Why is the bonding line of my veneer picking up stain?
The cement line ages differently from porcelain — and it shows first.
The junction where veneer meets tooth is filled with a thin line of resin cement. Resin is slightly more porous than glazed porcelain, so coffee, tea, red wine, and smoking discolor this line years before the shell itself changes.
Cosmetic line or leaking margin?
A thin, even brown line that a professional polish lightens is mostly cosmetic. A line that keeps widening, feels like a step when flossing, or comes with sensitivity suggests the margin is opening and letting fluid in — a different problem from stain.
Polishing, a margin refresh with new resin, or replacement each fit different stages, and staining speed differs with diet and habits from one person to the next. An exam can tell a surface stain from an opening margin in minutes, so ask your dentist to check it at the next visit.
MediIndex articles are for general information only and are not medical advice, diagnosis, or advertising. Outcomes vary by individual — consult a board-certified specialist for personal decisions.