LASER EFFECTS ON DENTAL HARD TISSUES

激光对牙齿硬组织的影响

• 批准号: 2130966
• 负责人: JOHN D FEATHERSTONE
• 金额: $ 26.94万
• 依托单位: EASTMAN DENTAL CENTER
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-01 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2130966
• 关键词: X ray crystallography; analytical chemistry; apatites; biomedical equipment safety; carbon dioxide; cementum; dental caries; dental pulp; dental structure; dentin; heat; human tissue; infrared spectrometry; laser therapy; lasers; light microscopy; light scattering; microradiography; normal ossification; preventive dentistry; pulse radiolysis; radiobiology; radiochemistry; radiowave radiation; scanning electron microscopy; statistics /biometry; tooth enamel; tooth root; tooth surface; topical fluoride therapy

The underlying hypothesis to be tested in the present proposal is that there is a specific set of irradiation conditions for laser light that most efficiently and effectively interacts with dental hard tissues. The efficient conversion of light energy to heat when a laser beam interacts with dental hard tissues is strongly wavelength dependent. The potential is excellent for the clinical use of specific lasers to provide protection against caries and for the treatment of early lesions. Before the clinical application can be realized the scientific basis for the choice for the specific conditions must be established and safety issues must be addressed. The purpose of the studies proposed here is to establish that basis. Lasers used in the studies have been selected to examine the most likely useful wavelength from IR though UV, namely CO2(9.3-11.0 micro m), Nd:YLF (1.o5 micro m, comparable to Nd:YAG), and its harmonics at 0.53 and 0.35 micro m. Diffuse transmission ad backscattering will be examined at all wavelengths using enamel, dentin and synthetic carbonated apatite (CAP). Scattering and absorption coefficients will be determined. We will determine quantitatively the heat propagation into enamel and dentin of various thicknesses using selected laser irradiation conditions (pulse length, energy, rep-rate, number of pulses). Laser interactions will be examined (using conditions determined from the optical and thermal studies) with (1) surfaces of tooth enamel, tooth roots and synthetic carbonated apatite, and (2) caries-like lesions in (a) dental enamel smooth and occlusal surfaces, (b) root surfaces with and without cementum, all with or without fluoride treatment. In all cases the experiments with caries-like lesions will be followed by studies to measure the inhibition of lesion progression using a Ph cycle model. Results will be assessed using a combination of polarized light microscopy, quantitative microradiography, x-ray diffraction, infrared spectroscopy, scanning electron microscopy, and chemical analysis. An indication of safety of the treatments will be assessed from the thermal studies and by temperature measurements in the pulp chamber and at the outer surfaces. All data will be analyzed statistically and interpreted to indicate whether specific irradiation conditions are associated with specific outcomes in dental hard tissues and mineral. It is anticipated that the present study will provide a range of laser irradiation conditions that will optimize the beneficial effects of increasing caries resistance with the ultimate aim of developing a laser system(s) for use as an improved method for the prevention and treatment of pit and fissure caries, early enamel caries, and root caries.

本提案中要检验的基本假设是 激光光有一组特定的辐照条件 最有效，有效地与牙齿硬组织相互作用。这 当激光束相互作用时，轻能的有效转化为加热 牙齿硬组织非常取决于波长。潜力 非常适合特定激光器提供的临床使用 保护龋齿和治疗早期病变。前 可以实现临床应用的科学基础 必须确定针对特定条件的选择并安全问题 必须解决。这里提出的研究的目的是 建立这个基础。研究中使用的激光器已选择 检查IR虽然紫外线的最可能有用的波长，即 CO2（9.3-11.0 Micro M），ND：YLF（1.O5 Micro M，与ND：YAG相当），并且 它的谐波为0.53和0.35微米。扩散传输广告 将使用牙釉质牙本质在所有波长下检查反向散射 和合成碳酸磷灰石（CAP）。散射和吸收 系数将被确定。我们将定量确定 使用使用的热量传播到搪瓷和牙本质的各种厚度 选定的激光辐照条件（脉冲长度，能量，代替率， 脉冲数）。将检查激光相互作用（使用条件 根据（1）表面的光学和热研究确定 牙釉质，牙根和合成碳酸磷灰石，（2） （a）牙齿牙釉质光滑和咬合表面中的龋齿状病变， （b）有或不带有或不带有或不带有或不带有或没有的根表面 氟化物处理。在所有情况下，使用龋齿样的实验 病变将进行研究以测量抑制病变 使用pH循环模型进行进程。结果将使用 偏振光显微镜的组合，定量 微影像学，X射线衍射，红外光谱，扫描 电子显微镜和化学分析。安全的指示 这些处理将从热研究中评估 纸浆腔和外表面的温度测量。 所有数据将进行统计分析，并解释以表明 特定的辐照条件是否与特定有关 牙齿硬组织和矿物质的结果。预计 目前的研究将提供一系列激光照射条件 将优化增加龋齿阻力的有益效果 以开发激光系统的最终目的 改进的预防和治疗坑和裂缝的方法 龋齿，早期的搪瓷龋和根龋。