Distribution of Malocclusion Traits in the Pediatric Population of Milan: An Observational Study

Background: Epidemiological investigations define the prevalence and distribution of the various types of malocclusions, and can help to identify etiological factors and set the most correct orthodontic therapy. Aim: The goal of this study was to verify the prevalence and distribution of various types of malocclusions in the pediatric population. Methods: The study was performed on a sample of 350 patients (ages 5-9) being treated at the ASST Grande Ospedale Metropolitano Niguarda in Milan. A comparison was presented with one similar epidemiological investigation conducted 22 years earlier by the same researchers. The values of the malocclusion indices were reported from the cephalometric analyzes of the patients and were differentiated on the basis of gender and ethnicity. Results: The predominant traits of malocclusion in the general population of the analyzed sample were: skeletal class II (47.43%), hyper-divergence (40.86%), maxillary retrusion (46%), mandibular retrusion (66%), maxillary hypoplasia (50%), mandibular hypoplasia (49.14%), Wits index > 2 mm (22.57%); overjet > 4 mm (31.1%) and overbite > 4 mm (24.86%). Substantial differences were found between Italian patients and patients belonging to different ethnic groups in almost all parameters, and between the male and female genders in some of them. Patients in the 2000 study had a higher prevalence of Class II and hyper-divergence. Conclusions: This epidemiological investigation can suggest different approaches in setting the orthodontic treatment plan based on the ethnic group of the patient taken in charge and encourage more specific and large-scale analytical studies on the subject.