Selection of the appropriate case and clinical competency in treatment modalities results in success in nonsurgical periodontal therapy. The patient with early periodontitis with significant local factors in the form of professionally accessible plaque and calculus is the most receptive to nonsurgical periodontal treatment. The clinician must make decisions centering around the important question, "Can the patient, or moreover, can the therapist delivering the debridement, gain access to the microbial subgingival plaque on a frequent basis below the host defense threshold of the respective patient?" If the answer is "yes," nonsurgical periodontal therapy will be rewarding. If the answer is "no," other modalities such as periodontal surgery must be instituted.