|Year : 2015 | Volume
| Issue : 3 | Page : 206-210
Fiber-reinforced composite: Post and core material in a pediatric patient: An alternative to usual
Sonu Acharya1, Shobha Tandon2
1 Department of Pediatric Dentistry, Institute of Dental Sciences, SOAU, Bhubaneswar, Odisha, India
2 Department of Pediatric Dentistry, Uttar Pradesh Dental College, Lucknow, Uttar Pradesh, India
|Date of Web Publication||4-Aug-2015|
Hig-48, Phase-I, 7 Acres, HB Colony, Chandrasekharpur, Bhubaneswar, Odisha - 751 016
Fractured teeth have always presented a challenge to the dentists. The predictability of root canal therapy, as it is today, can retain almost indefinitely, even very badly broken teeth. One of the widely accepted techniques involving restoration of extensively carious or badly fractured teeth is the fabrication of a post and core, utilizing the root canal space for anchorage. Thus far, the only materials that have been available to the dentists for this procedure have been a variety of metallic alloys. Hard and unyielding, these metals have to be cast in the precise shape of the prepared canals and cemented into place. Today, materials are available, which eliminate all the intermediate steps, and control is rendered in the hands of the dentists, to fabricate on the chair, a resilient, esthetic and bonded post and core. One such material is discussed here in pediatric permanent anterior tooth.
Keywords: Fiber-reinforced composite, pediatric patient, post and core, Ribbond
|How to cite this article:|
Acharya S, Tandon S. Fiber-reinforced composite: Post and core material in a pediatric patient: An alternative to usual. SRM J Res Dent Sci 2015;6:206-10
|How to cite this URL:|
Acharya S, Tandon S. Fiber-reinforced composite: Post and core material in a pediatric patient: An alternative to usual. SRM J Res Dent Sci [serial online] 2015 [cited 2019 Dec 6];6:206-10. Available from: http://www.srmjrds.in/text.asp?2015/6/3/206/162188
| Introduction|| |
Fiber-reinforced composite (FRC) is a bondable, biocompatible, esthetic, translucent and easy-to-use reinforced ribbon. By virtue of its wide spectrum of properties, it enjoys multiple uses in clinical dentistry. The development of FRC technology has brought a new material into the realm of metal-free, adhesive esthetic dentistry.  Not only has the combination of composite resin and FRC been shown to have significant benefits in terms of mechanical properties, the possibility of direct chairside application and the ability to bond to tooth structure make FRC an attractive choice for a variety of dental applications. , Different fiber types such as glass fibers, carbon fibers, kevlar fibers, vectran fibers, polyethylene fibers have been added to composite materials. Glass fibers consisting of glass interlaced filaments, improve the impact strength of composite materials. They have excellent esthetic properties but do not easily stick to resinous matrix. Carbon fibers prevent fatigue fracture and strengthen composite materials, but they have a dark color, which is undesirable esthetically. , Kevlar fibers made of an aromatic polyamide, are the evolution of nylon polyamide.  They increase the impact strength of composite materials. However, they are also unesthetic, and hence, their use is limited. Vectran fibers 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. Polyethylene fibers improve the impact strength, modulus elasticity, and flexural strength of composite materials. Unlike carbon and Kevlar fibers, polyethylene fibers are almost invisible in a resinous matrix and for these reasons, seem to be the most appropriate and esthetic strengtheners of composite materials.  The restoration for an endodontically treated tooth should be conservative and should not increase horizontal and vertical forces. Thus far, the only materials that have been available to the dentists for this procedure have been a variety of metallic alloys. Hard and unyielding, these metals have to be cast in the precise shape of the prepared canals and cemented into place. If too tight, they wedge the root and if too loose; they come off. Several intermediate steps in their fabrication (impression, poured cast, the wax pattern, casting, finishing), are extremely conducive to errors being committed. A recently developed bondable reinforcement fiber, Ribbond, (Ribbond THM, Ribbond Inc., Seattle, WA) is reported to be an alternative to conventional post materials because of its esthetic qualities, mechanical properties, and the neutral color of the reinforcing material.  Ribbond is a spectrum of 215 fibers with a very high molecular weight. First introduced to the market in 1992, Ribbond consists of bondable, reinforced ultra-high-strength polyethylene fibers.  The open and lace like architecture of Ribbond allows it to adapt closely to the teeth and dental arch. This is an advantage over prefabricated fiber posts where adaptability to root canals is difficult. Apart from this feature the Ribbond can be condensed properly in the canals with little microleakage. The application of a fiber layer increases the load bearing capacity of the restoration and prevents crack propagation from the restoration to the tooth. When prefabricated fiber post is placed in flexure, cracks appear on the tensile face and due to brittleness of the material rapidly propagates causing failure.  The purpose of using Ribbond as post and core material in the present case report stems from the above said features of Ribbond that made our choice for this material to be used as post and core.
