Fracture resistance and the mode of failure produced in metal-free crowns cemented onto zirconia abutments in dental implants

Abstract

The purpose of the investigation was to analyze fracture resistance and mode of failure of zirconium oxide (zirconia) abutments placed on dental implants bearing crowns of different esthetic materials: zirconia, lithium disilicate (LDS), and nano-ceramic resin, for replacing single teeth in the anterior sector. Eighty implant-abutment-crown units were divided into four groups: Group T-MC (control): 20 metal-ceramic crowns cemented onto titanium abutments; Group Z-Z: 20 zirconia crowns on zirconia abutments; Group Z-LD: 20 lithium disilicate crowns on zirconia abutments; and Group Z-NCR: 20 nano-ceramic resin crowns on zirconia abutments. Specimens underwent a fatiguing process (dynamic loading and thermocycling), followed by static loading to evaluate mechanical fracture resistance, and the mode of failure produced. Mean fracture resistance values were: Control Group T-MC, 575.85±120.01 N; Group Z-Z 459.64±66.52 N; Group Z-LD, 531.77±34.10 N; and Group Z-NCR, 587.05±59.27 N. In Group T-MC, fracture occurred in the prosthetic fixing screw in 100% of specimens. In Group Z-Z, 80% of fractures occurred in the fixing screw, 15% in the abutment, and 5% in the abutment and crown. In Group Z-LD, 60% of fractures were produced in the fixing screw and 40% in the abutment. In Group Z-NCR, 70% of fractures were produced in the fixing screw and 30% in the abutment. All the abutments and crowns analyzed have the potential to withstand the physiological occlusal forces to which they would be subject in the anterior region. Lithium disilicate and nano-ceramic resin crowns cemented onto zirconia abutments are a good restoration alternative for single implants in the anterior sector.

Biomaterials and Clinical Application of Dental Implants in Relation to Bone Density—A Narrative Review

“…Several studies have investigated the fracture resistance of zirconia as an abutment and values above the occlusal forces applied in the anterior section were achieved. This finding is consistent with Agustin-Panadero et al [126], who compared the fracture resistance and failure mode of esthetic crown materials (zirconia, lithium disilicate, nanoceramic resin) and confirmed that all zirconia abutments with the three different crown materials, can withstand the physiological loads that occur in the anterior region. However, zirconia abutments bearing zirconia crowns exhibited the lowest fracture resistance (459.63 ± 66.52 N), and the most common fracture locations were the screw (80%) and abutment (15%).…”

Scientific Trends in Clinical Research on Zirconia Dental Implants: A Bibliometric Review

“…Zirconia material is distinguished by its clear ivory appearance, which is very similar to the natural color of the teeth and is characterized by an intrinsic strength and physical resistance to the loading [24][25][26]; as a result, it has been introduced as a restorative material for dental crowns, bars, abutments, and specially designed drills and burs [26][27][28][29][30][31][32][33][34]. Therefore, zirconia has recently gained further attention in the scientific community by growing research activities to confirm the clinical effectiveness of zirconia as a dental implant material.…”

Impact of Prosthetic Material and Restoration Type on Peri-Implant Bone Resorption: A Retrospective Analysis in a Romanian Sample

“…Zirconia is a white material, so it masks better than titanium under the upper limit of the gingival margin, and also provides high strength values for anterior sector. The use of this type of abutment in the posterior sector would be extremely risky given the mechanical requirements in this area [ 21 ].…”