Comparative in vitro analysis of the sliding resistance of a modern 3D-printed polymer bracket in combination with different archwire types

Abstract

Objectives To analyse the sliding resistance of a modern 3D-printed polymer bracket combined with different archwire types and to compare the results with conventionally used polymeric, ceramic and metal brackets. It was of further interest which bracket-archwire combination could be best qualified for clinical use. Materials and methods The sliding behaviour was tested using an orthodontic measurement and simulation system (OMSS) for the use of two bracket types of the polymer, ceramic and metal group in combination with a 0.016 inch × 0.022 inch and 0.017 inch × 0.025 inch archwire of nickel-titanium (NiTi), titanium-molybdenum alloy (TMA) and stainless steel. Six bracket types were combined with six different archwire types and compared to each other. Results The sliding resistance showed significant differences between various the bracket-archwire complexes. The combination of 3D-printed polymer brackets with both steel archwire cross-sections showed the least values of sliding resistance (average 23–29%), while the combination of ceramic brackets with TMA archwires presented the highest (average 47%). Conclusions The present study could show that modern 3D-printed bracket materials can have similar or even better mechanical properties than conventional ones regarding sliding resistance. Although the combination of bracket and archwire material is decisive for low sliding resistance values, the selection of the bracket material seems to have a greater influence than the selection of the archwire material or its cross section. Clinical relevance It might be possible in future to combine aesthetic and biomechanical requirements for aesthetic brackets by using 3D-printing technology.

Clinically Relevant Properties of 3D Printable Materials for Intraoral Use in Orthodontics: A Critical Review of the Literature

“…After being subjected to instrumented indentation testing, both materials showed comparable Martens hardness, indentation modulus, and elastic index, and their mechanical characteristics were considered superior to those of commercially available plastic brackets [ 45 ]. The sliding resistance of a 3D-printed Self-ligating Shark SL bracket (Dentalline GmbH & Co. KG, Birkenfelt, Germany) was assessed in comparison to two ceramic, two metal, and one plastic commercially available bracket types, and in combination with archwires of different alloys (nickel–titanium, titanium–molibdenum, stainless steel) and cross-sections [ 46 ]. For all bracket-archwire combinations, 3D-printed polymer brackets showed a sliding resistance similar to that of commercially available polymer brackets and lower than that of ceramic and metal brackets [ 46 ].…”

Precision of slot widths and torque transmission of in-office 3D printed brackets

“…The possibilities of 3D printing are continuously expanding. It is not surprising that initial trials with in-office printed brackets have already taken place [22][23][24]26]. To establish its clinical use, further studies must determine whether the used PCR material really meets the requirements for a bracket material.…”

“…The material-specific shortcomings of both ceramic and current polymeric brackets have led to efforts in developing a more suitable material for tooth-colored brackets. With 3D printing being on the rise in dentistry, the first steps to produce in-office printed brackets have already been pub-lished [23][24][25][26]. A novel high-performance resin, Permanent Crown Resin ([PCR], Formlabs Inc., Somerville, MA, USA), approved for the fabrication of permanent dental crowns has recently become available for 3D stereolithographic printing (SLA).…”

Development and Evaluation of a New Orthodontic Ligature: Frictional Force Analysis

“…The main factors that influence the force released to the teeth by the bracket/wire complex are wire thickness, wire deflection, ligation method, and frictional forces. 10,20,21,27 The frictional force in orthodontics is influenced by factors such as the material used, the size of the arch, and the ligature methods. 3,7,21,28 The present study evaluated the frictional force of a ligature designed by the authors (H ligature), with two different materials, in comparison to different available ligature modes.…”

“…The tests were performed using rectangular 0.019 inch  0.025 inch stainless steel rod wires (Dental Morelli), [14][15][16][17]20,21 and conventional metallic brackets of the central incisor tooth, upper left, slot 0.022 inch  0.028 inch, and Roth prescription (5-degree angle and 12-degree torque) in all groups, in the "Light model" for the conventional ones and in the SLP (self-ligating Roth) model for the self-ligating passive, both from the Dental Morelli company.…”