A chief complaint from clinicians performing tooth preparations in operative dentistry is the occurrence of bur breakage. Objective: to compare breakage force of two piece stainless steel shank/carbide (SSC) and solid carbide (CA) dental burs using a standard sized bur FG-557. Methods: groups were divided as: Alpen (AL-CA); Alpen Speedster (ALS-CA); Axis (AX-SSC); Midwest (MW-SSC); Midwest MP (MD-SSC); Neo (NE-CA); SS White (SSW-SSC) and SS White Great White (GW-SSC). Following the ISO 8325- test methods for dental rotary instruments for neck strength placing a bur in a chuck at an angle of 22.5 degrees to the horizontal with force applied to the free end of the bur. The burs were randomized for run order (n=400; 8 subgroups of 50 samples). A standardized load was applied until the bur either broke or bent. Visual observation of the breakage mode was evaluated. Statistical analysis was conducted with one-way ANOVA followed by a post hoc Scheffe test. Results: Breakage force in Newtons (mean + SD): AL-CA= 41.5 (±3.4)c,d; ALS-CA= 33.9 (±3.8)d; AX-SSC= 42.4 (±7.6)c; MW-SSC = 39.6±7.48 c,d; MD-SSC= 42.9 (±6.9)c; NE-CA = 57.1 (±7.3)b; SSW-SSC = 73.0 (±22.0)a; GW-SSC = 75.4 (±26.7)a.Means with same letters after the SD are not statistically different at p=0.001.Conclusion: The breakage force required for the SSC groups SSW and GW was statistically higher than all other groups tested. The manufacturing mode (SSC or CA) doesn't seem to be a determinant on the occurrence of bur breakage. From visual examination there was no consistent breakage mode for the burs tested.