Development Of A Pulsed Light Emitting Diode Dental Photocuring System

描述（由申请人提供）：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。本提案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，这在确定固化时间、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”固化模式产生光聚合的最佳量子效率。该项目的第一阶段研究成功证明了所提出的脉冲LED光相对于传统光固化单元（LCU）的可行性和优势。结果发现，脉冲LED光产生10-12%以上的固化深度和更好的表面硬度比通过连续波（CW）光具有相同的曝光能量。在第二阶段，我们将建立一个简单但实用的模型来分析光聚合过程的动力学特性，并以该模型为指导，帮助我们进一步探索脉冲LED光用于牙科复合材料固化的潜力。一个拉曼光谱仪将与脉冲LED结合使用，用于光聚合过程的真实的实时和原位监测，以获得动力学模型中使用的参数。我们将对传统LCU和拟议的脉冲LED固化的牙科复合材料的物理性能进行系统的研究，这将用于进一步优化脉冲序列。一种新的自动固化时间控制方法，采用荧光水平监测在关闭时间的脉冲序列也将被探索。最后，我们将开发一种原型脉冲LED光固化系统，该系统能够在与使用激光辐射（通常为5-10秒）可获得的时间尺度相当的时间尺度内固化目前市场上的所有牙科聚合物树脂，并且在固化深度、硬度、收缩率、剪切粘合强度和树脂温度变化方面具有高的固化“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.