Introduction Laboratory Materials ADVANCES in PROSTHODONTIC

Annals of SBV Annals of SBV

and their potential role in apexogenesis and apexification. Int what is the critical size defect for pulp and dentin. Endod J. 2009;42(11):955–62. 2. In the cell free approach for pulpal 6. Trope M. Regenerative potential of dental pulp. J Endod. and dentin regeneration, migration of cells 2008;34(7 Suppl):S13–7. from nearby should occur to differentiate into 7. Huang GT-J. A paradigm shift in endodontic management of ADVANCES IN PROSTHODONTIC BIOMATERIALS odontoblastic lineages. Thus non-odonblastic lineage immature teeth: conservation of stem cells for regeneration. J Dent. 2008;36(6):379–86. Dr. P. S. Manoharan, Dr. Balaji J differentiating into the odontoblastic lineages 8. Jung I-Y, Lee S-J, Hargreaves KM. Biologically based and its predictability is not ascertained till now. treatment of immature permanent teeth with pulpal necrosis: a 3. While it has been proven that the pulp- case series. J Endod. 2008;34(7):876–87. dentin regeneration does occur in the experimental 9. Hargreaves KM, Giesler T, Henry M, Wang Y. Regeneration Abstract condition using cell based approach, non-cell potential of the young permanent tooth: what does the future based approaches have failed to do the same. hold? J Endod. 2008 ;34(7 Suppl):S51–6. Prosthodontics is a specialty that involves the replacement and restoration of lost dental structures with 10. Banchs F, Trope M. Revascularization of immature permanent Moreover, the quality of the pulp and dentin teeth with apical periodontitis: new treatment protocol? J artificial substitutes. Many biomaterials have been developed to satisfy the demands laid by the functional, formed in terms of function and prevention of Endod. 2004;30(4):196–200. esthetic requirements of the stomato-gnathic system. The considerable advancements in this particular field, further bacterial insult, is not being addressed. 11. Reynolds K, Johnson JD, Cohenca N. Pulp revascularization have often left the practicing dentist perplexed with regards to the correct choice. This paper provides an 4. Good manufacturing practice facilities are of necrotic bilateral bicuspids using a modified novel technique overview of the key recent advancements and milestones in biomaterial science in prosthodontics not cost effective to initiate stem cell based pulp to eliminate potential coronal discolouration: a case report. Int regeneration; the importance given is not much may Endod J. 2009;42(1):84–92. Key words: Prosthodontic biomaterials, impression materials, Ceramics, Implants, silicones. 12. Petrovic V, Stefanovic V. Dental tissue--new source for stem be pulpal disease is not a life threatening issues. cells. ScientificWorld Journal . 2009;9:1167–77. 13. Cells B. Stem cells for tooth engineering. European cells and Conclusion matierals.2008;16:1–9. Introduction following discussion will be based on the various 14. Peters O a. Translational opportunities in stem cell-based commonly encountered biomaterials with their state The current status of literature has also raised endodontic therapy: where are we and what are we missing? J Biomaterials used in the field of prosthodontia of art and recent updates. valid questions such as” Is odontoblast mandatory Endod . 2014;40(4 Suppl):S82–5. are those used for the replacement of the lost 15. Li Y, Shu L-H, Yan M, Dai W-Y, Li J-J, Zhang G-D, et for regenerated tissue?”; “Is complete mineralization al. Adult stem cell-based apexogenesis. World J Methodol. dentition. Of the plethora of Prosthodontic Laboratory Materials or just healthy connective tissue considered as the 2014;4(2):99–108. biomaterials available, the clinician is often puzzled [2] acceptable outcome of root canal therapy?” 16. Saber SEM. Tissue engineering in endodontics Key Elements with the choice of an appropriate biomaterial Denture Base Resins for Tissue Engineering. J Oral Sci. 2009;51(4):495–507. because of lack of sound scientific rationale and To translate the bench work to clinics, the 17. Galler KM, Eidt A, Schmalz G. Cell-free approaches for dental thorough knowledge and understanding of these Flexible denture base material directions should be clear whether the goal is pulp tissue engineering. J Endod . 2014;40(4 Suppl):S41–5. materials. Most commonly, the clinician is guided 18. Casagrande L, Cordeiro MM, Nör S a, Nör JE. Dental pulp repair or regeneration. Most importantly, what is stem cells in regenerative dentistry. Odontology. 2011;99(1):1– by hearsay knowledge of the use of materials These materials evolved as a result of dentist the replacement tissue needed as the end result of 7. from other clinicians and medical representatives. satisfying the patient’s need for a softer clasp the regenerative therapies? The research and growth 19. Nakashima M, Akamine A. The Application of Tissue Evidence based practices should be encouraged to and ease of insertion. This material (polyamide) in the pulpal regeneration is rapidlyevolving and in Engineering to Regeneration of Pulp and Dentin in gain confidence in the use of dental biomaterials by is considered to be ideal for partial dentures. The one/ two decades, there will be a paradigm shift in Endodontics. J Endod. 2005;31(10):711–8. any dental practitioner. resin is a biocompatible nylon thermoplastic. Its 20. Demarco Flávio Fernando, Conde Marcus Cristian Muniz, the clinical treatment protocol. Along with this, there Cavalcanti Bruno Neves, Casagrande Luciano, Sakai Vivien unique physical and aesthetic properties provide may be demand for newer diagnostic tools and new Advances are aimed at improving the existing unlimited design versatility and eliminates the Thiemy NJE.Dental Pulp Tissue Engineering . Braz Dent j. [1] disease classification. This will enable preservation of 2013;22(1):3–13. materials and to welcome new materials, so that the concern about acrylic allergies. The denture is healthy tooth structure, as more natural and biologic 21. Kitamura C, Nishihara T, Terashita M, Tabata Y, Washio A. final restoration is made biocompatible and survive thin and lightweight and flexible enough to enter material will be used for replacement for lost pulp- Local regeneration of dentin-pulp complex using controlled in the oral environment for considerable period below the undercuts. But it is unbreakable and does dentin tissue. release of fgf-2 and naturally derived sponge-like scaffolds. Int of time. It is important to be aware of the current not stain easily. It is comfortable to the patient as no J Dent. 2012;2012:190561. 22. El-Backly RM, Massoud AG, El-Badry AM, Sherif R a, Marei trend of dental practices and recent advancements of tooth or tissue preparation is needed. The denture is References MK. Regeneration of dentine/pulp-like tissue using a dental materials so that the dentist and the patient would esthetically very pleasing. pulp stem cell/poly(lactic-co-glycolic) acid scaffold construct be benefitted. 1. Goldberg M. Pulp healing and regeneration: more questions in New Zealand white rabbits. Aust Endod J. 2008;34(2):52– Microwave Cured Denture Base Resin than answers. Adv Dent Res.2011;23(3):270–4. 67. 