Patients seeking fixed orthodontic treatment that requires band placement will be enrolled in this study. This trial aims to compare the efficiency of rectangular cross-section nickel-titanium separators with elastomeric separators in creating sufficient interdental space for orthodontic band placement. In addition, the impact of both separator types on pain perception and gingival health during a 3-day placement period will be evaluated. Participants will be allocated to two groups in a split-mouth design. On the experimental side, nickel-titanium separators will be used, while elastomeric separators will be used as the control on the other side. Outcomes will include separation efficacy, pain perception over time, gingival inflammation, analgesic consumption, and separator loss.

In fixed orthodontic therapy, placement of separators is usually the first clinical step to create interdental space between posterior teeth, particularly the first molars, in preparation for orthodontic band placement. Failure to adequately separate teeth prior to banding may result in enamel damage, distortion of the band material, soft tissue injury, and increased patient discomfort. Improper band placement without sufficient separation can also lead to excessive pressure on the periodontal ligament (PDL), a risk of alveolar bone contact, and the formation of hyalinized areas within the PDL, evoking a pain response from resident mechanoreceptors. Pain is one of the primary reasons for patient dissatisfaction and discontinuation of orthodontic treatment. Therefore, identifying an ideal orthodontic separator that can produce adequate tooth separation while minimizing pain, discomfort, and gingival inflammation is of considerable clinical importance.

Inclusion Criteria:

• Class I skeletal and dental malocclusion.
• No history of previous orthodontic treatment.
• All permanent teeth in both arches, except third molars.
• Good oral hygiene and periodontal health.
• Good interproximal tooth contacts at the site of separator placement as
• checked by interdental floss.
• No caries or restorations on the proximal surfaces of first and second permanent molars, and second premolars.

Exclusion Criteria:

• Patients presenting with restorations or carious lesions on the proximal surfaces of the first or second molars or the second premolars.
• Patients with uncontrolled gingival or periodontal inflammation.
• Patients with a history of previous orthodontic treatment.
• Patients are skeletally classified as Class II or Class III.
• Patients are currently using opioid analgesics or have chronic pain conditions requiring regular analgesic intake.

Individual participant data will not be publicly shared because the dataset contains sensitive clinical and radiographic information, and participants did not provide consent for public sharing of individual-level data. De-identified aggregate results will be reported in the study publication.