ABSTRACT
A modified Nd:YAG laser was evaluated for its effect on root cementum topography and fibroblastic attachment. Fifteen extracted human teeth were curetted, sectioned, and divided into 60 areas representing 4 groups. Group I were non-lased controls, while groups II, III, and IV were lased with the same power (4 watts, 1 second), but at 3 different laser-target distances (1, 3, and 5 mm), thus delivering 3 different energy levels. Following lasing, 20 areas (5 per group) were examined under SEM for detection of any structural changes. Human gingival fibroblasts were cultured on both experimental and control samples of the remaining 40 areas. Photomicrographs at x 500 were obtained and the number of attached fibroblasts were counted. Results showed that lased cemental surfaces exhibited changes in surface topography which ranged from what appeared to be an apparent fusion of the surface of the covering smear layer (lowest energy level), to cracking and fissuring of the lased surface (highest energy level). When fibroblasts were cultured on the specimens, the results demonstrated the presence of a monolayer of cells on the control surfaces and on the surfaces lased with the lowest energy level (5 mm distance). Specimens lased at the mid-energy level (3 mm) showed decreased numbers of attached cells, but not significantly different from the controls. On the other hand lasing the cementum surface at the highest energy level (1 mm distance) caused a significant decrease in the number of the attached cells as compared to the controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Cell Adhesion/radiation effects , Dental Cementum/radiation effects , Laser Therapy , Absorption , Analysis of Variance , Dental Cementum/ultrastructure , Dose-Response Relationship, Radiation , Fibroblasts/radiation effects , Humans , Lasers/adverse effects , Microscopy, Electron, Scanning , Neodymium , Surface PropertiesABSTRACT
The use of a new, modified Nd:YAG laser called the KTP/532 laser was evaluated within root canals to determine whether it would modify dentin permeability or alter the scanning electron microscopic appearance of canal dentin. Energies and exposure times were chosen which did not permit periodontal temperatures to increase above 5 degrees C (1 W x 1 s-5 W x 0.5 s). Half of the root canals were covered with smear layer and half were treated with EDTA/NaOCI to remove the smear layer. The results showed that this laser did not change the permeability of the smear layer-covered dentin, although scanning electron microscopic examination revealed modifications to the surface of smear layer. Lasing of etched dentin produced modest increases in root permeability which were associated with enlargement and cracking of tubule orifices.
