Blum J Y, Peli J F, Abadie M J
University Hospital Center of Montpellier, Montpellier, France.
J Endod. 2000 Oct;26(10):588-92. doi: 10.1097/00004770-200010000-00003.
With new wavelengths that allow light transmission by optical fibers, the laser is now often used in endodontics either during treatment or retreatment. The aims of this study were to (i) specify the effects of laser irradiation on restorative materials in terms of topographic effects and (ii) describe different protocols for the first steps of retreatment. The laser used in this study was an optical fiber Nd:YAP (Lokki dt, Vienne, France) with a wavelength of 1.34 microns. Samples of the following restorative materials were prepared: amalgam, composite, permanent and temporary cements, and prosthodontic alloy. The handpiece of the Nd:YAP laser was fixed perpendicular to the surface of the different preparations. All trials were performed with the fiber tip either in contact with or at a distance of 2 mm from the material. The surface effects in all cases were (i) the creation of craters in the center of the lased areas, (ii) a border of fusion material at the edge of the craters, and (iii) cracks or fractures at a distance from the target areas. For the cements, amalgam and composite, the effects included a projection of material from the center to the edge of the lased area and/or the apparent photovolatization of light particles. For all materials the laser induced deeper absorption in the areas of direct contact than when it was held at a distance. This suggests that the fiber should be in contact with the restorative material for lasing in the straight part of the canal when the objective is either to pass through the material or alongside it between material and tooth. If the practitioner cannot determine the direction of the curve of the canal, lasing should be performed at a distance to weaken the material and thus permit more efficient use of an ultrasonic device. Lasing should in all cases be performed under close X-ray monitoring. Provided that sufficient caution is used, the laser may be helpful in removing restorative materials during retreatment.
随着新波长的出现使得光能够通过光纤进行传输，激光现在常用于牙髓病治疗或再治疗过程中。本研究的目的是：（i）从形貌效应方面明确激光照射对修复材料的影响；（ii）描述再治疗第一步的不同方案。本研究中使用的激光是波长为1.34微米的光纤Nd:YAP激光（Lokki dt，法国维也纳）。制备了以下修复材料的样本：汞合金、复合材料、永久性和临时性粘结剂以及口腔修复合金。Nd:YAP激光的手持件垂直固定在不同样本的表面。所有试验中，光纤尖端与材料接触或距离材料2毫米。所有情况下的表面效应为：（i）在激光照射区域中心形成凹坑；（ii）凹坑边缘有熔化材料的边界；（iii）在距目标区域一定距离处出现裂纹或断裂。对于粘结剂、汞合金和复合材料，其效应包括材料从激光照射区域中心向边缘的投射和/或轻质颗粒的明显光挥发。对于所有材料，激光在直接接触区域比保持一定距离时能引起更深的吸收。这表明，当目的是穿过材料或在材料与牙齿之间沿着材料进行激光照射时，光纤应与根管直线部分的修复材料接触。如果从业者无法确定根管弯曲的方向，应在一定距离处进行激光照射以削弱材料，从而更有效地使用超声设备。在所有情况下，激光照射都应在密切的X射线监测下进行。只要谨慎使用，激光在再治疗过程中可能有助于去除修复材料。
