The Clinical Applications of Fiber Reinforced Composites Dr E. Habibi
-Fiber reinforced composites are high strength filling materials composed of conventional composites and fibres.
FRCs are structural materials with two distinct constituents FRCs are structural materials with two distinct constituents. The reinforcing component provides stiffness and strength while the surrounding matrix supports the reinforcement and provides workability. The fibers most commonly employed in dental applications for reinforcement are polyethylene, glass, polypropylene, carbon or aramid. The matrix comprises of epoxy resin
Typically, fibers are 7 to 10 µm in diameter and span the length of the prosthesis or appliance. By comparison, the particles used in standard restorative dental composites are 1 to 5 µm in diameter, or submicron in size.
-Woven fiber is less technique-sensitive, has lesser flexural strength and easier to manipulate hence conforms to the desired shape and maintains its adaptation during placement and is the ideal choice while making an appliance for rotated or malpositioned teeth. - Unidirectional fiber has greater flexure strength and rigidity and is the better choice for high stress situations as in prosthodontic frameworks
The Two Approaches have Evolved Namely Non-Impregnated and Pre-Impregnated Pre-Impregnated Fibers
How FRC Materials Work? Types of fiber Direction of fibers
Periodontal Splinting Single Visit Bridges Provisional Bridges Composite Restoration Trauma Stabilization Space maintainer Endodontic Post and Cores
Periodontal Splinting Easy to Make Esthetic Strong Durable Proven
Fiber-reinforced Composite Resin Bridges
Loss of anterior tooth may be a catastrophic event for the patient Introduction Loss of anterior tooth may be a catastrophic event for the patient
The Fiber-Reinforced Resin-Bonded Bridge Advantages Cost effective Less or zero reduction in healthy tooth structure Takes short duration of time Hygienic Nonallergenic Single tooth replacement premolar or incisor ideal indication for lower incisors
The Fiber-Reinforced Resin-Bonded Bridge A review of the dental literature suggests that the FRC prostheses have good longevity, especially those which are made by the direct technique
The Fiber-Reinforced Resin-Bonded Bridge Three forms of pontics can be made for the FRC bridges: natural extracted teeth, with acrylic resin teeth using composite resin.
Natural Tooth Pontic If the natural tooth is available and if its crown is in good condition, it can be bonded easily to the adjacent teeth by using a light-cured restorative material. Using the natural tooth as a pontic offers the benefits of being the right size, shape and colour, along with producing good aesthetic and functional results
Considerations for Utilization of a Natural Tooth Pontic Several factors must be taken into consideration when choosing a natural tooth pontic as an interim provisional. First and foremost, the extracted tooth should possess an intact, clinical crown that is of ideal shape, contour, and shade, with intrinsic characterization that ideally matches the adjacent dentition. The functional occlusal stress on the pontic site should be minimal, and the patient's preoperative centric, working, and nonworking contacts must be assessed to determine whether displacing forces can be reduced or eliminated.
A 45-year-old female patient The patient was not in pain, and her primary dental concern was to remain current with her biannual prophylactic recare visits. A comprehensive examination including periodontal charting, intraoral photographs, and a full- mouth series of radiographs was performed.
Closer inspection of the periapical radiograph Tooth No. 21 exhibited Class I to Class II mobility with all other visual findings being within normal limits (Figure 1). Dental history, she indicated that, as a teenager, she had an accident that displaced teeth Nos. 11 and 21, and tooth No. 21 had required root canal therapy after becoming nonvital. Several cracks in both teeth were observed during the visual exam with transillumination, but none were symptomatic. Closer inspection of the periapical radiograph indicated that tooth No. 21 was in a state of active internal resorption and the tooth was diagnosed as hopeless (Figure 2). When the patient was informed that the diagnosis for her maxillary left central incisor was hopeless, she was heartbroken.
The 2-mm Ribbond THM ribbon was chosen for this case due to its minimal thickness, leno-weave construction, ease of adaptation to the teeth, and overall superior strength. A rectangular slot was prepared on the lingual aspect of the natural tooth pontic to secure the Ribbond THM and to assure that it remained out of occlusion. The finalized pontic with a rectangular lingual slot is shown in Figure 10
Ribbond strands cannot be cut with conventional scissors; this most recent product includes a slimmer and more compact industrial-grade scissor, as compared to the more bulky version supplied with earlier kits. The manufacturer recommends the use of Ribbond Wetting Resin (Ribbond), a product sold separately.
A thin coat of Ribbond Securing Resin (Ribbond) was applied to the lingual and interproximal surfaces of adjacent teeth. The Ribbond THM was then seated at the desired position and adapted first with finger pressure, then with a thin IPC hand instrument. Care must be taken to ensure that the edges of the fiber are flush against the teeth, and that the material wraps slightly into the interproximal areas roughly to the previous contact area.
Composite pontic A 76-year-old female patient presented with a missing mandibular left lateral incisor that had been recently extracted because of severe root caries on the distal surface that had made the tooth unrestorable (Figure 1).
Upon clinical and radiographic examination, it was noted that there was not enough remaining bone in the labial- lingual direction to consider an implant. Also, the teeth adjacent to the edentulous space, aside from having some crestal bone loss, were unrestored. The crown-to-root ratio and mesiodistal root diameter at the gingival crest of the mandibular left central incisor were not favorable due to the alveolar bone loss, making it a questionable abutment for a fixed partial denture.
A lingual view shows the abutment teeth that were prepared with a slot cut in the lingual surfaces to contain the imbedded fiber reinforcement to provide the "framework" to freehand the nanocomposite resin pontic in the edentulous space.
G-aenial Bond (GC America), a seventh-generation self-etching bonding agent, was dispensed into a disposable mixing well. The bonding agent was applied to all prepared surfaces using a microbrush. The bonding agent was then light-cured for 20 seconds
The flowable composite resin (G-aenial Universal Flo) with an applicator tip applied to the end of the syringe; the long, narrow cannula makes precise placement very easy. G-aenial Universal Flo was syringed into the preparations in a thin coat. The fiber reinforcement was placed into the floor of the preparations, and they were then filled with flowable composite to the cavosurface margins and light-cured.
Next, the flowable composite was placed on the stabilized fiberglass fiber (Connect [Kerr]) to wet the surface between the teeth with composite resin. It was then light- cured for 20 seconds This facial view shows the composite-reinforced fiberglass reinforcement in place
Kalore AO3 was used to begin building a pontic on the fiber between the abutment teeth. A plastic instrument (Goldstein Flexithin Mini 4 [Hu-Friedy]) was used for shaping A3.5 as the base dentin for the pontic. Kalore CV (B5) was used to simulate a root form similar to the adjacent teeth.
Kalore DT was used to create incisal translucency. A sable brush (Keystone No. 4 Flat [Patterson Dental]) was used to create surface texture and refine anatomic form. Kalore DT was used to create incisal translucency.
After initial contouring with an 8-fluted carbide composite finishing bur, contouring was completed using abrasive discs (Optidisc [Kerr]). A yellow disc (Jiffy Disc [Ultradent Products]) was then used to polish the labial surface, and to refine the reflective angles and surface texture.
Facial view of the completed fiber-reinforced direct nanocomposite resin bridge
Trauma Stabilization Easy to make and remove Thin, smooth, and non-irritating to the lip Easy to control the degree of rigidity Easy maintenance of oral hygiene Does not impinge on the gingiva Has no memory - does not move the teeth
Space maintainer
Endodontic Post and Cores
Fiber Post
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