2. Schmalz G, Galler KM. Tissue injury and pulp regeneration. J Biomaterial can be understood as any biologic 23. Rosa V, Zhang Z, Grande RHM, Nör JE. Dental pulp tissue or synthetic substance that can be introduced into This resin is manipulated similar to conventional Dent Res. 2011;90(7):828–9. engineering in full-length human root canals. J Dent Res. 3. Andreasen JO, Bakland LK. Pulp regeneration after non- 2013;92(11):970–5. body tissue as part of an implanted medical device resins up to the point of curing. The microwave infected and infected necrosis, what type of tissue do we want? 24. Fouad a F. The microbial challenge to pulp regeneration. Adv or used to replace an organ, bodily function, etc. The makes curing easier than conventional methods. A review. Dent Traumatol. 2012;28(1):13–8. Dent Res. 2011;23(3):285–9. 4. Murray PE, Garcia-Godoy F, Hargreaves KM. Regenerative 25. Alongi DJ, Yamaza T, Song Y, Fouad AF, Elaine E. Tissue endodontics: a review of current status and a call for action. J regeneration potential. 2011;5(4):617–31. * Dr. P. S. Manoharan, Prof and Head, *Dr. Balaji. J, Sr. Lecturer, Department of Prosthodontics and Crown & Endod. 2007;33(4):377–90. 26. Huang GT-J, Garcia-Godoy F. Missing Concepts in De Novo Bridge, Indira Gandhi Intitute Dental Sciences, Sri Balaji Vidyapeeth, Puducherry 607402, India. 5. Friedlander LT, Cullinan MP, Love RM. Dental stem cells Pulp Regeneration. J Dent Res. 2014;93(8):717–24.

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Three minutes and a standard 500 watt microwave of the cross-linked and micro-filled composite teeth. graphite die to erode the metal to final shape via need for the patient to have a bone graft, making are needed to cure higher quality and more precise [10] spark erosion. [12-14] the surgery simpler, faster and cheaper. dentures. This process saves time, while increasing the accuracy and strength of denture bases. Source Titanium and its Alloys Waxes Clipping implant systems of the activator is the heat generated by the colliding molecules which moves or vibrates around their axis. Titanium is the most popular and commonly Light curing waxes This screw-less dental implant system connects [2, 3] used among the metallic biomaterials in the field of implant and supra structure with a novel clipping medicine and dentistry. Titanium and its alloys are The wax patterns of the metallic frameworks mechanism. Fatigue of material, resulting in loose Ultra high impact heat-cured denture base resins getting much attention for biomedical applications of the removable partial dentures could be made or broken screws and unintended malformations, is because of excellent biocompatibility, light weight, directly on the cast, using profiled waxes like: Ti- a possibility. [19] These resins evolved with the demand for high excellent balance of mechanical properties and Light or LiWa (light curing waxes). These waxes impact strength for the denture base material. These corrosion resistance. Pure titanium and alpha + eliminate duplicating techniques for the working Surface modifications materials incorporate reinforcing materials and a beta type titanium alloys including the Ti-6Al-4V, models and saves time. They are used for all types curing temperature range that render them to be were originally designed for use as general structural of metal works, crowns, bridges, implants. After Dental implant surfaces are modified by titanium superior in their physical properties. These resins materials, especially for aerospace structures, and modeling, these waxes can be cured by any standard plasma spraying, acid etching, laser sintering or are claimed to be easily finished and polished, offer only later adopted for biomedical applications. lab UV or halogen light. These waxes are easy to use, sandblasting. Surface coating with crystalline accurate fit and require at least 2 hours for heat However, the toxicity of the beta-stabilizing element economic, cures quickly, has appreciable strength and amorphous phases of titanium fluorapatite polymerization. [4, 5] Vanadium was later pointed out. Therefore V in an elasticity and they are odorless and stable. [15, 16] and hydroxyapatite is done to enhance the the Ti-6Al- 4V has been replaced by other beta- osseointegration ability of titanium to bone. The Glass fiber reinforced denture base resins stabilizing elements Fe or Nb, both of which are Magnets in Prosthetic Dentistry titanium implant surface oxide layer modification considered to be safer for the living body can be done by anodically oxidising Ti in a Several types of fibers, including carbon, aramid, Magnets have generated great interest within proprietary electrolytic solution resulting in an woven polyethylene and glass fibers, have been Low-modulus beta-type titanium alloys dentistry and their application are numerous. The increased thickness of oxide layer (coronally 1-2µm used to strengthen denture base resins. Carbon and composed of nontoxic and non-allergic elements, two main areas of their interest are in the field of and apically 10µm) and a porous surface topography. aramid fibers strengthened the resin but caused such as Ti-29Nb-13 Ta- 4.6 have been developed for orthodontics as well as removable prosthodontics. Bio-chemical modifications of implant surfaces clinical problems, such as difficulty in polishing medical and dental applications. The low modulus The reason for their popularity is related to their by incorporation of bone morphogenetic proteins and poor aesthetics. Woven polyethylene fibers of this alloy effectively accelerates the healing of small size and strong attractive forces that allows and growth factors have done in the intention to are more aesthetic, but the process of etching, bone fracture and re-growth of bone. This type of them to be placed in prosthesis without being enhance the bone formation around the surface of preparing, and positioning layers of woven fibers alloy is also expected to be used in dental implants obtrusive within the mouth. the implant. may be impractical for the dental office. Silanated as well as in fixed dental prostheses such as crowns, glass fibers are the fibers of choice for reinforcing inlays, bridges, and dentures. Very recently, nickel The main magnetic materials used is the rare One approach for controlling cell-biomaterial denture base polymers. Improvement in flexural free shape-memory and/or super elastic beta- earth elements Neodymium-Iron Boron (Nd, Fe, interactions utilize cell adhesion molecules. properties and fatigue resistance are seen with the type titanium have been developed for biomedical and B). Other materials used include RE Alloy, Since identification of the Arg-Gly-Asp (RGD) use of glass fibers. [6-9] applications. Samarium-Cobalt (Sm-Co). Samarium iron nitride sequence as a mediator of attachment of cells to is a promising new candidate for permanent magnet several plasma and extra cellular matrix proteins, Denture Teeth Casting titanium application. including fibronectin, vitronectin, Type I collagen, osteopontin and bone sialoprotein, researchers have Composite Denture Teeth Titanium has a high melting point (16600c) and is Another advancement includes the encapsulation been depositing RGD – containing peptides on melted using electric plasma arc or inductive heating of the pre-existing magnets within a relatively inert biomaterials to promote cell attachment. Cell surface Micro filled denture teeth and Nano-filled in a melting chamber filled with inert gas or held alloys such as stainless steel or titanium. [17, 18] receptors in the integrin super family recognize the denture teeth are available. Knoop hardness values in a vacuum. The molten metal then is transferred RGD sequence and mediate attachment. [20] (KHN) ranged from 28.2 to 29.8 for micro-filled to the refractory mold via centrifugal or pressure- Implant Systems composite, 18.9 to 21.6 for cross-linked acrylic, vacuum filling.