DANIELA ANISTOROAEI, GEORGETA ZEGAN, IULIA CATALINA SAVEANU, ALINA SODOR, LOREDANA GOLOVCENCU THE PREVALENCE OF DENTAL MIDLINE DEVIATION IN A GROUP OF ORTHODONTIC PATIENTS The study aimed to determine the prevalence of dental midline deviation in an orthodontic group of patients.The study was performed on 384 orthodontic patients (164 boys and 220 girls), between 6-23 years old. The data collected from orthodontic records were analysed according to the gender, age stages, environments areas, type of dentition and Angle Classes of malocclusions. All analyses were carried out using the SPSS. In the studied group the prevalence of dental midline deviation was 20.70%. The prevalence of dental midline deviation was increased in girls (12.24%), in patients over 12 years old (8.35%), from urban areas (14.32%), with mixed dentition (11.45%) and with Class I (11.20%) and II division 1 (6.25%) malocclusions. We founded statistically significant high correlations between dental midline deviation and age stages (p=0.028), type of dentition (p=0.001) and Angle classes of malocclusions (p=0.006). The dental midline deviation, commonly encountered in orthodontic practice, must be accurately diagnosed from the beginning of the treatment because the symmetry of the midlines is an essential criterion in achieving the aesthetic and functional objectives of the orthodontic treatment.