Vacuum-formed Retainer Versus Bonded Retainer to Prevent Relapse After Orthodontic Treatment

Vacuum-formed Retainer Versus Bonded Retainer to Prevent Relapse After Orthodontic Treatment - A Randomized Controlled Trial About Stability and Patients' Perceptions

The purpose of this trial is to evaluate and compare stability after orthodontic treatment with an Essix retainer and a bonded cuspid-to-cuspid retainer (CTC), respectively in the mandibular arch and longitudinally follow these patients over time up to 5 years. The patients' perceptions of the two methods are also evaluated with questionnaires during the follow-up period. A further aim of this study is to analyze the relationship between diagnosis, treatment outcome, treatment time, age at start of treatment and stability with an Essix retainer in the maxilla. The null hypotheses are: that there is no difference in retention capacity between Essix retainer and cuspid-to-cuspid retainer that there is no difference in patients' perception between Essix retainer and cuspid-to-cuspid retainer that there is no difference in retention capacity for Essix retainer in the maxilla concerning diagnosis before treatment, treatment outcomes, treatment time and age at start of treatment

The study is conducted at the Orthodontic Clinic, Gävle, Sweden and consists of 104 patients. All patients are treated with fixed appliances in the upper and lower jaw (standard .022 straight wire), both with and without extractions. The patients are randomized into two groups with 52 patients in each group (Group A: cuspid-to-cuspid retainer, Group B: Essix retainer). Dental cast are obtained at the debond appointment (T1) and at the follow-up controls after six months (T2), 18 months (T3) and 60 months (T4) for both groups. At the visit two weeks in retention and at the follow-up visits after 6, 18 and 60 months the patients assess questionnaires in order to evaluate their experience of retention with the retention device.

The CTC is bonded directly after debonding. The Essix retainer maxilla is handed out to the patient the same day after removal of fixed appliances. Alginate impressions are taken at the follow-up visits. Questionnaires are completed at the follow-up visits.

The Essix retainer maxilla and Essix retainer mandible are handed out to the patient the same day after removal of fixed appliances. Alginate impressions are taken at the follow-up visits. Questionnaires are completed at the follow-up visits.

The CTC retainer consists of 0.8 hard Remanium® wire (Dentaurum, Germany) and is bonded with Tetric Flow (Ivoclar Vivadent, Liechtenstein) to the lower canines directly after debonding.

The Essix retainer is made of 1 mm Essix C+® Plastic (Dentsply, USA) and is handed out to the patient the same day after removal of fixed appliances.

The Essix retainer is made of 1 mm Essix C+® Plastic (Dentsply, USA) and is handed out to the patient the same day after removal of fixed appliances.

Alginate impressions are taken to made the cuspid-to-cuspid and Essix retainers, respectively. Dental casts are obtained at the debond appointment and at the follow-up visits after 6, 18 and 60 months.

Analyses of changes in tooth position on dental casts Little's Irregularity Index (in mm) 0=no crowding/irregularity, higher scores= more crowding/irregularity (worse outcome)

Changes in tooth position (Little's Irregularity Index) were analysed 5 years (T4) after debonding (T1)

Analyses of patients' perception by validated self-report questionnaires to evaluate experiences of the retention techniques VAS (visual analog scale, 0-100) 0= low satisfaction 100= high satisfaction

Inclusion Criteria: Patients treated with fixed appliances in both the maxilla and the mandible Exclusion Criteria: Rapid Maxillary Expansion (RME) for patients with severe transversal malocclusion Treatment with segmented appliances Patients with craniofacial anomalies and patients requiring orthognatic surgery Patients with missing mandibular incisor

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