To determine the frequency of calcific metamorphosis in traumatized teeth, it would have been better to follow-up traumatized teeth for a long period of time. However, from our experience, response to recall and follow-up visit is very poor. Therefore, it was decided to look into the incidence of calcific metamorphosis and pulpal necrosis in patients presenting with discoloured anterior teeth secondary to traumatic injuries. The study was carried out in Southwestern Nigeria; hence the population studied may not be representative of the total Nigerian population.
Most international surveys reported that males experienced significantly more dental trauma to the permanent dentition than females [14, 15]. In this study, we got a male: female ratio of 1.36:1, this falls within the usually quoted range of 1.3–2.3:1 [1–3]. However, a lower ratio of 0.9:1.0 has been reported for children less than seven years old . Domestic accidents accounted for most of the injuries in the present study (37.0%), this is in agreement with earlier studies [16, 17] that reported accidents at home and school to account for most injuries to the permanent dentition.
In the discoloured traumatized anterior teeth presented in this study, subluxations were the most frequent type of injury (45.8%), followed by concussions (31.6%) and fractures (22.6%). These were contrary to the findings of Petti et. al.  in which fractures (enamel, 67%; enamel-dentine, 19.3%) were the most frequent type of injury followed by concussions (8.3%). Also Rocha and Cardoso  reported fractures (51.4%) to be more frequent than luxation (48.6%). The differences are to be expected since the present study dealt with discoloured teeth secondary to trauma and not a survey of all the traumatized anterior teeth. It may be that patients who sustained severe injury to their teeth resulting in serious fractures had earlier sought treatment, hence the low frequency of fractures in this study. Because of the difficulty in determining the pulpal sequelae in traumatized teeth that have already been treated, they were excluded from the study. Also it is widely accepted that moderate injuries such as concussions and subluxations most of the time go unnoticed. Patients with such injuries usually presents later with discoloured teeth.
The reactions of the dental pulp to traumatic injuries can be extremely varied. They ranged from almost immediate pulp death to long-term slow pulp canal obliterations . In the sequelae of calcific degeneration, the clinical crown frequently becomes discoloured. In this study, obliteration of the pulp canal space was more frequent in concussion and subluxation injuries, while pulpal necrosis was more frequent in fractures. The differences were statistically significant p < 0.001. However, the differences in the frequency of partial or total obliteration of the pulp canal space were not statistically significant (p > 0.05) in relation to the injury type. In the present study, pulpal necrosis occurred in 9.4% of teeth subjected to concussions. This is much higher than the 3.0% reported by Andreasen and Vestergaard Pedersen . The authors could not proffer any reason for this. Injuries sustained during the 1st and 2nd decade of life resulted more in obliteration of the pulp canal space, while injuries sustained in the 3rd decade resulted in more pulpal necrosis. The differences were statistically significant (p < 0.001). It was observed that road traffic accident (RTA) was the major cause of injuries in the 3rd decade of life leading to enamel-dentine fractures.
Although prophylactic endodontic treatment in teeth displaying pulp canal obliteration on a routine basis does not seem justified, it has been reported that the incidence of pulpal necrosis increases over the course of time . In this study, the majority (70.0%) of teeth with partial obliteration of the pulp canal space presented with pain and showed pathologic periapical changes, which may have resulted from pulpal necrosis. However, this runs contrary to the findings of Jacobsen and Kerekes  who reported normal periapical conditions in all teeth with partial obliteration. Only 26.4% of teeth with total obliteration presented with pain and showed pathologic periapical changes. This is in partial agreement with the findings of Jacobsen and Kerekes  in which 21.0% of teeth with total obliteration developed pathologic periapical changes. From these, teeth with partial obliteration of the pulp canal space are more likely to be symptomatic than those with total obliteration. Although, an earlier study had suggested that increase in the amount of calcification might lead to partial or complete radiographic but not microscopic obliteration of the pulp chamber and root canals .