Several new pulp-capping materials have been introduced to the market recently. The physical properties of these new materials may affect their resistance to fracture under load during placement of a final restorative material or support of an overlying restorative material over time.
Objective: The purpose of this study was to evaluate the flexural strength/modulus and compressive strength of the new pulp-capping materials (TheraCal LC, Bisco; Biodentine, Septodont) compared to mineral trioxide aggregate (ProRoot MTA, Dentsply), and calcium hydroxide (Dycal, Dentsply) over time.
Method: Ten specimens per group were formed as per manufacturers’ directions in a 2x2x25mm split mold for flexural strength/modulus testing and in a 6mm long x 4mm diameter split mold for compressive strength testing. Specimens were stored in darkness at 37°C and 98% humidity in a lab oven. After 15 minutes, 3 hours, and 24 hours, specimens were tested to failure in a universal testing machine (Instron). Flexural modulus was determined from the slope of the linear region of the load-deflection curve. A mean and standard deviation was determined per group. Data was analyzed with multiple ANOVA/Tukey’s test (alpha=0.007).
Result: A significant difference was found between groups based on material or time (p<0.007).
Conclusion: MTA did not set at 15 minutes. At all time periods, TheraCal had the greatest flexural and compressive strength. After 3 and 24 hours, Biodentine had the greatest flexural modulus.
Discussion: TheraCal had greater early strength to potentially resist fracture during immediate placement of a final restorative material. However, Biodentine was the least flexible after three hours for potentially greater support of an overlying restoration under function over time.
Flexural Strength MPa (st dev)
|
Material
|
Time
|
15 mins
|
3 hrs
|
24 hrs
|
Dycal
|
2.7 (0.5) Bb
|
4.9 (1.3) Ab
|
6.3 (1.7) Ac
|
MTA
|
Did not set
|
1.1 (0.6) Bb
|
4.8 (3.5) Ac
|
Biodentine
|
0.6 (0.5) Bb
|
9.4 (5.0) Ab
|
13.4 (5.2) Ab
|
TheraCal
|
31.1 (9.2) Aa
|
41.2 (10.1) Aa
|
33.3 (6.5) Aa
|
Groups with the same upper case letter per row or lower case letter per column are not significantly different (p>0.007).
|
|
Flexural Modulus GPa (st dev)
|
Material
|
Time
|
15 mins
|
3 hrs
|
24 hrs
|
Dycal
|
0.7 (0.3) Cb
|
2.2 (0.4) Bb
|
3.5 (1.1) Ab
|
MTA
|
Did not set
|
1.7 (1.4) Bb
|
6.6 (3.3) Ab
|
Biodentine
|
0.6 (0.8) Cb
|
9.3 (4.1) Ba
|
24.1 (5.5) Aa
|
TheraCal
|
1.9 (0.7) Aa
|
1.8 (0.6) Ab
|
2.0 (0.6) Ab
|
Groups with the same upper case letter per row or lower case letter per column are not significantly different (p>0.007).
|
|
Compressive Strength MPa (st dev)
|
Material
|
Time
|
15 mins
|
3 hrs
|
24 hrs
|
Dycal
|
7.7 (2.1) Bb
|
16.3 (5.0) Abc
|
20.4 (5.8) Abc
|
MTA
|
Did not set
|
0.5 (0.2) Bc
|
5.9 (2.2) Ac
|
Biodentine
|
1.3 (0.5) Bb
|
33.9 (13.1) Ab
|
40.1 (10.1) Ab
|
TheraCal
|
87.7 (18.8) Aa
|
95.8 (20.9) Aa
|
102.8 (26.9) Aa
|
Groups with the same upper case letter per row or lower case letter per column are not significantly different (p>0.007).
|
