Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket
Abstract Background Proper torque control is crucial to the outcome of orthodontic treatment. This study aimed to employ finite element analysis to compare the torque capabilities of a novel spherical self-ligating bracket with a lock-hook system against those of commonly used passive self-ligating...
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| Language: | English |
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BMC
2025-01-01
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| Series: | BMC Oral Health |
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| Online Access: | https://doi.org/10.1186/s12903-025-05423-6 |
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| author | Yudong Liu Longmei Guo Yanqing Feng Jiahao Hua Qingyuan Dai Ziyang Chen Wenlu Song Bing Guo Taicong Chen Li Ji |
| author_facet | Yudong Liu Longmei Guo Yanqing Feng Jiahao Hua Qingyuan Dai Ziyang Chen Wenlu Song Bing Guo Taicong Chen Li Ji |
| author_sort | Yudong Liu |
| collection | DOAJ |
| description | Abstract Background Proper torque control is crucial to the outcome of orthodontic treatment. This study aimed to employ finite element analysis to compare the torque capabilities of a novel spherical self-ligating bracket with a lock-hook system against those of commonly used passive self-ligating and conventional bracket systems, as well as to reveal the biomechanical changes in the periodontal ligament (PDL) during torque expression. Methods A maxillary right central incisor, along with its PDL and alveolar bone, were modeled. Three types of brackets were selected: a spherical self-ligating bracket with a lock-hook system, a passive self-ligating bracket (Damon), and a conventional bracket (Discovery). Each bracket was equipped with a 0.022-inch slot and a 0.019 × 0.025-inch stainless steel archwire. A palatal root torque of 20° was applied. The torque moment, as well as the von Mises stress and strain in the PDL, were calculated. A clinical case involving the lingual inclination of the upper anterior teeth was utilized to assess the feasibility of using the spherical self-ligating bracket with the lock-hook system to express torque. Results At a twist angle of 20°, the maximum torque generated by the spherical self-ligating bracket with a lock-hook system (27.8 N·mm) was approximately 1.6 times greater than that of the Damon bracket (17.5 N·mm) and the Discovery bracket (17.3 N·mm). As the twist angle increased, both the von Mises stress and the strain in the PDL also increased. When the maximum PDL stress was less than 0.026 MPa and the percentage of the PDL good strain area (defined as the area with PDL strain ≥ 0.3%) exceeded 50%, the torque range for the maxillary incisor was between 10.2 and 17.5 N·mm. The clinical case demonstrated that the use of the spherical self-ligating bracket with the lock-hook system effectively corrected the unfavorable linguoclination of the maxillary incisors. Conclusions The spherical self-ligating bracket with a lock-hook system can significantly enhance torque expression. The optimal torque range for the maxillary incisor is between 10.2 and 17.5 N·mm. |
| format | Article |
| id | doaj-art-e4d740228f0b47cd87a47dbd6b8102df |
| institution | Kabale University |
| issn | 1472-6831 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Oral Health |
| spelling | doaj-art-e4d740228f0b47cd87a47dbd6b8102df2025-01-12T12:42:06ZengBMCBMC Oral Health1472-68312025-01-0125111210.1186/s12903-025-05423-6Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracketYudong Liu0Longmei Guo1Yanqing Feng2Jiahao Hua3Qingyuan Dai4Ziyang Chen5Wenlu Song6Bing Guo7Taicong Chen8Li Ji9Department of Stomatology, The First Affiliated Hospital, Sun Yat-Sen UniversityDepartment of Stomatology, The First Affiliated Hospital, Sun Yat-Sen UniversityDepartment of Stomatology, The First Affiliated Hospital, Sun Yat-Sen UniversitySchool of Civil Engineering and Transportation, South China University of TechnologySchool of Civil Engineering and Transportation, South China University of TechnologyGuangzhou OO Stomatology InstituteGuangzhou OO Stomatology InstituteDepartment of Stomatology, The First Affiliated Hospital, Sun Yat-Sen UniversitySchool of Civil Engineering and Transportation, South China University of TechnologyDepartment of Stomatology, The First Affiliated Hospital, Sun Yat-Sen UniversityAbstract Background Proper torque control is crucial to the outcome of orthodontic treatment. This study aimed to employ finite element analysis to compare the torque capabilities of a novel spherical self-ligating bracket with a lock-hook system against those of commonly used passive self-ligating and conventional bracket systems, as well as to reveal the biomechanical changes in the periodontal ligament (PDL) during torque expression. Methods A maxillary right central incisor, along with its PDL and alveolar bone, were modeled. Three types of brackets were selected: a spherical self-ligating bracket with a lock-hook system, a passive self-ligating bracket (Damon), and a conventional bracket (Discovery). Each bracket was equipped with a 0.022-inch slot and a 0.019 × 0.025-inch stainless steel archwire. A palatal root torque of 20° was applied. The torque moment, as well as the von Mises stress and strain in the PDL, were calculated. A clinical case involving the lingual inclination of the upper anterior teeth was utilized to assess the feasibility of using the spherical self-ligating bracket with the lock-hook system to express torque. Results At a twist angle of 20°, the maximum torque generated by the spherical self-ligating bracket with a lock-hook system (27.8 N·mm) was approximately 1.6 times greater than that of the Damon bracket (17.5 N·mm) and the Discovery bracket (17.3 N·mm). As the twist angle increased, both the von Mises stress and the strain in the PDL also increased. When the maximum PDL stress was less than 0.026 MPa and the percentage of the PDL good strain area (defined as the area with PDL strain ≥ 0.3%) exceeded 50%, the torque range for the maxillary incisor was between 10.2 and 17.5 N·mm. The clinical case demonstrated that the use of the spherical self-ligating bracket with the lock-hook system effectively corrected the unfavorable linguoclination of the maxillary incisors. Conclusions The spherical self-ligating bracket with a lock-hook system can significantly enhance torque expression. The optimal torque range for the maxillary incisor is between 10.2 and 17.5 N·mm.https://doi.org/10.1186/s12903-025-05423-6Torque expressionSpherical self-ligating bracketLock-hook systemBiomechanicsFinite element analysis |
| spellingShingle | Yudong Liu Longmei Guo Yanqing Feng Jiahao Hua Qingyuan Dai Ziyang Chen Wenlu Song Bing Guo Taicong Chen Li Ji Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket BMC Oral Health Torque expression Spherical self-ligating bracket Lock-hook system Biomechanics Finite element analysis |
| title | Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket |
| title_full | Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket |
| title_fullStr | Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket |
| title_full_unstemmed | Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket |
| title_short | Comparative study of torque expression and its biomechanical effects: spherical self-ligating bracket with lock-hook system versus passive self-ligating bracket and conventional bracket |
| title_sort | comparative study of torque expression and its biomechanical effects spherical self ligating bracket with lock hook system versus passive self ligating bracket and conventional bracket |
| topic | Torque expression Spherical self-ligating bracket Lock-hook system Biomechanics Finite element analysis |
| url | https://doi.org/10.1186/s12903-025-05423-6 |
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