Inclusion Criteria:  patients willing to begin fixed multibracket therapy with metallic or ceramic brackets; full permanent dentition; all teeth from central incisors to second premolars.  Exclusion Criteria:  patients suffering from systemic diseases; patients taking medications that could alter periodontal conditions (NSAIDS, steroids, etc.); patients with low compliance; patients unable to give informed consent; presence of congenital enamel defects; extractions for orthodontic reasons; oral/orthognathic surgery; presence of dental implants on teeth from central incisors to second premolars.