840 Determination of Fracture Toughness of Provisional Dental Materials

Friday, March 23, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
C. LARSEN, M. HARSONO, M. FINKELMAN, and R.D. PERRY, Tufts University, Boston, MA

Objectives:   To determine and compare the fracture toughness of five provisional dental materials. 

Methods:   Five groups of ten samples each of provisional materials were tested in this study. The samples were made using a stainless steel mold 2 mm in height, 4.95 mm in width, and 25 mm in length.  After 24 hours of polymerization,  a notch (2.6 ± .05 mm) was inserted into the middle of each sample using a separating disc (thickness 320 µm) attached to an immobilized low speed handpiece .  Microscope examination was used to observe any defects.  The three-point bending test was performed using a universal testing machine (Instron, 5566A) at a cross-head speed of 1mm/min (load cell 500 N).   The notch was positioned centrally beneath the contact and the distance between the two supports was 20 mm. The radius of each support was 1 mm.

The fracture toughness (K1C) was calculated according to ISO 13586.  The Kolmogorov-Smirnov test was used to determine normal distribution and the homogeneity of the samples was checked using the Levene test.  A one-way ANOVA was used to test the mean fracture toughness between groups.  Statistical significance was predetermined at level p<0.05.






Mean Fracture Toughness

(MPa ∙ m0.5)


Structur Premium (Voco)

1.36 ± .14b


Protemp Plus (3M)

1.66 ± .22c,d


Luxatemp (DMG)

1.05 ± .11a


Luxatemp Ultra (DMG.)

1.54 ± .17b,d


Experimental (Dentsply Caulk)

1.35 ± .17b


Conclusions:   Group 3 exhibited a statistically lower resistance to crack propagation than all other groups, whereas Group 2 exhibited a statistically higher resistance than Group 1, Group 3, and Group 5.  No statistical difference is evident between Groups 1, 3, and 5.

This abstract is based on research that was funded entirely or partially by an outside source: Dentsply Caulk

Keywords: Dental materials, Hardness, Polymerization and Provisional Materials