[11] A second approach to biochemical surface 22.7 for nano-composite, and 18.6 for conventional Porous Titanium Foam Implants modification uses biomolecules with demonstrated acrylic teeth. All micro-filled composite teeth were Machining titanium osteotropic effects. Many growth factors have significantly harder than other teeth. The wear depth The new porous titanium foam dental implants been cloned and are recombinantly expressed. values were 90.5 μm for the nano-composite, 69.8 Dental implants generally are machined from has been developed at the NRC Industrial Materials They have effects ranging from mitogenicity (e.g., to 93.0 μm for the micro-filled composite, 80.8 to billet stock of pure metal or alloy. Dental crowns Institute (NRC-IMI) in Longueil. Unlike current interlukin growth factor-1, FGF-2 and platelet 104.0 μm for the cross-linked acrylic, and 162.5 μm and bridge frameworks also can be machined from solid titanium implants, the NRC-IMI material is rich plasma to increase activity of bone cells (e.g. for conventional acrylic teeth. The nano-composite solid metal stock via computer-aided machining. porous. This provides a site for bone cells to grow Transforming growth factor –1. (TGF—1) enhances tooth was harder and more wear resistant than the Another method for fabricating dental appliances is into the implant and more solidly anchor it. This new collagen synthesis) to osteoinduction (e.g., bone acrylic teeth but not significantly different from most electric discharge machining, which uses a fabricated porous yet durable material facilitates the creation morphogenetic proteins (BMPs). By delivering one of implants in smaller sizes. Its use will avoid the or more of these molecules which normally play

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Page 32 Ann. SBV, July - Dec 2014;3(2) Ann. SBV, July - Dec 2014;3(2) Page 33 Annals of SBV ADVANCES IN PROSTHODONTIC BIOMATERIALS essential roles in osteogenesis , directly to the tissue- Stay put attributed to finely dispersed Lucite crystals, which Procera System implant interface, it is possible that bone formation increase the resistance to crack propagation. [24] may be promoted in implant applications. Platelet Stay put is so pliable that it stays where you put These all-ceramic individual restorations comprise rich plasma (PRP) , a modification of fibrin glue it. Stay-put is a unique combination of softly braided Advantages are lack of metal, translucent ceramic a densely sintered alumina core. It contains 99.9% made from autogenous blood, is being used to deliver retraction cord and an ultra fine copper filament core, high flexural strength, Excellent fit and alumina and it the hardest among ceramics used. It growth factors in high concentration to sites where which can be easily adapted and can be preformed. esthetics. Disadvantages are potential for fracture if can be used for anterior, posterior crowns, veneers, bone formation is needed. Growth factors released It does not lift out of the sulcus, does not unravel, no used in posterior region. Its use is limited to use as a onlays and inlays. [27, 28, 29] from plasma includes platelet derived growth factor overlapping is required and it is non-impregnated; core material for crowns and very short span bridges. (PDGF), transforming growth factor(TGF), platelet but can be impregnated with an astringent or Captek System derived epidermal growth factor, platelet derived hemostatic solution as required. (22 23) Techcerem angiogenesis factor, insulin growth factor 1(IGF-1) Captek is acronym for capillary casting technology. and platelet factor. [21] Ceramics A thin (0.1 – 1.0) alumina core base layer is An alternative methodology for elimination of the produced using thermal spray technique resulting casting process from metal-bonded crowns and Gingival Retraction Systems Dental Ceramics are non-metallic, inorganic, in a density of 80 to 90%. Optimum strength and bridges. This technique involves the adaptation of structures primarily containing compounds of translucency are achieved by a sintering process at a wax strip, impregnated with a gold platinum- Expasyl oxygen with one or more metallic or semi-metallic 1170°C. The range of base layer thickness makes palladium powdered alloy, to a refractory die. Firing elements. They are characterized by their refractory this technique versatile and appropriate to a range produces a rigid porous layer which is then in filled It is temporary gingival retraction system. It nature, high hardness, susceptibility to brittle fracture of restoration types. Subsequent reproduction of with gold from a second wax strip by capillary action. is an alternate to traditional gingival retraction at relatively low stresses and chemical inertness. aesthetics is achieved by the incremental application The finalized metal coping is then veneered with procedures (gingival retraction cords). It is a painless, Recent advances in ceramic materials are In Ceram, of a range of specially developed porcelains in the porcelain. The advantages of this system are said to fast, reliable and high quality system for temporary Empress, Tech Ceram, Cad/Cam, Procera system, traditional manner include improved marginal fit (attributed to use of opening of sulcus. Captek system, the capillary cast, rather than the lost wax technique) CAD/CAM and enhanced aesthetics and biocompatibility.[30] Expasyl is aluminum chloride in paste form. In-Ceram Expasyl system separates marginal gingiva from Computer aided designing and computer Recent Core Materials and Technologies tooth without harming the epithelial attachment. In-Ceram is supplied as one of the three core aided manufacturing (CAD/CAM) technology in Opening of sulcus does not cause bleeding. The materials dentistry is increasing, both in the dental laboratory The most recent core materials for all-ceramic risk of gingival recession or bone resorption that 1. In Ceram Spinel and general practice settings, to fabricate all-ceramic FPDs are the yttrium tetragonal Y-TZP-based are sequel to damage caused to epithelial attachment 2. In Ceram Alumina inlays, onlays, crowns, and veneers. Only one CAD/ materials. Y-TZP-based materials were initially is eliminated. 