Development Of A Pulsed Light Emitting Diode Dental Photocuring System

描述(申请人提供)：基于LED的固化灯开始取代传统的卤素灯，成为牙科光固化应用的首选。这项建议的目标是开发新一代LED牙科固化灯。这将是根据牙科复合材料的动力学响应进行优化的第一个固化光，它在决定固化时间、固化树脂的质量和产热方面起着关键作用。所提出的LED光通过一系列短持续时间的光脉冲来固化牙科复合材料，其中脉冲宽度和脉冲周期的时间尺度被设计为与光引发过程的响应时间相匹配。这种“共振”固化模式为光聚合提供了最佳的量子效率。该项目的第一阶段研究成功地展示了拟议的脉冲LED灯相对于传统光固化单元(LCU)的可行性和优势。结果表明，与相同曝光能量的连续波(CW)光相比，脉冲LED光的固化深度增加了10~12%，表面硬度提高了10~12%。对于二期工程，我们将建立一个简单而实用的模型来分析光聚合过程的动力学特征，并以该模型为指导，进一步挖掘脉冲LED光在牙科复合材料固化中的潜力。利用拉曼光谱仪与脉冲发光二极管相结合，对光聚合过程进行实时、实时的监测，以获得动力学模型中使用的参数。我们将对传统LC U和所提出的脉冲LED固化的牙科复合材料的物理性能进行系统的研究，这将被用于进一步优化脉冲序列。还将探索一种新的自动固化时间控制方法，该方法在脉冲序列的关闭时间处使用荧光水平监测。最后，我们将开发一种原型脉冲LED光固化系统，能够在与使用激光辐射(通常为5-10秒)获得的时间尺度相当的时间范围内固化目前市场上的所有牙科聚合物树脂，并在固化深度、硬度、收缩、剪切粘结强度和树脂温度变化方面具有较高的固化质量。

DESCRIPTION (provided by applicant): LED based curing lights are beginning to replace conventional halogen lamps as the first choice for dental photo-curing applications. The target of this proposal is to develop a new generation LED dental curing light. It will be the first curing light that is optimized according to the kinetic response of the dental composite, which plays a key role in determining the curing time, the quality of the cured resin, and the heat production. The proposed LED light cures the dental composite by a train of short-duration light pulses, where the time scale of the pulse width and pulse period is designed to match with the response time of the photo-initiation process. This 'resonant' curing mode yields the best quantum efficiency for photo-polymerization. Phase I study of this project leads to successful demonstration of the feasibility and advantages of the proposed pulsed LED light over conventional light curing units (LCUs). It was found that the pulsed LED light yields 10-12% more curing depth and better surface hardness than that obtained by a continuous wave (CW) light with same exposure energy. For phase II project, we will establish a simple but practical model to analyze the kinetic characteristics of the photo-polymerization process and use the model as a guide to help us further explore the potential of the pulsed LED light for dental composite curing. A Raman spectrometer will be utilized in combination with the pulsed LED for real time and in situ monitoring of the photo-polymerization process as to obtain the parameters used in the kinetic model. We will conduct a systematic study on the physical properties of the dental composite cured by both conventional LCUs and the proposed pulsed LED, which will be used to further optimize the pulse sequence. A novel automatic curing time control method employing fluorescence level monitoring at off-time of the pulse train will also be explored. Finally, we will develop a prototype pulsed LED photo-curing system capable of curing all dental polymer resins currently on the market in a time scale comparable to that can be obtained using laser radiation (typically 5-10 seconds) and with a high "quality" of cure in terms of depth of cure, hardness, shrinkage, shear bond strength, and temperature change in the resin.