Fiber-reinforced composites in fixed partial dentures

Fiber-reinforced composite resin (FRC) prostheses offer the advantages of good aesthetics, minimal invasive treatment, and an ability to bond to the abutment teeth, thereby compensating for less-than-optimal abutment tooth retention and resistance form. These prostheses are composed of two types of composite materials: fiber composites to build the framework and hybrid or microfill particulate composites to create the external veneer surface. This review concentrates on the use of fiber reinforcement in the fabrication of laboratory or chairsidemade composite-fixed partial dentures of conventional preparation. Other applications of FRC in dentistry are briefly mentioned. The possibilities fiber reinforcement technology offers must be emphasized to the dental community. Rather than limiting discussion to whether FRC prostheses will replace metal-ceramic or full-ceramic prostheses, attention should be focused on the additional treatment options brought by the use of fibers. However, more clinical experience is needed

Resin-Bonded Fiber-Reinforced Composite for Direct Replacement of Missing Anterior Teeth: A Clinical Report

Missing anterior teeth is of serious concern in the social life of a patient in most of societies. While conventional fixed partial dentures and implant-supported restorations may often be the treatment of choice, fiber-reinforced composite (FRC) resins offer a conservative, fast, and cost-effective alternative for single and multiple teeth replacement. This paper presents two cases where FRC technology was successfully used to restore anterior edentulous areas in terms of esthetic values and functionality

Bioblock technique to treat severe internal resorption with subsequent periapical pathology: a case report

A variety of therapeutic modalities can be used for the endodontic treatment of a traumatized tooth with internal root resorption (IRR). The authors present a case report of the successful restoration of a traumatized upper central incisor that was weakened due to severe IRR and subsequent periapical lesion formation. A 20-year-old female patient was referred to our clinic with severe internal resorption and subsequent periapical pathosis destroying the buccal bone wall. Root canal treatment had been initiated previously at another dental practice, but at that time, the patient's condition could not be managed even with several treatments. After cone-beam computed tomography imaging and proper chemomechanical cleaning, the tooth was managed with a mineral trioxide aggregate plug followed by root canal filling using short fiber-reinforced composite, known as the Bioblock technique. This report is the first documentation of the use of the Bioblock technique in the restoration of a traumatized tooth. The Bioblock technique appears to be ideal for restoring wide irregular root canals, as in cases of severe internal resorption, because it can uniquely fill out the hollow irregularities of the canal. However, further long-term clinical investigations are required to provide additional information about this new technique.</p

Development and characterization of ion-releasing fiber-reinforced flowable composite

Objective: This study aimed to develop and characterize an ion-releasing experimental fiber-reinforced flowable composite (Bio-SFRC) and dentin treatment solution made of poly(acrylic acid) (PAA) with a high molecular weight. In addition we also evaluated the interface structure and mineralization potential between the Bio-SFRC and dentin.Methods: Some mechanical properties (flexural properties and fracture toughness) of Bio-SFRC in comparison with commercial inert (G-aenial Flo X) and ion-releasing materials (ACTIVA-BioActive Base/Liner and Fuji II LC) were assessed (n = 8/group). Calcium-release at different time-points was measured during the first six weeks by using a calcium-ion selective electrode. Surface analysis of composites after being stored in simulated body fluid (SBF) was investigated by using SEM/EDS. Dentin disks (n = 50) were prepared from extracted sound teeth and demineralization was simulated by acid etching. SEM/EDS was used to evaluate the microstructure of dentin on the top surface and at interface with composites after being stored in SBF.Results: Bio-SFRC showed higher fracture toughness (1.6 MPa m1/2) (p 1/2), ACTIVA (1 MPa m1/2) and Fuji II LC (0.8 MPa m1/2). Accumulative calcium release after six weeks from Bio-SFRC (15 mg/l) was higher than other tested ion-releasing materials (≈ 6 mg/l). Mineralization was clearly seen at the interface between treated dentin and Bio-SFRC. None of the commercial tested materials showed signs of mineralization at the interface and dentinal tubules remained open.Significance: Developing such reinforced ion-releasing flowable composite and PAA solution might offer the potential for mineralization at the interface and inside the organic matrix of demineralized dentin.</p

Shear-bond strength and optical properties of short fiber-reinforced CAD/CAM composite blocks

The aim of this study was to assess the shear-bond strength (SBS) of resin-luting cement to experimental short fiber-reinforced CAD/CAM composite (SFRC) compared to conventional CAD/CAM (Cerasmart 270), 3D printed (GC TEMP PRINT, Pro3dure GR-17), and laboratory (Gradia Plus) composites. Moreover, translucency parameter values and light transmission were evaluated. For each of the five types of composites, discs were prepared (n = 16/group) and divided into subgroups (n = 8/group) according to surface treatment protocol (hydrofluoric acid or air-particle abrasion). SBS test was performed using universal testing machine until failure, and failure modes were visually analyzed. Translucency parameter and curing-light transmission values through 1, 2, and 3 mm thickness were quantified using spectrophotometry and the MARC resin calibrator, respectively. Scanning electron microscopy (SEM) was used to examine the CAD/CAM composites after surface treatment. Composite type and surface treatment had a significant effect on SBS. Laboratory composite showed the highest SBS value (22.4 MPa). Cerasmart 270 exhibited higher translucency parameter values (19.8, 11.0, 5.0) than SFRC (14.5, 5.2, 1.6) at the three composite thicknesses tested. Air-particle abrasion was more effective in enhancing SBS than acid etching. Experimental SFRC CAD/CAM composite showed higher SBS values than Cerasmart 270. For all composites, translucency parameter values and light transmission decreased as thickness increased.</p

