The 'slingshot' technique to align palatally impacted canines with elastomeric chain

Three-dimensional ultrastructural analysis and histomorphometry of collagen bundles in the periodontal ligament using focused ion beam/scanning electron microscope tomography

BACKGROUND AND OBJECTIVE

The periodontal ligament (PDL) is an essential tissue for tooth function. However, the 3-dimensional ultrastructure of these PDL collagen bundles on a mesoscale is not clear. We investigated the 3-dimensional ultrastructure of these collagen bundles and quantitatively analyzed their histomorphometry using focused ion beam/scanning electron microscope (FIB/SEM) tomography.

MATERIAL AND METHODS

The PDLs of the first mandibular molar of male C57BL/6 mice were analyzed using FIB/SEM tomography. The serial images of the collagen bundles so obtained were reconstructed. The collagen bundles were analyzed quantitatively using 3-dimensional histomorphometry.

RESULTS

Collagen bundles of the PDL demonstrated multiple branched structures, rather than a single rope-like structure, and were wrapped in cytoplasm sheets. The structure of the horizontal fiber of the collagen bundle was an extensive meshwork. In contrast, the oblique and apical fibers of the collagen bundle showed a chain-like structure. The area and the minor and major axis lengths of cross-sections of the horizontal fiber, as determined from 3-dimensional images, were significantly different from those of the oblique and apical fibers.

CONCLUSION

These findings indicate that collagen bundles in horizontal fiber areas have high strength and that the tooth is firmly anchored to the alveolar bone by the horizontal fibers, but is not secured evenly to the alveolar bone. The tooth is firmly anchored around the cervical area, creating a "slingshot-like structure." This study has provided further insights into the structure of the PDL and forms the basis for the development of more effective therapies for periodontal tissue regeneration.

Slingshot - An Easy Way Out

Orthodontic alignment of ectopically placed incisors or canines can be challenging and time consuming. A variety of techniques are used to align such palatally or lingually placed teeth including indirect ties with ligature wires, E-chains, piggy-back methods. This article presents two case reports to describe an effective technique using 'slingshot' method. It is a relatively simple and rapid method which is operator friendly and easily tolerated by the patients.