FIBRE REINFORCED COMPOSITE USEC IN CONSERVATIVE DENTISTRY AND ENDODONTICS

FIBRE REINFORCED COMPOSITES ARE CLASS OF COMPOSITES WHERE FIBRES ARE REINFORCED TO IMPROVE PHYSICAL PROPERTIES

1. FIBRE REINFORCED COMPOSITES

2. Fiber-reinforced composite (FRC) is a synthetic material composite which is a combination of a polymeric matrix and reinforcing fillers. FRC materials present high stiffness and strength per weight when compared with other structural materials along with adequate toughness . INTRODUCTION Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

3. FRCs have been used for numerous applications in various engineering and biomedical fields for a long time ,more commonly applied as restorative and prosthetic materials Fiber is a rope or string used as a reinforcing component of composite materials . Fibers can be as oriented fibre fabrics (a weave) of random fibers (a mat, a veil), into sheets (in plane) . Fibers can also be three-dimensionally oriented. The strongest engineering materials are generally made of continuous unidirectional fibers Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

4. CLASSIFICATION: The reinforcing fibers can be continuous unidirectional ( yarns), continuous bidirectional (weaves and fabrics) continuous random oriented (mat) or discontinuous (short and chopped) random or oriented fibers Fibre reinforced composites in dental application, By Haya Basim Rasan

5. ADVANTAGE S A Review on Fibre Reinforced Composite Resins,Annals of Prosthodontics and Restorative Dentistry

6. DISADVANTAGES A Review on Fibre Reinforced Composite Resins,Annals of Prosthodontics and Restorative Dentistry

7. COMPOSITION & ARCHITECTURE 1 .THE MATRIX IN FRC The polymeric matrix, consisting of polymerized monomers, has the function of holding the fibers together in the composite structure. It also transfers stresses between fibers and protects the fibers from the outside environment such as chemicals, moisture and mechanical shocks. Thus the matrix may influence the compressive strength and other various properties

8. Two types of resins, the cross linked or linear, are used in FRCs. A) The cross linking polymer is also called a thermoset polymer, which include multifunctional or dimethacrylate resins such as epoxy resin, bisphenol A- glycidyl methacrylate (BISGMA) and urethane di-methacrylate (UDMA). B)The linear polymer is also called a thermoplastic polymer, referring to monofunctional methacrylate polymers. In some FRCs the matrix is IPN type, so-called interpenetrating polymer network structure that contains poly bis -GMA as the cross linked phase and poly methyl methacrylate (PMMA) as a linear phase Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

9. 2.THE FIBRES IN FRC Fibres represent the largest volume (from 40 to 65 vol.%) and contribute to stiffness and strength of the matrix and determine the load bearing capacity of FRCs structure . Carbon , Kevlar (p- phenylene diamine ), polyethylene, and glass fibres with micron scale diameter have been used in either unidirectional or woven orientation as reinforcements for dental FRCs. In dentistry, glass fibre reinforcement is frequently used Mechanical and physical properties are related to the orientation of the reinforcement . FRCs can be arranged in different directions (i) unidirectional fiber laminates (ii) discontinuous short and long fiber (iii) bidirectional ( iv) textile fabrics (woven, knitted and braided fabrics) laminates Fibre reinforced composite as dental material

10. unidirectional continuous fibers - anisotropic (have different properties in different direction) Bidirectional - orthotropic (same properties in two directions) Continuous bidirectional - orthotropic properties in a plane Random oriented fibres - isotropic properties(direction independent) Fiber diameters are 6 -18 µm in diameter. With a controlled manufacturing process, a volume fraction of glass fibre can be incroporated into matrix can be 45-65 %. F lexural strength for fibre with 65% fibres is 1230 MPa . Fibre reinforced composite as dental material

11. 3 FIBRE-MATRIX INTERFACE Silanation of fibres has been shown to enhance the surface wettability and improve the adhesion by forming siloxane bridges and hydrogen bonds on the fibre surface The interfacial adhesion of the fibre /matrix depends on the interactions between the components and can either be mechanical or chemical in nature. Mechanical bonding depends on the morphology and surface texture of the fibres , while a chemical covalent bond can be achieved by using appropriate coupling agents .

