LASER EFFECTS ON DENTAL HARD TISSUES

描述（改编自研究者摘要）：总体 研究的目的是了解 激光与牙齿硬组织的相互作用， 安全有效使用激光治疗的科学依据 牙齿硬组织，包括龋齿预防和龋齿去除。 有七个具体目标。第一个具体目标是确定 牙釉质和牙本质的吸收系数，重点是9.3 和9.6微米波长，这是无法充分研究与 以前的激光器。调查人员现在可以使用二氧化碳 具有较短脉冲持续时间的激光，这将使测量 在这些波长下的高吸收（体外）。 第二个具体目标是研究牙釉质和牙本质的热行为 在选定的波长下进行跟随激光照射， 用一维、二维和三维有限差分热计算模拟 传导数字代码。这一目标改进了他们以前的1-D 建模工作（体外）。第三个具体目标是研究 激光作用下牙釉质和牙本质的热分解动力学 辐照这一目标将利用六项技术：（1）热响应 基于表面温度的红外辐射测量的分析， (2)扫描X射线衍射，（3）FTIR反射光谱，（4） 放出气体分析，（5）酸溶解速率测量，和（6） 扫描电子显微镜（体外）。第四个具体目标是 在人体内进行安全性研究，以确定程度和影响 在激光照射过程中热量传递到纸浆。研究涉及 25名志愿者计划拔除第三磨牙， 热电偶放置在牙髓牙本质交界处的任何温度上升 在激光照射期间（体内）。具体目标5是确定 激光照射参数，有和没有氟化物处理， 最佳地抑制釉质中龋齿样损伤的进展， 牙根酸溶解测定用于产生测量， 牙齿材料通过激光硬化（体外）。第六个具体目标 是在人类口腔内进行研究， 牙科材料，在体外预处理的激光，进入口腔 人类志愿者的长期研究能力的激光 照射以硬化牙科材料。本试验将在 通过与印第安纳州大学的合作（体内）。的 第七个具体目的是研究周围继发龋的抑制作用 激光照射（体外）。

DESCRIPTION (adapted from the Investigator's abstract): The overall objective of the research is to develop an understanding of the interactions of laser light with dental hard tissues and to establish a scientific basis for the safe and effective use of lasers for treatment of dental hard tissues including caries prevention and caries removal. There are seven specific aims. The first specific aim is to determine the absorption coefficients for enamel and dentin, with emphasis on the 9.3 and 9.6 um wavelengths which were not able to be fully studied with the lasers available previously. The investigators now have access to a CO2 laser with a shorter pulse duration which will enable measurement of the high absorption at these wavelengths (in vitro). The second specific aim is study the thermal behavior of enamel and dentin follower laser irradiation at selected wavelengths and to model with computer simulations using 1-, 2-, and 3-D finite difference heat conduction numerical codes. This aim improves on their previous 1-D modeling efforts (in vitro). The third specific aim is to study the thermal decomposition kinetics of enamel and dentin during laser irradiation. This aim will utilize six techniques: (1) thermal response analysis based on infrared radiometry measurements of surface temperature, (2) glancing x-ray diffraction, (3) FTIR reflectance spectroscopy, (4) evolved gas analysis, (5) acid dissolution rate measurements, and (6) scanning electron microscopy (in vitro). The fourth specific aim is to carry out safety studies in humans in vivo to establish degree and effects of heat transfer to the pulp during laser irradiation. The study involves 25 volunteers scheduled for removal of 3rd molar teeth in which thermocouple placed at the pulp-dentin junction any temperature rise during laser irradiation (in vivo). Specific Aim 5 is to determine the laser irradiation parameters, with and without fluoride treatments, that optimally inhibit the progression of caries-like lesions in enamel and tooth roots. An acid dissolution assay is used to generate a measure to tooth material hardening by the laser (in vitro). The sixth specific aim is to conduct intra-oral studies in humans involving the placement of dental materials, pretreated in vitro by the laser, into the oral cavity of human volunteers for prolonged periods to study the ability of laser irradiation to harden dental materials. This assay will be conducted through a subcontract with the University of Indiana (in vivo). The seventh specific aim is to study the inhibition of secondary caries around restorations by laser irradiation (in vitro).