Title: 0874 - Effect of Thickness on Fracture Strength of Posterior CAD-CAM Crowns


Mayara Noronha, University of Campinas
Veber Azevedo, University of Campinas
Oswaldo Andrade, National Service of Comercial Learning
Adriana Carvalho, State University of Southern Bahia
Stéphanie Favero, University of Sao Paulo
Paulo Cesar, University of Sao Paulo
Marcelo Giannini (Presenter)
University of Campinas


Objectives: This in vitro study evaluated the effect of thickness on the ultimate fracture strength of posterior full crowns obtained from CAD-CAM materials.

Methods: Forty-five upper human molars were prepared with different preparations to receive prosthetic full crowns with thicknesses of 0.5, 1.0 and 1.5mm. Three CAD-CAM materials were tested (e-max CAD/Ivoclar Vivadent, Enamic/Vita and Suprinity/Vita). CAD/CAM blocks were milled at CEREC MCXL (Sirona Dentsply) and final processing, as well as treatment of the intaglio surface occurred according to manufacturer’s instructions. Crowns were placed using Panavia V5 (Kuraray Noritake) and tested after 24h in a universal testing machine (Instron). Teeth were submitted to axial loading until failure using a stainless steel sphere (3mm diameter), in order to determine the ultimate crown strength. Data were expressed in Newton (N) and analyzed by 2-way ANOVA e Tukey’s test (pre-set alpha=5%).

Results: Means of ultimate fracture strength are presented in Table 1. The 2-way ANOVA demonstrated that both thickness (p<0.0001) and CAD/CAM material (p<0.0001) significantly influenced the fracture strength results.

Conclusions: For all materials, 1.5mm-thick prosthetic crowns resulted in significantly greater ultimate fracture strength than 0.5mm-thick crowns, whereas 1.0mm-thick crown showed intermediate results. Suprinity crowns showed the lowest fracture strength compared the other materials, regardless the thickness.


Thickness e-Max CAD Enamic Suprinity
0.5 1628.6 (449.2) A b 1110.5 (400.9) A b 325.1 (107.9) B b
1.0 1680.9 (449.2) A b 1494.7 (413.1) A ab 433.5 (142.3) B a
1.5 2126.4 (750.5) A a 1828.7 (446.8) A a 477.8 (125.4) B a

This abstract is based on research that was funded entirely or partially by an outside source:
FAPESP # 2015/02461-0

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE