The Efficacy of Retention Appliances after Fixed Orthodontic Treatment: A Systematic Review and Meta-Analysis

A Novel 3-Dimensional Printed Nanoceramic Hybrid Resin Fixed Lingual Retainer: Characterization and Mechanical Tests

Introduction: An innovative retention protocol was developed to create a new 3D-printed fixed retainer employing SprintRay OnX nanoceramic hybrid resin. The feasibility and usability of the retainer were subsequently evaluated. Methods: Identification and characterization of SprintRay OnX was done using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray (SEM-EDX), field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), and flexural strength. Load-deflection and pull-out tests were conducted on the 3D-printed straight wires, with three distinct cross-sectional geometries: round (1 mm), oval (1 mm × 1.5 mm) and semielliptical (1 mm × 1.5 mm). Twisted G&H and coaxial Respond stainless steel multistrand retainers were used for comparison. In the load-deflection test, a three-point bending test (3PBT) was employed. For the pull-out test, the retainer wire was inserted into the composite, which was placed in a centrally located hole of an acrylic block; the retainer wire was subjected to a tensile force along its long axis. Results: Characteristic bands close to those of PMMA were observed in the FTIR spectra. SEM-EDX and XRD revealed a crystalline material with homogeneously distributed Yb element signals (19.4%). On FE-SEM micrographs, small clumps were displayed on smooth surfaces. The flexural strength and the flexural modulus were, respectively, 142.48 MPa and 7.842 GPa. All groups of 3D-printed wires exhibited significantly higher load-deflection levels than the multistrand wires (MSWs). Concerning pull-out forces, they fell in between twisted G&H (96 N) and coaxial Respond (48.09 N) retainer wires. The 3D-printed wires fractured cohesively without detachment from the adhesive, suggesting that the chemical bond was adequate for satisfactory wire integration, yet the wire's strength was compromised. Concerning the cross-sectional geometry, the load-deflection and the pull-out forces of 3D-printed oval and semielliptical wires were significantly higher than that of 3D-printed round wires, which was attributed to the larger cross-sections of the wires. Conclusion: Oval and semielliptical 3D-printed wires offered favorable features as lingual retainers.

Keeping the teeth in line: Exploring the necessity of bonded retainers in orthodontics: A narrative review

In most recent studies, long-term retention after orthodontic treatment has been hypothesized that may be necessary to maintain the stability of the dentition and avoid post-treatment changes. The bonded fixed retainer is characterized by its clinical effectiveness, patient acceptance, and lack of patient complaints as compared with a removable retainer. An electronic database (such as PubMed, PubMed Central, Web of Science, Science Direct, Cochrane Library, Scopus, and ResearchGate) has been collected using specific keywords. Of the 152 articles, only randomized clinical trials that investigated different types of fixed retainers or compared fixed with removable retainers were illustrated in tables and included in this review. The present review has gone some way towards enhancing our understanding of the bonded fixed retainer, types, material, bonding methods, and how to improve its the success rate, besides the importance of new technology in fixed orthodontic retention.

Preclinical in vitro study of streptococcus mutans accumulation in three fixed retainer designs: Microbiological assay

The use of fixed retainers in the lower arch is frequent; however, its presence increases the accumulation of biofilm and dental calculus. The objective of this research was to evaluate, in vitro, the accumulation of Streptococcus mutans (S. mutans) in 3 designs of fixed retainers. Nine models were reproduced in heat-cured acrylic resin and divided into groups: straight retainer (SR), retainer with vertical strap (RVS), retainer with horizontal strap (RHS). The accumulation of S. mutans was assessed using the MTT assay (3-4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetrazolium bromide) and then measured using an automated reader. The RHS group showed less biofilm accumulation compared to the other groups (p<0.05). The distance between the tooth surface and the retainer showed a strong negative correlation with biofilm accumulation (rs=-0.79, p=0.00037). The RHS showed significantly less accumulation of S. mutans due to the distance between the retainer and the tooth surface. This research provides relevant data for a future randomized clinical trial.

Oral Health and Related Factors Associated with General Health and Quality of Life

Oral well-being is an integral part of individual general health. The mouth and teeth are, in fact, part of our body, increasingly characterizing personal identity. Oral diseases are a public health problem that has a growing prevalence. Oral pathologies can occur in childhood, and as they have a chronic and progressive course, if not properly treated, they can affect the relational, psychological, and social skills of an individual. The population most affected are those with a low socio-economic level, so much so that the presence of diseases of the oral cavity is considered a marker of social disadvantage. In this regard, much effort is needed from scientists, and their applied sciences, in order to give the knowledge required for public health personal to take note of the seriousness of the situation and to start changing the way we deal with the problem.

A Full Diagnostic Process for the Orthodontic Treatment Strategy: A Documented Case Report

The need for extractions in orthodontic treatment has always been a controversial topic. However, to date there is not a specific clinical guideline that can help the clinicians deciding to plan an extractive or a non-extractive orthodontic treatment. In this respect, clinicians must deal with patients’ occlusal, functional, periodontal and aesthetics characteristics before planning an orthodontic treatment including extraction. Considering the absence of specific guidelines, the choice to extract teeth or not is complicated, particularly in borderline cases. In this case report, we present a borderline case of a patient with the skeletal Class III pattern and significant crowding in both arches that could be treated with or without extraction, illustrating the diagnostic and decision-making processes that were conducted for the orthodontic treatment strategy.