Beschreibung:
<jats:p><jats:bold>Background:</jats:bold> Removing subgingival plaque and calculus is a major goal of periodontal treatment. Few attempts have been made to evaluate the use of lasers for root surface debridement in periodontal therapy. The aim of the present study was to compare, histologically, the effects of hand instrumentation, ultrasonic instrumentation, and CO<jats:sub>2</jats:sub> lasers on the root surfaces of teeth treated in situ.</jats:p><jats:p><jats:bold>Methods:</jats:bold> A total of 33 teeth scheduled for extraction due to severe periodontal disease were divided into three groups. In the first group, teeth were treated by ultrasonic bactericidal curettage (UBC) with an ultrasonic scaler; in the second group, teeth were treated by hand instrumentation; and in the third group, after hand instrumentation, roots were lased by a CO<jats:sub>2</jats:sub> laser. The samples were then processed for histological examination.</jats:p><jats:p><jats:bold>Results:</jats:bold> In the first and second groups, plaque and calculus were present in interradicular septa, lacunae, and surface concavities. In the third group, surfaces of specimens treated by a low‐power defocused CO<jats:sub>2</jats:sub> laser showed areas devoid of cementum, with completely sealed dentinal tubules, and no bacterial cell remnants.</jats:p><jats:p><jats:bold>Conclusions:</jats:bold> The CO<jats:sub>2</jats:sub> laser treatment, used at low power and in the defocused mode, combined with traditional mechanical instrumentation, could improve root surface debridement of periodontally involved teeth. More extensive, long‐term studies are needed to confirm this hypothesis. <jats:italic>J Periodontol 2005;76: 476‐481</jats:italic>.</jats:p>