Orthodontic appliances, whether constructed on many bands supposed to ” protect ” the teeth from caries or on a few to simplify the treatment and do ” as little harm as possible ” to the teeth, may induce oral conditions that increase susceptibility to caries. Six empiric rules for hygienic construction of orthodontic appliances are submitted below. The author has found that when these rules are observed, caries-frequency in treated patients can be reduced to a minimum. The abnormal position of teeth, in bite anomalies, is itself responsible for increased caries-frequency. If that is taken into consideration, proper orthodontic treatment does not increase caries-susceptibility.
(1) Whenever wires—arches, ligatures, or springs—touch the surface of a tooth, or extend less than 1 mm. and cannot be removed by the patient for cleansing purposes, protecting bands should be applied. Ligatures (of any material) on bare teeth should be avoided, even if the form of the tooth does not require bands for mechanical reasons. Exception may be made for finger-springs on lingual surfaces of teeth in apparently caries-resistant mouths. (2) Proper bands fulfill several requirements, the most important of which are these : (a) A band should fit exactly the surface of the tooth, at all margins of the band. (b) Band margins should be on areas that are not susceptible to caries—as for margins of fillings, according to the rule first stated by Black. (c) Bands should be fixed with a cementing medium that is harmless to enamel. Many popular cements appear to cause decalcification-areas under fixed bands. (d) Band materials should be made of metals that do not oxidize or dissolve in the mouth. This is true for solders and all other materials in use. The old Angle materials should be avoided. Band material should be as thin as possible, and the surfaces of bands polished and shined. (e) A band should remain fixed at the same place for only a limited time. Modern treatment usually requires that bands be left in place for periods not exceeding eight months. This should be considered as the maximum. In exceptional cases, bands should be removed at shorter intervals, the teeth well cleaned, and the bands fixed again under conditions stated above. (3) The mouth and teeth should be cleansed by special methods. Ordinary means of keeping the mouth clean are insufficient. All appliances, removable and non-removable, should be cleaned with brush and threads after each meal. (4) Teeth that erupt during treatment should be given special care. They tend to acquire caries during devel‑opment. (5) Appliances should never be permitted to irritate gums or soft tissues. (6) At short intervals, regular search for caries, by clinical and x-ray examinations, is necessary. Caries, if found, should be treated immediately, preferably with inlays ; but if prevented by an appliance, tentative treatment should be by cement fillings and exact restoration made when the appliance is removed temporarily or permanently.
Reference: Praktische Orthodontie, 1936 (Urban and Schwarzenberg, Vienna and Berlin).