Efficacy of Fluorinated Experimental Bonding Agents in Microleakage of Nanocomposite Resins: An Experimental Study

Marginal microleakage is a major concern in restorative dentistry and affects the longevity of dental restorations. This study evaluated whether fluorinated dental bonding resins could reduce microleakage in composite resins. Experimental light-cure bonding resins—both filled (F) and unfilled (U)—were created with a base resin (45% BIS-EMA, 40% TEGDMA, 15% HEMA). Fluorinated TEGDMA (f-TEGDMA) replaced TEGDMA at concentrations of 0–30 wt%. Class V restorations were performed on 50 extracted human molars at the cementoenamel junction. Eight experimental formulations and two commercial bonding resins (OptiBond Solo Plus and All-Bond 2) were tested (n = 5 each). After 1500 thermocycles between 5 °C and 55 °C, teeth were immersed in a 50% silver nitrate solution and sectioned, and dye penetration at the occlusal and cervical margins was measured under magnification. Data were analyzed using analysis of variance and a post hoc test (α < 0.05). Incorporating f-TEGDMA into bonding resins did not significantly reduce microleakage at either margin. At occlusal margins, OptiBond Solo Plus and non-fluorinated filled resins exhibited significantly less leakage than fluorinated experimental resins. At cervical margins, commercial resins and fluorinated experimental resins demonstrated comparable penetration. These findings reinforce the challenges of achieving durable tooth-restoration interfaces and emphasize the ongoing need for improved bonding systems in restorative dentistry.