LASER EFFECTS ON DENTAL HARD TISSUES

描述（由申请人提供）：使用特定的激光治疗来防止牙釉质龋齿的发展的概念即将成为令人兴奋的临床现实。研究的总体目标是深入了解激光与牙齿硬组织（牙釉质和牙本质）的相互作用，并为安全有效地在这些组织上使用激光建立科学基础。在本提案中要测试的基本假设是，光到热的有效转换导致晶体组成和结构的变化，从而增加牙科矿物（牙釉质和牙本质）对酸溶解的抵抗力。具体目的：(1)以正畸托槽周围牙釉质龋为模型系统，开展人类活牙龋抑制的中试规模临床研究。(2)验证激光照射条件对牙釉质和牙本质的龋抑制作用不会对组织的力学性能产生不良影响的假设。(3)验证红外激光消融牙釉质时，在牙釉质表面添加高吸收层水，消除了磷酸钙的非磷灰石次生相，并使激光照射显著降低牙釉质的酸溶解度的假设。(4)验证一种假设，即先前被证明最有效地与牙釉质相互作用以诱导对龋齿的抵抗的特定激光照射条件可以被修改为抑制牙本质龋齿。拟议的研究将提供信息，将导致一个改进的方法来治疗坑和裂隙龋齿，这是当今最普遍的龋齿形式。此外，使用激光治疗牙本质和牙根龋齿也是可能的。此外，这些研究预计将导致确定激光照射条件，不仅可以用于预防龋齿，还可以用于去除龋齿病变。经济的、物理上易于管理的、低能量的激光器，在专门设计的波长、脉冲持续时间和影响条件下，在牙科诊所预防和去除龋齿的发展，是一个真实的和令人兴奋的未来的可能性。

DESCRIPTION (provided by applicant): The concept of using specific laser treatment to prevent the progression of dental caries in enamel is close to becoming an exciting clinical reality. The overall objective of the studies is to develop an in-depth understanding of the interactions of laser light with dental hard tissues (enamel and dentin) and to establish a scientific basis for the safe and effective use of lasers on these tissues. The underlying hypothesis to be tested in the present proposal is that efficient conversion of light to heat results in changes in crystal composition and structure which increase the resistance of dental mineral (enamel and dentin) to dissolution by acid. Specific Aims: (1) To conduct a pilot scale clinical study of caries inhibition in living teeth in humans using caries in enamel around orthodontic brackets as a model system. (2) To test the hypothesis that laser irradiation conditions that provide caries inhibition for enamel and dentin will not have undesirable effects on the mechanical properties of the tissues. (3) To test the hypothesis that the addition of a highly absorbing layer of water to the surface of dental enamel during ablation by IR laser irradiation eliminates secondary non-apatite phases of calcium phosphate and allows the laser irradiation to markedly reduce the acid solubility of the enamel. (4) To test the hypothesis that the specific sets of laser irradiation conditions previously shown to most effectively interact with enamel to induce resistance to dental caries can be modified for caries inhibition in dentin. The proposed studies will provide information that will lead to an improved method for treating pit and fissure caries, the caries form that is most prevalent today. Further, the treatment of dentinal and root caries may be possible by the use of lasers. Additionally, the studies are expected to lead to the identification of laser irradiation conditions that can be used not only for caries prevention, but also for removal of carious lesions. The development of economical, physically manageable, low energy lasers for caries prevention and removal in the dental office, that operate at specifically designed wavelength, pulse duration, and fluence conditions, is a real and exciting possibility for the future.