3. In Ceram Zirconia. CAM system that is available for in-office chair introduced for biomedical use in orthopedics for total side use, namely CEREC® 3D. A digital image hip replacement and were highly successful because Magic foam cord A slurry of one of these materials is slip cast on is captured of the tooth preparation. This image of the material’s excellent mechanical properties a porous refractory die and heated in a furnace to contains three dimensional information regarding and biocompatibility. In the early 1990s, the use of Magic Foam Cord is the expanding PVS produce a partially sintered coping. The partially size of the tooth and defect being restored. The Y-TZP expanded into dentistry (endodontic posts material. Magic Foam Cord is a Non-haemostatic sintered core is infiltrated with glass to eliminate restoration is designed in the computer. A tooth and implant abutments) and Y-TZP is currently gingival retraction system. Designed for easy and porosity and strength slip core. Its fracture toughness colored block of ceramic or composite is then used being evaluated as an alternative core material for fast retraction of the gingival sulcus without the is higher than conventional porcelain. In-ceram to machine the restoration. full-coverage restorations such as all-ceramic crowns potentially traumatic and time consuming packing Spinel is indicated for anterior single unit inlays, and all-ceramic FPDs. of retraction cord. Magic Foam Cord material is on lays, crowns and veneers. In-ceram Alumina is Improvements to the original system include new syringed around the crown preparation margins indicated for anterior and posterior crowns and In- software, the introduction of finer grained porcelain Yttrium oxide is a stabilizing oxide added to pure and a cap (Comprecap) is placed to reportedly ceram Zirconia is indicated for posterior crowns and blocks to reduce oppositional wear, a wider range of zirconia to stabilize it at room temperature and to maintain pressure. After five minutes, the cap and FPD. The collective advantages of all three glass- preformed ceramic block shades and conversion to generate a multi phase material known as partially foam are removed and the tooth is ready for the infiltrated core materials are an electric turbine with better cutting control for stabilized zirconia. The exceptional mechanical final impression. 1. Lack of metal. greater fitting accuracy. The newer milling systems properties of YTZP (high initial strength and fracture 2. Relative high flexural strength and toughness. include the use of the blocks in gradient form to toughness) are due to the unique physical property Advantages are non-traumatic method of 3. Ability to be use any luting cement. mimic the translucency of the tooth structure. All of partially stabilized zirconia. Tensile stresses acting temporary gingival retraction, easy and fast the blocks which are being used in the recent past are at the crack tip induce a transformation of the meta- application directly to the sulcus without pressure or Empress bar coded, that holds the information of the block stable tetragonal zirconium oxide form into the packing, effortless removal. It contains no hemostatic used with the CAD data, which would enable the monoclinic form. chemicals that may contaminate the impression This ceramic is hot pressed injection molded technician to fabricate a similar restoration, in case ceramics. It utilizes the lost wax technique. A of clinical failure of a restoration. [25, 26] This transformation is associated with a local Lucite re-enforced glass ceramic is pressed into the increase of 3% to 5% in volume. This increase in mold at 1050 temperature. The increased strength is volume results in localized compressive stresses

Page 34 Ann. SBV, July - Dec 2014;3(2) Ann. SBV, July - Dec 2014;3(2) Page 35 Annals of SBV ADVANCES IN PROSTHODONTIC BIOMATERIALS essential roles in osteogenesis , directly to the tissue- Stay put attributed to finely dispersed Lucite crystals, which Procera System implant interface, it is possible that bone formation increase the resistance to crack propagation. [24] may be promoted in implant applications. Platelet Stay put is so pliable that it stays where you put These all-ceramic individual restorations comprise rich plasma (PRP) , a modification of fibrin glue it. Stay-put is a unique combination of softly braided Advantages are lack of metal, translucent ceramic a densely sintered alumina core. It contains 99.9% made from autogenous blood, is being used to deliver retraction cord and an ultra fine copper filament core, high flexural strength, Excellent fit and alumina and it the hardest among ceramics used. It growth factors in high concentration to sites where which can be easily adapted and can be preformed. esthetics. Disadvantages are potential for fracture if can be used for anterior, posterior crowns, veneers, bone formation is needed. Growth factors released It does not lift out of the sulcus, does not unravel, no used in posterior region. Its use is limited to use as a onlays and inlays. [27, 28, 29] from plasma includes platelet derived growth factor overlapping is required and it is non-impregnated; core material for crowns and very short span bridges. (PDGF), transforming growth factor(TGF), platelet but can be impregnated with an astringent or Captek System derived epidermal growth factor, platelet derived hemostatic solution as required. (22 23) Techcerem angiogenesis factor, insulin growth factor 1(IGF-1) Captek is acronym for capillary casting technology. and platelet factor. [21] Ceramics A thin (0.1 – 1.0) alumina core base layer is An alternative methodology for elimination of the produced using thermal spray technique resulting casting process from metal-bonded crowns and Gingival Retraction Systems Dental Ceramics are non-metallic, inorganic, in a density of 80 to 90%. Optimum strength and bridges. This technique involves the adaptation of structures primarily containing compounds of translucency are achieved by a sintering process at a wax strip, impregnated with a gold platinum- Expasyl oxygen with one or more metallic or semi-metallic 1170°C. The range of base layer thickness makes palladium powdered alloy, to a refractory die. Firing elements. They are characterized by their refractory this technique versatile and appropriate to a range produces a rigid porous layer which is then in filled It is temporary gingival retraction system. It nature, high hardness, susceptibility to brittle fracture of restoration types. Subsequent reproduction of with gold from a second wax strip by capillary action. is an alternate to traditional gingival retraction at relatively low stresses and chemical inertness. aesthetics is achieved by the incremental application The finalized metal coping is then veneered with procedures (gingival retraction cords). It is a painless, Recent advances in ceramic materials are In Ceram, of a range of specially developed porcelains in the porcelain. The advantages of this system are said to fast, reliable and high quality system for temporary Empress, Tech Ceram, Cad/Cam, Procera system, traditional manner include improved marginal fit (attributed to use of opening of sulcus. Captek system, the capillary cast, rather than the lost wax technique) CAD/CAM and enhanced aesthetics and biocompatibility.