The subgingival dental plaque is a microbial biofilm consisting of highly variable bacterial microcolonies embedded within a self-produced matrix of extracellular polymeric substance. In contrast to microorganisms growing in a planktonic state, the inhabitants of a biofilm are effectively protected within this dense structure from host defense mechanisms and from therapeutic agents, including antimicrobials. The mechanical removal of the microbial biofilm and the establishment of meticulous plaque control measures comprise the key elements for the success of non-surgical periodontal treatment. Ultrasonic devices are effective in disrupting the biofilm, and carefully remove soft and hard deposits from a root surface with minimal trauma to the tooth structure. Controversies and modern trends in non-surgical periodontal therapy - such as quadrant-wise treatment modalities versus full-mouth approaches, hand-versus power-driven instrumentation, and the time frame of non-surgical periodontal therapy - are discussed here in depth in order to provide an insight into modern approaches to non-surgical biofilm management. Clinical, microbiological and immunological findings following different treatment protocols, in addition to cost-effective benefits of these clinical modalities, are discussed.