AIM: The aim of this study was to evaluate the clinical and radiographic effects of hyaluronic acid (HA) gel application as an adjunct to minimally invasive nonsurgical treatment (MINST) in intrabony defects ≥3 mm. METHODS: A total of 36 patients were included and randomly assigned to two groups: (a) MINST + HA (test
n = 17) and (b) MINST (control, n = 19). Subgingival 0.8% HA gel was applied in intrabony defects of test group and repeated 4 weeks following MINST protocol. Clinical measurements including probing depth (PD), clinical attachment level (CAL), and gingival recession (GR) were recorded at baseline and repeated at 3 and 6 months. Radiographic evaluation was performed at baseline and 6 months. RESULTS: Test group showed significantly greater reduction in PD and gain in CAL at 3 months compared to baseline than that of controls (p <
.05), but the changes (Δ) at 6 months compared to baseline did not differ between the groups (p >
.05). Although, both groups showed statistically significant GR in all evaluated time periods (p <
.05), control group showed higher ΔGR than that of test group (p <
.05). There was no significant difference between the groups in terms of radiographic defect fill/bone gain (p >
.05). CONCLUSIONS: The additional use of 0.8% HA gel in the treatment of periodontal intrabony defects did not provide additional benefits in clinical and radiographic parameters. On the other hand, GR measurements showed favorable results in the test group.