[30] Expasyl is aluminum chloride in paste form. In-Ceram Expasyl system separates marginal gingiva from Computer aided designing and computer Recent Core Materials and Technologies tooth without harming the epithelial attachment. In-Ceram is supplied as one of the three core aided manufacturing (CAD/CAM) technology in Opening of sulcus does not cause bleeding. The materials dentistry is increasing, both in the dental laboratory The most recent core materials for all-ceramic risk of gingival recession or bone resorption that 1. In Ceram Spinel and general practice settings, to fabricate all-ceramic FPDs are the yttrium tetragonal Y-TZP-based are sequel to damage caused to epithelial attachment 2. In Ceram Alumina inlays, onlays, crowns, and veneers. Only one CAD/ materials. Y-TZP-based materials were initially is eliminated. 3. In Ceram Zirconia. CAM system that is available for in-office chair introduced for biomedical use in orthopedics for total side use, namely CEREC® 3D. A digital image hip replacement and were highly successful because Magic foam cord A slurry of one of these materials is slip cast on is captured of the tooth preparation. This image of the material’s excellent mechanical properties a porous refractory die and heated in a furnace to contains three dimensional information regarding and biocompatibility. In the early 1990s, the use of Magic Foam Cord is the expanding PVS produce a partially sintered coping. The partially size of the tooth and defect being restored. The Y-TZP expanded into dentistry (endodontic posts material. Magic Foam Cord is a Non-haemostatic sintered core is infiltrated with glass to eliminate restoration is designed in the computer. A tooth and implant abutments) and Y-TZP is currently gingival retraction system. Designed for easy and porosity and strength slip core. Its fracture toughness colored block of ceramic or composite is then used being evaluated as an alternative core material for fast retraction of the gingival sulcus without the is higher than conventional porcelain. In-ceram to machine the restoration. full-coverage restorations such as all-ceramic crowns potentially traumatic and time consuming packing Spinel is indicated for anterior single unit inlays, and all-ceramic FPDs. of retraction cord. Magic Foam Cord material is on lays, crowns and veneers. In-ceram Alumina is Improvements to the original system include new syringed around the crown preparation margins indicated for anterior and posterior crowns and In- software, the introduction of finer grained porcelain Yttrium oxide is a stabilizing oxide added to pure and a cap (Comprecap) is placed to reportedly ceram Zirconia is indicated for posterior crowns and blocks to reduce oppositional wear, a wider range of zirconia to stabilize it at room temperature and to maintain pressure. After five minutes, the cap and FPD. The collective advantages of all three glass- preformed ceramic block shades and conversion to generate a multi phase material known as partially foam are removed and the tooth is ready for the infiltrated core materials are an electric turbine with better cutting control for stabilized zirconia. The exceptional mechanical final impression. 1. Lack of metal. greater fitting accuracy. The newer milling systems properties of YTZP (high initial strength and fracture 2. Relative high flexural strength and toughness. include the use of the blocks in gradient form to toughness) are due to the unique physical property Advantages are non-traumatic method of 3. Ability to be use any luting cement. mimic the translucency of the tooth structure. All of partially stabilized zirconia. Tensile stresses acting temporary gingival retraction, easy and fast the blocks which are being used in the recent past are at the crack tip induce a transformation of the meta- application directly to the sulcus without pressure or Empress bar coded, that holds the information of the block stable tetragonal zirconium oxide form into the packing, effortless removal. It contains no hemostatic used with the CAD data, which would enable the monoclinic form. chemicals that may contaminate the impression This ceramic is hot pressed injection molded technician to fabricate a similar restoration, in case ceramics. It utilizes the lost wax technique. A of clinical failure of a restoration. [25, 26] This transformation is associated with a local Lucite re-enforced glass ceramic is pressed into the increase of 3% to 5% in volume. This increase in mold at 1050 temperature. The increased strength is volume results in localized compressive stresses

Page 34 Ann. SBV, July - Dec 2014;3(2) Ann. SBV, July - Dec 2014;3(2) Page 35 Annals of SBV ADVANCES IN PROSTHODONTIC BIOMATERIALS being generated around and at the tip of the crack Fluoride containing alginate Hydrophilic Polyvinyl Siloxane With the siloxane groups on the polymer chain, that counteract the external tensile stresses acting a material that is dimensionally stable and has on the fracture tip. This physical property is known Addition of NaF or SnF2 in an alginate To improve hydrophilic properties, surfactant good recovery from deformation is combined with as transformation toughening. impression material may result in effective release and hydrophilic monomer are added which result hydrophilic properties that the polyether groups of fluoride without deteriorating the properties of in a truly low contact angle. A lower contact angle produce. SENN has a platinum catalyst. The tear Because of their material-inherent advantages, material itself. Fluoride-containing dental alginate measure means greater “wettability”, displacing oral strength is a little low, but the wetting properties of Y-TZP-based all-ceramic restorative systems may impression materials can exert a considerable fluids for a more detailed impression. These additives SENN are good. It is supplied as a putty - heavy, allow prosthodontists to use traditional clinical reduction in enamel solubility also increase surface energy within the material, and medium, and wash materials - in either a fast or procedures similar to those used in the fabrication therefore increase detailed reproductions, even in the regular set material. These hybrid materials have of metal-ceramic restorations in terms of preparation Chromatic Alginate presence of blood and saliva. However, addition of the intrinsic hydrophilicity necessary to improve design and cementation procedures. With Y-TZP- surfactants makes the preparation of electroformed impression making by wetting a tooth and allowing based systems that use a CAD/CAM technology, This alginate provides rapid processing and dies more difficult as the metallizing powder does easy pouring for cast fabrication. [35] ceramists use new techniques and technologies in setting times. It has improved compatibility with not adhere well to the surface of hydrophilic addition addition to traditional ones. Such new technologies plaster of paris. It is thixotropic, does not drip and silicone.