The partial aetiological overlap between overweight/obesity and oral diseases has aroused interest in the medical environment. Studies to investigate the causal relationship between these two diseases are underway. However, most of the available literature reports fail to confirm the direct positive correlation between obesity and dental caries. On the other hand, overweight and obesity are considered risk factors for periodontal diseases. The proinflammatory mediators secreted by adipocytes in obese individuals may impair immune functions, thereby modifying host responses to dental plaque antigens and contributing to blocked defence functions in periodontal diseases. Gingivitis observed in overweight and obese patients is a result of metabolic disorders, inflammatory factors and improper oral hygiene habits. The latter ones are associated with frequent consumption of sweetened, pulpy and highly processed food products and sweetened carbonated beverages, which is a risk factor for overweight, particularly in children and adolescents. Undoubtedly, overweight and obesity affect salivary secretion and properties, including changes in the microbiological composition of saliva. Obese patients are at increased risk of adverse affects of dental treatment, dental surgeries in particular. Overweight and obese individuals require permanent preventive and medical dental care addressing their periodontal preventive and therapeutic needs. Dentists should actively participate in the prevention of overweight and obesity, especially in children and adolescents, taking advantage of frequent contact with this group of patients. Obese individuals may participate in integrated therapeutic management by means of dental treatment limiting food intake.