Cutting Efficiency of Diamond Burs for Dental Zirconia

Objectives: To evaluate cutting efficiency of diamond burs used for dental zirconia
Methods: A zirconia block (Lava Esthetic, 3M ESPE) was sectioned into 5.4 mm thick sections with a lapidary saw. Specimens were then sintered according to the manufacturers recommendation resulting in a final thickness of 2.43 mm. Diamond burs were used to cut the zirconia blocks. in a custom UAB Bur Testing Device which used a computer controlled cutting turbine (40,000 RPM) with water spray (5.45L/min) and a 0.98N load. Two cuts were made on every zirconia block for 10 minutes each while using the same bur for both cuts. Four different diamond burs were tested(n=6). A digital light microscope with image analysis software was then used to measure the distance each cut made in the zirconia block. Representative zirconia specimens and diamond burs from each group were gold-coated and examined in a SEM (Quanta FEG 650, FEI) using the secondary electron (SE). The edges of the cutting surfaces were examined for edge chipping. Data were analyzed with 2-way ANOVA and Tukey post-hoc analysis for factors bur type and order of cut (i.e. first or second cut).
Results: Table attached below with results*
Conclusions: Factors bur type, order of cut and their interaction were all significant (p<.01). There was no significant difference between cuts for the first cut, however, the NeoDiamond and Komet 4ZR burs produced longer cuts for the second cut. All burs showed significantly greater first cut than second cut. SEM imaging reveals that edge chipping can be observed on the cuts used with the Neodiamond, Komet 4ZR, and Komet 5856