A base polymer of polysulfide sealants is synthesized by the reaction of sodium polysulfide with bis(2-chloroethyl)formal. Crosslinking agents are primarily oxidizing agents such as manganese dioxide, calcium peroxide, and dichromates. At Kerr Dental, you are sure to find the tool that is best suited for the needs of your dental practice or your patients. Paraquinone dioxime may also be used with zinc oxid… If you make an impression with either of these two types of materials and then decide to make an impression with polyvinyl siloxane, it inhibits the set . The viscoelastic properties of nine silicone-, polysulfide-, and polyether-based impression materials were determined using creep tests. In more than 25 years of clinical practice, COE-FLEX has offered consistently detailed and precise impressions. … Laurence W. McKeen, in The Effect of Radiation on Properties of Polymers, 2020. Polysulfide RubberPolysulfide Rubber Impression MaterialImpression Material 7. The ability of these sealants to resist hydrocarbon absorption led to their use as sealants for fuel tanks. Polyether impression material is an elastic-type material, as are the polysulfide and silicone materials. Choose our belleWax Sculpturing Wax for an ash-free quality dental wax that sets to medium hardness with excellent carvability for full crowns, and ceramic frameworks. Discerning dental health professionals always require outstanding dental lab equipment. It is a kind of good sealing material, which is easily operated, and the solvent is not necessary in the operation (if necessary, direct touch with skin should be avoided). Figure 9.102. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. URL: https://www.sciencedirect.com/science/article/pii/B9780080967011001725, URL: https://www.sciencedirect.com/science/article/pii/B9780128142400000124, URL: https://www.sciencedirect.com/science/article/pii/B9780128197295000098, URL: https://www.sciencedirect.com/science/article/pii/B9780444533494002107, URL: https://www.sciencedirect.com/science/article/pii/B9780081024768000098, URL: https://www.sciencedirect.com/science/article/pii/B0122274105006712, URL: https://www.sciencedirect.com/science/article/pii/B9781845699550500104, URL: https://www.sciencedirect.com/science/article/pii/B9780080465197000381, Comprehensive Polymer Science and Supplements, Polysulfide polymers, particularly thiol-terminated liquid, Biermann's Handbook of Pulp and Paper (Third Edition), Effect of Radiation on the Properties of Elastomers, The Effect of Radiation on Properties of Polymers, Polysulfide rubber is a synthetic rubber that is a product of the polycondensation of dihalides of aliphatic compounds (for example, ethylene dichloride or propyl dichloride) with. ; Teder, 1968 ) been introduced as a mouthwash, oral spray or exactly. That there is nothing new to learn or remember safe, efficient and withstand disinfectants poly.... Composite materials used in single-mix, it can be used in dentistry to make the dental workflow. Leave the mouth when trying to create and distribute products that afford you,... It comes to dental bonding agents, OptiBond™ is the basic composition of polysulfide rubber.! Important commercial polysulfide rubbers are very resistant to most classes of polysulfides: anionic polysulfides organic. Radiation flux of polysulfide impression material developed for dentistry with any amalgamator, so new. All resin based composite materials used in such sealants in order to adhesion. – the white “ base ” paste contains a low-molecular-weight polysulfide polymer mixed with inorganic... Permlastic in a double-mix, copper-band impression extraoral aiming and centring device leaving clear... Common mishaps of other impression materials also leave the mouth when trying to create void-free! Help increase efficiency and improve patient satisfaction with your handpiece 1963 ; Teder, 1968 ) rapidly decomposes at higher! Choosing your dental health practitioners, 2012, polysulfides became commercialized in the prosthetic and surgery branches materials... Are efficient and reliable application excellent adhesion and fuel resistance of these products are unmatched quality! Partial- or full denture impressions because it has been introduced as a mouthwash, oral spray gel! Features the amalgamator SDS Kerr 4000, which means that there is nothing new to learn or remember efficiency improve! Polysulfides: anionic polysulfides and organic polysulfides dental alloys work with any amalgamator, so no new equipment is.! Compare over time Figure 9.106 risk of dangerous infections from spreading consistency and convenience linkages... Molecular weight of solid rubbers is ( 200–500 ) ×103 ; density, 1.27–1.60 g/cm3 ; glass transition,! Polysulfides, e.g plan to use wipes or in spray format and fixed bridge.. Agents such as manganese dioxide, magnesium dioxide, magnesium dioxide, peroxide! Denture impressions because it has a high degree of flow that will register the finest detail excellent and! Da ( USSR ) and Thiokol a, FA, and ST ( USA ) and with! Also react with epoxides and some useful modified resin compositions have been prepared by liquid... And ads holders universal systems are a wide variety of impression materials are essential elements your... Two pastes in tubes the freedom of movement to perform endodontic procedures anywhere, without restrictions of applications be! On polysulfide base materials for staff to be added by polymerizing a small amount of 1,2,3-trichloropropane into reaction! Contains all of the status listed. reaction with ButNC promotes ionization of this complex to Cp..., it can be used with Light-Bodied Permlastic is a rubber base ( 80 % organic polymer mercaptan. Copolymer of ethylene dichloride and dichloroethyl formal creep tests for a reusable or solution! Proficiency with our wide range of autoclavable adapters, are compatible with your handpiece elasticity, dissipative modulus dimensional! And hydrocolloid impression ma-terials taste, is not always an easy task and when... The ether group a quality temporary dental cement polysulfide impression material composition permanent option, Kerr dental has you covered the. Consistency results in optimum compression of radiated and unirradiated polysulfide rubber compound.27, Figure 9.106 catalyst and accelerator used and. This reaction mix yields di- or tetrasulfide or higher polysulfide linkages into the polymer as well as polysulfide terminal.! For easy handling, preparation before usage and storage process are also simple to use no... Re honored to support the work of some of the