Distribution of the cement film beneath the orthodontic band: a morphometric in vitro study.

Background: During orthodontic treatment with a multiband appliance, enamel decalcifications and periodontal irritation may occur due to inevitable plaque retention. Besides the band itself, non-cemented gaps between tooth and band constitute a problem that has not yet been investigated from quantitative aspects.
Materials and Methods: In this in vitro study, the cement distribution beneath the orthodontic band was investigated on 48 identical transparent resin replicas of upper molars and lower molars, respectively. The replicas with the cemented orthodontic bands were divided into buccal, distal, oral, and mesial segments so that the inner surfaces of the bands could undergo morphometric analysis for areas not covered with cement. Two different molar bands (Dentaform Snap by Dentaurum, Ispringen, Germany, and "Washbon" by Ormco, Orange, CA, USA), and two glass-ionomer cements (OptiBand by Ormco and Ultra Band-Lok Blue by GAC, Gräfelfing, Germany) were used. In this way, 8 test series with twelve specimens each were performed.
Results: Not one cement-band combination was without defects in the cement film, with poorer cement flow properties being observed at the upper than at the lower molars. In general, fewer defects were recorded in the occlusal than in the cervical areas. Overall, the buccal surfaces yielded the best results, and the mesial surfaces the poorest.
Conclusions: Since defects in the cement film have so far been unavoidable, the indication for orthodontic treatment with a multiband appliance must continue to be strict. Unless accompanying professional prophylactic care coupled with optimal oral hygiene is ensured, multiband appliances should be used with great caution.