Rodrigo Keigo Nakagawa, DDS, MSc, PhD, postdoctoral researcher, Department of Restorative Dentistry, Federal University of Minas Gerais, Bel o Horizonte, Brazil.
Hans Hatner Araújo de Oliveira, DDS, MSc student, Department of Restorative Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Oper Dent. 2024 Jan 1;49(1):43-51. doi: 10.2341/22-045-L.
The rise in temperature in pulp tissues is related not only to heat transfer by high-irradiance light-curing units (LCUs), but also to restorative procedures. This research aimed to compare the rise in pulp temperature (PT) induced by three LCUs at each restorative step while considering the influence of resin composite shade and thickness. To accomplish this, the investigators used a proposed experimental model replicating pulp fluid circulation with a controlled, simulated intraoral temperature in bovine incisors. The recorded external and internal PT ranged from 36.7°C to 37.1°C and 32.7°C to 33.0°C, respectively. A significant decrease of internal temperature was recorded during class V preparation, followed by a progressive and representative rise of temperature in the subsequent restorative steps. The temperature was significantly higher during light curing of the adhesive system using Valo compared to light curing using Elipar and Radii Cal. However, none of the analyzed devices produced a temperature that exceeded the pulp tolerance limit (a temperature increase over 5.5°C). The paired test showed no significant difference in pulp temperature associated with the thickness of the increment of resin composite. However, shade was found to have more influence on the amount of energy absorbed by pulp tissue-A1 samples showed significantly higher temperature variation compared to samples using the A4 shade of resin composite. To conclude, the microcirculation and the performance of procedures under constant air-water flux dissipate the heat absorbed by the pulp. Additionally, the data suggest that all three LCUs analyzed can be safely used in clinical procedures, and that the resin composite shade may influence the amount of irradiance delivered to the tooth surface and represents a significant factor in pulp temperature variance.
牙髓组织温度的升高不仅与高强度光固化单元（LCU）的热传递有关，还与修复程序有关。本研究旨在比较三种 LCU 在每个修复步骤引起的牙髓温度（PT）升高，同时考虑树脂复合材料的色调和厚度的影响。为此，研究人员使用了一种模拟实验模型，该模型复制了具有受控、模拟口腔内温度的牙髓液循环，在牛切牙中进行。记录的外部和内部 PT 分别为 36.7°C 至 37.1°C 和 32.7°C 至 33.0°C。在 V 类预备过程中记录到内部温度显著下降，随后在随后的修复步骤中温度逐渐升高并具有代表性。与使用 Elipar 和 Radii Cal 相比，使用 Valo 光固化时，粘合系统的内部温度显著升高。然而，没有一种分析设备产生的温度超过牙髓耐受极限（温度升高超过 5.5°C）。配对检验显示，与树脂复合材料增量厚度相关的牙髓温度没有显著差异。然而，色调对牙髓组织吸收的能量有更大的影响——A1 样本的温度变化明显高于使用 A4 色调的树脂复合材料样本。总之，微循环和恒定空气-水流下的程序性能会消散牙髓吸收的热量。此外，数据表明，分析的三种 LCU 都可以在临床程序中安全使用，并且树脂复合材料的色调可能会影响到牙齿表面的辐照度，这是牙髓温度变化的一个重要因素。