12. A dhesion is promoted with chemical surface treatment of fibers, called silanization Silane coupling agents are synthetic hybrid inorganic-organic compounds conaining one or more Si-C (or Si-H) bonds. They are used mainly as surface-coating agents for surface modification and as coupling agents. Adhesion of glass fibers to the resin matrix via silane coupling agent -RO groups are hydrophobic alkoxy groups that hydrolyze to hydrophilic Si-OH ( silanols ) which then condense forming chemical bonds and creating a hydrophobic siloxane film Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

13. PROPERTIES OF FIBRE REINFORCED COMPOSIT E WATER SORPTION The matrix absorbs water because of the polarity of the water molecule and because it is smaller than the inter chain distance in the polymer. The water sorption of FRC is 0.3 % and below 2.FLEXURE STRENGTH Flexural strength is  the mechanical parameter of material, which is defined as the material's ability to resist deformation under load. Flexure strength of FRC - 200 to 1,000 Mpa , enamel is 179 dentin is 212- 227 Mpa , composite is 100 to 150 3.FRACTURE TOUGHNESS The fracture toughness of a material reflects the resistance of a material to fracture and represents the energy required to propagate a crack through the material to complete fracture. Fracture toughness of a monomethacrylate -based material is lower than in a dimethacrylate -based material

14. 4.POLYMERIZATION SHRINKAGE continuous unidirectional FRC materials, the shrinkage strain along the fiber was low, whereas the main shrinkage occurred in the transverse direction of the fiber. continuous unidirectional FRCs, the bidirectional FRC showed very little shrinkage strain in either direction. FRC with randomly oriented fibers showed low polymerization shrinkage, but slightly higher than the bidirectional FRC. The short fibers were also effective in restricting the shrinkage anisotropic properties of FRCs results in very low polymerization shrink a ge along the fiber direction, and comparable shrinkage to restorative composite Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

15. TYPES OF FIBER REINFORCEMENTS 1 GLASS FIBER Glass fibers (GFs) have been employed in various forms such as longitudinal, woven mat, chopped fiber (distinct) and chopped mats to enhance the mechanical and tribological properties of the fiber reinforced composites Glass fibers are one of the most widely used polymer reinforcements with nearly 90% of all FRCs made of glass fibers. Of which, the oldest and the most popular form is the E-glass or electrical grade glass. A-glass or alkali glass C-glass or chemical resistant glass high strength R-glass S glass

16. PROPERTIES: tensile strength 3400 Mpa . Glass fibers possess similar refractive index to that of resin .  viscoelastic behavior of polymers reinforced using glass fibers was 15.32 GPa which is comparable to dentin (17GPa)  linear coefficient of thermal expansion for unidirectional glass fiber was found to have an average of 5.0 whereas, dentin is 8.3 enamel is 11.4 and composites 14 -15 ADVANTAGES: acceptable aesthetics non-corrosiveness high toughness non-allergic effect biocompatibility ability to be tailored to meet the specific requirement of many dental applications Fibre reinforced composite as dental material

17. LIMITATIONS can only be used in the particular direction , due to the anisotropy property. Overlying veneering composite is prone to wear. Deficient rigidity for use in long-span bridges. adequate moisture control for adhesive technique. Posterior occlusal restorations should have sufficient space Relatively higher density of glass fibers compared to other fibers as carbon and organic fibers. The S-glass is very costly though their service life is short. A Review on Fibre Reinforced Composite Resins,Annals of Prosthodontics and Restorative Dentistry

18. 2 CARBON FIBER Carbon fiber is the union of many thousands of filaments. Each Filament is made of 99.9% chemically pure carbon with a 5–10 μm diameter .. Carbon fibers were mainly used to improve fatigue behavior and impact strength of the prosthesis. They mainly offer a quality restoration with desirable properties.

19. Advantages of carbon fibres 1-High quality. 2- Light weight. 3-No special equipment required . 4- Better adhesion . 5- Economical. 6-Fracture resistant. Disadvantages of carbon fibres : 1- Unaesthetic. 2- Cannot be recycled and reused. Properties of carbon fibres : 1- Low density . 2- High Stiffness . 3- Abrasion resistance . 4- High fracture strength . Fibre reinforced composites in dental application, By Haya Basim Rasan

