Comparative evaluation of rate of debonding in orthodontic bonding carried out with and without primer: a randomized clinical trial

Orthodontic treatment focuses on dentoalveolar and orthopaedic corrections to restore form, function and esthetics. The brackets form an integral component of fixed orthodontic therapy. The edgewise bracket system was introduced by E.H. Anglein 1928. Initially, these brackets were welded to orthodontic bands and then cemented over the tooth. Later, the technique of acid etching paved way for bonding the brackets directly to the teeth. The bonding materials have evolved significantly since the time of their introduction by Buonocore in 1955 and currently, fourth generation bonding agents are in use in orthodontic bonding. The optimal bond strength required for orthodontic adhesive should be at least 6 – 8 MPa. The use of primer is considered to produce better bonding and ensures high bond strength for treatment success.However, few studies have reported equitable bonding success rate in bonding without primer. Such studies on bonding without the use of primer have usually been carried out under in-vitro conditions or with low sample size but inconclusive results. Thus, controversy in the literature exists regarding the bond failure of brackets with and without the use of primer. Considering the constancy of other factors involved in bond failure  such as age, patient compliance, type of primer, curing lamp and bracket material, bonding with and without primer can be additional factor in determining the success of bonding. This study endeavours to add to the existing sparse literature on this topic of bond failure rate in direct bonding carried out with and without the use of primer. The study will be carried out,  under in-vivo conditions, as a randomized clinical trial to bridge the knowledge gap and provide evidence for clinical usage.