Evaluation of salivary pH with self-ligation, elastomeric ligation, and stainless steel ligation in fixed orthodontic treatment: A pilot study

Objectives: Fixed orthodontic appliances create retentive niches that favor plaque accumulation and may alter salivary chemistry, increasing demineralization risk. This study compared early changes in unstimulated salivary pH among patients treated with self-ligation (SL), elastomeric modules (EM), and stainless-steel ligation (SS). Material and Methods: In this three-arm, randomized clinical trial, patients were allocated (1:1:1) to SL, EM or SS. Unstimulated whole saliva was collected at baseline, 4 weeks, and 8 weeks under standardized conditions. Salivary pH was measured with a calibrated digital pH meter. The primary outcome was the mean salivary pH at 4 and 8 weeks. Between-group differences were assessed by one-way analysis of variance with post hoc testing; pairwise mean differences, 95% confidence intervals and Cohen’s d effect sizes were reported. Results: At 4 weeks, EM showed a marked reduction in pH (5.96 ± 0.65) compared with SS (7.12 ± 0.12) and SL (7.05 ± 0.16), with large effect sizes (Cohen’s d ≈ 2.3–2.5). These differences persisted at 8 weeks, while SL and SS did not differ meaningfully. Conclusion: Elastomeric ligatures were associated with a substantial early decrease in salivary pH compared with SS and self-ligating systems. Clinicians should consider this increased early acidogenic challenge when treating patients at high caries risk and intensify preventive measures for patients using EM.