Fracture resistance and color stability of monolithic CAD/CAM crowns: effect of occlusal thickness and thermocycling
4 affiliations
- 1Department of Prosthodontics, Faculty of Dentistry, Atlas University, Istanbul, Turkey
- 2Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
- 3Department of Prosthodontics, Faculty of Dentistry, Biruni University, Istanbul, Turkey
- 4Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Biruni University, Istanbul, Turkey
Abstract
Purpose This in vitro study evaluated the effects of occlusal thickness and thermocycling on the fracture resistance and color stability of monolithic CAD/CAM crown materials. Materials and methods Standardized full-coverage crowns were fabricated from four CAD/CAM materials: resin nano-ceramic (CM), extra-translucent zirconia (VXT), translucent zirconia (VT), and zirconia-reinforced lithium silicate (VS). Two occlusal thicknesses (1.0 mm and 1.5 mm) were designed. Specimens from each material–thickness combination were divided into non-aged and thermocycled subgroups (n = 10 each). The thermocycled subgroups were subjected to 10,000 cycles between 5 °C and 55 °C. Fracture resistance was measured using a universal testing machine. Color measurements (L*, a*, b*) were obtained using a spectrophotometer before and after thermocycling, and color differences (ΔE₀₀) were calculated. Data were analyzed using two-way and three-way ANOVA with post hoc Tukey tests (α = 0.05). Results Material type (P < .001; ηp² = 0.52) and occlusal thickness (P = .003; ηp² = 0.11) had significant effects on fracture resistance. Increasing occlusal thickness resulted in higher fracture resistance values across all tested materials. VXT demonstrated the highest fracture resistance, whereas VS exhibited the lowest values. Thermocycling did not have a significant main effect on fracture resistance (P = .178; ηp² = 0.02). Color differences (ΔE₀₀) varied significantly among materials (P < .05); however, all values remained below the clinically acceptable threshold. Conclusions Occlusal thickness and material type significantly influence the mechanical performance of monolithic CAD/CAM crowns. Although thermocycling had a limited effect on fracture resistance, all materials maintained clinically acceptable color stability. These findings support the use of reduced-thickness restorations with appropriate material selection.
Related
- Association of CT-Derived Psoas Muscle Parameters and Trochanteric Subcutaneous Fat Thickness With Intertrochanteric Fracture Stability in Older Adults
- Effects of thermocycling on color stability and mechanical properties of universal resin composites: an in vitro comparison.
- Running style and stability during uphill running are largely preserved with increasing shoe sole thickness
- Development of a therapist-supervised flexibility and resistance exercise intervention for adults aged 50 years and over with a distal radius fracture in the Wrist Injury Strengthening Exercise (WISE) trial.
- The effect of fiber bundle posts used with different core materials on fracture resistance: an in vitro study
BibTeX
@article{ozcan2026fracture,
title = {{Fracture resistance and color stability of monolithic CAD/CAM crowns: effect of occlusal thickness and thermocycling}},
author = {Erkin Özcan and Deger Ongul and Rafat Sasany and Ibrahim Bulent Sermet and Ilknur Özcan},
journal = {BMC Oral Health},
year = {2026},
month = jul,
doi = {10.1186/s12903-026-09149-x},
url = {https://doi.org/10.1186/s12903-026-09149-x},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Fracture resistance and color stability of monolithic CAD/CAM crowns: effect of occlusal thickness and thermocycling
AU - Erkin Özcan
AU - Deger Ongul
AU - Rafat Sasany
AU - Ibrahim Bulent Sermet
AU - Ilknur Özcan
PY - 2026
DA - 2026/07/01
JO - BMC Oral Health
DO - 10.1186/s12903-026-09149-x
UR - https://doi.org/10.1186/s12903-026-09149-x
AB - Purpose This in vitro study evaluated the effects of occlusal thickness and thermocycling on the fracture resistance and color stability of monolithic CAD/CAM crown materials. Materials and methods Standardized full-coverage crowns were fabricated from four CAD/CAM materials: resin nano-ceramic (CM), extra-translucent zirconia (VXT), translucent zirconia (VT), and zirconia-reinforced lithium silicate (VS). Two occlusal thicknesses (1.0 mm and 1.5 mm) were designed. Specimens from each material–thickness combination were divided into non-aged and thermocycled subgroups (n = 10 each). The thermocycled subgroups were subjected to 10,000 cycles between 5 °C and 55 °C. Fracture resistance was measured using a universal testing machine. Color measurements (L*, a*, b*) were obtained using a spectrophotometer before and after thermocycling, and color differences (ΔE₀₀) were calculated. Data were analyzed using two-way and three-way ANOVA with post hoc Tukey tests (α = 0.05). Results Material type (P < .001; ηp² = 0.52) and occlusal thickness (P = .003; ηp² = 0.11) had significant effects on fracture resistance. Increasing occlusal thickness resulted in higher fracture resistance values across all tested materials. VXT demonstrated the highest fracture resistance, whereas VS exhibited the lowest values. Thermocycling did not have a significant main effect on fracture resistance (P = .178; ηp² = 0.02). Color differences (ΔE₀₀) varied significantly among materials (P < .05); however, all values remained below the clinically acceptable threshold. Conclusions Occlusal thickness and material type significantly influence the mechanical performance of monolithic CAD/CAM crowns. Although thermocycling had a limited effect on fracture resistance, all materials maintained clinically acceptable color stability. These findings support the use of reduced-thickness restorations with appropriate material selection.
SN - 1472-6831
ER -