Short Fiber Reinforced Composite – a New Alternative for Direct Onlay Restorations

OBJECTIVES:To determine the static load-bearing capacity of direct composite onlay restorations made of novel filling composite resin system which combines short fiber-reinforced composite resin (FC) and conventional particulate filler composite resin (PFC).METHODS:Three groups of onlay restorations were fabricated (n = 8/group); Group A: made from conventional particulate filler composite resin (Z250, 3M-ESPE, USA, control), Group B: made from short fiber-reinforced composite resin (EverX posterior, StickTeck Ltd, member of GC group, Turku, Finland) as substructure with 1 mm surface layer of PFC, Group C: made from FC composite resin. The specimens were incrementally polymerized with a hand-light curing unit for 80 s before they were statically loaded with two different sizes (3 & 6 mm) of steel ball until fracture. Failure modes were visually examined. Data were analyzed using ANOVA (p = 0.05).RESULTS:ANOVA revealed that onlay restorations made from FC composite resin had statistically significantly higher load-bearing capacity (1733 N) ( p SIGNIFICANCE:Onlay restorations combining base of short fiber reinforced composite resin as substructure and surface layer of conventional composite resin displayed promising performance in high load bearing areas.</p

Clinical evaluation of fiber-reinforced composite restorations in posterior teeth - results of 2.5 year follow-up

Objectives: The aim of this study was to evaluate the clinical performance of posterior composite restorations reinforced by bulk base of short-fiber composite (everX Posterior, GC Corporation). Methods: 36 short fiber-reinforced composite restorations were placed in premolar and molar teeth of 33 patients. Eight of the teeth were vital and 28 non-vital.  Average follow up time of the restorations was 30.6 months (2.5 years), ranging from 16.2 to 51.3 months (1.3 - 4.3 years). Results: One restoration failed during the follow-up period due to secondary caries, at time point 39.5 months. Three fillings had minor fractures during the follow-up. Overall survival rate of the restorations was 97.2 % and success rate (no maintenance needed) 88.9 % respectively. Conclusion: Posterior composite restorations with bulk base of short-fiber composite showed good clinical performance in the short term evaluation. </p

Effect of discontinuous glass fibers on mechanical properties of glass ionomer cement

This study investigated the reinforcing effect of discontinuous glass microfibers with various loading fractions on selected mechanical properties of self-cure glass ionomer cement (GIC). Experimental fiber reinforced GIC (Exp-GIC) was prepared by adding discontinuous glass microfiber (silane/non-silane treated) of 200-300 µm in length to the powder of self-cure GIC (GC Fuji IX) with various mass ratios (15,20,25,35, and 45 mass%) using a high speed mixing device. Flexural strength, flexural modulus, work of fracture, compressive strength and diametral tensile strength were determined for each experimental and control materials. The specimens (n=8) were wet stored (37 °C for one day) before testing. Scanning electron microscopy equipped with energy dispersive spectrometer was used to analysis the surface of silanized or non-silanized fibers after treated with cement liquid. The results were analysed with using multivariate analysis of variance MANOVA. Fiber-reinforced GIC (25 mass%) had significantly higher mechanical performance of flexural modulus (3.8 GPa), flexural strength (48 MPa), and diametral tensile strength (18 MPa) (p<0.05) compared to unreinforced material (0.9 GPa, 26 MPa and 8 MPa). No statistical significant difference in tested mechanical properties was recorded between silanized and non-silanized Exp-GIC groups. Compressive strength did not show any significant differences (p>0.05) between the fiber-reinforced and unreinforced GIC. The use of discontinuous glass microfibers with self-cure GIC matrix considerably increased the all of the studied properties except compressive strength. </p

Fracture behavior of discontinuous fiber-reinforced composite inlay-retained fixed partial denture before and after fatigue aging

Purpose: To evaluate the fracture behavior of inlay-retained fixed partial dentures (IRFPDs) made of experimental short fiber-reinforced composite (SFRC) computer-aided design/computer-aided manufacturing (CAD/CAM) block before and after cyclic fatigue aging.Methods: Five groups (n=20/group) of three-unit posterior IRFPDs were fabricated. The first and second groups were CAD/CAM fabricated from experimental SFRC blocks or lithium-disilicate (IPS e.max CAD, IVOCLAR) materials, the third group comprised a three-dimensional-printed composite (Temp PRINT, GC), and the fourth and fifth groups comprised conventional laboratory flowable composite (Gradia Plus, GC) and commercial flowable SFRC (everX Flow, GC), respectively. All IRFPDs were luted into a metal jig with adhesive dual-cure resin cement (RelyX Ultimate, 3M ESPE). Half the IRFPDs per group (n=10) were subjected to fatigue aging for 10,000 cycles. The remaining half were statically loaded until fracture without fatigue aging. The load was applied vertically between triangular ridges of the buccal and lingual cusps. The fracture mode was visually examined using optical and scanning electron microscopy (SEM). Data were statistically analyzed using a two-way analysis of variance (ANOVA) followed by Tukey's HSD test.Results: ANOVA revealed that IRFPDs made of experimental SFRC CAD/CAM had the highest (pp>0.05) of all tested prostheses, except for the experimental SFRC CAD/CAM and conventional laboratory composite IRFPDs (p>0.05). SEM images showed the ability of discontinuous short fibers in the experimental SFRC CAD/CAM composite to redirect and hinder crack propagation.Conclusion: CAD/CAM-fabricated IRFPDs made of experimental SFRC blocks showed promising performance in clinical testing in terms of fracture behavior.</p