Prototype to measure bracket debonding force in vivo

Abstract

Introduction: Material biodegradation that occurs in the mouth may interfere in the bonding strength between the bracket and the enamel, causing lower bond strength values in vivo, in comparison with in vitro studies. Objective: To develop a prototype to measure bracket debonding force in vivo and to evaluate, in vitro, the bond strength obtained with the prototype.Methods: A original plier (3M Unitek) was modified by adding one strain gauge directly connected to its claw. An electronic circuit performed the reading of the strain gauge, and the software installed in a computer recorded the values of the bracket debonding force, in kgf. Orthodontic brackets were bonded to the facial surface of 30 bovine incisors with adhesive materials. In Group 1 (n = 15), debonding was carried out with the prototype, while tensile bond strength testing was performed in Group 2 (n = 15). A universal testing machine was used for the second group. The adhesive remnant index (ARI) was recorded.Results: According to Student’s t test (α = 0.05), Group 1 (2.96 MPa) and Group 2 (3.08 MPa) were not significantly different. ARI score of 3 was predominant in the two groups.Conclusion: The prototype proved to be reliable for obtaining in vivo bond strength values for orthodontic brackets.

Validation and reliability of a prototype orthodontic bracket debonding device equipped with force-sensitive resistor (FSR): a novel method of measuring orthodontic bracket debonding force in vivo

“…Validation of the prototype device is crucial to justify its clinical application. For validation, the comparison between the “gold standard” universal testing machine and the prototype device was made as some of the previous prototype devices [4, 6, 12, 13]. One study reported a difference of orthodontic bond strength between the universal testing machine and their prototype bracket debonding device due to the difference in the type of force application and rate of loading [6].…”

“…Hence, it was emphasized on the introduction of a device that is designed to debond brackets clinically according to the manufacturer’s direction while providing the quantitative magnitude of the applied force [1]. Various prototypes were introduced equipped with either digital force gauge (DFG) or strain gauge [4, 6, 8–13]. They were attached either with the modified elastic spacer instrument or the manufacturer-made debonding pliers.…”

“…On the other hand, strain gauge relies on the deformation of the plier handles on which it is attached. Hence, the results may vary with the plier types and the manner in which they are held [13].…”

Comparison of Orthodontic Bracket Debonding Force and Bracket Failure Pattern on Different Teeth In Vivo by a Prototype Debonding Device

“…Therefore, a conventional manufacturer-made plier capable of measuring the force while debonding brackets simultaneously in a standardized manner was recommended [2]. Devices introduced so far for measuring the clinical bracket debonding force are either made of digital force gauge (DFG) or strain gauge [3,5,[7][8][9][10][11]. The DFG-equipped devices were elastic spacer instrument modified purposefully for debonding, not a regular debonding plier.…”

“…On the contrary, the strain gauge relies solely on the elastic straining of the plier handles. Besides, some of the devices were not validated and some of them were not applied clinically [7,[9][10][11]. Bracket failure patterns by some devices are unknown which might risk enamel damage [3,6,8].…”