Are composite fillings noticable when smiling?

Not if done well: In the hands of a good dentist, tooth colored composite fillings are almost undetectable to completely invisible compared to natural teeth.

Maintain hygiene: As doctor sandler said, if done well they will blend with natural variations of the teeth. However, maintaining good oral hygiene is important to keep them looking great. Coffee, tea and smoking can discolor the teeth or restorations over time. Also, if you want to whiten, do so before you have composite fillings done, at least 10 days to 2 weeks before.

Shouldn't when new!: Composite fillings are a manmade substitute for natural tooth enamel. They are not made from the same materials and can only expect to approximate the naturalness of the enamel. When done well, they can look great for 3-8 years. However, made from acrylic they are slightly "porous" and are subject to absorbing unremovable stain. And their bonded edges eventually separate and stain there too!

Almost always not: Composite fillings (anterior and posterior) come in an almost infinite variety of shades. A skilled cosmetic dentist can match the color of your adjacent teeth and create the absolutely correct shape so that your composite filling will blend perfectly!