Clinical Performance of Bulk‐Fill Versus Incremental Composite Placement Approaches in Vital Posterior Teeth: A 24 Months Randomized Controlled Trial

Abstract

BACKGROUND: Composite resin placement technique may influence marginal integrity, polymerization stress distribution, and long-term clinical performance of posterior restorations. This randomized controlled clinical trial evaluated the 24-month clinical performance of four different placement techniques in Class I posterior composite restorations. METHODS: Fifty patients aged 20-35 years presenting with four occlusal carious lesions each were enrolled, resulting in 200 restorations. Cavities (4-5 mm depth) were prepared according to caries extension. Restorations were randomly allocated into four equal groups (n = 50) according to placement technique: stamp technique, snowplow technique, modified incremental "pizza" technique, and bulk-fill technique. All materials were applied following manufacturers' instructions. Clinical evaluation was performed at baseline and after 6, 12, and 24 months using FDI criteria. Functional (fracture/retention, marginal adaptation), esthetic (marginal staining, anatomical form), and biological (postoperative sensitivity, secondary caries) properties were assessed by two calibrated evaluators. Statistical analysis was performed at a significance level of α = 0.05. RESULTS: Thirty-eight patients with a total of 152 restorations were evaluated at the end of the 24 months in line with FDI at the end of the study with 76% recall rates. No statistically significant differences were observed among groups regarding fracture/retention or secondary caries (p > 0.05). Marginal adaptation and marginal staining demonstrated minor deterioration over time across all groups, with statistically significant intergroup differences found (p < 0.05). Postoperative sensitivity was minimal and transient in all groups with no significant difference (p = 0.181). CONCLUSIONS: Within the limitations of this 24-month follow-up, the four placement techniques demonstrated comparable clinical performance in Class I posterior composite restorations. Selection of technique may therefore be guided by clinical preference and procedural efficiency rather than differences in short-term clinical outcomes. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT07415317.