Traditional periodontal therapy is subgingival debridement with maintenance of good oral hygiene. This approach is either definitive or the initial phase before surgical therapy in severe cases of periodontitis. Mechanical therapy, either hand instrumentation or ultrasonic debridement, is the most common therapy for periodontitis and its success is well documented (Badersten et al. 1984). This non-surgical therapy involves considerable amounts of time, a high level of operator skill and dedication, and some unavoidable discomfort for the patient. It has often been remarked that the time taken for periodontal therapy of severe periodontitis cases exceeds that needed for cardiac arterial bypass surgery. Quirynen et al. (1995) re-introduced the one-stage full-mouth disinfection and compared the clinical and microbiological effects of this treatment strategy (FMRP) with the widespread practice of quadrant scaling and root planing at 2-week intervals (QRP). The rationale behind their treatment strategy was to prevent re-infection of the treated sites from the remaining untreated pockets and intra-oral niches. The results revealed a significant reduction in pocket depth for the FMRP over QRP group for deep pockets. Quirynen et al. (2000) concluded that the elimination of the periodontopathogens in addition to the possible host response benefits after the one-stage full-mouth therapy is the effective aspect of this therapy rather than oral chlorhexidine disinfection. Recently, Kinane's group in Glasgow failed to demonstrate differences in the clinical, microbiological or immunological outcome between QRP and FMRP. FMRP was well tolerated by patients and these authors concluded that the clinician should select the treatment modality based on practical considerations related to patient preference and clinical workload. Koshy et al. (2005) re-analysed the effects of FMRP and QRP using ultrasonics and concluded that either full-mouth or quadrant ultrasonic debridement are just as effective.