IADR Abstract Archives
Pulp-chamber Temperature After Irradiation with 11 Light-curing-units: in vitro Study
Objectives: To measure the intrapulpar temperature as a function of the light curing unit (LCU) and the distance from the pulp-chamber wall.
Methods: A 0.5mm thick tooth slab with the original pulp-chamber roof, obtained from a molar, was mounted with sticky wax on top of a central hole of a flat plastic dish mounted 9 cm above the base plate, with an infrared camera for I-phone (FLIR ONE PRO, FLIR Systems) focused on the bottom of the dish with the tooth slab. For the blood- flow-simulation, water of 35oC was pumped with a peristaltic pump from a large water tank stabilized by a thermostat into the dish creating a flowing 0.5mm water-film on the inside of the dish. Using a mechanical arm the 12 LCU were positioned at 1.0, 1.5 and 2.0 mm from the surface. During the 20s irradiance the temperature rise at the pulpal roof was measured. For every LCU and distance 3 measurements were taken with a cooling phase to 35oC in-between. Two-way ANOVA with LCU and distance as variables and Tukey’s test were used to analyze the data.
Results: Significant main effects, and significant interactions were found. The results are presented in the table. At 1mm, temperatures varied from 70Co to 50oC respectively 50.7oC. For the highest and lowest temperatures, the same ranking was maintained at 1.5mm and 2.0mm distance. The temperature decrease from 1mm to 2mm distance was not uniform. It varied from 0.3oC to 6.3oC. This explains the significant interaction and may be due to the different beam profiles of the measured LCUs at different distances, which should be further investigated.
Conclusions: The clinical importance of these findings is that with a thin pulpal wall remaining, long irradiation times should be avoided, because the temperature rise is higher than the accepted threshold value of 4.5oC above 37oC.
Methods: A 0.5mm thick tooth slab with the original pulp-chamber roof, obtained from a molar, was mounted with sticky wax on top of a central hole of a flat plastic dish mounted 9 cm above the base plate, with an infrared camera for I-phone (FLIR ONE PRO, FLIR Systems) focused on the bottom of the dish with the tooth slab. For the blood- flow-simulation, water of 35oC was pumped with a peristaltic pump from a large water tank stabilized by a thermostat into the dish creating a flowing 0.5mm water-film on the inside of the dish. Using a mechanical arm the 12 LCU were positioned at 1.0, 1.5 and 2.0 mm from the surface. During the 20s irradiance the temperature rise at the pulpal roof was measured. For every LCU and distance 3 measurements were taken with a cooling phase to 35oC in-between. Two-way ANOVA with LCU and distance as variables and Tukey’s test were used to analyze the data.
Results: Significant main effects, and significant interactions were found. The results are presented in the table. At 1mm, temperatures varied from 70Co to 50oC respectively 50.7oC. For the highest and lowest temperatures, the same ranking was maintained at 1.5mm and 2.0mm distance. The temperature decrease from 1mm to 2mm distance was not uniform. It varied from 0.3oC to 6.3oC. This explains the significant interaction and may be due to the different beam profiles of the measured LCUs at different distances, which should be further investigated.
Conclusions: The clinical importance of these findings is that with a thin pulpal wall remaining, long irradiation times should be avoided, because the temperature rise is higher than the accepted threshold value of 4.5oC above 37oC.
IMAGES
3324371_File000001.jpg
3324371_File000001.jpg