Color instability: it’s an unsightly problem with CAD/CAM restorations placed with traditional cementation systems. Why, exactly, do resin cements shift in color? It’s a question that has been researched and discussed at length, and the answer should factor into material selection.
According to a study in the Journal of Oral Science, discoloration can be due to either extrinsic factors, such as food, smoking, and beverages, or intrinsic factors related to the restorative material, such as chemical composition. Dual-cure resins, in particular, contain tertiary amines and benzoyl peroxide (BPO) and tend to darken over time. The authors note that recently, new resin cements without a benzoyl peroxide/amine redox initiator system have been shown to be more color stable. NX3 XTR from Kerr Restoratives is one such cement that excels in color stability for this very reason.
Kerr’s Nexus Technology corrects color stability flaws typically found in tertiary amine/BPO initiator systems of self- and dual-cure resin cements. NX3 non-BPO catalyst paste minimizes color shift that typically occurs during cement storage, while the NX3 amine-free initiator system significantly improves color stability for longer-lasting esthetic restorations.
Excellent color stability is just one of the standout features of NX3 XTR. The NX3 Nexus Third Generation universal dental cement is also blended with OptiBond XTR, a two-component, self-etch, universal dental bonding agent, for permanent cementation of all esthetic materials. The marriage of these materials eliminates the need to light-cure the adhesive, resulting in virtually no film thickness, fewer seating issues, and imperceptible margins, according to Kerr.
Moreover, the combination of NX3 and OptiBond XTR minimizes the cost of stocking multiple bonding agents and cements, for two reasons:
1. NX3 XTR requires no additional activators for use in total dark-cure mode.
2. OptiBond XTR can be used in place of silane and metal primers.
See the chart below to see how NX3 XTR helps to streamline inventory and procedures while cutting costs:
Dr. Scoles is impressed by the cement cleanup, marginal integrity, and the material gel phase, which doesn’t adhere to the adjacent tooth.
“The bonding process is the most difficult, the most technique sensitive, and the most critical to the success of the crown, and with the NX3, we’re less anxious about it. It’s lowered our stress level,” he concludes.