A wide spectrum of TDIs has been reported, including crown fractures, crown fractures with pulpal exposure, avulsion, root fractures amongst others. In most studies, fractures involving the enamel alone or enamel and dentine without pulpal involvement were the most prevalent TDIs (Osadolor, 2019, Ogordi et al., 2019; Eigbobo et al., 2016; Taiwo and Jalo, 2011; Adekoya-Sofowora et al., 2009; Adekoya-Sofowora et al., 2004). Root fractures are relatively uncommon, with studies either reporting no cases of root fractures among TDIs, or a prevalence ranging from 1.2 to 7.0% (Abbott, 2019).

Common causes of TDIs include falls, collisions (with objects, surfaces or other people), violence, sports related accidents, road traffic accidents and misuse of teeth e.g. opening of bottle covers using the teeth (Eigbobo and Etim, 2016; Zaleckiene et al., 2014;Taiwo and Jalo, 2011; Adekoya-Sofowora et al., 2009). In childhood, most TDIs are usually the result of falls as children develop motor functions and learn to walk. In adolescents, with an increase in sporting activities and interpersonal conflicts, the major causes of TDIs are violence and sports related accidents, whereas in adults, road traffic accidents play a more prominent role (Enabulele et al., 2016; Lam, 2016; Anderson, 2013). Previous Nigerian studies have all reported falls to be the most common cause of TDIs with frequencies ranging from 26.4 to 34.3% in adults (Osadolor, 2019;Enabulele et al., 2016; Ajayi et al., 2012) and 42.6 to 64.2% in adolescents (Ogordi et al., 2019; Taiwo and Jalo, 2011; Adekoya-Sofowora et al., 2009; Adekoya-Sofowora et al., 2004). Studies from other parts of the world have also found falls to be the commonest cause of TDIs (Naidoo et al., 2009; Soriano et al., 2007).

The adolescent population is an important population to study   with    regards    to    TDIs.    Much   health-related behaviour such as crime, smoking and alcohol use develop during adolescence. These, in addition to an increase in sporting activities, may increase the risk of a TDI occurring and such injuries have been shown to peak in adolescence (David et al., 2009; Glendor et al., 2007). A better understanding of the causes of TDIs, especially in such a high-risk population like adolescents will go a long way in creating awareness amongst the populace, and in formulating preventive measures to help reduce the burden of the condition.

In Nigeria, many studies (Ogordi et al., 2019; Osadolor, 2019; Eigbobo et al., 2016; Enabulele et al., 2016; Ajayi et al., 2012; Taiwo and Jalo, 2011; Adekoya-Sofowora et al., 2009) have been carried out on traumatic dental injuries, but few of them have been restricted to adolescents. Many of the studies in adolescents have focused on a specific age rather than broader period of adolescence (Taiwo and Jalo, 2011; Adekoya-Sofowora et al., 2009). Moreover, the bulk of these studies have been from the South-west zone, with paucity of similar studies from the South-south Geo-political zone. Furthermore, available studies have not adequately compared the causes, scene and types of TDIs between males and females. Therefore, the aim of this study is to determine the causes, scene and types of traumatic dental injuries among 12-15-year-old adolescents in secondary schools in Port Harcourt, South-south Nigeria, and to compare the findings in males with those in females. The null hypothesis for this study states that there is no difference in the pattern (causes, scene and types) of traumatic dental injuries between male and female adolescents in secondary schools in Port Harcourt. The alternate hypothesis states that there is a difference in the pattern (causes, scene and types) of traumatic dental injuries between male and female adolescents in secondary schools in Port Harcourt.

This is a cross-sectional study carried out among 12-15-year old adolescents in junior secondary schools in Obio-Akpor Local Government Area (LGA), Port Harcourt, Rivers state, Nigeria. A list of twenty (20) secondary schools in the LGA and approval to carry out the study was obtained from the Rivers State Universal Basic Education Board, and the names of the schools were then listed in alphabetical order. The minimum sample size was calculated using the formula,

N = Z² xP(1-P) / D²,

Where:N is the minimum sample size; Z is the standard score for a given confidence level, usually set at 1.96 which corresponds to 95% confidence level; P is the estimated prevalence of TDIsobtained from a previous study = 9.1% (Adekoya-Sofowora et al., 2004);D is the maximum allowable error or the degree of accuracy desired, set at 0.05.

The minimum sample size calculated using the above formula was   127.   However,   a  total  of  200  participants  were   selected systematically as follows. Four schools were selected from the list of 20 schools. This was done using systematic random sampling, by selecting every fifth school, after selection of the first school using simple random sampling technique. In each school, all the junior secondary school students between the ages of 12-15 years were selected, and numbers were assigned to them. A table of random numbers was then used to select fifty participants from each of the schools, giving a total number of two hundred participants.

Information was elicited from the students by means of a close-ended, structured, self-administered questionnaire. Information elicited included age, gender, previous experience of trauma to the oral cavity/dentition, cause(s) of injury, scene of injury, type of injury sustained, the number of teeth that were injured and history of visitation to the dental clinic.Data were analyzed using SPSS version 20 (IBM corp., USA). Tests of association between variables were done using Pearson’s chi square, with p-values of ≤ 0.05 considered statistically significant.

There were two hundred participants in the study, comprising 98 (49%) males and 102 (51%) females. Falls were the most common cause of traumatic dental injuries overall (40.1%), and were also the leading cause in both genders. There was no significant association between gender and cause of injury (p= 0.604). Overall, majority of the injuries occurred at home (56.3%). However, while males suffered more injuries in school, injuries in females happened mostly at home. This was statistically significant (p= 0.006). Themost common type of TDI reported was luxation (49.5%). Table 1 shows the injury characteristics in both genders. Injury related to one tooth was most (62.3%) frequently experienced. Of the total number of participants who had suffered a TDI, only 33.7% had ever visited a dental clinic, and 2.5% did so on account of the injury.

This study found that most cases of traumatic dental injuries in adolescents in Port Harcourt were caused by falls. Injuries in females occurred mostly at home, while those in males were more frequent in schools. The commonest type of TDI was luxation injuries. They had a poor health-seeking behaviour.

The authors have not declared any conflict of interests.