Multiforce orthodontic archwires are thermodynamic wires made of nickel-titanium alloy (Ni-Ti). They release biologically tolerable forces along their length, progressively increasing from front to back. The frontal archwires’ segments distribute the weakest force: the premolar, the greater, and the molar, the greatest. The aim of the present study was to determine the influence of clinical use on the mechanical properties of two types of multi-force orthodontic archwires (TriTanium^®, American orthodontics; Bio-Active^®, GC) with dimensions of 0.016 × 0.022 inches for periods of up to 8 weeks and over 8 weeks of in-vivo use. A three-point bending test was used, and the data gained is statistically analyzed through a multi-variance comparison Mann-Whitney test. We found that after uses of up to 8 weeks and over 8 weeks, the shape memory effect and superelasticity are preserved, as well as the tendency for differential force release along the length of the archwires is kept.

Rationale: Orthodontic archwires undergo chemical and structural changes in the complex intraoral environment. The present work aims to investigate the safe duration for intraoral use (related to the nickel release hypothesis) of different types of nickel-containing wires. By analyzing how the nickel content (NC) varies over time, we aim to provide practical recommendations for the optimal use of said archwires. Materials and Methods: Our analysis focuses on the following nickel-containing archwires: stainless steel, Ni-Ti superelastic, heat-activated NiTi and CuNiTi, and multi-force archwires. The studied archwires of each type were divided into three groups: group 1, as received; group 2, retrieved after intraoral exposure for less than 6 weeks; group 3, used for more than 8 weeks. To assess NC, measurements using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and laser-induced breakdown spectroscopy (LIBS) were performed in multiple regions of each wire. Statistical analysis of the measured values using one-way ANOVA and multiple group comparisons showed significant differences in nickel content between groups. The dynamic behavior of the statistical results for NC was then modeled using logistic regression and fitted with cubic splines. Conclusions: The proposed behavior model, with further refinement, could enable orthodontists to make informed, patient-specific decisions regarding the safe and effective use of orthodontic floss. The overall conclusion of the study is that due to stability, SS-CrNi, HA-Ni-Ti with Cu, and TriTanium^TM are suitable for long-term use, and due to higher nickel release, Ni-Ti-Superelastic, HA-Ni-Ti without Cu, and Bio-Active^TM are better for short- to medium-term use.

Multiforce nickel–titanium (NiTi) orthodontic archwires release progressively increasing forces in a front-to-back direction along their length. The properties of NiTi orthodontic archwires depend on the correlation and characteristics of their microstructural phases (austenite, martensite and the intermediate R-phase). From a clinical and manufacturing point of view, the determination of the austenite finish (Af) temperature is of the greatest importance, as in the austenitic phase, the alloy is most stable and exhibits the final workable form. The main purpose of using multiforce orthodontic archwires is to decrease the intensity of the applied forces to the teeth with a small root surface area, such as the lower central incisors, and also provide forces high enough to move the molars. With the optimally dosed forces of multiforce orthodontic archwires in the frontal, premolar and molar segments, the feeling of pain can be reduced. This will contribute to the greater cooperation of the patient, which is of utmost importance to achieve optimal results. The aim of this research was to determine the Af temperature at each segment of as-received and retrieved Bio-Active^® and TriTanium^® archwires with dimensions of 0.016 × 0.022 inches, investigated by the differential scanning calorimetry (DSC) method. A classical Kruskal–Wallis one-way ANOVA test and multi-variance comparison based on the ANOVA test statistic using the Bonferroni corrected Mann–Whitney test for multiple comparisons were used. The incisor, premolar and molar segments have different Af temperatures, and they decrease from the anterior to posterior so that the posterior segment has the lowest Af. Bio-Active^® and TriTanium^® with dimensions of 0.016 × 0.022 inches can be used as first leveling archwires by additional cooling and are not recommended for use on patients with mouth breathing.

In interceptive treatments in which impacted teeth (incisor or first permanent molar) should be included into the dental arch, the main clinical problem is the provision of an anchorage area and a suitable appliance. The use of a laser-sintered metal orthodontic printed dento-alveolar anchorage (PDaA), designed and printed digitally, has expanded the boundaries of orthodontic treatment, especially in its interceptive phase. Our aim is to describe a laser-sintered metal appliance to provide anchorage during orthodontic surgical traction of impacted teeth in the mixed dentition period. The presented clinical cases were treated with digitally projected and printed metal PDaA. In the described clinical cases, individually designed anchorage systems were used. They were created through design software and, after that, the metal appliances were printed. The devices were placed in the oral area and did not disturb the aesthetics of the patient. The advantages of individual designed metal PDaA allow the accommodation of the morphology of the hard palate and alveolar bone. This makes the PDaA comfortable for the patient and rigid enough to perform orthodontic traction at the same time. The PDaA is applicable in mixed dentition and, in complicated clinical cases, in permanent dentition. Their individuality allows for segmental treatments or treatments in cases requiring additional anchorage further away from the active force.

Background/Objectives: The nasomaxillary complex is a compound anatomical structure in which the correlation between changes in palatal width and height has been poorly investigated. Methods: A three-year prospective study with 28 patients treated with printed expanders was conducted. Measurements on CBCT images were performed before and after treatment; the width and height parameters were measured on a coronal slice of a CBCT image at the level of the first molars and upper first molar inclination relative to the palatal plane. Results: A significant difference was found between the values measured before and after treatment, including an increase in the measured width parameters and a statistically significant decrease in palatal height (0.75 ± 0.97). The mean change in the upper molar inclination was not significant (tooth 16: 0.60 ± 6.42; tooth 26: 2.19 ± 4.51). The regression analysis did not establish a significant correlation between the expansion of the maxillary occlusal width and palatal height change or a significant correlation between the increase in the upper molar inclination and palatal height change. Conclusions: The use of a printed tooth-borne expander causes predictable and reproducible skeletal changes. It is a feasible treatment option, allowing for precise screw positioning to achieve bodily movement of the teeth and decrease the change in molar inclination.