In-vitro evaluation of frictional resistance with 5 ligation methods and Gianelly-type working wires.

INTRODUCTION: Numerous in-vitro studies have been conducted with various archwire-ligation combinations to evaluate the effect of wire size and ligation method on frictional resistance. The aim of this in-vitro study was to compare the frictional resistance during sliding mechanics with Gianelly-type stainless steel working wires, Leone slide ligature, conventional elastic ligature, and stainless steel (SS) ligature, and a conventional bracket and active and passive self-ligating brackets. METHODS: Three ligation methods with Victory (V) brackets--Leone (VLeone), conventional (regular) elastic (VReg), and SS (VSS)--were used with standard SS brackets, and 2 self-ligating brackets--Damon MX (Ormco/"A", St. Paul, Minn) (DMX) and In-Ovation R (GAC Intl., Bohemia, NY)--were used with 2 rectangular SS wires (0.016 x 0.022 and 0.018 x 0.022 in). Therefore, 5 ligation methods and 2 wire sizes were evaluated with respect to their effects on frictional resistance. RESULTS: No statistically significant differences were found between the SS ligation method and DMX (neither produced measurable static friction). For the wire size 0.016 x 0.022-in SS, the DMX and SS produced significantly less static friction than the In-Ovation R, VLeone, and VReg. The In-Ovation R produced significantly less friction than both the VLeone and VReg, whereas the VLeone produced significantly less friction than the VReg. For the wire size 0.018 x 0.022-in SS, the overall results were the same, except that the In-Ovation R produced significantly more friction than the VLeone. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (except DMX and VSS, which showed no measurable friction at either wire size). CONCLUSIONS: The Leone slide ligature showed less friction at both wire sizes than VReg; however, it showed significantly more friction than both DMX and VSS. DMX and VSS brackets produced no measurable friction with either 0.016 x 0.022-in or 0.018 x 0.022-in wires. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (excluding DMX and VSS, which showed no measurable friction at either wire size).

Orthodontic treatment of patients using bisphosphonates: a report of 2 cases.

The pharmacologic agent bisphosphonate has recently received much attention in the dental literature. Bisphosphonates in oral or intravenous forms are used to treat various diseases such as certain cancers, bone- and calcium-related disorders, osteoporosis, and osteopenia. Bisphosphonates inhibit bone turnover and result in increased bone-mineral density. The most serious dental side effect of bisphosphonate treatment (particularly when it is administered intravenously) is, paradoxically, osteonecrosis of the mandible or the maxilla represented by exposed nonhealing bone. Other related complications include decreased bone healing and inhibition of orthodontic tooth movement. This article reports the orthodontic treatment of 2 patients who were taking bisphosphonates.