LASER EFFECTS ON DENTAL HARD TISSUES

激光对牙齿硬组织的影响

• 批准号: 6379659
• 负责人: JOHN D FEATHERSTONE
• 金额: $ 30.45万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6379659
• 关键词: X ray crystallography; apatites; cementum; clinical research; computer simulation; crystallization; dental caries; dental caries inhibitor; dental pulp; dentin; gas; human subject; infrared spectrometry; laser therapy; lasers; method development; phase change; preventive dentistry; radiation therapy dosage; radiochemistry; scanning electron microscopy; solubility; thermostability; tooth enamel; tooth root

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).

描述（改编自研究者的摘要）：总体 研究的目的是加深对 激光与牙齿硬组织的相互作用并建立 安全有效使用激光治疗的科学依据 牙齿硬组织包括防龋和除龋。 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 um 波长，无法用 以前可用的激光器。研究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，这将能够测量 在这些波长下有高吸收（体外）。 第二个具体目标是研究牙釉质和牙本质的热行为 选定波长的跟随激光照射并建模 使用 1、2 和 3 维有限差分热的计算机模拟 传导数字代码。这个目标改进了他们之前的一维目标 建模工作（体外）。第三个具体目标是研究 激光过程中牙釉质和牙本质的热分解动力学 辐照。这一目标将利用六种技术：(1) 热响应 基于表面温度的红外辐射测量的分析， (2) 掠射 X 射线衍射，(3) FTIR 反射光谱，(4) 逸出气体分析，(5) 酸溶解速率测量，以及 (6) 扫描电子显微镜（体外）。第四个具体目标是 在人体体内进行安全性研究以确定程度和效果 激光照射期间向纸浆的热传递。该研究涉及 25 名志愿者计划拔除第三磨牙，其中 放置在牙髓-牙本质交界处的热电偶任何温度上升 激光照射期间（体内）。具体目标 5 是确定 激光照射参数，有或没有氟化处理， 最佳地抑制牙釉质中龋齿样病变的进展， 牙根。酸溶解测定用于产生测量结果 通过激光硬化牙齿材料（体外）。六、具体目标 是对人类进行口腔内研究，涉及放置 经过激光体外预处理的牙科材料进入口腔 人类志愿者长时间研究激光的能力 辐射使牙科材料硬化。该测定将进行 通过与印第安纳大学的分包合同（体内）。这 第七个具体目标是研究周围继发龋的抑制 激光照射修复体（体外）。