traumatic injuries not only pose a health risk worldwide , but are also regarded among serious social problems ( 1 ) . one important category is dental trauma ( 2 ) , accounting for a major part of health problems in children and adolescents ( 3 - 6 ) . studies conducted in different countries report various prevalence rates for traumatic dental injuries among children and adolescents ( 7 - 10 ) . dental trauma occurs in children mainly because of their weak balance and just having learnt to walk ( 11 ) . demographic evaluations indicate a higher prevalence for trauma in males compared to females ( 12 - 14 ) . falling , fight , sports , accidents , and hitting items or people are among common etiologic factors ( 15 - 18 ) . home setting , school and street are places with the highest frequency of dental traumatic injuries ( 19,20 ) , which most importantly include enamel fracture and enamel and dentin fracture without pulp exposure ( 21 - 24 ) . 
 
 according to the heterogeneity among the individual study results and the importance of preventing dental trauma , it is of importance to accurately determine the prevalence of dental trauma using appropriate research methodology . also identifying the influencing factors therefore , the present study aimed to conduct a systematic review and meta - analysis on the prevalence of dental trauma among children and adolescents in different countries and other related variables . the required date were collected searching for key words including traumatic dental injuries , dental trauma , dental injury , dental trauma , tooth injuries , tooth trauma , traumatized teeth , dentoalveolar trauma , oral trauma , epidemiology , etiology , prevalence , incidence , occurrence , child * , and adolescence in scopus , cinahl , science direct , pubmed , google scholar . manual journal searching and an extensive hand search of the gray literature were also conducted . articles from the reference list of the studies which were found to be relevant were also considered . articles in english and persian that reported dental trauma ( injury to the teeth and/or periodontium , and nearby soft tissues ) and those studies ( 2 ) that were conducted on children and adolescents with age range of 0 - 18 years and cross - sectional studies were also included . exclusion criteria were as follows : studies on trauma from sport activities , studies on trauma from medical interventions such as endoscopy , studies on individuals with medical or special conditions , conference presentations , case reports and interventional studies ( such as randomized controlled trials ) . two reviewers evaluated the articles according to the checklist of strengthening the reporting of observational studies in epidemiology ( strobe ) ( appendex . first , articles with non - relevant titles to the subject of this review were excluded . then , the abstracts and the full texts of the articles were reviewed respectively to exclude those articles that matched the exclusion criteria of the study , or had a weak relevance to the subject of the study . computer software for reference management ( endnote x5 ) was used for organizing and assessing the titles and abstracts as well as recognizing the repetitive items . the searches returned 3197 articles , but those articles that were non - relevant , and repetitive between databases , with weak relevance to the study or matched the exclusion criteria were excluded ; finally , 44 relevant articles were selected ( fig . 1 ) . these articles were fully read , and the required data for the systematic review were extracted into the extraction table designed for the purpose of the study in spreadsheet computer software ( excel , microsoft office ; microsoft , us ) . spss 17 was used to analyze some of the quantitative data . 
  literature review and retrieval flow diagram trauma place of occurrence 
 to determine the overall prevalence of dental traumatic injuries and perform the meta - analysis , computer software ( cma - comprehensive meta - analysis ; englewood , nj , usa ) was employed . the results were reported using forest plots , in which the size of each square indicates the sample size and the lines drawn on each side of the square indicate the confidence interval ( ci ) of approximately 95% for dental trauma . random model was in contrast with the fixed model that demonstrates the observed quantities with respect to the explanatory variables which are treated as if the variable were not random . from a total of 3197 relevant articles , 44 completely relevant articles were included in the study . most studies were conducted in brazil ( 16 articles ) , and the oldest was conducted in jordan ( 1995 ) ; most of the studies were done in dental clinics , and only two out of the 44 ( 4% ) studies were conducted in iran . the overall number of participants was 69502 children and adolescents aged 0 - 18 years ( mean , 1579 each study ) . the meansd prevalence of dental trauma was 10.2%  4.70 among boys and 6.5%  3.40 girls , which was statistically significant ( p < 0.001 ) . 1 . 
 
 places with the highest frequency of traumatic dental injuries are demonstrated in table 1 . the mean of enamel fracture had the highest frequency ( 55% ) among the types of dental trauma in children and adolescents ( fig . type of dental trauma 
 to perform the meta - analysis , the heterogeneity index was determined within the articles using the heterogeneity i test . after confirmation of heterogeneity of the 
 studies , the best estimation of the prevalence of trauma was determined based on the random effect model ( fig . the prevalence of dental trauma in children and adolescents based on the random effect model . the prevalence of dental trauma in children and adolescents based on the random effect was determined to be 17.5% ( 95% ci : 14.6%-20.4 % ) ; 95% ci for the prevalence was drawn for each study in the horizontal line format ( q= 3631.17 , df= 43 , p<0.001 ) . the frequency distribution for dental trauma based on the location variable ( continent ) is shown in figs . the prevalence of dental trauma in children and adolescents in the continent of america was estimated based on the random effect of 21.2% ( 95% ci:16.6%-26.7% ) ; 95% ci was drawn for each prevalence in the horizontal line format ( i= 98.7 ) . the prevalence of dental trauma in children and adolescents in europe was estimated based on the random effect of 19.1% ( 95% ci:13.7%-24.1% ) ; 95% ci was drawn for each prevalence in the horizontal line format ( i= 97.9 ) . the prevalence of dental trauma in children and adolescents in asia was estimated based on the random effect of 14.7% ( 95% ci : 11.3%-19.0 % ) ; 95% ci was drawn for each prevalence in the horizontal line format ( i2 = 98.4 ) . 
 to assess the publication bias , funnel plot dental trauma is a major health problem in many societies ( 26,29,30 ) , with higher prevalence rates among children and adolescents ( 25,26,29,48,64 ) . the present study revealed the prevalence of dental trauma in children and adolescents ( under 18 years of age ) to be 17.5% , but with variances among different geographic regions . 
 
