Orthodontic Retention—Protocols and Materials—A Questionnaire Pilot Study among Polish Practitioners

The aim of the study was to analyze retention protocols and materials for fixed retainers used by clinicians providing orthodontic treatment in Poland. The survey was carried out from February to April 2021. The questionnaire was designed using the Google Forms tool. After validation, the questionnaire was delivered to verified active orthodontists gathered in a closed social media group of 615 members. Finally, 104 answers were received. Answers to individual questions were provided in percentages and tabularized. A chi-squared test of proportion was used to compare: the proportion of clinicians using retainers of different characteristics and the proportions of clinicians indicating the superiority of a given clinical solution. Rectangular steel braided wire was rated as most reliable. However, doctors who declared to use gold chain were mostly solely using this type of wire. Multistranded round wire was rated the worst. Fiber-reinforced composite was mainly used in periodontal patients. The protocols used by Polish orthodontic practitioners relied on double long-term retention with regular follow-up. The most popular material was stainless steel braided rectangular wire bonded with a flowable composite. Most clinicians believed they could maintain the treatment results, but they declared that patients’ cooperation was a challenge.

Retrospective Study Regarding Orthodontic Retention Complications in Clinical Practice

At the end of any orthodontic treatment, retention is a necessary phase. Unfortunately, the current retention devices and the lack of proper oral hygiene on the part of patients lead to the accumulation of dental plaque, periodontal inflammation, and gingival retraction. Our retrospective study included 116 adult patients wearing various types of orthodontic retainers. To quantitatively determine the accumulation of dental plaque, we used the Quigley–Hein plaque index modified by Turesky and the Navy plaque index modified by Rustogi. Another studied parameter was related to the gingival recession associated with retention devices. We had investigated the correctness of patients’ dental hygiene, their preferences for auxiliary means of oral hygiene, the consistency with which they wear the mobile retainers, and respect the orthodontist’s instructions; we also investigated the inconveniences and the accidents that may occur during the retention period. Statistical analysis showed that plaque accumulation is significantly lower in the case of mobile retainer than fixed retainer wearers; the exception was the Hawley plate, where the interdental plaque was more than in all the other studied retainers. Periodontal recessions were more frequent in the case of fixed retainer wearing. Flossing was the most commonly used auxiliary mean for oral hygiene. The compliance of women in wearing vacuum-formed retainers was better than that of men. Patients with a class III history had more plaque accumulation, and class II/1 had the most problems related to detachment/damage of fixed retainers. Mobile retainers proved better results for oral hygiene, but fixed retainers cannot be waved.

Comparative assessment of relapse and failure between CAD/CAM stainless steel and standard stainless steel fixed retainers in orthodontic retention patients:

ABSTRACT Objectives To compare relapse and failure rates of computer-aided design/computer-aided manufacturing (CAD/CAM) and standard fixed retainers. Materials and Methods This single-center, single-blinded, prospective randomized clinical trial included 46 patients who completed active orthodontic treatment and complied with retention visits. The patients were randomly assigned to three groups: CAD/CAM group with multistranded stainless steel wires (CAD/CAM, n = 16), Lab group with the same multistranded wires (lab, n = 16), and control group with stainless steel Ortho-FlexTech wires (traditional, n = 14). Intraoral scans were obtained at placement of fixed retainers (T1), 3-month visit (T2), and 6-month visit (T3) and measured for intercanine width and Little's Irregularity Index. Failures were recorded. Results The CAD/CAM group experienced less intercanine width decrease than the traditional group at 3 months (mean difference, 0.83 ± 0.16 mm; 95% confidence interval [CI], 0.44–1.22; P < .001) and 6 months (mean difference, 1.23 ± 0.40 mm; 95% CI, 0.19–2.27; P < .05). The CAD/CAM group experienced less increase in Little's Irregularity Index compared with the lab group within 3 months (mean difference, 0.81 ± 0.27 mm; 95% CI, 0.12–1.49; P < .05). Failures from greatest to least were experienced by the lab group (43.8%), the CAD/CAM group (25%), and the traditional group (14.3%). Conclusions Within 6 months of bonding fixed retainers, CAD/CAM fixed retainers showed less relapse than lab-based and traditional chairside retainers and less failures than lab-based retainers.

