Fracture Resistance of Additively Manufactured Zirconia Crowns when Cemented to Implant Supported Zirconia Abutments: An in vitro Study

Abstract

Purpose To compare the fracture resistance of implant‐supported milled zirconia, milled lithium disilicate, and additively manufactured zirconia crowns. Materials and Methods Maxillary cast with a dental implant replacing right second bicuspid was obtained. Custom abutments and full‐contour crowns for milled zirconia, milled lithium disilicate, and additively manufactured zirconia crowns (n = 10/group) were digitally designed and fabricated. The crowns were cemented to implant‐supported zirconia abutments and mounted onto polyurethane blocks. Fracture resistance was determined by vertical force application using a universal testing machine at a crosshead speed of 2 mm/minute. Kruskal‐Wallis test was used to analyze data and failure mode was determined for all the groups. Results Milled zirconia crowns demonstrated the highest median fracture resistance (1292 ± 189 N), followed by milled lithium disilicate (1289 ± 142 N) and additively manufactured zirconia (1243.5 ± 265.5 N) crowns. Statistical analysis showed no significant differences in fracture resistance between the groups (p = 0.4). All specimens fractured at the implant‐abutment interface. Conclusion Additively manufactured zirconia crowns demonstrated similar fracture resistance to milled ceramic crowns, when cemented to implant supported zirconia abutments. The results of this in vitro study signify the promising potential of additive manufacturing for the fabrication of all ceramic zirconia crowns.

Additive Manufacturing of Zirconia Ceramic and Its Application in Clinical Dentistry: A Review

“…The fracture resistance of implant-supported milled zirconia, milled lithium disilicate, and stereolithography (SLA) additively manufactured zirconia crowns were compared by Zandinejad et al [ 18 ]. Zirconia implant abutments were designed with a chamfer finish line and having 6 mm buccal and lingual wall height and 4 mm proximal wall height.…”

“…The American Society for Testing and Materials (ASTM) divides AM technologies into seven classifications to construct a product layer by layer: stereolithography (SLA), material jetting (MJ), material extrusion (ME), binder jetting (BJ), powder base fusion (PBF), sheet lamination (SL), and direct energy deposition (DEP), as all can be used to form ceramic components [ 16 , 17 , 18 ].…”

Effect of Fabrication Method on Fracture Strength of Provisional Implant-Supported Fixed Dental Prostheses

“…The advantages of provisional restorations via CAD-CAM process over conventional curing include increased durability [1,3,4,12,13], improved fit [3,4] and color stability [4]. However, fabrication with milling also has disadvantages: material waste, introduction of microcracks and limited reproduction of surface details depending on the size of the milling instrumentation [14].…”

“…With the increasing availability of 3D printers, digitally-designed provisional restorations can be printed in addition to being milled. Additive manufacturing creates less raw material waste, reduces manufacturing time and allows for mass production as compared to milling [6,14,15] but 3D-printed structures have limited shade selection, display a less finished surface due to anisotropy and the staircase effect and require expensive post-processing for ceramic [6,14]. Recently, investigators found that the accuracy of dental restorations fabricated by additive manufacturing methods is higher than that of subtractive methods [16].…”

The Fracture Resistance of Additively Manufactured Monolithic Zirconia vs. Bi-Layered Alumina Toughened Zirconia Crowns When Cemented to Zirconia Abutments. Evaluating the Potential of 3D Printing of Ceramic Crowns: An In Vitro Study

“…The thickness of the crown ranged from 1.0 mm (at the margin) to 2.0 mm (at the occlusal surface). The STL 2 file was used to fabricate (CeraMaker 900; 3DCeram Co. Lemonge, France) 10 full-contour zirconia (3DMix ZrO 2 paste; 3DCeram Co. Lemonge, France) crowns [38]. Thereafter, the STL 2 file was split in thickness into 2 layers (Figure 3).…”