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Effects of Nd:YAG Laser Radiation on Removal of a Root Surface Smear Layer after Root Planing: A Scanning Electron Microscopic Study
Author(s) -
Ito Koichi,
Nishikata Junichi,
Murai Seidai
Publication year - 1993
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.1993.64.6.547
Subject(s) - smear layer , citric acid , irradiation , materials science , scanning electron microscope , dentistry , laser , radiation , nuclear chemistry , nuclear medicine , composite material , chemistry , medicine , optics , physics , organic chemistry , nuclear physics
A scanning electron microscopy (SEM) study was conducted to evaluate the effects of Nd:YAG laser radiation on removal of a root surface smear layer after root planing in comparison with citric acid treatment. The experimental materials were 15 human teeth affected by severe periodontal disease, which were extracted because of a hopeless prognosis. The teeth had at least 5 mm of attachment loss on the proximal surface tested. After removing all visible calculus using an ultrasonic sealer, each proximal surface was vigorously scaled and root planed with a Gracey curet. Thirty specimens were cut from the root‐planed proximal surfaces and assigned randomly to one of two groups: Group A (25 specimens) was divided into 5 subgroups and irradiated with a Nd:YAG laser, using non‐contact delivery (3 mm beam diameter, distance from the tip to the specimen 5 cm), at a measured power of 20 W for 0.3, 0.5, 1.0, 2.0, or 3.0 seconds corresponding to energy densities of 84.93, 141.54, 283.09, 566.17, or 849.26 J/cm 2 ; Group B (5 specimens) was not irradiated, but treated for 3 minutes with saturated citric acid (pH 1). The center of each specimen in Group A was used as the experimental area (Exp A) treated by laser irradiation and the peripheral area of the specimen served as a control (Cont A). In Group B, one half of the specimen was used as the experimental area (Exp B) treated by citric acid and the other half served as a control (Cont B). The specimens were then fixed and examined by SEM. The surface of the root‐planed specimens (Cont A and B) was irregular, corresponding to the presence of a smear layer, and had an amorphous appearance. Both root surfaces of Exp A and B exhibited clear orifices of dentinal tubules and intertubular dentin without a smear layer. Although the root surface of Exp A showed clear orifices of dentinal tubules with a flat morphology, the root surface of Exp B showed widened funnel‐shaped dentinal tubule orifices with a fibrillar, mat‐like morphology. The present results indicate that Nd:YAG radiation effectively removes the smear layer, uncovers dentinal tubules, and exposes collagen fibers on the root surface without widening the orifices of dentinal tubules after root planing. J Periodontol 1993; 64:547–552 .