Lasers in nonsurgical periodontal therapy A KIRA A OKI ,K ATIA M IYUKI S ASAKI ,H ISASHI W ATANABE &I SAO I SHIKAWA This article reviews the current and potential appli- cations of laser technology in nonsurgical therapy for the treatment of periodontal diseases. Based on its various characteristics, such as ablation or vaporiza- tion, hemostasis, and sterilization effect, laser treat- ment may serve as an adjunct or alternative to conventional, mechanical periodontal therapy. The Carbon dioxide (CO 2 ) and the Neodymium- doped:Yttrium-Aluminum-Garnet (Nd:YAG) lasers were previously approved for soft tissue treatment in periodontics (1, 2, 4), because of their superior ability of soft tissue ablation, accompanied by strong he- mostatic and bactericidal effects (6, 37, 143, 170, 218). However, when these lasers are applied to dental hard tissues the result is major thermal damage, especially at a high-energy output, rendering them unsuitable for hard tissue treatment (56, 214). Recently, the Erbium-doped:Yttrium-Aluminum- Garnet (Er:YAG) laser was developed in dentistry (71, 85, 87). As it is capable of ablation in both soft and hard tissues, the Er:YAG laser can be used for perio- dontal hard tissue treatment such as root surface debridement, as well as soft tissue management (78). The use of lasers within the periodontal pocket has become a topic of much interest and is a promising field in periodontal therapy. This article deals with recent advances in nonsurgical laser therapy for periodontal disease, and will briefly describe the advantages and disadvantages of various laser types. Nonsurgical periodontal therapy and lasers In periodontal pockets, the root surfaces are con- taminated with an accumulation of plaque and cal- culus, as well as infiltration of bacteria and bacterial endotoxins into cementum (5). Complete removal of these harmful substances is essential for the healing of periodontal tissue. Formation of biofilms on the exposed root surface within periodontal pockets impedes the infiltration of antibiotics, and therefore mechanical disruption of the biofilm is necessary during periodontal treatment (36). Basically, the aim of periodontal treatment is to restore the biological compatibility of periodontally diseased root surfaces for subsequent attachment of periodontal tissues to the treated root surface. During the initial periodontal treatment, debridement of the diseased root surface is usually performed by mechanical scaling and root planing using manual or power-driven instruments. Power-driven instruments (power scalers) such as ultrasonic or air scalers are frequently used for root surface treatment as they render the procedure easy and less stressful for the operator, while improving the efficiency of treatment. However, conventional mechanical debridement using curettes is still technically demanding and time consuming, and power scalers cause uncomfortable stress to the patients from noise and vibration. Complete removal of bacterial deposits and their toxins from the root surface and within the perio- dontal pockets is not necessarily achieved with con- ventional, mechanical therapy (5). In addition, access to areas such as furcations, concavities, grooves, and distal sites of molars is limited. Although systemic and local antibiotics are occasionally administered into periodontal pockets for the purpose of disinfec- tion, with frequent use of antibiotics there is a potential risk of producing resistant microorganisms. Therefore, development of novel systems for scaling and root planing, as well as further improvement of currently used mechanical instruments, is required. As lasers can achieve excellent tissue ablation with strong bactericidal and detoxification effects, they are one of the most promising new technical modalities for nonsurgical periodontal treatment. Another advantage of lasers is that they can reach sites that conventional mechanical instrumentation cannot. The adjunctive or alternative use of lasers with 59 Periodontology 2000, Vol. 36, 2004, 59–97 Printed in Denmark. All rights reserved Copyright Ó Blackwell Munksgaard 2004 PERIODONTOLOGY 2000