Does artificial aging affect mechanical properties of CAD/CAM composite materials

: Egilmez F, Ergun G, Cekic-Nagas I, Vallittu PK, Lassila LVJ

Publisher: ELSEVIER IRELAND LTD

: 2018

: Journal of Prosthodontic Research

: JOURNAL OF PROSTHODONTIC RESEARCH

: J PROSTHODONT RES

: 62

: 1

: 65

: 74

: 10

: 1883-1958

DOI: https://doi.org/10.1016/j.jpor.2017.06.001

Purpose: The purpose of this study was to determine the flexural strength and Weibull characteristics of different CAD/CAM materials after different in vitro aging conditions.Methods: The specimens were randomly assigned to one of the six in vitro aging conditions: (1) water storage (37 degrees C, 3 weeks), (2) boiling water (24 h), (3) hydrochloric acid exposure (pH: 1.2, 24 h), (4) autoclave treatment (134 degrees C, 200 kPa, 12 h), (5) thermal cycling (5000 times, 5-55 degrees C), (6) cyclic loading (100N, 50,000 cycles). No treatment was applied to the specimens in control group. Three-point bending test was used for the calculation of flexural strength. The reliability of the strength was assessed by Weibull distribution. Surface roughness and topography was examined by coherence scanning interferometry. Evaluated parameters were compared using the Kruskall-Wallis or Mann-Whitney U test.Results: Water storage, autoclave treatment and thermal cycling significantly decreased the flexural strength of all materials (p < 0.05), whereas HCl exposure or cyclic loading did not affect the properties (p > 0.05). Weibull moduli of CerasmartTM and LavaTM Ultimate were similar with control. Vita Enamic1 exhibited similar Weibull moduli in all aging groups except the HCl treated group (p > 0.05). Ra values of CerasmartTM and LavaTM Ultimate were in the range of 0.053-0.088 mm in the aged groups. However Ra results of Vita Enamic1 were larger than 0.2 mm.Conclusions: Flexural strength of newly developed restorative CAD/CAM materials was significantly decreased by artificial aging. Cyclic loading or HCl exposure does not affect to the flexural strength and structural reliability of CerasmartTM and LavaTM Ultimate.