As a preventive measure, it is advisable to visit the orthodontist at six years of age, which is when the first molars begin to appear, and this is when we can see how the molars close/fit together and we can foresee how the dentition is likely to evolve. Between six and twelve years of age, the orthodontist will evaluate how the baby-to-adult dental replacement is progressing, how the upper and lower teeth fit together, and spacing issues, are among the factors to consider when putting a treatment plan in place for each individual case.