20. 5- High fatigue and creep resistance. 6- Biocompatibility. 7- Chemically inert. 8- Dimensional stability. 9- Low coefficient of thermal expansion. 10-Cost effectiveness Indications of carbon fibre : 1-Implant supported Overdentures . 2-Long span bridges. 3- In High strength endodontic posts . 4- Full mouth rehabilitation . 5- Metal free frameworks. 6- Light weight prosthesis. Contraindications of carbon fibre reinforced : 1-High aesthetic concern. 2- Bulky restoration Fibre reinforced composites in dental application, By Haya Basim Rasan

21. KEVLAR FIBER Kevlar is a strong, heat resistant synthetic fiber, related to other aramids Developed by Stephanie in 1965. Kevlar is a manmade fibre , it is as an organic fibre in aromatic polyamide family. The unique properties and distinct chemical composition of aromatic polyamides (aramids) distinguish them from other manmade fibre . Kevlar has a unique combination of high strength, high modulus, toughness and thermal stability. Aramid fibers are widely used for reinforcing composite materials, often in combination with carbon fiber and glass fiber.

22. RIBBOND FIBER A bondable reinforcement material, available commercially since 1992, introduced by D avid N Rudo This material is composed of preimpregnated , silanized , plasma treated, leno woven, ultra high molecular weight (UHMW) polyethylene fibres . ( Leno weave is a special pattern of cross linked, locked stitched threads which increase the durability, stability and shear strength of the fabric). The open and lace- like architecture of the leno woven ribbon allows it to adapt closely to the contours of the teeth and dental arch. The dense network of locked nodal intersections of the material reduces the potential for damage to the fabric architecture by preventing the fibres from shifting during manipulation and adaptation before polymerization. Ribbond is a spectrum of 215 fibers with a very high molecular weight.  . Fiber-reinforced composites in endodontic practice: a review international journal of dental materials

23. Why and how Ribbond composite restorations work INCREASED MICRO-TENSILE BOND STRENGTH The micro-tensile bond strength of the composite is significantly increased when Ribbond is closely adapted and bonded against the cavity walls . MITIGATING THE HARMFUL EFFECT OF C-FACTOR The increased micro-tensile bond strengths decreases the negative c-factor effects.  This phenomenon is especially evident with deep and narrow Class I restorations. MINIMIZES POLYMERIZATION AND DECREASES SHRINKAGE AND LEAKAGE Polymerization shrinkage can result in leakage, and sensitivity.  Closely lining the preparation with Ribbond significantly reduces and minimizes these harmful effects of polymerization shrinkage.   Because the Ribbond is closely adapted to the cavity walls, there is less volume of composite to shrink and less polymerization shrinkage results in less leakage and less sensitivity Fiber-reinforced composites in endodontic practice: a review

24. The material has a three dimensional structure due to the leno weave or triaxial braid. High coefficient elasticity of 117 Gpa Ribbond fibers are also characterized by an impact strength five times higher than that of iron. These features provide mechanical interlocking of the resin and composite resin at different planes, thereby enabling a wide processing window. In addition, micro cracking is minimised during polymerization of the resin .

25. INCREASED MICRO-TENSILE BOND STRENGTH The micro-tensile bond strength of the composite is significantly increased when Ribbond is closely adapted and bonded against the cavity walls. MITIGATING THE HARMFUL EFFECT OF C-FACTOR The increased micro-tensile bond strengths decreases the negative c-factor effects.  This phenomenon is especially evident with deep and narrow Class I restorations. MINIMIZES POLYMERIZATION AND DECREASES SHRINKAGE AND LEAKAGE Polymerization shrinkage can result in leakage, and sensitivity.  Closely lining the preparation with Ribbond significantly reduces and minimizes these harmful effects of polymerization shrinkage.   Because the Ribbond is closely adapted to the cavity walls, there is less volume of composite to shrink and less polymerization shrinkage results in less leakage and less sensitivity. BRIDGING CRACKS ON PULPAL FLOOR Ribbond bridges the cracks that are commonly seen in the pulpal floor of old amalgam restorations.  Ribbond acts like staples across the cracks and may hold the parts of the tooth on both sides of the crack together. 