[33] Maxillofacial Prosthesis Materials [36,37] may allow the production of consistent high- only flows when pressure is exerted during the quality Y - TZP frameworks in terms of design and impression procedure. It is also uniform, smoother Vinyl Poly ether Silicone These biomaterials are developed to fabricate fabrication, strength, fracture toughness, and stress- and the compact surface enables a higher definition restorations of acquired or congenital maxillofacial corrosion resistance. of detail. Three-phases of chromatic alginate are as Yet another effort to improve the mechanical defects. The polymethyl methacrylate resins are gold follows: Purple phase denotes mixing time, orange and physical properties of the elastomer is the standard for rehabilitations intraorally. The extra oral They are esthetic, have clinically acceptable phase denotes processing time and the yellow phase introduction of Vinyl Poly Ether Silicone which defects need restorations which not only closes the marginal fit, and allow the ceramist to use traditional indicates insertion into the mouth. is a hybrid of poly-vinyl siloxane and polyether. defect but also resist the ravages of time, temperature veneering procedures with the compatible esthetic This material is made hydrophilic and relatively and other mechanical and physical properties such porcelain. In addition, such systems may prove to be Auto-Mix Alginate rigid by virtue of the polyether component and the as dimensional stability, colour stability etc. A few simple to handle and less technique sensitive from properties of flow and detail reproduction is offered of the recently evolved maxillofacial materials have a clinical standpoint while providing patients with AlgiNot is a time-saving, cost-effective alternative by polyvinyl siloxane. been discussed below, which has stood the test of esthetic and functional restorations. to traditional alginate. It is not hand mixed, time. improving the handling characteristics. Thus it saves This material is available in light body, monophase The long-term results of these studies are time. This material is not affected by the disinfectant, and heavy body consistencies which can be used in Isophorone Polyurethane paramount to the assessment of their long-term thus infection control is assured. a single step technique, double step technique and success and for the establishment of more specific putty wash technique. It is claimed that there may be A unique polyurethane elastomers based on a guidelines for proper patient selection that will Silgimix a possible loss of detail reproduction if the material cycloaliphatic di isocyanate monomer is being ensure long-term predictable esthetic and functional in incompletely mixed. Although the manufacturers developed and tested. The material is formulated success. [31, 32] This is an alginate replacement impression claim mechanical and physical properties superior as a three-component kit comprising an isocyanate- material. Silgimix is developed from vinyl polysiloxane to other elastomers, further studies are required to terminated prepolymer, a triol as the cross-linking Impression Materials chemistry. It addresses the shortcomings of alginate substantiate the evidence.[34] agent, and an organotin catalyst. The elastomers materials by giving users the ability to disinfect, the have unusually high strength compared to other Alginate is the most commonly used impression option of pouring multiple times and the ability to Nano-filled Poly vinyl Siloxane aliphatic polyurethanes. This is due to cycloaliphatic material and has the advantages such as quick setting scan the impression electronically. isopherone moiety in the vulcanized network. The time, low cost, and mild flavor. But it has considerable Nano-fillers are integrated in poly vinyl siloxane aliphatic nature of the polymer improves resistance disadvantages like poor dimensional stability, messy, Rubber based impression materials are non- impression material It has improved hydrophilic to the sunlight degradation common to aromatic hazardous dust, and needs repetitive hand mixing. aqueous impression materials. The most widely properties, better flow, enhanced detail and polyurethanes. The system is not hazardous to the used rubber based impression material is polyvinyl precision. The newest class of elastomeric impression prosthodontist or the patient. Dustless Alginate siloxane (PVS). This widespread use is attributed to materials is a vinyl-polyether hybrid material called its dimensional stability, ease of handling, excellent SENN. SE-4524U To overcome these disadvantages various elastic recovery, good detail reproduction, ability modifications have been done like dustless Alginate to pour multiple casts from single impression. A SENN combines properties from addition This silicone is representative of family of which Contain high algin content. Glycerin is significant limitation of PVS is its hydrophobicity. silicone and polyether impression materials. It is polymers that require moderate to high temperatures incorporated on alginate particles. The high align This causes difficulty in impression making a polymer with polyether and siloxane (addition for the initiation of the cross-linking reaction. content provides for a quality impression without procedure in presence of blood and saliva and also silicone) groups. With the polyether groups, a the excessive flow. during pouring a cast. To overcome this limitation hydrophilic material is produced without the use The Silastics 44514 and 44515 available from hydrophilic polyvinyl siloxane has been introduced. of a surfactant. Dow Corning are of the same general type. General Electronic provides the SE-4524U material in the

Page 36 Ann. SBV, July - Dec 2014;3(2) Ann. SBV, July - Dec 2014;3(2) Page 37 Annals of SBV ADVANCES IN PROSTHODONTIC BIOMATERIALS being generated around and at the tip of the crack Fluoride containing alginate Hydrophilic Polyvinyl Siloxane With the siloxane groups on the polymer chain, that counteract the external tensile stresses acting a material that is dimensionally stable and has on the fracture tip. This physical property is known Addition of NaF or SnF2 in an alginate To improve hydrophilic properties, surfactant good recovery from deformation is combined with as transformation toughening. impression material may result in effective release and hydrophilic monomer are added which result hydrophilic properties that the polyether groups of fluoride without deteriorating the properties of in a truly low contact angle. A lower contact angle produce. SENN has a platinum catalyst. The tear Because of their material-inherent advantages, material itself. Fluoride-containing dental alginate measure means greater “wettability”, displacing oral strength is a little low, but the wetting properties of Y-TZP-based all-ceramic restorative systems may impression materials can exert a considerable fluids for a more detailed impression. These additives SENN are good. It is supplied as a putty - heavy, allow prosthodontists to use traditional clinical reduction in enamel solubility also increase surface energy within the material, and medium, and wash materials - in either a fast or procedures similar to those used in the fabrication therefore increase detailed reproductions, even in the regular set material. These hybrid materials have of metal-ceramic restorations in terms of preparation Chromatic Alginate presence of blood and saliva. However, addition of the intrinsic hydrophilicity necessary to improve design and cementation procedures. With Y-TZP- surfactants makes the preparation of electroformed impression making by wetting a tooth and allowing based systems that use a CAD/CAM technology, This alginate provides rapid processing and dies more difficult as the metallizing powder does easy pouring for cast fabrication. [35] ceramists use new techniques and technologies in setting times. It has improved compatibility with not adhere well to the surface of hydrophilic addition addition to traditional ones. Such new technologies plaster of paris. It is thixotropic, does not drip and silicone.