The relationship to pain level of extent of injury (as measured by number of teeth extracted) and attention paid to the injury (as measured by frequency of pain ratings) was studied in patients with dental postoperative pain. Patients had either 2 or 4 impacted wisdom teeth removed and rated their pain either 2 or 5 times during the experiment. A positive correlation was found between extent of injury and reported pain level as well as between frequency of pain rating and pain level. The correlation between frequency of pain rating and pain level was found only in patients with 4 teeth extracted. To our knowledge, this is the first study which quantitatively evaluates the relationship between amount of injury and level of pain. This study also suggests that the degree to which manipulations of psychological variables alter an individual's pain perception may depend on the extent of injury.