LASER EFFECTS ON DENTAL HARD TISSUES

描述(改编自调查者摘要)：总体 这项研究的目的是加深对 激光与牙体硬组织的相互作用 安全有效地使用激光治疗癌症的科学依据 牙科硬组织，包括防龋剂和去龋剂。 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，这些波长不能用 以前提供的激光。调查人员现在可以接触到二氧化碳 具有更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)。 第二个具体目的是研究牙釉质和牙本质的热行为。 在选定波长下的跟随激光照射，并用 一维、二维和三维有限差热的计算机模拟 传导数字代码。这一目标改进了他们以前的1-D (体外)建模工作。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 辐射。这一目标将利用六种技术：(1)热响应 基于红外辐射测量表面温度的分析， (2)掠射X射线衍射；(3)傅立叶变换红外反射光谱；(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 激光照射过程中对牙髓的热传递的影响。这项研究涉及 25名计划拔除第三磨牙的志愿者 放置在牙髓-牙本质交界处的热电偶 在激光照射期间(在体内)。具体目标5是确定 激光照射参数，有无氟化物处理， 最佳抑制牙釉质和牙本质中龋样病变的进展 牙根。酸溶解试验被用来产生一种措施来 牙齿材料通过激光(体外)硬化。第六个具体目标 是在人类身上进行口腔内研究，包括放置 经激光体外处理的牙科材料进入口腔 对人体志愿者进行长时间的激光能力研究 辐照使牙科材料变硬。这项化验将进行 通过与印第安纳大学的分包合同(在体内)。这个 第七个具体目标是研究对周围继发性龋病的抑制作用 激光照射修复(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).