In vivo comparison of gingival tissue effects and success rates of fixed Lingual retainers of different thicknesses applied with direct and indirect adhesive techniques

The aim of this study is to compare the gingival effects and success rates of fixed lingual retainers of different thicknesses applied with indirect and direct technique. 100 patients, who received orthodontic treatment in Baskent University Faculty of Dentistry, and started retantion treatment were included in the study. Patients were randomly divided into 5 groups. 0,0215 inch multistranded retainer was applied with direct technique in the first group, 0,0215 inch multistranded retainer was applied with indirect technique in the second group, 0,0175 inch multistranded retainer was applied with direct technique in the third group, 0,0175 inch multistranded retainer was applied with indirect technique in the fourth group. In the fifth group, retention was achieved with essix apliances without fixed retainer wires. Following bending of the retainer wires the hard plaster models were isolated with a lacquer in the indirect adhesive groups. After being positioned in correct place the retainer wires were bonded with light-cured Transbond LR (3M) resin on models. Transfer trays were prepared with transparent silicone measuring material. 37% orthophosphoric acid was applied for 30 seconds, washed and then the bond was applied. Transbond Supreme LV adhesive was applied on the bases of the composite pads in the transfer trays. In the direct adhesive groups, the retainer wires are bent on the hard plaster models. 37% orthophosphoric acid was applied for 30 seconds, washed and then the bond was applied. The retainers were positioned in correct place by using ligature wires placed between lateral and canine teeth and then bonded with Transbond LR (3M). Plaque index, gingival index, sulcus depth, bleeding in gingival sulcus while probing, amount of gingival retraction- growth, and failure rates of retainers were evaluated with comprehensive, inspections just before beginning the procedures and in 1 week, 1 month,3 months, 6 months follow up appointments. The obtained data was analysed by Shapiro Wilk, Mann Whitney U, Kruskal Wallis-H Tests, Post-Hoc Multiple Comparison Test, Chi-Square Analysis, Fisher's Exact Test and Pearson Chi-Square Analysis. Conclusion: There was no statistically significant difference between the bonding techniques and retainer thicknesses in gingival depth, gingival index, plaque index, gingival recession-growth and bleeding values. Better results were obtained in gingival index and bleeding evaluations in the control group with essix appliances than in the retainer groups. It is observed that use of retainer wires for retantion does not have a negative effect on peridontal health. A total of 10 breakage were seen in 80 patient who had fixed retainer. 5 of these were in direct bonding groups and 5 were in indirect bonding groups. Less breakage rate was observed in canines compared to incisor teeth.