IADR Abstract Archives
Temperature Generated on the Zirconia Back-Surface During Different Cutting Processes
Objectives: The purpose of this laboratory study was to evaluate the temperature generated on the back-surface of different types of zirconia ceramic during different cutting processes. In addition, the cutting duration was investigated.
Methods: A conventional (C) diamond rotary instrument (Brasseler, grainsize 107µm) and one (Z) specifically marketed to cut zirconia (4ZR, Brasseler, grainsize 126µm) were tested on 3Y-TZP (Katana Zirconia HTML Plus, Kuraray) and 4Y-TZP zirconia (Katana Zirconia STML, Kuraray) with a rotation speed of 100,000rpm (100) and 200,000rpm (200). Zirconia specimens (2mm thickness) were divided into 8 groups (n=8): HTML-C-200, HTML-Z-200, HTML-C-100, HTML-Z-100, STML-C-200, STML-Z-200, STML-C-100 and STML-Z-100. All specimens were cut under water spray cooling (110ml/min) in a custom-made holder attached to a universal testing machine (Z010, Zwick) using a force of 2N. Cutting duration and temperature with infrared sensors pointing at the back-surface of zirconia specimens were recorded.
Results: Mean maximum temperatures ranged from 44.1±8.1°C (STML-C-100) to 76.5±8.3°C (HTML-Z-200) when the specimen thickness was reduced to 0.5mm. A rotation speed of 200,000rpm led to significant higher temperatures at the back-surface of zirconia specimens in all groups compared with 100,000rpm. No statistically significant differences in temperature were found for the different diamond rotary instruments and ceramics within the groups.
A statistically significant effect of the diamond rotary instrument type and material was observed with significantly shorter cutting durations for C than for Z and higher cutting durations for HTML than for STML. Cutting duration was significantly reduced by increasing rotation speed for Z only. Mean duration of cutting 2 mm material thickness ranged from 143.9±10.3s (STML-C-200) to 1311.7±426.2s (HTML-Z-100).
Conclusions: To avoid high temperature development when cutting zirconia in clinical use, the diamond rotary instrument C with 100,000rpm can be recommended. Additionally, instrument C was more efficient than instrument Z in terms of the cutting duration.
Methods: A conventional (C) diamond rotary instrument (Brasseler, grainsize 107µm) and one (Z) specifically marketed to cut zirconia (4ZR, Brasseler, grainsize 126µm) were tested on 3Y-TZP (Katana Zirconia HTML Plus, Kuraray) and 4Y-TZP zirconia (Katana Zirconia STML, Kuraray) with a rotation speed of 100,000rpm (100) and 200,000rpm (200). Zirconia specimens (2mm thickness) were divided into 8 groups (n=8): HTML-C-200, HTML-Z-200, HTML-C-100, HTML-Z-100, STML-C-200, STML-Z-200, STML-C-100 and STML-Z-100. All specimens were cut under water spray cooling (110ml/min) in a custom-made holder attached to a universal testing machine (Z010, Zwick) using a force of 2N. Cutting duration and temperature with infrared sensors pointing at the back-surface of zirconia specimens were recorded.
Results: Mean maximum temperatures ranged from 44.1±8.1°C (STML-C-100) to 76.5±8.3°C (HTML-Z-200) when the specimen thickness was reduced to 0.5mm. A rotation speed of 200,000rpm led to significant higher temperatures at the back-surface of zirconia specimens in all groups compared with 100,000rpm. No statistically significant differences in temperature were found for the different diamond rotary instruments and ceramics within the groups.
A statistically significant effect of the diamond rotary instrument type and material was observed with significantly shorter cutting durations for C than for Z and higher cutting durations for HTML than for STML. Cutting duration was significantly reduced by increasing rotation speed for Z only. Mean duration of cutting 2 mm material thickness ranged from 143.9±10.3s (STML-C-200) to 1311.7±426.2s (HTML-Z-100).
Conclusions: To avoid high temperature development when cutting zirconia in clinical use, the diamond rotary instrument C with 100,000rpm can be recommended. Additionally, instrument C was more efficient than instrument Z in terms of the cutting duration.