Bacteria present in dental plaque are recognized as the principal cause of caries and periodontal disease. Therefore, prevention and treatment of these two diseases are mainly based on dental plaque removal. Professional scaling and oral prophylaxis are the most effective methods to reduce pathogenic organisms and also for plaque removal. However, personal oral hygiene, using a toothbrush and dental floss daily, is very crucial for satisfactory maintenance. Those patients who are undergoing orthodontic treatment have greater difficulty in maintaining oral hygiene. Orthodontic bands, brackets and wires are hindrances to brushing and flossing, frequently facilitating accumulation of plaque to jeopardize gingival health^.  There is a significant increase in Streptococcus mutans and lactobacilli after the bonding of fixed appliances. Orthodontic treatment can increase inflammation, bleeding, and enlargement of the gingiva as well as increasing probing pocket depth.

Enamel demineralization after fixed orthodontic therapy can occur in up to 50% of patients. Enamel demineralization is caused by organic acids produced mainly by mutans streptococci (MS), which are known to be the prime causative organism of dental caries. S mutans is the most frequently isolated from human oral cavities and have been implicated as the main causative organisms of dental caries.Extensive plaque accumulation is associated with bonded orthodontic brackets , and a fixed appliance with orthodontic brackets causes specific changes in the oral environment, such as decreased pH and increased plaque accumulation.The bacterial adhesion to orthodontic brackets can be the primary step leading to pathogenic plaque formation and enamel demineralization around orthodontic brackets, because the adhering bacteria continue to grow on the tooth surfaces near the brackets. Therefore, information on the prevalence of S mutans in orthodontic treatment is helpful for identifying patients at risk of developing enamel demineralization and for planning caries-prevention programs during orthodontic treatment.

Many clinical indices ,instrumental examinations ,and laboratory tests are available now a days in order to study and define periodontal condition. Among them ,clinical indices remain the most commonly used criteria for an ordinary evaluation, due to their viability.Various indices used for gingival and periodontal health evaluation are gingival bleeding index, plaque index, interdental pressure index, papillary bleeding index and Ortho-plaque index.As streptococcus mutans are considered as the main pathogens in initiation of dental caries,the assessment  of plaque accumulation and prevalence of white spot lesions around the brackets  can be done by counting the colonies of streptococcus mutans.

Various aids to maintain oral hygiene in orthodontic treatment include manual toothbrushes, dental floss, inter dental toothbrushes, three headed toothbrushes, powered toothbrushes ,sonic and ultrasonic toothbrushes. Initially, manual toothbrushes were commonly advised for the patients with orthodontic treatment. Because of shortcomings of manual toothbrushes in plaque removal, powered toothbrushes have been evaluated across a broad array of population groups and study designs and have demonstrated similar or significantly greater plaque removal compared with standard manual toothbrushes.

Among various types of powered toothbrushes, existing evidence suggested that rotation-oscillation, ionic, and ultrasonic brushes performed better than manual toothbrushes in plaque reduction. They have been shown to remove significantly greater in vitro Streptococcus mutans biofilm from hydroxyapatite surfaces without bristle contacts compared with rotation-oscillation toothbrushes.Home care products to remove plaque, particularly in difficult-to access areas, is key to improving patient compliance and avoiding disease. Beyond their clinically proven efficacy in removing plaque, power toothbrushes can enhance patient motivation, leading to increased tooth brushing frequency and duration. The use of electric toothbrushes can offer better fluoride distribution throughout the mouth .

The first ultrasonic toothbrush was patented in USA in the year 1992 by Robert T. Bock. Ultrasonic toothbrushes mainly differ from conventional electrical toothbrushes in their higher operating frequency (>20 kHz) .The used frequency range is not audible for the human ear and may be beneficial since hydrodynamic forces (such as flow rate of the dental fluid and the formation of bubbles) are significantly increased. Still, the exact relation between the energy transfer from the brush to the biofilm and the contribution of acoustic waves to biofilm removal remain unclear.The ultrasound moves the bristles on the brush at a high speed and pressure.  The toothbrush head vibrates causing the bristles to rotate. Because of this movement and speed, and as the toothbrush is moved over the surface of the teeth, the toothbrush scrubs and eliminates more plaque than a normal toothbrush would. This means that they move the brush head at such a rapid rate, that they are able to turbulently move particles of water and air in a gentle and effective enough way to easily clean between teeth and below the gum line. Ultrasound projected into the slurry causes the expansion of the bubbles and contact lead to dislodgement of the plaque bacteria adhering to the tooth surfaces Studies have even shown that ultrasonic toothbrushes still provide superior plaque removal even when they are held up to 4mm away from the tooth’s surface. The handle of the brush is large enough to grip safely, and the head of the device can be changed easily with simple instructions. The only restriction for use is in patients with pacemakers because of the ultrasonic transducer’s ability to adversely affect pacemaker function. 

A number of studies showed that ultrasonic toothbrushes could reduce more dental plaque but there is insufficient data to show the streptococcus count in patients using different types of brushes. Hence the present study is designed to compare the efficacy of manual, electric and ultrasonic toothbrushes in the patients undergoing fixed orthodontic treatment by quantifying streptococcus mutans in plaque in the Department of Orthodontics and Dentofacial Orthopaedics,Faculty of Dental Sciences,SGT University,Budhera ,Gurugram.