Short term comparison of effects on gingival tissues and success rate of fixed retainer wires prepared with conventional and CAD-CAM technique

Yasemin Kartal, Short term comparison of effects on gingival tissues and success rate of fixed retainer wires prepared with conventional and CAD-CAM technique, Baskent University, Health Sciences Institute, Orthodontics Doctorate Programme, Doctorate Thesis, 2018 The aim of this study was to evaluate short-term success rates and impacts on gingival tissues of the retainer bent in a 0.0215 inch five-stranded stainless steel tread, which is the most widely used with the newly introduced rectangular nickel-titanium fixed retainers of 0.014 × 0.014 inches in thickness, prepared with the CAD-CAM technique. The study included 52 patients who underwent orthodontic treatment in the Baskent University Department of Orthodontics and planned to undergo consolidation therapy with fixed retainers on 6 permanent teeth (right and left canines and incisors) for retention in the mandibulary arch. Patients were divided in 2 groups. 0.014 × 0.014 inch nickel-titanium CAD-CAM prepared Memotain (CA-DIGITAL, Mettmann, Germany) retainer wires were applied directly to the lingual surface of lower front teeth in 26 individuals included in group 1. 0.0215 inch five-stranded stainless steel (GC Orthodontics America Inc, Alsip, USA) retainer wires were directly applied to the lingual surface 6 anterior teeth in 26 individuals included in group 2 . All of the retiners in group 2 were prepared by the same person. Patients were recalled for control sessions in 1st 3rd and 6th months following bonding of the retainers. Failure rates of retainers (tooth movement, breakage, splitting) and periodontal measurements were noted during control sessions. For periodontal evaluation pocket depth, gingival index, plaque index, gingival enlargement/ recession, and bleeding on probing were measured. In the present study the over-all success rate for all fixed retainers was 75%, success rate for memotain was 76.9% and success rate for the 0.0215-inch multistrand retainer was 73.1% at the end of 6 months. No statistical difference were observed between the groups for success rate in any control sessions. Failure type was 100% debonding between enamel and adhesive. Debonding of the retainers were mostly observed in incisor teeth, and canines were least affected. No significant difference was found between the gingival parameters for the two types of retainers at week 1, month 1, month 3 and month 6 of the study. In the first 6 months, the fixed retainers have not had negative effects on the periodontal health of the patients. Key words: Fixed retainer, periodontal index, CAD/CAM, Memotain, Retention