Accuracy of Artificial Intelligence-Assisted Landmark Identification in Serial Lateral Cephalograms of Class III Patients Who Underwent Two-Jaw Orthognathic Surgery

To compare the accuracy of artificial intelligence-assisted landmark identification in serial lateral cephalograms of Class III patients who underwent two-jaw orthognathic surgery using a convolutional neural network (CNN) algorithm. 3,188 lateral cephalograms of Class III patients were allocated into the training and validation sets (3,004 cephalograms of 751 patients) and test set (184 cephalograms of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n=23 per group)]. Each patient in the test set had four cephalograms: initial (T0), pre-surgery [T1, presence of orthodontic brackets (OBs)], post-surgery [T2, presence of OBs and surgical plates and screws (S-PS)], and debonding [T3, presence of S-PS and fixed retainers (FR)]. Statistical analysis was performed using mean errors of 20 landmarks between human gold standard and the CNN model. The total mean error was 1.17 mm without significant difference among four time-points. Before and after surgery, ANS, A point, and B point showed an increased error, while Mx6D and Md6D showed a decreased error. No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. The CNN model can be used for landmark identification in serial cephalograms despite presence of OB, S-PS, FR, genioplasty, and bone remodeling.

Universal Adhesive for Fixed Retainer Bonding: In Vitro Evaluation and Randomized Clinical Trial

This study aims to assess the efficacy of a universal adhesive (Scotchbond Universal, 3M ESPE) (SB) in total-etch mode, compared to a traditional orthodontic primer (Transbond XT Primer, 3M ESPE) (XT Primer), to perform bonding of orthodontic fixed retainers along with the Transbond XT Light Cure Adhesive Paste (3M ESPE). For the in vitro study, a round section wire (Ortosmail Krugg) was bonded using XT Primer for 20 bovine incisors (Group 1) and SB for other 20 (Group 2). Samples were debonded in a universal testing machine applying a tangential force to specimens (crosshead speed of 1 millimeter per minute). Shear bond strength (SBS) and adhesive remnant index (ARI) scores were calculated. For the in vivo study, 100 patients needing upper and lower canine-to-canine fixed retainers after orthodontic treatment were randomly assigned to two groups of 50 participants each, i.e., group 1 (retainer bonding with XT Primer) and group 2 (retainer bonding with SB). Over two years, examinations were carried out monthly, and detachments were registered by considering the teeth and arches affected. In vitro, no statistically significant differences in SBS and ARI scores were demonstrated between the two groups, both showing a mean bond strength of about 12 MPa and major frequency of ARI “2” (>50% remnant adhesive on the enamel). Conversely, a significantly lower failure rate over 2 years was assessed clinically for group 2 in both arches. Independently of the adhesive and arch, incisors reported a significantly higher failure rate than canines. Scotchbond Universal used in total-etch mode could be a valid alternative to the traditional orthodontic Transbond XT Primer.

In vitro comparison of the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers in orthodontics

Objective: To assess the torsional load transfer of various commercially available stainless-steel wires used for fixed retainers. Design: An in vitro study using a robotic device. Setting: Department of Pediatric Oral Health and Orthodontics, University of Basel. Methods: A 10° proclination of a maxillary lateral incisor of a 2-2 retainer was simulated with a robotic device. Eight stainless-steel wires with different shapes (round or rectangular), types (plain, braided, coaxial or chain) and dimensions were selected to measure the torsional load transfer at the adjacent central incisor. The influence of annealing was also tested. Results: The 0.016 × 0.016 and Bond-A-Braid™ wires (0.02645 × 0.01055-inch, 8-stranded, braided) showed the largest relative torsional load transfer (3.7% and 3.3%, respectively). The two multistranded wires - Triple Flex™ and Respond® - showed the smallest values of 1.0% and 0.7%, respectively. The spiral direction of these two multistranded wires affected the load transfer, the twisting showing larger torsional load transfer than the untwisting one. Conclusion: The effective torsional load transfer depends on the dimension, shape and type of a wire. Plain and braided retainers were more predictable in torsional load transfer than multistranded retainers, which may have stored more energy in the area between the composite bonding sites. This may explain the unexpected complications reported in multistranded retainers.

Evaluation of the Biomechanical Properties of Austenitic Stainless Steel Fixed Retainers

The insertion of the fixed retention is an important stage of the orthodontic treatment after fixed appliances. The fixed retainers used in orthodontic treatments must be passive towards teeth, without developing any stress. This characteristic is challenging to achieve due to the mechanical properties (bending properties, stiffness) of the materials the retainers are manufactured from. Residual stress might be generated because of their flexibility and because the chemical composition of the stainless steel wires.This study aims to determine the mechanical properties of different austenitic stainlees steel wires used in retention. Also, we have compared the mechanical properties of wires with different sizes, as well as wires with the same size, new and intra-orally used. The results confirm that the mechanical parameters of the two types of wires used in fixed retention (3 braided round wires and 6 braided Flat wires) present statistically insignificant differences. The study also reflects that the mechanical properties of the intra-orally used wires showed decreased values of the parameters.