| Case Report|| |
A 12-year-old female patient visited the department of pediatric dentistry with complain of broken left lower front tooth since 4 months. The patient did not complain of any pain [Figure 1]. On enquiry from the parent of the child, it was revealed that the mentioned tooth had been root canal treated 6 months back and restored, but the restoration came out within a month. The re-restoration also did not last >15 days. On examination lower left central incisor was fractured, and there was neither pain reported nor tenderness to percussion. The tooth structure was less for a composite make-up or a crown. After thorough examination, it was decided to go for a post and core and composite make-up. As it was an anterior tooth in a young patient it was decided to go for FRC (Ribbond, Ribbond THM, Ribbond Inc., Seattle, WA) as post and core material as it is esthetic and has adequate strength. As the tooth was adequately obturated [Figure 2], preparation of the canal space was done [Figure 3] and [Figure 4]. The use of Ribbond does not require additional tooth preparation as is required for metal posts. The remaining tooth structure being less, rubber dam isolation could not be accomplished, and we decided for high suction evacuation with cotton rolls to be suitable for isolation. Gutta percha was removed using gutta percha solvent (Endosolv, Septodont, USA) until the desired length for the post was achieved. The post hole was shaped using gates glidden drills (Roydent, West Palm Beach, FL), cleaned with 5% sodium hypochlorite and dried. The width of Ribbond (Ribbond THM, 2, 3 or 4 mm, Ribbond Inc., Seattle WA) is decided on the root canal space available. The depth of the post space was measured using a periodontal probe, and a 3 mm wide Ribbond was cut using special scissors provided with the kit (Ribbond starter kit, Ribbond THM, Seattle), measuring twice the depth of the post space and 3-4 times the height of the core build-up [Figure 5] and placed in dual cure adhesive resin and set aside in light protected container. The root canal wall was etched for 15 s, washed for 30 s and then gently air-dried. Excess water was removed from the post space using paper points (Spident, SPI Dental Mfg. Inc., Korea). The dual cure adhesive resin (Ed Primer II A and B) was applied using a microbrush in 2 consecutive coats and gently air-dried to evaporate the solvent. Dual cure resin cement (Panavia F, Kuraray, Japan) is injected in the canal space. The Ribbond was removed from the resin and the excess resin was removed using a hand instrument [Figure 6], folded in a V-shape and coated with dual-curing resin cement (Panavia, Kuraray Medical Inc., Japan). The piece of ribbon was then placed in the post space in a facial-lingual direction with an endodontic plugger [Figure 7]. Excess resin cement was removed, and the cement was cured for 20 s. These two protruding ends of the Ribbond strips formed the reinforcement for the core build-up to replace the lost coronal portion of the tooth. The remaining resin mix from the syringe was extruded onto this framework to create a core resembling the shape of the central incisor. It was ensured that the space between the protruding ribbon ends was filled with resin so as not to leave any voids. Composite resin was also placed so as to cover the Ribbon ends completely and leave none of them exposed on the outer surface of the core. All the material was thoroughly light cured to create an external set surface. The material was left in the mouth for a couple of hours to ensure a complete set of the self-curing component of the resin mix. What emerged from this procedure was a post-cum-core (single piece), which was bonded onto the root, creating a solid structure without any wedging effect on the root. Moreover, the resin conforming to the inside shape of the canal space ensured no voids and eliminated "fitting" problems normally associated with cast post and cores. The bands of Ribbond reinforced the resin material and made it extremely strong and durable. Bonding of the entire entity also created a monobloc, which is the essence sought for favorable occlusal force transmission and for resistance against debonding of the entire unit. Best of all, there was no metal to mask with the crown since the base shade of the composite was a close enough match to the tooth and was translucent. The Ribbond strips, though opaque, were white in color and after being completely encased in the composite, were not visible anyway. However, they did not contribute to the color of the core in any adverse way. The restorative procedure was completed by building up the tooth using dual cure hybrid composite resin following technique of small progressive build-up without any matrix [Figure 8]. All these increments were fully light-cured. Finishing and polishing procedures were performed using Sof-Lex contouring and polishing discs (Sof-Lex; 3M ESPE, St. Paul, MN, USA) [Figure 9]. The patient was advised for a crown at a later stage after complete development of occlusion. The patient has been under follow-up for 4 years now with 6-month follow-up intervals, and the restoration is still in good condition. As because the occlusion is not yet established we have decided to give the crown on a later date.
