The devices compared in this study are 'retainers', i.e. fixed orthodontic retainers applied to the lingual surface of the central and lateral incisors and lower canines bilaterally. Their function is to maintain dental alignment once fixed orthodontic therapy has ended. In particular, the CAD/CAM device Keeppy patented by the company Leone SpA (Via Ponte a Quaracchi 50, Sesto Fiorentino, Florence) will be compared with the standard retainer made from a steel braided wire (Ortho FlexTech, Reliance Orthodontic Products Inc., 1540 West Thorndale Ave, Itasca, Illinois, USA).
This is a single-center, national, controlled, superiority, randomized, crossover, open-label study.
The aim of this study is to evaluate whether the CAD/CAM retainer results in fewer failures (fractures or detachments) over a period of 6 months and 2 years compared to the standard retainer. In addition, the aim of the study is to evaluate whether the Keeppy device results in the maintenance of better periodontal health as judged by the use of plaque and bleeding indices on the surfaces of the lower six anterior teeth compared to the standard retainer. Other objectives consist of the patient's assessment of pain, difficulty in speaking and esthetic satisfaction and the stability of the lower anterior tooth sector.
Patients who have completed fixed orthodontic therapy between the ages of 13 and 20 years;
Patients whose parents will sign the informed consent
Presence of dental anomalies in number (excess or deficiency) in the lower anterior teeth
Patients with metal allergies.
Parallel
CAD/CAM mandibular fixed retainer
DeviceKeeppy 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).
Conventional mandibular fixed retainer
DeviceThe 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.
Retainer failure at 6-month and 2-year follow-ups
The primary endpoint is retainer failures at 6-month and 2-year follow-ups. Failure is defined as any complication requiring a retainer repair, in particular total or partial detachment and total or partial fracture.
Assessment of the plaque and gingival bleeding index at the central and lateral incisors and lower canines.
Assessment of the plaque and gingival bleeding index at the central and lateral incisors and lower canines.
Pain reported by patients
Pain measured through Visual Analogue Scale (VAS) with minimum value of 0 and maximum value of 10. Higher scores mean worse pain.
Difficulty in speaking reported by patients
Difficulty in speaking measured through Visual Analogue Scale (VAS) with minimum value of 0 and maximum value of 10. Higher scores mean worse difficulty in speaking.
Aesthetic satisfaction reported by patients
Aesthetic satisfaction measured through Visual Analogue Scale (VAS) with minimum value of 0 and maximum value of 10. Higher scores mean higher aesthetic satisfaction.
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