Most of these problems are inherited, but some are acquired. Hereditary problems include crowding of the teeth, excessive space between the teeth (diastema), extra or missing teeth, cleft lip and palate, and a wide variety of other irregularities of the jaws and face.

Acquired problems can be caused by thumb or pacifier sucking, atypical swallowing, upper airways obstructed by enlarged tonsils or adenoids, dental disease, or premature loss of deciduous or permanent teeth. Whether acquired or hereditary, many of these problems affect not only the alignment of the teeth, but also have functional and aesthetic consequences, influencing facial appearance.

Ideally, the first evaluation of a patient should be performed at approximately 7 years of age. An early examination allows the orthodontist to determine when a child should be treated with the best results, in the shortest amount of time and financial cost. In many patients, preventive treatment achieves results that are unattainable once the face and jaws have finished growing.

Orthodontic treatment can be performed at any age. In fact, approximately 30% of patients currently treated are adults. The biological process involved in tooth movement is the same in adults and children. The health of an individual's teeth, gums, and alveolar bone is what is most important in determining the likelihood of improving an adult patient's smile and dental health. Furthermore, with the evolution of treatment systems (faster) and new materials (more aesthetic appliances), the acceptance of this type of treatment by patients has increased significantly.

However, certain corrections cannot be achieved with conventional braces treatment alone. Significant facial changes are achieved with a combination of surgical and orthodontic procedures for individuals who are eligible for this type of treatment (ortho-surgical treatment).