Endodontics

Use of LLLT does not have a bactericidal effect, and surgical lasers are the preferred instruments to reduce bacteria in infected root canals. Few manufacturers of therapeutic lasers offer probes that could reach the root canals. However, IR light can reach all apices, and visible red light can reach the more superficial apices through the mucosa and produce an antiinflammatory and pain-reducing effect.

Sousa et al. analyzed the effect of LLLT on the secretory activity of macrophages activated by interferon gamma (IFN-γ) and lipopolysaccharide (LPS) and stimulated by substances leached from an epoxy resin–based sealer (AH-Plus) and a calcium hydroxide sealer (Sealapex). The production of tumor necrosis factor alpha (TNF-α) was significantly decreased by LLLT, regardless of experimental group. The level of secretion of matrix metalloproteinase-1 (MMP-1) was similar in all groups.

Laser application after overinstrumentation and overfilling is a good example of an indication for LLLT in endodontics. Because LLLT can stimulate bone formation, apical bone resorption probably can heal faster after completed endodontic treatment if LLLT is applied. Energy needed is related to the depth of the apex, ranging from 4 to 8 J per apex. For the same reason, intraoperative and postoperative LLLT in apical surgery has potential,but solid scientific documentation is still lacking. However, irradiation over the suture line will stimulate fibroblast proliferation and increase tensile strength.

In patients with acute pulpitis, when the affected tooth or root is difficult to pinpoint, the laser can be applied over the apices in the involved area. The affected tooth may react by a pain increase, probably because of increased microcirculatory pressure in the pulpal chamber. LLLT can also be used as an adjunct therapy in pulp capping and pulpotomy. In both cases the exposed pulp is irradiated at low intensities, applying 2 to 3 J before traditional methods are used. The irradiation will reduce inflammation, preserve odontoblastic integrity, and stimulate cellular proliferation.