The Effects of Differentially Placed Orthodontic Bands on the Gingiva of Dogs

Abstract

There has been long-standing controversy among dentists concerning "proper" band placement. No definitive evidence has substantiated an "optimal" band location on teeth. This 90-day investigation was designed to document clinical, histologic, and radiographic effects of three occlusogingival band levels on hard and soft tissues of the periodontium. Conventional orthodontic bands, brackets and wires were placed on half the anterior teeth of three one-year-old male Beagle dogs. The other 24 anterior teeth were controls. Of the 24 bands, six were 2 mm supragingival, six were at the gingival level, and 12 were 2 mm subgingival. Frequent toothbrushing and periodic clinical re-evaluations were employed. Procion red dye was injected intraperitoneally in one animal on Day 75 to identify any alveolar bone changes. Some bands were placed or removed during the 90-day period so that the significance of time could be related to inflammation and healing responses. For the same reason Dog #1 was sacrificed on Day 60, 30 days before the other two. The results demonstrated good clinical and histologic correlation. Radiographic findings were negative because the only bony alterations were physiologic. Soft tissue changes were rapid. Supragingival bands had no effect on oral tissues, and gingival level bands induced slight inflammation that resolved completely with 45 days of healing. However, 2 mm subgingival bands caused moderate inflammation, increased pocket depths even after a suitable healing period and, in some cases, root surface damage and apical proliferation of the epithelial attachment. The findings demonstrated predictable patterns of tissue response to different band levels and the potential risk of improper band placement. This is significant to the orthodontist, especially in choosing an occlusogingival band level. It would appear that bands which penetrate the epithelial attachment cause permanent pocket depth increases. The manipulation of subgingival band margins requires appropriate skill and modification to avoid permanent sequelae.