Fatigue damage of monolithic posterior computer aided designed/computer aided manufactured crowns

Maximiliane Amelie Schlenz; Alexander Schmidt; Peter Rehmann; Bernd Wöstmann

doi:10.1016/j.jpor.2019.02.003

Fatigue damage of monolithic posterior computer aided designed/computer aided manufactured crowns

J Prosthodont Res. 2019 Jul;63(3):368-373. doi: 10.1016/j.jpor.2019.02.003. Epub 2019 Mar 13.

Authors

Maximiliane Amelie Schlenz¹, Alexander Schmidt², Peter Rehmann², Bernd Wöstmann²

Affiliations

¹ Justus-Liebig-University, Dental Clinic, Department of Prosthodontics, Giessen, Germany. Electronic address: maximiliane.a.schlenz@dentist.med.uni-giessen.de.
² Justus-Liebig-University, Dental Clinic, Department of Prosthodontics, Giessen, Germany.

PMID: 30878521
DOI: 10.1016/j.jpor.2019.02.003

Abstract

Purpose: To analyse fatigue damage of monolithic computer-aided-designed/computer-aided-manufactured (CAD/CAM)-materials after loading with high masticatory forces in standardized posterior crowns in a mouth-motion-simulator.

Methods: For manufacturing of test specimens (5 groups, 16 specimens each), two corresponding Standard-Tessellation-Language-(STL)-data-sets (one for the teeth and one for the crowns) were designed. The teeth were CAD/CAM-milled of human third molars and the crowns of three different CAD/CAM composite blocks (Lava Ultimate,'LU'; Brilliant Crios'BC'; Cerasmart,'CS'), one polymer-infiltrated-ceramic network (Vita Enamic,'VE') and a control group of lithium disilicate ceramics (IPS e.max CAD,'EM'). Crowns were adhesively cemented with their corresponding luting system on the human teeth. Half of the specimens were light-cured ('LC') and the others were chemical-cured ('CC'). A mouth-motion-simulator (WL-tec, 2 Hz, 37 °C) applied dynamic cyclic loading between 50-500 N for a period of 1 million cycles. Afterwards, a dye penetration test (aqueous basic-fuchsine) revealed damage of test specimens. Each specimen was sectioned into four equidistant slices and the area without damage was measured with a digital microscope (Zeiss) and radial cracks at the cementation surface were assessed. Data were subjected to Tukey's test.

Results: All specimens showed fatigue damage in the occlusal contact area. LU, BC and CS exhibited a significant greater area without damage compared to VE and EM (p < .05). EM and VE showed additional radial cracks at the cementation interface in both curing modes, whereas LU, BC and CS showed only radial cracks with chemical-cured luting cement.

Conclusions: Monolithic CAD/CAM composite crowns showed significantly lower fatigue damage, particularly if the luting system was light-cured.

Keywords: CAD/CAM-composite; Fatigue damage; Glass ceramics; Hybrid ceramics; Microcracks.

MeSH terms

Ceramics
Computer-Aided Design
Crowns*
Dental Porcelain
Dental Restoration Failure*
Dental Stress Analysis
Fatigue
Humans
Materials Testing

Substances

Dental Porcelain