| Discussion|| |
Fiber-reinforced composite can be used in stabilizing traumatized teeth, restoring fractured teeth and creating a fixed partial denture and for direct-bonded endodontic posts and cores, orthodontic fixed lingual retainers and the space maintainer.  Despite this versatility, there are few reports on the use of Ribbond in pediatric dentistry. Various types of FRC posts have recently come into widespread use as an alternative to cast or prefabricated metal posts in the restoration of endodontically treated teeth. Few authors have also suggested that restoration of endodontically treated teeth with fiber post and direct resin composites is a treatment option that in the short term conserves remaining tooth structure and results in good patient compliance.  Earlier the post systems were simple, quick and inexpensive.  These posts were usually cast in precious alloy or prefabricated in stainless steel, titanium or precious alloy. They did not take into account the individual shape of the root canal and hence their adaptation was not ideal.  The post and core system should show differing rigidity in their components. The more rigid component can resist forces without distortion and so the stress would be transferred to less rigid component which may well be fractured.  The difference in modulus of elasticity of dentin and that of post material may, therefore, be a source of stress to the root structures. FRCs root canal posts with modulus of elasticity close to dentin were introduced in 1990s.  Esthetic fiber posts fabricated from fiber ribbons to restore endodontically treated teeth provide for root reinforcement and retention of composite resin cores.  Ribbond is used in combination with composite resin. The physical properties of this material allow the fabrication of a conservative, esthetic post and core system that adapts well to roots individually and prevents root fractures.  The relative flexibility of fiber composite laminate post minimizes crack propagation in the roots.  Thus, we have a very good option of utilizing Ribbond as post and core material. Compared to preformed posts, there is no additional tooth removal after endodontic treatment. This maintains the natural strength of the tooth. Eliminates the possibility of root perforation. Because it is made when the and Ribbond is in a pliable state, it conforms to the natural contours and undercuts of the canal and provides additional mechanical retention. There are no stress concentrations at the tooth-post interface. The Ribbond post and core is passive and highly retentive. Furthermore, because Ribbond's translucent fibers take on the color characteristics of the composite it allows for the natural transmission of light through teeth and crowns. This provides an exceptionally esthetic result. , Although there are so many advantages discussed in favor of FRCs, there are certain limitations also. The disadvantages of nonmetal posts also have to be taken note of. Metal posts have a well-established record of successful clinical service. High success rates have been reported from retrospective studies over periods of time that have not yet been matched by nonmetal posts. Also, the cast metals have greater strength in thin sections than the composites adjacent to the posts. This allows for the production of ferrules that is not possible with nonmetal posts. There have been some reported cases of fiber ribbons being used as post and core material in primary teeth. ,, The results suggested that this material is quite good as post and core material when used in primary teeth for pediatric patients [Figure 9]. Traumatized permanent anterior teeth in children need quick esthetic and functional repair because of psychological damage they can create in children. Esthetic requirements of anterior teeth require the use of composite materials that, in the most complex cases, can be used in association with fibers so as to improve their mechanical resistance [Figure 10]. The authors considered parameters such as physical properties, water absorption, ease of cutting and of laying. Polyethylene fibers appear to have the best properties in elasticity, translucency, adaptability, tenaciousness, resistance to traction and to impact. This material also has been utilized in permanent anterior teeth in adult patients, but few have reported the use in children. , Hence, we tried to use fiber ribbons as post and core in permanent anterior tooth in a child and obtained reasonably good result.
| Conclusion|| |
The number of endodontic procedures has increased steadily in the past decade with highly predictable results. Therefore, restoration of teeth after endodontic treatment is becoming an integral part of the restorative practice in dentistry. FRCs have been used for similar cases in pediatric dentistry in deciduous teeth, but there are very few cases reported for permanent anterior teeth in pediatric patients. We have tried to use this as a post and core material in a permanent tooth for a pediatric patient with satisfying esthetic results and improved mechanical properties. Long-term follow-up of more cases is required for this material to become more popular especially in pediatric dentistry.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]