26. RELIEVES CAUSES OF SYMPTOMS OF SPLIT TOOTH SYNDROME Split tooth syndrome has been successfully relieved when Ribbond has been used as a buccal -lingual cross cusp splint under the occlusal surface to bridge cracks.  The cross cusp Ribbond splint prevents the parts of the split tooth from moving. INCREASED FRACTURE TOUGHNESS Ribbond fiber reinforcements greatly increases the fracture toughness of dental composite restorations.  Ribbond’s unique combinations of fixed nodal intersections and tough ultra-high molecular weight polyethylene fibers inhibits and prevents crack propagation it composite resin. STRESS DISTRIBUTION AND ENERGY ABSORPTION MECHANISM Ribbond acts as a stress distribution and energy absorption mechanism.  It minimizes the stress concentrations by distributing forces over a greater area, which prevents crack formation and propagation. It also absorbs the energy from repeated occlusal impacts. FAIL-SAFE DESIGN. Studies demonstrate that if a crack starts in a Ribbond lined composite restoration, the crack is redirected Fiber-reinforced composites in endodontic practice: a review

27. RIBBOND FIBER REINFORCEMENTS Introduced in 2013, Ribbond -ULTRA is our premium dental fiber. It is only 0.12 mm thick and offers enhanced strength qualities. Introduced in 2001, Ribbond -THM (0.18 mm thick) is an excellent all-purpose fiber. Since 1992 , Ribbond Original (.35 mm thick) set the standard for ease of use and durability. Ribbond Triaxial is designed primarily for bridges with preparations and offers the greatest load-carrying capacity

28. VECTRAN FIBERS These are synthetic fibers of a new generation, made of aromatic polyesters. They show a good resistance to abrasion and impact strength, but they are expensive and not easily wielded

29. EVERSTICK GLASS FIBER REINFORCEMENTS everStick fiber reinforcements are made of silanated glass fibers in thermoplastic polymer and light curing resin matrix Glass fibre reinforcement for minimally invasive composite bridges For every indication to replace missing teeth either temporarily Full cover crowns & bridges. Surface-retained and implant-supported bridges. Inlay, onlay and hybrid bridges . everStickPERIO Glass fibre reinforcement for periodontal splinting Surface-retained or intra-coronal splinting. Combined periodontal splints and surface-retained bridg es.  

30. everStickORTHO Glass fibre reinforcement for aesthetic orthodontic retainers Patient-friendly metal-free orthodontic retainers.   everStickPOST Individually formable glass fibre root canal posts Especially suited to fit the morphology of atypical canals such as curved, oval as well as very large root canals.   everStickNET Glass fibre reinforcement for labial splinting Labial splinting of traumatized teeth Labial periodontal splinting Repair and reinforcing of veneers, crown

31. CLINICAL APPLICATIONS IN CONSERVATIVE DENTISTRY For Fillings and core build-ups Conservatively, the treatment of lost tooth structure involves direct composite restorations The use of resin composites increased tremendously during the last two decades. Today, resin composites are selected on a regular basis for direct and laboratory-made posterior restorations

32. FRC has the ability to conduct and scatter the curing light better than conventional hybrid composites and thus it is suitable for use in bulk of 4 mm layer thickness. Wear and surface roughness related limitations of FRC can be overcome by adopting a biomimetic restorative approach, in which dentine is replaced by FRC and covered by a layer of normal composite Fiber-reinforced composites in endodontic practice: a review international journal of dental materials

33. FRC is intended as dentin ereplacing material (base filling material) in high stress-bearing areas especially in Fillings and core build-ups large cavities of vital and nonvital teeth. SFRC can therefore be used for direct and indirect biomimetic composite restorations, which are indicated for: 1. Restoration of endodontically treated teeth, including core build-ups, post-and-core restorations, and endocrowns 2 . Medium to large Class I and II restorations 3 . Cusp-protecting and cusp-replacing restorations 4 . Crown build-ups Fiber-reinforced composites in endodontic practice: a review international journal of dental materials

34. DIRECT BIOMIMETIC COMPOSITE RESTORATION

35. CLINICAL APPLICATIONS IN PROSTHODONTICS Many clinical studies recommend the use of fibre reinforcement in removable dentures. Both unidirectional and woven light polymerized FRC strips can be used effectively for chair side repairs of fractured acrylic resin prostheses . FRC materials are well suited to the dynamic treatment approach due to their high mechanical strength and versatile clinical indications.