[33] Maxillofacial Prosthesis Materials [36,37] may allow the production of consistent high- only flows when pressure is exerted during the quality Y - TZP frameworks in terms of design and impression procedure. It is also uniform, smoother Vinyl Poly ether Silicone These biomaterials are developed to fabricate fabrication, strength, fracture toughness, and stress- and the compact surface enables a higher definition restorations of acquired or congenital maxillofacial corrosion resistance. of detail. Three-phases of chromatic alginate are as Yet another effort to improve the mechanical defects. The polymethyl methacrylate resins are gold follows: Purple phase denotes mixing time, orange and physical properties of the elastomer is the standard for rehabilitations intraorally. The extra oral They are esthetic, have clinically acceptable phase denotes processing time and the yellow phase introduction of Vinyl Poly Ether Silicone which defects need restorations which not only closes the marginal fit, and allow the ceramist to use traditional indicates insertion into the mouth. is a hybrid of poly-vinyl siloxane and polyether. defect but also resist the ravages of time, temperature veneering procedures with the compatible esthetic This material is made hydrophilic and relatively and other mechanical and physical properties such porcelain. In addition, such systems may prove to be Auto-Mix Alginate rigid by virtue of the polyether component and the as dimensional stability, colour stability etc. A few simple to handle and less technique sensitive from properties of flow and detail reproduction is offered of the recently evolved maxillofacial materials have a clinical standpoint while providing patients with AlgiNot is a time-saving, cost-effective alternative by polyvinyl siloxane. been discussed below, which has stood the test of esthetic and functional restorations. to traditional alginate. It is not hand mixed, time. improving the handling characteristics. Thus it saves This material is available in light body, monophase The long-term results of these studies are time. This material is not affected by the disinfectant, and heavy body consistencies which can be used in Isophorone Polyurethane paramount to the assessment of their long-term thus infection control is assured. a single step technique, double step technique and success and for the establishment of more specific putty wash technique. It is claimed that there may be A unique polyurethane elastomers based on a guidelines for proper patient selection that will Silgimix a possible loss of detail reproduction if the material cycloaliphatic di isocyanate monomer is being ensure long-term predictable esthetic and functional in incompletely mixed. Although the manufacturers developed and tested. The material is formulated success. [31, 32] This is an alginate replacement impression claim mechanical and physical properties superior as a three-component kit comprising an isocyanate- material. Silgimix is developed from vinyl polysiloxane to other elastomers, further studies are required to terminated prepolymer, a triol as the cross-linking Impression Materials chemistry. It addresses the shortcomings of alginate substantiate the evidence.[34] agent, and an organotin catalyst. The elastomers materials by giving users the ability to disinfect, the have unusually high strength compared to other Alginate is the most commonly used impression option of pouring multiple times and the ability to Nano-filled Poly vinyl Siloxane aliphatic polyurethanes. This is due to cycloaliphatic material and has the advantages such as quick setting scan the impression electronically. isopherone moiety in the vulcanized network. The time, low cost, and mild flavor. But it has considerable Nano-fillers are integrated in poly vinyl siloxane aliphatic nature of the polymer improves resistance disadvantages like poor dimensional stability, messy, Rubber based impression materials are non- impression material It has improved hydrophilic to the sunlight degradation common to aromatic hazardous dust, and needs repetitive hand mixing. aqueous impression materials. The most widely properties, better flow, enhanced detail and polyurethanes. The system is not hazardous to the used rubber based impression material is polyvinyl precision. The newest class of elastomeric impression prosthodontist or the patient. Dustless Alginate siloxane (PVS). This widespread use is attributed to materials is a vinyl-polyether hybrid material called its dimensional stability, ease of handling, excellent SENN. SE-4524U To overcome these disadvantages various elastic recovery, good detail reproduction, ability modifications have been done like dustless Alginate to pour multiple casts from single impression. A SENN combines properties from addition This silicone is representative of family of which Contain high algin content. Glycerin is significant limitation of PVS is its hydrophobicity. silicone and polyether impression materials. It is polymers that require moderate to high temperatures incorporated on alginate particles. The high align This causes difficulty in impression making a polymer with polyether and siloxane (addition for the initiation of the cross-linking reaction. content provides for a quality impression without procedure in presence of blood and saliva and also silicone) groups. With the polyether groups, a the excessive flow. during pouring a cast. To overcome this limitation hydrophilic material is produced without the use The Silastics 44514 and 44515 available from hydrophilic polyvinyl siloxane has been introduced. of a surfactant. Dow Corning are of the same general type. General Electronic provides the SE-4524U material in the

Page 36 Ann. SBV, July - Dec 2014;3(2) Ann. SBV, July - Dec 2014;3(2) Page 37 Annals of SBV ADVANCES IN PROSTHODONTIC BIOMATERIALS

