A medical endoscope has been modified for assisting the clinician in subgingival scaling and root planing. The dental endoscope provides real-time indirect visualization of the root surface for aiding the removal of root deposits and biofilm. When the majority of biofilm and visible calculus is removed from the root surface in a periodontal pocket, the pocket will most often close, resulting in a shallow sulcus. Many lesions on single-rooted teeth can be treated successfully with this technique, resulting in a significant reduction in probable pocket depth and a gain in the calibrated attachment level. Other sites, such as furcations and maxillary first bicuspids, may demonstrate significant improvement but not complete resolution of these parameters. Perioscopy is scaling and root planing aided by indirect vision with an endoscope. This technique can offer many patients an alternative to periodontal surgery in carefully selected sites. This article describes the clinical rationale for perioscopy, defines those sites that most predictably will respond to this mode of therapy, and offers some guidelines on integrating this technology into the dental practice. The observations and recommendations in this article are based on the author's 3-year experience with the dental endoscope in his periodontal practice, the experience of other periodontists and dental hygienists, and published reports.