Braiding Thermoplastic and Glass Fibers in Composite Dental Post Improves Their Mechanical Compatibility, In Vitro Experiment

Abstract

Mechanical compatibility with the human dentin is a considerable issue when fabricating dental fiber posts. To this purpose, this study introduces a new method of fabricating compatible dental posts using braiding techniques of thermoplastic fibers (matrix) with glass fibers (reinforcement). Fifty fiber-reinforced composite (FRC) posts of thermoplastic yarns polypropylene (PP) braided with continuous filaments glass fibers (GFs) for reinforcement, varying in fiber volume fraction (FVF), and core types are fabricated and tested. Posts are performed using a braiding machine, and braids are placed in an aluminum mold. The filled mold is playced inside an oven at the melting temperature of the polypropylene to produce the final post’s shape. An ultrasonic test is conducted to measure the shear modulus and Young’s modulus of FRC post specimens by measuring the velocities of both the P-wave and S-wave. In order to ensure the accuracy of the measurements, each sample is measured three times, and then the means and standard deviations of each sample are calculated before analyzing the test results using the means of two steps, namely, clustering and comparing the P and R² values of each cluster, which revealed that FVF, fiber mass, and core type of the specimen had a significant effect on the resulted Young’s and shear modulus. The results indicate that the proposed method can fabricate competitive dental posts with regard to different fabricating variables. The samples show Young’s modulus ranges of from 10.08 GPa to 31.83 GPa. The following tested hypothesis is supported: the braiding technique of thermoplastic fibers with glass fibers will improve the mechanical compatibility of the resulting posts (ex vivo).

Braided Composite Configurations for Dental Applications

“…-Fiberglass yarns were generously donated by AGY industries, located in the U.S. -Fiberglass yarns were divided into two main categories according their silane: -First category was E-glass fiber treated with starch (ECE225) with a count of "22 Tex" -Second category was consisting mainly of two types of glass fiber with a specialized silane for coupling with thermoplastic fibers under a commercial name of "561 sizing" as follows: E-glass type (ECDE75) with a count of "66 Tex" S-glass type (SCG75) with a count of "68 Tex". Different yarn specifications are listed in Tables 1, 2, and 3 11 .…”

“…The first type was polyester (PET), second one was Polypropylene (PP) and the third one was polyamide (Nylon 6, PA). The technical specs and physical properties of each thermoplastic yarn type are listed in table 4 11 .…”

Flexural Strength of Dental Fiber Composite Post Manufactured with a Novel Approach

“…Compounds containing anhydride groups need to be used to increase the surface polarity and interfacial adhesion with the reinforcing phase [17]. The current used approach for fabrication of fiber composite posts has been recently discussed [18]. Braiding of three different types of GF (de-sized stash E-GF, pre-silanized E and S-GF) with thermoplastic PP resins yarns representing the resin matrix were prepared and the FRCPs Young's modulus was evaluated [18].…”

“…The current used approach for fabrication of fiber composite posts has been recently discussed [18]. Braiding of three different types of GF (de-sized stash E-GF, pre-silanized E and S-GF) with thermoplastic PP resins yarns representing the resin matrix were prepared and the FRCPs Young's modulus was evaluated [18]. The current study focuses on testing the flexural strength of the prepared FRCPs with more technique refinement for the experimental post-manufacturing technique.…”