Objective: White spot lesions (WSLs) are the most prominent complications of fixed orthodontic appliances. The aim of this study is to assess the efficiency of an antibacterial monomer-containing adhesive in the reduction of the WSLs around orthodontic brackets Compared to the conventional adhesive system (in-Vivo). Materials and Methods: fourteen patients were enrolled who had to extract the maxillary first premolars for orthodontic indications.  They were referred to the department of Periodontology for taking the necessary measures. After that, an examination of the right and left upper first premolars to record the gingival index (GI) and the sulcus bleeding index (SBI). The left maxillary first premolar represented the control side while the right was the experimental one. The metal brackets were bonded to the left maxillary first premolars using Transbond XT light cure adhesive (3M Unitek). Meanwhile, they were bonded to the right one using Clearfil SE protect (kuraray). After 120 days, both teeth were extracted, and examined by Scanning Electron Microscopy (SEM). The assessment of the change of the morphology, crystalline structure of the tooth surfaces in the area surrounding the bracket. Analysis of the Spearman correlation was used (P<0.05). Results:The study showed a significant difference between the antibacterial monomer-containing adhesive and the conventional adhesive system in the prevention of the WSLs formation. Conclusions:  using of antibacterial monomer-containing adhesive can minimize the demineralization around brackets (in-Vivo) after 120 days compared to the conventional one.