Original Article
Effect of the bracket debonding force and residual adhesives on enamel cracks
Fan Hao, Yuan Rui, Zhang Huan, Si Minmin, Gao Meiya, Feng Zhiyuan
Published 2023-06-20
Cite as Chin J Orthod, 2023, 30(2): 92-96. DOI: 10.3760/cma.j.cn115797-20220510-23207
Abstract
ObjectiveThe aim of this study is to investigate the effects of mechanical factors related to the debonding force and residual adhesives on the change of enamel cracks in the vitro process under the different curing modes of orthodontic bracket adhesives.
MethodsFifty isolated premolars were collected and divided into two groups for a randomized controlled trial. The number and total length of initial enamel cracks were recorded. In vitro models of metal bracket debonding were constructed with different curing methods of orthodontic bracket adhesives: group A (chemical-cured) and group B (light-cured), 25 cases in each group. The universal testing machine was used to apply force to the bracket removal plier in vitro to mimic the uini-direction force during debonding. The force of bracket debonding, adhesive remnant index (ARI) of tooth surface and the number and total length of enamel cracks were recorded. The difference of debonding force, Adhesive Remnant Index and the change of number and total length of cracks between group A and group B were compared. Respectively, Group A and B were divided into two subgroups, A1, A2, B1 and B2, according to whether the number of enamel cracks on the tooth surface increased after the bracket debonding. (Group 1 with no increase in the number of enamel cracks, and group 2 with increase). The risk factors of increasing the number of enamel cracks in vitro were discussed.
ResultsThe mean debonding force of group A was higher than that of group B [group A: (208.37±30.51) N, group B : (178.31±30.13) N, P<0.001]. There was no statistical significance between group A and group B regarding the ARI and the change of number and total length of enamel cracks. The median ARI of group A1 was higher than group A2 [group A1: 5.00(1.00), group A2: 3.00(2.00), P=0.016], the median ARI of group B1 was also higher than group B2 [group B1: 5.00(1.00), group B2: 4.00(1.25), P=0.035], and the differences were statistically significant.
ConclusionsThe difference of debonding force between the Chemical-cured and Light-cured adhesive groups had no significant effect on the change of enamel cracks after bracket removed. In the process of bracket debonding, we should carefully apply force to the bracket removal pliers in both directions, and increase the amount of remnant adhesive on tooth surface to reduce the direct force on the enamel to avoid mechanical damage on the enamel cracks.
Key words:
Metal bracket; Bracket debonding; Enamel crack; Adhesive remnant index
Contributor Information
Fan Hao
ShanXi Medical University School and Hospital of Stomatology, Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, China
Yuan Rui
ShanXi Medical University School and Hospital of Stomatology, Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, China
Zhang Huan
ShanXi Medical University School and Hospital of Stomatology, Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, China
Si Minmin
ShanXi Medical University School and Hospital of Stomatology, Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, China
Gao Meiya
Department of Orthodontics, The Fifth Clinical Medical College of Shanxi Medical University, Taiyuan 030001, China
Feng Zhiyuan
Department of Orthodontics, The Fifth Clinical Medical College of Shanxi Medical University, Taiyuan 030001, China
面的距离而增加[1]，受力时的反应可能也略有差异。当牙齿颊面承受的力超过其本身所具有的损伤耐受性[8]时可能会影响牙面釉质裂纹数量和总长度。
