Peroxides are unsettled, unstable chemicals. Due to this, they can quickly decompose chemically and expose the substances that whiten teeth. The disadvantage of these unstable structures is that the teeth whitening gels, immediately after manufactured, are in a continuous chemical reaction.
Why should we store gels in a cold environment?
Even at room temperature, the concentration of hydrogen peroxide gels gradually decreases and they lose their activity. Higher temperatures accelerate this process of deterioration. Teeth whitening gels are exposed to much higher temperatures in many places in the storage, transport, production and distribution chain. The interior temperature of sales representative car may easily reach + 45C on a sunny summer day.
Unsuitable distribution and storage environments cause peroxides to become more rapidly degraded by exposure to heat. We all have witnessed that tooth whitening gels are exhibited for days under the heat-emitting spot lights at fairs or seminars. Even the products of the same production date differ in levels of active substance and the changes that the dentists see in the performance of the product are mostly due to inappropriate storage and transportation conditions.
Although having a cold chain from production to Dentist almost stops hydrogen peroxide reaction process, it is a costly and difficult-to-follow process.
For this reason, a more cost-effective method to extend the shelf life of the whitening gel is to keep the hydrogen peroxide ratio high and add chemical stabilizers for stability. Even in highly stable gels, the decomposition process cannot be stopped, but simply slows down. Even if they are stored in cold conditions, where shelf life would be 1.5 years, when exposed to heat for a long time, they will complete half of their shelf-life within a few months.
Solutions to remove restrictions such as shelf life, stabilization, and cold storage often produce a low pH and acidic product. Low pH and acidic products react more slowly and cause more sensitivity risk due to acidic environment. Such products not stored in cold conditions, comes out to be a constantly changing whitening effectiveness and a high level of tooth sensitivity.