Skeletal anchorage for tooth movements : mini implants vs osseointegrated implants

In some adult patients, orthodontic anchorage may be more difficult to achieve because of missing teeth and wide edentulous space. The implants may be used initially as skeletal anchorage to facilitate tooth movement, and secondarily as abutments for fixed prostheses. It has been studied I that a 4-5 months healing period is adequate for implant osseointegration, so to resist at orthodontic force application (Robert et al.,1984). Kanomi et al (1997) introduced the mini-implants and showed (2003) that a three-week healing period was sufficient for orthodontic loading in dogs and 4-5 weeks in present humans. By this present clinical study has been that there were no significant differences between 4,8 and 16 week healing period before orthodontic force application on mini-implants inserted in a good quality bone. Edentulism is usually associated with the adult patient, but total or partial tooth loss also affects young patients, mainly as a result of agenesis, trauma, decay, anodontia or congenital and acquired jaw defects involving the alveolar processes. Experimental studies have clearly shown that osseointegrated implants should not be inserted in patients who are still growing, until the permanent dentition is fully erupted and skeletal growth is completed (Odman et al 1991; Thilander et al 1992; Lekholm 1993; Sennerby 1993; Thilander et al 1999). Fixtures don’t act like natural teeth during the growing of the jaws. They behave like an ankylotic tooth, which don’t move together with the growing surrounding structures. There is an obvious risk that the fixture-supported prostheses could end up in infraocclusion if inserted too early in children. Ankylotic teeth in infraocclusion often create malocclusions, and in most instances, are also extracted to facilitate the normal growth and development of the jaws. Consequently implants may be at risk for similar problems when inserted in growing patients, and cause a negative influence on the local and general growth and development of the dentoalveolar processes. It has been suggested that osseointegrated implants should not be inserted in children until after the growth maximum of the jaws has been reached, at the age of 14-15 for girls and about 1 year later for boys. The individual growth curve should be studied before any implants are placed. The need for interdisciplinary approach within the various areas of dentistry to collaborate in the complex rehabilitation become very important. Above all many implantologists are guilty of treating from an unidisciplinary point of view, that can lead to incomplete diagnostics, improper treatment planning, and compromised results. A single specialist, often, develops treatment plans according to his own specialized capabilities, expertise and skills, rather than by what the patient actually needs and by the treatment options dentistry can provide. This approach can lead to secondary problems, from esthetical, functional, skeletal, neuromuscular, periodontal and stability stand points. Sometimes using osseointegrated implants as anchorage there are often problems because of severity of surgery, the discomfort of initial healing, a longer period of treatment time and they could only be inserted in retromolar, tuber and edentulous areas, evidencing limitations for the direction of force application. The use of mini-implants as anchorage produces a satisfactory result in a short period of time with two minimal surgical procedures, and enables to insert an appliance in any aimed position and carries out easily the tooth movements also in young growing patients. This is very important for preventing dental, periodontal, esthetical and psychological problems during orthodontic treatment. Anchorage control is essential to successful orthodontic treatment. Implants are skeletal anchorage units that are not dependent on patient compliance, but are limited in range of application by their relatively large size. Using mini-screws, more most sites are available, the surgery is relatively less traumatic, and the duration of the healing period before loading may be reduced till to 4 weeks without waiting for osseintegration. Tooth movement that is difficult or impossible by conventional tooth-borne and osseointegrated fixture anchorage, is possible by mini-implants. They are indicated to correct dental-skeletal deformities and during intermaxillary fixation after orthognathic surgery.