Changes in teeth and gingiva of dogs following laser surgery: a block surface light microscope study

The effect of laser surgery on tissues of the periodontal apparatus was studied histologically in dogs using block surface light microscopy, a novel microscopical method. With this approach, changes in the hard and soft tissue components were concomitantly demonstrated; the method enabled preservation of the in situ relationship between these components. Following laser surgery, healing in the gingiva was delayed as suggested by the presence of epithelial ulcerations and dense inflammatory infiltrate. In the enamel and cementum the application of laser resulted in crater-like defects that could be avoided only partially by insertion of a tinfoil shield into the gingival sulcus. In the vicinity of the cementoenamel junction these defects were filled with epithelium or periodontal ligament fibers; the close proximity of the hard and soft tissues at the defect sites suggested occurrence of new attachment. Enamel defects located coronal to the gingiva contained bacterial plaque. These histologic results do not demonstrate any substantial advantage of laser over conventional knife gingivectomy. Such advantage may be accomplished with the design of a special intraoral handpiece and further experiments.