Relevance. Research into the effects of nickel-titanium alloys and heavy metal ions on the development of inflammatory oral diseases is becoming increasingly significant in orthodontics. The relationship between toxic elements and inflammatory responses remains under-researched and controversial. Data on the connection between heavy metals and inflammatory reactions could influence the choice of orthodontic appliance materials and guide the subsequent management and monitoring of patients with braces. The question of the safe use of nickel-titanium alloy braces continues to be a relevant concern.Purpose. To assess the levels of heavy metals in the oral fluid of young patients with braces, both in those who developed plaque-induced gingivitis and those who did not.Materials and Methods. The study involved 50 clinically healthy patients (Groups I and II health categories) with intact teeth, including patients with compensated dental caries (isolated carious lesions – Grade I) and no periodontal diseases (PMA index <20), presenting with dental crowding and malocclusion (K07.2, K07.3). The average age of the patients was 22.1 ± 2.7 years, all of whom were undergoing treatment with metal braces. Oral fluid samples were analyzed for 12 heavy metal elements using inductively coupled plasma mass spectrometry (ICP-MS) in a laboratory setting. Additionally, lysozyme activity and oral fluid pH were measured before appliance placement and six months into orthodontic treatment.Results. Adaptation to braces in young patients is frequently complicated by the development of gingivitis and periodontitis due to impaired oral hygiene and the mechanical pressure exerted on teeth and gums, leading to elemental imbalances. Patients with gingivitis during orthodontic treatment are particularly at risk of developing such imbalances and therefore require timely correction of their mineral metabolism.