Title Wire and Bracket Combination Can Influence the Efficiency and Consistency of Orthodontic Therapy While Minimizing Pain
Clinical Question In patients undergoing orthodontic treatment, can the combination of wire and bracket influence the efficiency of forces in order to optimize treatment and reduce pain?
Clinical Bottom Line The combination of a Copper/Nickel/Titanium (CuNiTi) wire and self-ligating brackets may provide more consistent and even orthodontic forces leading to more predictable, efficient treatment. Studies have indicated that orthodontic forces that are of reduced magnitude, yet continuous, may in fact be more efficient in manipulating tooth movement when compared to inconsistent forces of higher intensity.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
28125144Higa/201610 samples in each experimental groupLaboratory study
Key resultsIn this study, three different types of wires were used in combination with three different bracket types in order to examine the forces exerted after wire deflection. Stainless steel, Nickel/Titanium (NiTi), and Copper/Nickel/Titanium (CuNiTi) wires were all deflected to 0.5 mm, 0.8 mm, and 1.0 mm. Each wire type was combined with conventional and self-ligating brackets (active and passive). Stainless steel wires in combination with self-ligating brackets exerted the largest forces; however, these may be so large that necrosis and hyalinization of surrounding tissues may occur, leading to the risk of more intense pain and possible root resorption during treatment. The NiTi wires showed the most inconsistent forces upon deflection of the three types. The variance depended on brand manufacturer. Within the NiTi group, the conventional brackets produced the weakest forces, while the self-ligating brackets displayed higher forces, with passive being the highest. The CuNiTi wire released the least amount of force upon deflection due to its elasticity; however, the forces were released continuously and evenly. The combination of conventional brackets with CuNiTi wires may release suboptimal treatment forces due to the ligature placing friction on the wire itself. Greater freedom of the wire within the bracket slot seemed to reduce friction and allow for the greater exertion of forces from the combination of wire and bracket. The conventional brackets demonstrated the least amount of deflection forces, followed by active self ligating brackets and passive self ligating brackets, which demonstrated the highest amount of deflection force. The low friction application contributed to the ability of the passive self-ligating bracket to produce efficacious, continuous force when combined with the CuNiTi wire.
27812620Francisconi/2016400 round-section Nitinol wires and 5 different bracket typesLaboratory study
Key resultsThere is ongoing debate as to which orthodontic bracket type is the most efficient in orthodontic treatment. This study demonstrates that self-ligating brackets are more consistent in torque delivery across a variety of wire deflection distances compared conventional brackets and esthetic brackets. Conventional and esthetic brackets showed more inconsistent torque forces across varying wire deflection measurements, thereby ultimately delivering less consistent forces during orthodontic therapy. A clinical simulation model was used to evaluate performance via a universal testing machine. Stainless steel wires of 0.014”, 0.016”, 0.018”, and 0.020” diameters were all set to deflections of 0.5 mm, 1.0 mm, 2.0 mm, and 3.0 mm in a clinical simulation device that represented the 10 teeth of the maxillary arch. A structure representing the right maxillary central incisor was tested for the levels of torque exhibited by the different bracket types (conventional, esthetic, and self-ligating) and different deflection measurements. One-way ANOVA and Tukey tests were used for statistical analysis. Friction of the wire moving through the bracket seemed to play a large part in determining the deflection forces of the wire being transmitted to the tooth.
20534713Luppanapornlarp/201016 subjects (2 males and 14 females), aged 18–24 years, diagnosed with Class I bimaxillary protrusion and treated with first premolar extractionsClinical Trial
Key resultsThis study analyzed the efficiency of orthodontic forces in moving maxillary canines into the desired position. The patients in this study received randomized retraction treatment on the maxillary canines; the left or right received 150 grams of force while the other received 50 grams of force. An orthodontic force gauge was used to measure the accuracy of the force delivered. One of the patient’s mandibular canines was used as a control. Outcomes evaluated were IL-1beta concentrations in the gingival crevicular fluid around the manipulated canines, perceived pain, and the amount of tooth movement. The gingival crevicular fluid was retrieved from the distal sites of both the tooth being moved and the control tooth. This was done before retraction as a baseline, and after retraction at multiple time increments of 1 hour, 24 hours, 1 week, 1 month, and 2 months. The concentrations of IL-1beta from each sample were then analyzed. Patients were asked to identify their intensity of pain for the two maxillary canines separately. They were also asked to rank the pain from the control mandibular canine separately. Patients ranked the intensity of their pain by placing a mark on a 100-mm visual analog scale. Tooth movement was measured by evaluating dental models made before treatment and at 2 months of treatment. At the end of the 2-month study period the 150-g group showed elevated levels of IL-beta at two times the amount at 24 hours and 2 months when compared to the 50-g group. The 50-g group showed less pain than the 150-g group throughout the study. Surprisingly at the end of treatment there was no significant difference in canine retraction between either of the groups. This demonstrates that orthodontic forces of lesser magnitude can efficiently accomplish the desired tooth movement while minimizing pain.
Evidence Search ("ego"[MeSH Terms] OR "ego"[All Fields] OR "self"[All Fields]) AND ligating[All Fields] AND ("orthodontic brackets"[MeSH Terms] OR ("orthodontic"[All Fields] AND "brackets"[All Fields]) OR "orthodontic brackets"[All Fields])
Comments on
The Evidence
Validity: These three studies exhibited fair and unbiased treatment among the comparators. The studies showed consistent performance results from the group of self-ligating brackets in transmitting forces across varying wire deflections when compared to conventional brackets. The friction produced by ligation methods seems to play a large role in the ability of the brackets to produce the required forces for orthodontic therapy. Also, the combination of self-ligating brackets along with a wire exhibiting more elastic properties will produce forces of lower magnitude that minimizes pain while maintaining the desired tooth movement. This information is an integral part of orthodontic treatment planning. Perspective: Two of the studies were similar in that they both looked at the forces produced by conventional and self-ligating brackets comparatively. However, one of the studies (Higa/2016) also looked at these brackets producing forces from three different wire types; stainless steel, Nickel Titanium, and Copper Nickel Titanium. The third study demonstrates that orthodontic forces of lower magnitude will accomplish comparable amounts of tooth movement to forces of greater magnitude while greatly reducing inflammation and pain experienced by the patient.
Applicability These three studies demonstrate a realistic, functional application of the variety of combinations of orthodontic materials and the forces they will produce. They also demonstrate that efficient orthodontic therapy can be done with lower continuous forces that cause less pain and inflammation.
Specialty (General Dentistry) (Orthodontics) (Pediatric Dentistry)
Keywords Orthodontic wires, self-ligating brackets, conventional brackets, treatment forces, treatment pain
ID# 3184
Date of submission 03/28/2017
E-mail cookseyw@livemail.uthscsa.edu
Author Wesley Cooksey
Co-author(s) e-mail
Faculty mentor Brent J. Callegari, DDS
Faculty mentor e-mail callegari@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available