Teeth that are suffering damage from gum disease will always be more sensitive to cold and if you avoid cleaning them due to this sensitivity, it can only make the problem worse.
After dental treatment, some teeth may be more sensitive because this is their way of dealing with injury. Injuries to teeth such as cavities, gum infection and jaw clenching can damage the nerves in a tooth. The sensitivity should not last long after treatment as long as your teeth are kept clean, otherwise the sensitivity is likely to get worse. If your teeth are ever extra sensitive, please consult with Dr. Dokhanchi as this could be a sign that you need a root canal or gum tissue treatment.