16. Kenneth J. Anusavice. Philips’ Science of dental Materials, 28. Anusavice K J. Recent developments in restorative dental form of unprocessed gum stock, with or without and esthetic requirements of the restorations and W.B. Saunders Company; A division of Harcourt Brace & ceramics. J Am Dent Assoc 1993; 124: 72-84. incorporated catalyst. The vulcanization reaction replacements in the complex oral environment. Company, 11th edition,1999. 29. Jason AG. Recent advances in materials for all-ceramic involves the combination of methyl groups on the 17. Highton R, Caputo AA, Pezzoli M, Matyas J. Retentive restorations. Dent clin N Am 2007: 51; 713-27. polymer chains. An organic peroxide is used to It is mandatary that clinicians should be updated characteristics of different magnetic systems for dental 30. Rizkalla AS, Jones DW. Indentation fracture toughness and initiate the cross-linking reaction. about various biomaterials and their manipulative applications. J Prosthet Dent 1986;56:104-6. dynamic elastic moduli for commercial feldspathic dental 18. Riley MA, Walmsley AD, Harris IR. Magnets in prosthetic porcelain materials. Dent Mater 2004; 20:198–206. characteristics and technical considerations which dentistry. J Prosthet Dent 2001; 86:137–42. 31. Luthardt RG, Holzhuter MS, Rudolph H, et al. CAD/ With this material, the prostheses must be would enable them to render quality care for patients. 19. Tomas A, Wennerberg A. Oral implant surface: part 2 – CAM-machining effects on Y-TZP zirconia. Dent Mater fabricated at a temperature high enough to cause review focusing on clinical knowledge of different surfaces. 2004;20:655-662. decomposition of the peroxide catalyst. References Int J Prosthodont 2004; 17: 544-64. 32. Giordano R, Morgano S, Papanagiotou H, and Pober R. 20. John B. Brunski. Biomaterials and Biomechanics of Oral Invitro evaluation of low temperature aging effects and PDM Siloxane 1. Prashanti E, Jain N, Shenoy VK, Reddy JM, Shetty B T, and Maxillofacial Implants: Current Status and Future finishing procedures on the flexural strength and structural Saldanha S. Flexible dentures: A flexible option to treat Developments. Int J Oral Maxillofac Implants 2000;15: 15- stability of Y-TZP dental ceramics. J Prosthet Dent 2006; edentulous patients. Journal of Nepal dental association 46. 96:154-64. It is a type of HTV silicone that has physical 2010; 11: 85-7. 21. G. Ajay kumar. Recent Advances in Dental Implantology. 33. Shetty R M, Bhander G R, Mehtha D. Vinyl polysiloxane and mechanical properties that exceeded values 2. Yannikakis S, Zissis A, Polyzois G, Andreopoulos A. Journal of Dental and Medical Sciences 2012;3: 28-30. ether – A breakthrough in Elastomeric impression material. considered clinically acceptable. Evaluation of porosity in microwave-processed acrylic resin 22. Ferrari M, Cagidiaco MC, Ercoli C. Tissue management World journal of dentistry 2014; 5(2): 134-37. using a photographic method. J Prosthet Dent 2002; 87: with a new gingival retraction material: a preliminary clinical 34. Johnson GH, Chellis KD, Gordon GE, lepe X. Dimensional Q7-4635, Q7-4650, Q7-4735, SE-4524 U 613-9. report. J Prosthet Dent 1996: 75; 242-47. stability and detail reproduction of irreversible hydrocolloid 3. Levin B, Sanders JL, Reitz PV. The use of microwave energy 23. Bowles WH, Tardy SJ, Vahadi A. Evaluation of new gingival and elastomeric impression disinfected by immersion. J for processing acrylic resins. J Prosthet Dent 1989; 61:381- retraction agents. J Dent Res 1991; 70: 1447-52. Prosthet Dent 1998; 79: 446-53. These are new generation of HTV silicones, which 85. 24. Rouse JS. Use of heat-pressed leucite reinforced porcelain 35. Wadhwani CP, Johnson GH, Lepe X, Wataha JC. Accuracy have improved mechanical and physical properties. 4. Yadav NS, Elkawash H. Flexural strength of denture base in “difficult” veneer cases: A clinical report. J Prosthet Dent of reformulated fast set vinyl poly siloxane impression The processing characteristics of Q7-4635 and SE- resin reinforced with aluminum oxide and processed by 1996; 76(5): 461-63. material using dual arch trays. J Prosthet Dent 2009; 101 : 4524U were particularly favorable because of their different processing techniques. J Adv Dental Research 2011; 25. Dianne Rekow. Dental CAD CAM Systems. State of the art. 332-41. single component system with unlimited shelf life. 26: 214-19. J Am Dent Assoc 1991;122: 43-48. 36. Woofaardt JF, Chandler HD, Smith BA. Mechanical 5. John J, Gangadhar SA, Shah I. Flexural strength of heat- 26. Werner H Mormann, Andreas Bindel. All ceramic, chairside properties of a new facial prosthetic material. J Prosthet Dent polymerized polymethyl methacrylate denture resin computer aided dental restoration. Dent Clin N Am 2002: 1985; 53: 228-36. MDX 4-4210 reinforced with glass, aramid, or nylon fibers. J Prosthet Dent 46; 405-26. 37. John F Lontz. State of the art material used for maxillofacial 2001; 86:424-27 27. Brunton PA, Smith P, Mc Cord JF, Willson NH. Procera all- prosthetic reconcstruction. Dent Clin N Am 1990: 34; 2-14. Because of remarkable improvements over the 6. Franklin P, Wood DJ, Bubb NL. Reinforcement of poly ceramic crowns: a new approach to an old problem? Br Dent older Silastic polymers, this material has become (methyl methacrylate) denture base with glass flake. Dent J 1999;186: 430 – 34. Mater 2005; 21:365-70. increasingly popular in the maxillofacial clinics. 7. Puri G, Berzins DW, Dhuru VB, Raj PA, Rambhia SK, The elastomer is based primarily on a modified Gunjan Dhir, Dentino AR, Effect of phosphate group poly dimethyl siloxane (PDMS) structure, and the addition on the properties of denture base resins. J Prosthet vulcanization mechanism involves the addition of Dent 2008; 100: 302-08. Si-H groups to Si-vinyl units. A platinum catalyst 8. Vuorinen AM, Dyer SR, Lassila LVJ, Vallittu PK. Effect of initiates the cross-linking reaction; the curing rigid rod polymer filler on mechanical properties of polymethyl methacrylate denture base material. Dent Mater reaction is sensitive to any contaminant which is 2008; 24: 708–13. capable of coordination with the platinum catalyst. 9. Cheng Y, Sakai T, Moroi R, Nakagawa M, Sakai H Self- Amines, sulfur and tin compounds are especially cleaning Ability of a Photo catalyst-containing Denture troublesome and inhibit the cure of the material. Base Material. Dent Mater 2008; 27: 179-86. 10. Suzuki S. In vitro wear of nano-composite denture teeth. Int A-2186 J Prosthodont. 2004; 13(4):238-43. 11. Low D, Mori T. Titanium full crown casting: thermal expansion of investments and crowns accuracy. Dent Mater It is a recently developed material whole physical 1999; 15:185-90. and mechanical properties are inferior compared to 12. Hung CC, Hou GC, Tsai CC. Pure titanium casting into MDX 4-4210. zirconia-modified magnesia-based investment molds. Dent Mater 2004; 20: 846–51. 13. Paulino SM, Leal BC, Pagnano VO, Bezzon OL. The Conclusion castability of pure titanium compared with Ni-Cr and Ni- Cr-Be alloys. J Prosthet Dent 2007; 98: 445-54. Although, marked breakthrough in technology 14. Ellingsen JE, Johansson CB, Wennerberg A, Holmen and recent advancements in biomaterials present with A. Improved retention and bone to implant contact with a massive assortment of materials and techniques, fluoride modified titanium implants. Int J Oral Maxillofac it is ultimately the job of the practicing dentist to Implants 2004; 19: 659-66. choose the materials to suit the biological, functional 15. William J.O’brein: Dental Materials and their selection: Quintessence Publishing Co., 3rd edition; 1985.

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