We are grateful that orthodontists are showing considerable interest in our new method of uprighting a mesially tipped molar. The following are the responses to some points you raised.
Extracting the third molar and uprighting the second molar to replace the missing first molar with a dental implant has been a traditional multidisciplinary approach in dentistry. However, uprighting and anteriorly protracting posterior teeth has become a reasonable alternative treatment in orthodontics since the introduction of temporary skeletal anchorage devices. Regardless of the numerous advantages in anterior molar protraction, some patients still prefer the former treatment option because the treatment period is shorter than the latter. In general, closing the space of the missing molar requires more root movement than is visible from the clinical crown, and a healthy periodontium should be a prerequisite condition. The patient shown in this article had a vertical alveolar bone defect on the mesial root of the third molar (Fig 6). Therefore, extracting the third molar was clearly a better choice than protracting it.
A removable orthodontic appliance could be more expensive and uncomfortable than a partial fixed orthodontic appliance to patients in some countries, depending on the health care system and cultural backgrounds. As for the 2 patients presented in this article, older people in our country usually express discomfort toward removable appliances because of their bulkiness and the disturbance they create in pronunciation. The technique discussed in this article uses only a single piece of wire and resin on the buccal side of the molar; this reduces the bulkiness that disturbs pronunciation. Moreover, removable appliances are not less expensive than partially fixed appliances in our clinic.
A round 0.014-in nickel-titanium (Ni-Ti) wire releases a very light force in uprighting a molar, but there is no clearance around the wire because the appliance is bracketless. This causes the force to be transferred directly to the tooth. We tried using a larger wire (0.016 × 0.02-in Ni-Ti) to upright the molar at first but discovered soon that the force was greater than we had expected. We gradually lowered the force to 0.014-in Ni-Ti and found that the molars did upright despite our worries that the wire was not rigid enough. We recommend that you try using a 0.014-in NiTi wire to upright a molar. You will be surprised to see how the tooth moves with even just a light pressure.
As in conventional orthodontics, distal forces applied on the buccal side of a molar cause rotation. An antirotational moment is generated by the custom resin base made from a setup model. If more antirotational moment is needed, it could be acquired by overcorrecting the rotation in the setup model. Deformation of the appliance under occlusal force can occur in most orthodontic wires used in dental clinics, but Ni-Ti wire has a shape-memory effect, which reduces the chance of deformation under occlusal force.
Thank you again for your interest in our new bracketless molar uprighting technique. There is no doubt that the Ni-Ti wire method for uprighting a molar has opened a new treatment option for patients, and it has been successful thus far. We hope that it will continue to return positive results.