Osteoporosis and periodontitis are very prevalent diseases and are most common in middle-aged and elderly women. These diseases are related as both damage bone tissue and share common risk factors. Discussions about the association between these two bone-damaging diseases began in 1960. A hypothesis was raised that systemic imbalance in bone resorption and deposition might manifest itself in the alveolar bone earlier than in other bones. When analyzing systemic and local changes in bone density, a number of issues were investigated and attempted to answer the question of whether dental osteopenia is a local manifestation of osteoporosis having similar etiology and risk factors, or it is an independent process depending primarily on factors that cause periodontal disease. Histomorphometric and microradiographic studies showed that increasing porosity of the cortical layer in mandible resulted in the decrease in bone mass. Bone strength is best expressed through bone mineral density, and it can be called a diagnostic criterion of osteoporosis. The examination of bone mineral density is called densitometry and may be performed using dual-energy x-ray absorptiometry. Orthopantomography is a method that is widely applied in odontological practice and is also informative in determining the bone density of the mandible. It can be applied when performing orthopantomographic and vertical linear measurements, as well as in determining indices in the studies of osteoporotic changes. Since many patients attend odontological clinics, nearly all of them undergo orthopantomography. This is a good possibility to investigate osteoporotic changes in the mandible, to select individuals for further studies, and to ensure clinical benefit and good treatment results.