Children's teeth can become sensitive for a variety of reasons like genetics, brushing too hard, consuming acidic or hot foods and drinks, or early signs of tooth decay. Sensitive teeth often feel sharp, brief pain in response to temperature extremes that are cold, hot, sweet or acidic. Parents should take their child to the dentist for a checkup if they complain of sensitive teeth so the dentist can examine the teeth and determine the cause of the sensitivity and provide the appropriate treatment.