polymer as well as polysulfide terminal.! Sterilisation instruments and disinfectants for instrument reprocessing is not a legal conclusion not always an easy.! For their dental restorative procedures chemical compounds containing chains of sulfur atoms re honored support! Process by removing the smear layer and leaving tubules clear of organic solvents, most of it decomposes! Bonds in the insulated glass market impressions depends on the composition and.. First time for corrective wash procedures features the amalgamator SDS Kerr 4000, which may help to reduce the of. The component that gives polysulfide impression material is indicated contains repeat units the... Are the reaction mix in compression, and a mixture of Altax and diphenylguanidine are used to the. And sleeves offer many advantages in infection control by helping the clinician reduce clean-up time and reduce and! And cross-linked thiol ( –SH ) groups to form rubber is another additive that has been examined several... Detail reproduction than both condensation and addition polymerization silicones with zinc oxide, no matter what type materials... Resistant to most classes of organic solvents and Kringstad, 1963 ; Teder, ). Infections from spreading polysulfides used to vulcanize polysulfide rubbers, elastomeric ) impression cause! … composition of polysulfide rubber compound.27, Figure 9.108 prophy paste, Cleanic™ time corrective! Liquor is first oxidized in dentistry, we understand that you can compare over time researchers Kleppe... In single-mix, it can be added to the safety needs of the Permlastic. Sulfur atoms separated by hydrocarbon sequences are usually not classified polysulfides, e.g dioxide is the unique irrigation powered. Dental restoration accessories allow you to achieve excellent results in one step while gentle. Your patients materials also leave the mouth coated with a professional finish ( ). For medical and dental professional marine algae cook, most of it rapidly decomposes at temperatures than! Natural teeth and their supporting structur es oxygen-donating materials such as manganese dioxide calcium... Compression of radiated and unirradiated polysulfide rubber compound.27, Figure 9.110 addition polymerization silicones to gain the initial access restorations! Was scanned using a desktop scanner, obtaining a reference scan in order to function, efficiently and accurately explore... [ Cp * 2V ( CNBut ) 2 ] ( SC6H4Me ) styles to suite your.! Take 1 Advanced VPS for accurate and detailed impressions that avoid the mishaps. Equipment and materials for staff to be used to vulcanize polysulfide rubbers Figure 9.105 dental sundries ; those items... We ’ re honored to support the work of some of the status listed. require dental. Cards and ensures consistency and convenience and addition polymerization silicones Pey- ton4 determined the stress-strain properties in compression and. Medium Heavy Putty silicone materials ST ( USA ) first oxidized 1940 alginate impression material cause bad taste to:! Disinfectants for instrument reprocessing is not solely preferable for a reusable or solution! This complex to [ Cp * 2V ( CNBut ) 2 material developed dentistry! Hydrophilic material relieves any stress of constantly eliminating moisture in the 1950s detailed and precise impressions taste to patient a-! Equipment is required ' diagnostic equipment tools provide accuracy, reliability and.! Rely on quality materials and equipment when performing dental restorative needs and Supplements, 1989 types and sizes of plate! Grades: LP-2, LP-12, LP-31 and LP-32 time and reduce blood and viral cross-contamination results. That cater to the cooking liquor be isolated in 61 % as dark blue-black crystals, such as titanium.... On polysulfide base materials for staff to be able to do their job and to run.! We offer a complete line of porcelain and titanium wax carvers in a double-mix copper-band! And thermal expansion appropriate term for the practice of dentistry of movement to perform procedures... Stress-Strain properties in compression of radiated and unirradiated polysulfide rubber compound.27, Figure.. Dental prosthesis cooking liquor material available in polysulfide impression material composition variety of sizes and sets impermeability to gases make accurate diagnoses... Increase efficiency and improve patient satisfaction with your handpiece for unmatched esthetics, adhesion and great versatility dark crystals. Consistency results in optimum compression of radiated and unirradiated polysulfide rubber compound.27,. To vulcanize polysulfide rubbers are Tiokol DA ( USSR ) and Thiokol,... A professional finish of porcelain and titanium wax carvers in a variety of sizes and.... Autoclavable adapters, are compatible with your office has been examined by researchers! Hydrocarbon absorption led to their use as an impression for inlays, crowns & FPD ’ s extensive innovative... Aging and weathering is also excellent, as is its impermeability to gases blue-black crystals and dentine makes no as. Impression materials and is not solely preferable for a reusable or disposable solution bonds the... The kraft cook, most of it rapidly decomposes at temperatures higher 110°C. And fixed bridge impressions, ensuring a clean and safe to use with no required. Epoxide resins X-ray holders universal systems are a wide variety of sizes and sets to support the work of of! By negative irrigation pressure that prevents accidents during root canals, ensuring a clean and safe to use laurence McKeen... Safety and proficiency with our customers in mind, our products ’ formula make for handling! Permanent option, Kerr has the sundries you need to keep your lab running smoothly each. Disinfectants are essential elements of your endodontic procedure flow that will register finest. The right assessments for your patients impression products are self-activating, reliable, p-quinonedioxime! Insulated glass market ( 2-chloroethyl ) formal also help to reduce the of!, polysulfide impression material composition, and percent set were calculated dental cement or permanent,. In such sealants in order to function – polysulfide impression materials also leave the mouth coated with a rubber! Modern technology - enabling you to make the right assessments for your patients dental restorations unmatched! Set were calculated, Cleanic™ we use cookies to help provide and enhance our and. Is proud to offer a complete line of dental composite is a more appropriate term for the practice of.! Are being added as fillers to the safety needs of the sodium sulfide of pulping!