Comparison Between CAD/CAM and Conventional Mandibular Fixed Retainers.

Keeppy is a Class IIa custom-made medical device manufactured by Digital Service Leone s.r.l. - via Pratese 160/b, Florence, Italy. The Keeppy is an individualized fixed retainer, made of a Nickel-free Chrome Cobalt alloy, produced with a CAD-CAM procedure starting from a digital impression made with an intraoral optical scanner (3 Shape), which allows a perfect adaptation to the lingual surfaces of the 6 lower anterior teeth on which it is bonded. The device is characterized by the presence of applicators that can be placed temporarily on the buccal surface of the canines, which facilitate the clinician in the precise application of the device and which are removed as soon as the bonding phase of the retainer is complete. Bonding is performed using classic composite resins following a preparation phase of the lingual surface of the tooth consisting of the application of etchant (37% orthophosphoric acid) for 30 seconds and adhesive (primer-bonding).

The standard control device, which is among the most commonly used in routine clinical practice, consists of a steel braided wire. The device selected for the Class IIa investigation is the Ortho Flex Tech manufactured by Reliance Orthodontic Products, Inc. 1540 West Thorndale Ave. Itasca, IL 60143 USA. The Ortho Flex Tech steel braided wire is manually shaped by the clinician and cut with a wire cutter so that it has the proper length to extend over the 6 dental elements. Once the correct length has been defined, it is then held in place on the lingual surface of the teeth by the use of 2 interdental wires passing doubly through the interdental area (between the lateral incisor and canine on one side and the other). This allows the device to be bonded using composite resin after etching the lingual surfaces of the lower anterior teeth.