Characterization of Heat-Polymerized Monomer Formulations for Dental Infiltrated Ceramic Networks

Janine Tiu,Renan Belli,Ulrich Lohbauer

doi:10.3390/app11167370

Janine Tiu, Renan Belli + Show 1 more

Open Access

https://doi.org/10.3390/app11167370

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Journal: Applied sciences	Publication Date: Aug 11, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Erlangen-Nuremberg

Abstract

(1) Objectives: This work examined properties of dental monomer formulations of an aromatic dimethacylate (BisGMA), aliphatic urethane dimethacrylate (UDMA), and triethylene glycol dimethacrylate (TEGDMA). The monomers were combined in different ratio formulations and heat-polymerized containing the initiator benzoyl peroxide (BPO) specifically for the purpose of infiltration into polymer-infiltrated composite structures. (2) Methods: The monomers were combined in different weight ratios and underwent rheological analysis (viscosity and temperature dependence), degree of conversion, and mechanical properties (elastic modulus, hardness, fracture toughness). (3) Results: Rheological properties showed Newtonian behavior for monomers with a large dependence on temperature. The addition of BPO allowed for gelation in the range of 72.0–75.9 °C. Degree of conversion was found between 74% and 87% DC, unaffected by an increase of TEGDMA (up to 70 wt%). Elastic modulus, hardness, and fracture toughness were inversely proportional to an increase in TEGDMA. Elastic modulus and hardness were found slightly increased for UDMA versus BisGMA formulations, while fracture toughness ranged between 0.26 and 0.93 MPa·m0.5 for UDMA- and 0.18 and 0.68 MPa·m0.5 for BisGMA-based formulations. (4) Significance: Heat-polymerization allows for greater range of monomer formulations based on viscosity and degree of conversion when selecting for infiltrated composite structures. Therefore, selection should be based on mechanical properties. The measured data for fracture toughness combined with the reduced viscosity at higher UDMA:TEGDMA ratios favor such formulations over BisGMA:TEGDMA mixtures.

Highlights

Resin composites are successful and versatile in dental restorative applications
(4) Significance: Heat-polymerization allows for greater range of monomer formulations based on viscosity and degree of conversion when selecting for infiltrated composite structures
resistance curve (R-curve) is seen in interpenetrating networks ofmonomer metals and ceramperformed onincreasing

Summary

Introduction

Resin composites are successful and versatile in dental restorative applications. The assembled constituents of organic polymers, inorganic fillers, and silane coupling agent [1,2]result in an expansive array of mechanical and structural properties. The assembled constituents of organic polymers, inorganic fillers, and silane coupling agent [1,2]. Several groups have challenged convention and moved towards composites with continuous and interconnected rigid and pliable constituents [3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]. Known as polymer infiltrated ceramic networks (PICN), these materials must be preprocessed as CAD/CAM (computer aided design/computer aided manufacturing) blocks or discs. The conditions for infiltration through a rigid porous structure differ from the mixing of conventional particle reinforced structures [18,19]. The infiltration process can be represented by Darcy’s Law, which describes fluid flow through a porous medium [20]

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