Characterization of occlusal splint materials: CAD-CAM versus conventional resins

Mona Gibreel; Leila Perea-Lowery; Pekka K Vallittu; Lippo Lassila

doi:10.1016/j.jmbbm.2021.104813

Characterization of occlusal splint materials: CAD-CAM versus conventional resins

J Mech Behav Biomed Mater. 2021 Dec:124:104813. doi: 10.1016/j.jmbbm.2021.104813. Epub 2021 Sep 7.

Authors

Mona Gibreel¹, Leila Perea-Lowery², Pekka K Vallittu³, Lippo Lassila⁴

Affiliations

¹ Department of Biomaterials Science and Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland. Electronic address: mona.f.gibreel@utu.fi.
² Department of Biomaterials Science, Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland.
³ Professor and Chair of Biomaterials Science Department, University of Turku, Welfare Division, Turku, Finland.
⁴ Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland.

PMID: 34530298
DOI: 10.1016/j.jmbbm.2021.104813

Abstract

Aim: The aim of this in vitro study was to assess the mechanical properties of five commercially available subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) milled splint materials, as well as to compare them with conventional heat-polymerized and autopolymerizing resins used in the construction of conventional splints.

Material and methods: Five CAD-CAM milled (ProArt CAD Splint, Therapon Transpa, Temp Premium Flexible Transpa, Cast, and Aqua), one autopolymerizing (Palapress), and one heat-polymerized (Paladon 65) resin materials were evaluated. Flexural strength, E-modulus, Vickers hardness, fracture toughness, fracture work, water sorption, and water solubility were measured. Samples were evaluated after dry and water storage for 30 days at 37 °C. Data were collected and statistically analyzed.

Results: Under both storage circumstances, the flexural strength values of Paladon 65, Therapon Transpa, Temp Premium Flexible Transpa, and Aqua were statistically non-significant (P=0.055). The polycarbonate-based CAD-CAM material Temp Premium Flexible Transpa had the highest statistically significant values of the fracture toughness and fracture work (P<0.001). Moreover, it exhibited the lowest percentages of water sorption and water solubility among the investigated materials (P<0.001). All of the CAD-CAM materials exhibited dry elastic moduli greater than Palapress and lower than Paladon 65. One of the CAD-CAM materials, Cast, had the highest dry Vickers hardness value, which was non-significant when compared to Therapon Transpa (P=0.762).

Conclusion: CAD-CAM polycarbonate-based splint materials exhibit higher fracture toughness and fracture work as well as lower water sorption and solubility than polymethyl methacrylate-based ones. The mechanical characteristics of the assessed CAD-CAM milled splint materials were not typically superior to those of the conventional heat-polymerized resin. However, some of them outperformed the autopolymerizing acrylic resin in terms of flexural strength, surface microhardness, water sorption, and water solubility.

Keywords: Flexural strength; Modulus; Polymethyl methacrylate; Splints; Toughness; Water sorption.

MeSH terms

Computer-Aided Design*
Dental Materials
Flexural Strength
Materials Testing
Occlusal Splints*
Polymethyl Methacrylate
Surface Properties

Substances

Dental Materials
Polymethyl Methacrylate