36. APPLICATIONS IN ENDODONTICS Prefabricated fibre reinforced composite posts consist of a resin matrix, in which structural reinforcing carbon fibres or quartz/glass fibres are embedded. The FRC posts offer greater flexure and fatigue strength, a modulus of elasticity close to that of dentin, the ability to form a single bonded complex within the root canal for a unified root post complex, and improved aesthetics The properties of this post design have the potential to reinforce a compromised root and to distribute stress more uniformly on loading to prevent root fracture moreover, the FRC post will yield prior to catastrophic root failure better than will custom made cast metal or prefabricated metal post systems

37. Two categories of FRC posts are available: chair side-fabricated and prefabricated. Chair side fabricated posts are custom designs that use polyethylene non preimpregnated woven fibres ( Ribbond , Connect) or glass fibres (ever Stick) to reinforce the root and hold a composite core PREFABRICATED POST 1. CARBON POST Carbon fibre posts ( Composipost , C-Post) were the first prefabricated FRC posts introduced to the market in the 1990s . The posts were made of continuous unidirectional carbon fibres embedded in an epoxy matrix .

38. One of the most important proposed advantages with carbon fibre posts was the lower elastic modulus (more flexible) compared to metal posts, which was thought that forces would be distributed more evenly in the root, resulting in fewer unfavourable tooth fractures. The lack of radiopacity and black colouration limits their use due to poor aesthetics under all ceramic crowns

39. GLASS FIBRE POSTS The glass FRC posts with a translucent or white appearance, The translucency would facilitate the polymerisation process of light cured luting cements with a consequent improvement of their mechanical properties Glass FRC posts are fabricated from different types of glasses that differ in their chemical composition. E-glass is the most commonly used glass,is a mixture of a calcium- alumino -borosilicate with low alkali content . A potential advantage of glass FRC posts is that their modulus of elasticity is close to that of dentine

40. All glass fiber posts are available in four sizes: 0, 1, 2, and 3. Colour codes ensure an accurate match to the drills. Drills (available in five sizes including one universal drill)  Glass posts dissipate occlusal stress and do not transmit it as metal posts do Fiber-reinforced composites in endodontic practice: a review international journal of dental materials

41. CLINICAL APPLICATIONS IN PEDIATRIC DENTISTRY In pediatric dentistry FRCs can be used in restorations, space maintainers, splints, or other frameworks The main difference is that the enamel of primary teeth is significantly different compared to permanent enamel. The differences have been mainly detected in composition FRC space maintainers can be prepared on plaster models of patients and fixed directly to the adjacent teeth .

42. APPLICATIONS IN ORTHODONTICS The main use of FRCs in clinical orthodonties is as fixed retention After orthodontic treatment FRCs splints over convenctional metallic retention is esthatics . Fibers are barely invisible and do not effect translucency of teeth. Applications of fibre reinforced composite in orthodontic practice include: 1. Fixed orthodontic retention appliance 2. Fixed space maintainer 3. Temporary esthetic retention appliance 4. Post traumatic stabilization splint . Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry

43. APPLICATIONS IN PERIODONTOLOGY Periodontal or post traumatic FRC splints have been reported in clinical periodontology fiber reinforced frameworks showed higher flexural forces when compared with conventional metallic wires . Moreover, FRC splints showed high flexural resistance also when polymerized directly with polymerization lamp without laboratory oven post polymerization, thus reducing the number of clinical steps and number of appointments for the patients FRC splints can be easily repaired

44. CONCLUSION FRC materials offer a combination of strength and modulus that is either comparable to dental tissues. The specific mechanical and physical strength and specific modulus of these fiber reinforced composite materials may be markedly superior to those of existing resin-based composites and metallic materials. In the short term, reasonable success for glass fiber-based restorations including endodontic posts, fixed partial denture, and posterior restorations. For these reasons, FRC have emerged as a major class of structural material and are either used or being considered as substitutes for traditional materials in dental applications

45. REFRENCES Fibre reinforced composites in dental application, By Haya Basim Rasan Republic of Iraq Ministry of Higher Education and Scientific Research University of Baghdad College of Dentistry 2023 Clinical Guide to Principles of Fiber-Reinforced Composites in Dentistry Mutlu O¨zcan University of Zurich, Zurich, Switzerland woodhead publishing series in biomaterials Fibre reinforced composite as dental material Pekka K.  Vallittu , in  non metallic tooth replacement and repair 2013 Fiber-reinforced composites in endodontic practice: a review international journal of dental materials DOI:  https:// doi.org/10.37983/IJDM.2020.2404 A Review on Fibre Reinforced Composite Resins,Annals of Prosthodontics and Restorative Dentistry, January-March,2016;2(1): 11-16

46. Thank you