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

Abstract

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 airparticle abrasion). SBS test was performed using universal testing machine until failure, and failure modes were visually analyzed. Translucency parameter and curinglight 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. K E Y W O R D S3D printed composite, air-particle abrasion, laboratory composite, shear-bond strength testThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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

“…Short fiber-reinforced composites (SFRCs) have been developed to improve the mechanical properties of conventional particulatefilled composites and decrease complications that might negatively affect the long-term clinical success [11][12][13]. Experimental SFRC CAD/ CAM composites have previously demonstrated promising performance when their mechanical, optical, surface, and bonding properties have been tested [14][15][16]. Concurrently, no data are available on the fracture behavior of this material when it is used to fabricate IRF-PDs.…”

Load‐bearing capacity and wear characteristics of short fiber‐reinforced composite and glass ceramic fixed partial dentures

“…Although the loading cycles were identical in terms of number, frequency, and chewing force, the wear behavior of the tested CAD/CAM blocks varied based on the material type (Figure 6). SFRC CAD showed lower wear depth than lithium‐disilicate, and as seen in a previous study [23], microfibers were polished down together with the composite matrix. Lithium‐disilicate CAD exhibits wear tracks with smooth, elongated scratches.…”

“…The suboptimal wear resistance is seen as one of the primary limitations of the composites [22]. The wear characteristics of direct SFRC have been investigated in previous studies, and it has been found that the incorporation of short fibers into the composite does not have a negative impact on its wear [23,24].…”

Effect of interfacial surface treatment on bond strength of particulate-filled composite to short fiber-reinforced composite

“…Roughening the SFRC surface by grinding followed by phosphoric acid etching (Group 6), resulted in a higher shear bond strength compared to the group without surface treatment ( Figure 2 ). This favorable finding may be explained by the resulting high surface irregularity, which increases the bonded surface area and offers higher micro-mechanical interlocking at the interface between SFRC and PFCs [ 25 , 26 ]. Moreover, this procedure of grinding and etching the surface with phosphoric acid could be beneficial in the case of composite repairs where there is no oxygen inhibition layer.…”

“…There is no consensus as to a required minimum composite interlayer shear bond strength value. However, based on literature, values in the range 15 MPa to 35 MPa seem relevant [ 19–23 , 25 , 26 , 28 , 29 ]. In our study, the shear bond strength values obtained were within this range, except for the significantly highest value (43.7 MPa) found between the two SFRC layers (Group 8).…”