LASER EFFECTS ON DENTAL HARD TISSUES

激光对牙齿硬组织的影响

• 批准号: 2700997
• 负责人: JOHN D FEATHERSTONE
• 金额: $ 29.36万
• 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 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2700997
• 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（根据调查员的摘要改编）：总体 研究的目的是建立对 激光光与牙科硬组织的相互作用并建立 科学的基础，可安全有效地使用激光治疗 牙齿硬组织，包括预防龋齿和去除龋齿。 有七个具体目标。第一个具体目的是确定 牙釉质和牙本质的吸收系数，重点是9.3 和9.6 UM波长，无法与 激光以前可用。调查人员现在可以使用CO2 激光持续时间较短，可以测量 在这些波长（体外）处高吸收。 第二个特定目的是研究搪瓷和牙本质的热行为 在选定波长处的跟随器激光照射，并与 使用1-，2-和3-D有限差热的计算机模拟 传导数值代码。这个目标改善了他们以前的1-D 建模工作（体外）。第三个具体目的是研究 激光期间的搪瓷和牙本质的热分解动力学 辐照。此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测量的分析， （2）扫视X射线衍射，（3）FTIR反射光谱，（4） 进化的气体分析，（5）酸溶解速率测量和（6） 扫描电子显微镜（体外）。第四个具体目的是 在体内进行人类的安全研究以建立学位和影响 在激光照射期间传热到纸浆。该研究涉及 25名志愿者计划去除第三摩尔牙齿 温度升高，放置在纸浆丁丁交界处的热电偶 在激光照射期间（体内）。具体目标5是确定 激光辐照参数，有或没有氟化物处理， 最佳抑制搪瓷中龋齿样病变的进展 牙根。酸溶解测定法用于生成量度 用激光（体外）硬化的牙齿材料。第六个特定目标 是在人类中进行口腔内研究，涉及 通过激光在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 辐照对牙科材料的辐射。该测定将进行 通过与印第安纳大学（体内）的分包合同。这 第七个特定目的是研究抑制次要龋齿 激光照射（体外）的修复。