Dr. Roman Khodosh

In-office whitening treatments typically take about 60 to 90 minutes. At-home treatments can vary, from 20 minutes to overnight, depending on the product's strength and the desired results.

For in-office treatments, many dentists recommend waiting at least 6 months between sessions. For at-home products, follow the manufacturer's recommendations. Over-whitening can lead to enamel damage and increased tooth sensitivity.

Sensitivity from tooth whitening is always transient. If there is any sensitivity caused by the whitening, it goes away within one to two days after the treatment, and the patient returns to the state of sensitivity he or she had prior to starting the whitening process.

Most people are candidates for tooth whitening, but again, each situation is unique and it's best to contact your dental professional.

Typically you can expect whitening to last from six months to two years, although some studies report results lasting up to 10 years. Avoiding red wine, coffee, and smoking—all of which can cause staining—helps preserve the results.

Yes, many studies have proven that tooth whitening is safe. You can protect your tooth enamel by using calcium sulfate and fluoride.

Tooth whitening has little or no effect on restorative materials such as porcelain or crowns, but it may temporarily reduce the bond strength between enamel and composite restorations. This is why it is a good idea to check with your dental professional before beginning any course of tooth whitening.

Products developed from carbamide peroxide, hydrogen peroxide, and urea (substances found in every human cell), should be used cautiously to alleviate concern. Those who have issues are the ones who don't follow instructions and overuse the products for months or years.

For the first 48 hours after whitening, it's best to avoid staining foods and drinks like coffee, tea, red wine, and dark-colored sodas. Acidic foods and drinks, such as citrus fruits or soft drinks, should also be avoided as they can increase sensitivity and weaken the enamel.