1. Introduction
The most common facial trauma in children are dentoalveolar trauma and soft tissue injuries followed by bone fractures. The prevalence of maxillofacial injuries is 1-14% in children under 16 years of age and 0.87-1% in children under five years of age [1, 2]. Children have partially erupted and impacted teeth. It makes it difficult to treat this age group with internal fixation due to the possibility of damage to the permanent tooth buds. [3]
The most concern about children with head and facial trauma is the effect of the trauma and the treatment on their growth [4], considering the possibility that the teeth with different stages of evolution in the line of fracture have different prognoses in growth and deformity. The present study aims to examine the teeth in the fracture line to check the trauma’s effect on these teeth.
2. Materials & Methods
This study was conducted on 28 patients under 12 years of age with jaw fractures admitted to the Bahonar Hospital, Kerman, Iran from 2010 until 2016. Patients’ data, including panoramic X-rays before and after surgery were extracted from their medical files. The teeth in the fracture line were clinically evaluated in terms of vitality (response to cold test), tooth color (clinical color comparison of tooth in the fracture line and other vital teeth), and tooth mobility (horizontal displacement more than 1 mm in the socket). Panoramic graphs were examined immediately after and 6 to 24 months after the surgery. Surgical methods of these patients included closed and open reduction methods. The information examined in the panoramic graphs were the internal and external erosion rate, the pathological lesion, and the eruption rate of the teeth in the fracture line. 
Demographic information was collected by a checklist. Data were analyzed in SPSS v. 22 software using descriptive statistics and chi-square test to compare the internal and external erosion, pathologic lesion, and growth rate of teeth buds in the fracture line between closed and open treatment methods and between the upper and lower jaws.
3. Results
The most common cause of trauma in children was accidents; 60.7% of the fractures occurred in the lower jaw, of which 67.9% were treated using closed reduction method, 10.7% by open reduction method, and 21.4% were under monitoring. Pathological lesions were not observed in 89.3% of the teeth in the fracture line, and there was no discoloration in 78.63% of teeth. Moreover, in 71.4%, teeth necrosis was not observed; in 82.1%, the eruption of these teeth occurred completely. Root resorption was not present in 82.1% of cases. Crown deformity was observed in 25% of cases, with changes in dimensions and number of tooth cusps. Root deformity was observed in 7.1% of cases. Ectopic eruption of the teeth in the fracture line was observed in 32.1% of patients. None of patients underwent endodontic treatment for the teeth in the fracture line, and no looseness was observed in any teeth (Table 1). 


Most children in both closed and open reduction treatment groups had no mentioned complications. There were more pathological lesions, tooth discoloration, root canal treatment, necrosis, looseness, root resorption, crown deformity, and ectopic eruption in closed reduction treatment group than in open reduction treatment group. Furthermore, the complete eruption of permanent teeth in the fracture line was observed more in patients received closed reduction treatment (n=21) than in patients with open reduction treatment (n=2) (Table 1).
4. Discussion & Conclusion
In this study, most of the teeth in the fracture line erupted without problems (82%) and 30% of these teeth had ectopic eruptions. The results are similar to the study by Jenkins et al. However, in the present study, the pathological lesion was evident in 11% of the teeth in the fracture line that contradicts the results of Jenkins et al., which showed no pathological lesions in the teeth. [16]. We found that 71.4% of these teeth maintained their pulp vitality, similar to the studies by Hosgor and Aulakh [17, 18]. In the present study, 17.9% of teeth had root resorption and 7.1% had root deformity, consistent with Mittal et al.’s results [20].
None of the teeth in the fracture line were loose in our study. Contrary to this result, Lee et al. observed that 13.3% of the teeth were loose [21]. There was no significant difference between the patients received open and closed reduction treatments, which may be due to low number of samples in the open reduction treatment group. In one study, 33% of patients had open reduction treatment with an internal fixator, and 67% had closed reduction treatment, and no difference was observed between the types of treatment [22], which is consistent with our study. Aizenbud et al. concluded that the rate of complications in closed reduction treatment is lower than in open reduction treatment [24], which is not consistent with the present study. 
It is concluded that the majority of teeth in the fracture line have normal eruption with no pathological lesion, discoloration, crown and root deformity, and looseness, and there is no significant difference between the children received open and closed reduction treatments.

Ethical Considerations
Compliance with ethical guidelines
This article was approved by the Ethics Committee of Kerman University of Medical Sciences (Code: IR.KMU.REC.1396.1398). 

Funding
This study was supported by the Vice-Chancellor for Research of Kerman University of Medical Sciences, Kerman. 

Authors' contributions
Conceptualization, data collection and analysis: Mahsa Kimiaiy Talab; Preparing a draft of the article and correcting it: Seyed Amir Abas Noorbakhsh.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
The authors thank the Kerman University of Medical Sciences for its technical support in conducting this research study.
 

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