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الجامعة الليبية الدولية للعلوم الطبية - أوراق علمية

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Use of short fiber-reinforced composite with semi-interpenetrating polymer network matrix in fixed partial dentures

Abstract

Objectives: The aim of this study was to determine the static load-bearing capacity of fixed partial dentures (FPDs) made of experimental composite resin (FC) with short fiber fillers and interpenetrating polymer network (IPN) polymer matrix. Materials and methods: Experimental composite FC resin was prepared by mixing short Eglass fibers (3 mm in length) of 22.5 wt% and IPN-resin 22.5 wt% with silane treated silica fillers 55 wt%. Four groups of FPDs (3-unit) were fabricated (n = 6); Group A: made from commercial composite resin (Sinfony dentin, 3M-ESPE, control), Group B: Sinfony and fiberreinforced composite (FRC) substructure, Group C: made from FC, Group D: made from FC with 1 mmsurface layer of Sinfony. The bridges were polymerized with a hand-light curing unit for 40 s then post-cured in vacuum curing device (Visio Beta) for 15 min before they were statically loaded with speed of 1 mm/min until fracture. Failure modes were visually examined. Data were analyzed using ANOVA ( p = 0.05). Results: ANOVA revealed that bridges made from experimental fiber composite had statistically significantly higher load-bearing capacity (2171 N) ( p < 0.05) than the control restorations (1482 N). Significance: Restorations made from short glass fiber containing composite resin with IPNpolymer matrix showed better load bearing capacity than in those made with conventional composites resin and similar with those reinforced with FRC-substructure.

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The influence of frame work design on the load-bearing capacity of laboratory-made inlay-retained fibre-reinforced composite fixed dental prostheses

Abstract

Delamination of the veneering composite is frequently encountered with fibre-reinforced composite (FRC) fixed dental prosthesis (FDPs). The aim of this study is to evaluate the influence of framework design on the load-bearing capacity of laboratory-made three-unit inlay-retained FRC-FDPs. Inlayretained FRC-FDPs replacing a lower first molar were constructed. Seven framework designs were evaluated: PFC, made of particulate filler composite (PFC) without fibre-reinforcement; FRC1, one bundle of unidirectional FRC; FRC2, two bundles of unidirectional FRC; FRC3, two bundles of unidirectional FRC covered by two pieces of short unidirectional FRC placed perpendicular to the main framework; SFRC1, two bundles of unidirectional FRC covered by new experimental short randomorientated FRC (S-FRC) and veneered with 1.5mm of PFC; SFRC2, completely made of S-FRC; SFRC3, two bundles of unidirectional FRC covered by S-FRC. Load-bearing capacity was determined for two loading conditions (n ¼ 6): central fossa loading and buccal cusp loading. FRC-FDPs with a modified framework design made of unidirectional FRC and S-FRC exhibited a significant higher load-bearing capacity (po0.05) (927774 N) than FRC-FDPs with a conventional framework design (6097119 N) and PFC-FDPs (702786 N). Central fossa loading allowed significant higher load-bearing capacities than buccal cusp loading. This study revealed that all S-FRC frameworks exhibited comparable or higher load-bearing capacity in comparison to an already established improved framework design. So S-FRC seems to be a viable material for improving the framework of FRC-FDPs. Highest load-bearing capacity was observed with FRC frameworks made of a combination of unidirectional FRC and S-FRC.

 

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Static and fatigue compression test for particulate filler composite resin with fiber-reinforced composite substructure

Abstract

Objectives. The aim of this study was to determine static load-bearing capacity and compressive fatigue limits (CFL) of laboratory particulate filler composite resin (PFC) with three different types of fiber-reinforced composite (FRC) substructures. Methods. A total of 420 test specimenswere prepared having 1.0mmof FRC layer as substructure (short random, continuous unidirectional and bidirectional fiber orientations), and a 2.0-mm thick surface layer of PFC. Control specimens were prepared from plain FRC or PFC. The specimens (n = 15) were either dry stored or water stored (37 ◦C for 2 weeks) before they were loaded with a steel ball (Ø 3.0mm) under static load until fracture and cyclic load with maximum controlled regimen following a staircase approach with maximum 103 cycles. The decrease in CFL compared to static load was calculated and data were analyzed using ANOVA and Weibull statistics. Results. The highest static loads were registered for plain FRC specimens [short random 1842 N(205), continuous bidirectional 2258 N(233) and unidirectional fiber orientation 538 N(254)]. The specimens with FRC substructure and PFC coverage gave load values of 1517 N(249), 1670 N(241) and 677 N(240), respectively. The specimens made of PFC only, failed with 1047 N(230) load. The CFL for 103 cycles ranged between 19 and 39% of the static load values. ANOVA revealed that all factors significantly affected the load bearing capacity (p < 0.001).

 

 

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Short glass fiber reinforced restorative composite resin with semi-inter penetrating polymer network matrix

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Objectives. The purpose of this study was to investigate the reinforcing effect of short E-glass fiber fillers on some mechanical properties of dental composite resin with interpenetrating polymer network (IPN)-polymer matrix. Materials and methods. Experimental composite resin was prepared by mixing short fibers (3mm in length) with a fraction of 22.5wt% and IPN-resin 22.5wt% with silane treated silica filler 55wt% using high speed mixing machine. Test specimens (2mm×2mm×25mm) and (9.5mm×5.5mm×3mm) were made from the experimental composite (FC) and conventional particulate composite resin (control, Z250, 3M-ESPE). The test specimens (n=6) were either dry stored or water stored (37 ◦C for 30 days) before the mechanical tests. Threepoint bending test was carried out according to ISO 10477 and compression loading test was carried out using a steel ball (Ø3.0mm) with speed of 1.0mm/min until fracture. Degree of monomer conversion (DC %) of both composites was determined by FTIR spectrometry. Water sorption and solubility of specimens were also measured. Scanning electron microscopy was used to evaluate the microstructure of the composite.

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Polymerization shrinkage of experimental short glass fiber-reinforced composite with semi-inter penetrating polymer network matrix

Abstract

Objectives. The aim of this study was to determine the magnitude of short fiber-reinforced composite resin, with a semi-IPN-polymer matrix, on polymerization resin shrinkage-strain, shrinkage stress and marginal microleakage of the restoration. Materials and methods. Experimental composite FC resin was prepared by mixing 22.5 wt.% of short E-glass fibers, 22.5 wt.% of IPN-resin and 55 wt.% of silane treated silica fillers using a high speed mixing machine. As control material, commercial particulate filler composite resin (PFC) was used. Polymerization shrinkage-strain and stress of the specimens (n = 5) were measured using the bonded-disc technique and tensilometer, respectively with respect to time. FC composite and PFC were placed incrementally in class II cavities sized 4mm×4mm×6mm (n = 8/group) using total-etch adhesive system according to manufacturer’s instructions. After the class II restorations were completed, the specimens were finished and polished, thermocycled, stained, sectioned, and viewed under a stereo-microscope for leakage at occlusal/enamel and gingival/dentin margins. The data were analyzed using ANOVA.

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