The appearance of nutrient canals in the mandibular anterior region was studied by evaluating the complete-mouth dental radiographs of 1,586 patients who were subdivided into four groups. The incidence of nutrient canals was very high in patients with periodontal disease, in patients of advanced age, and especially in endentulous patients. Nutrient canals appeared most frequently in radiographs demonstrating "above average" bone density with small diminutive trabecular spaces. Other factors influencing the presence of nutrient canals included the thickness of the alveolar bone, the quality of both cortical and cancellous bone, and the loss of mandibular teeth.