Adhesion and growth of cultured human gingival fibroblasts on periodontally involved root surfaces treated by Er:YAG laser

Background: The application of Er:YAG laser irradiation, approved in 1997 to be used on dental hard tissues, has been investigated for periodontal therapy. The aim of this study was to analyze the bio-compatibility of root surfaces treated by Er:YAG laser. Methods: Adhesion and growth of cultured human gingival fibroblasts on root surfaces treated by either irradiation with Er:YAG laser or curet were compared. Thirty single-rooted teeth extracted because of periodontal disease were used. Calculus deposits on all experimental surfaces were removed, and the teeth were divided into three groups according to the applied treatment: group A, root planing with Gracey curet no. 3/4; group B, two irradiations with laser (60 mJ/pulse, 10 Hz; 10" each with 10-second interval, 3 J/cm(2)); group C, two irradiations with laser (100 mJ/pulse, 10 Hz; 10" each with 1 0-second interval, 5 J/cm2). Fragments (5 mm x 6 mm) were obtained from the experimental surfaces. Then, 1 x 10(3) cells were seeded on the top of each fragment. One, 2, and 3 days after seeding the specimens were prepared for scanning electron microscopy analysis, and the cells on the electronmicrographs were counted. The data obtained in triplicate were statistically compared by the Kruskall-Wallis test complemented by the Dunn test (Pless than or equal to0.05). Results: Human gingival fibroblasts adhered to and grew on all treated surfaces. Group B presented a significantly higher cell count than did the other two groups at days 1 and 2. Three days after seeding the cultured fibroblasts of groups A and B reached total confluence. The cell count of group B was significantly higher than that of group C. Conclusion: The surfaces treated with 60 mJ/pulse Er:YAG laser irradiation promoted faster adhesion and growth than surfaces treated with either root planing or 100 mJ/pulse Er:YAG laser irradiation.