 in the present study , the prevalence of dental traumas for all subjects was determined to be 17.5% , which necessitates efficient planning and intervention to prevent their incidence . moreover , considering the negative influence of dental traumas on individuals quality of life ( 39,65 ) , psychological and social problems ( 66,67 ) , and direct and indirect costs of treatment ( 68 ) , developing effective interventional strategies to deal with this issue is of prime importance . the difference in the prevalence of dental trauma among the studied geographic regions might be a reflection of their different cultural , sanitary , and economic conditions , type of activities and professions practiced , and ecological characteristics like the fluoride concentration of drinking tap water . for instance , the prevalence of dental trauma was found to be higher in the continent of america compared to asia or europe , and this could be the result of sports activities of youth , as most studies in the region pertained to brazil . furthermore , the fluoride concentration of water in regions with mild and humid weather condition is usually low ( 69 ) , resulting in lower fluoride content in teeth which can render teeth more prone to dental trauma . this notion highlights the importance of local and regional considerations during planning and interventions by policy makers . the prevalence of dental trauma was higher in boys compared to girls ( 10.2  4.7 vs. 6.5  3.4 ) . previous studies also agree on the higher prevalence of dental trauma in boys than girls ( 27,51,70 - 72 ) , which might be due to boys performing more activities like sports , bicycle riding , fighting , working , etc . , the most important cause for dental trauma was falling , which is in agreement with previous literature ( 74 - 78 ) . this can be explained by the imbalance of the newly walking children leading to falling accidents . thus , children should be cared more prudently , reinforced by measures to eliminate the risk of falling . the other important cause of dental trauma in this study was sports , which is in line with previous research ( 79,80 ) . ensuring the existence of sound safety measures in sports venues accompanied by the use of protective athletic appliances such as mouth guards , and educating children and adolescents who engage in sports activities are among suggestions that can be effective in reducing the incidence of dental trauma in this age range ( 81,82 ) . fights and violence were also among the causes of dental trauma in children and adolescents in the present study , which is indicative of the behavioral characteristics of this age range , with dominant , violent , emotional , and illogical traits . in this regard , special attention should be given to social education at home and school , fostering a culture of self - control and social respect towards others . the findings of this study revealed that dental traumatic accidents occurred most frequently at home , and this is in line with many previous studies ( 83 - 85 ) . this is explainable by the fact that children and adolescents spend a significant part of their time at home ; and therefore , special safety measures should be considered at houses in which families live with their children . based on the analysis of the study data , enamel fracture was the most frequent type of dental traumatic accidents , confirming the findings of other studies ( 34,42,56,86 ) . therefore , dentists and other health - care professionals as well as lay people should have adequate knowledge regarding the management of dental traumatic events ( 87 - 90 ) . the study was also limited by the fact that it only included articles in english and persian and only included studies conducted since 1995 . the results of this study indicated a significant prevalence for dental traumatic accidents among children and adolescents , which necessitates efficient planning and interventions in order to prevent their incidence . safety measures would be most effective when implemented at home where dental traumatic accidents occur most frequently .
background : dental traumas 
 are common among children and adolescents in many societies posing health and 
 social problems . 
 the aim of this study was to conduct a systematic review and 
 meta - analysis on prevalence , etiology , types , and other epidemiologic aspects 
 of dental trauma in children and adolescents ( 0 - 18 years old ) . 
 methods : in this systematic meta - analytical review , data 
 were collected searching for key words including traumatic dental injuries , 
 dental trauma , dental injury , dental trauma , tooth injuries , tooth trauma , 
 traumatized teeth , dentoalveolar trauma , oral trauma , epidemiology , etiology , 
 prevalence , incidence , occurrence , child * , and adolescence in the following 
 databases : scopus , cinahl , science direct , pubmed and google scholar . 

 results : from the total of 3197 articles , 44 completely 
 relevant papers were included in the study . the prevalence of dental trauma was 
 variable based on geographical area and was estimated 17.5% in the population , 
 with higher prevalence in boys . falling was the major cause for dental trauma , 
 and the most frequent location was home . 
 the most frequent type of trauma was 
 enamel fracture . 
 conclusion : a relatively high prevalence was detected for 
 dental trauma , which calls for effective planning and intervention to prevent 
 the occurrence in children and adolescents . 
 these may include special care for 
 children , eliminating fall - prone areas , installing safety measures at homes , 
 using protective appliances in sports , education , and raising the knowledge and 
 availability of services to address enamel fracture . 
 region - specific criteria 
 should be taken into account in programs and interventions .