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Wang Y, Chen J, Qin S, Han X, Liao L, Sima X, Guo W. An in vivo evaluation of clear aligners for optimal orthodontic force and movement to determine high-efficacy and periodontal-friendly aligner staging. Heliyon 2023; 9:e15317. [PMID: 37113787 PMCID: PMC10126945 DOI: 10.1016/j.heliyon.2023.e15317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 03/15/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Objectives To investigate the effect of aligner displacement on tooth movement and periodontal health to improve the efficiency of aligner treatment and explore the mechanism in vivo. Methods A two-tooth site was established by a finite element (FE) model to virtually evaluate aligner staging. A randomized controlled experiment was conducted when the tooth sites in beagles were treated with fixed or aligner appliances with different movement and force, and tooth movement and internal structure were recorded during the alignment. After sacrificing five dogs, bone-periodontal ligament (PDL)-tooth specimens were removed and processed to conduct uniaxial compression and tensile tests as well as micro-CT imaging and histological analysis. Results Three displacements of 0.25, 0.35 and 0.45 mm were obtained from FE analysis and applied in beagles. In general, aligners had poorer performance on movement compared to fixed systems in vivo, but the aligner with a staging of 0.35 mm had the highest accuracy (67.46%) (P < 0.01). Loaded with severe force, fixed sites exhibited tissue damage due to excess force and rapid movement, while aligners showed better safety. The PDL under a 0.35-mm aligner treatment had the highest elastic modulus in the biomechanical test (551.4275 and 1298.305 kPa) (P < 0.05). Conclusions Compared to fixed appliances, aligners achieve slightly slower movement but better periodontal condition. Aligners with an interval of 0.35 mm have the highest accuracy and best PDL biomechanical and biological capacities, achieving the most effective and safest movement. Even with complexity of oral cavity and lack of evaluation of other factors, these results provide insight into faster displacement as a method to improve the efficacy of aligners.
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Affiliation(s)
- Yuru Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China School/Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jie Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China School/Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Siwen Qin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China School/Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xue Han
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China School/Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Lijun Liao
- Sichuan Hospital of Stomatology, Chengdu, China
| | - Xiutian Sima
- Department of Neurosurgery, West China School of Medicine/West China Hospital, Sichuan University, Chengdu, China
- Corresponding author. Department of Neurosurgery, West China Hospital, Sichuan University, 37# Wainan Guoxue Road, Chengdu 610041, China.
| | - Weihua Guo
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China School/Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Corresponding author. Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, No. 14, 3rd Sec., Ren Min Nan Road, Chengdu 610041, China.
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Zhou J, Song Y, Shi X, Zhang C. Tensile creep mechanical behavior of periodontal ligament: A hyper-viscoelastic constitutive model. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 207:106224. [PMID: 34146838 DOI: 10.1016/j.cmpb.2021.106224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 05/30/2021] [Indexed: 06/12/2023]
Abstract
OBJECTIVE In orthodontic treatment, the biomechanical response of periodontal ligament (PDL) induces tooth movement. Coupling modeling of PDL can effectively reflect its biomechanical response. The nonlinear creep mechanical behavior of PDL was studied by uniaxial tensile creep test and a new hyper-viscoelastic constitutive model. Two coupling modeling methods with limitations were excluded. METHODS PDL specimens were prepared from the central incisors of pig mandible. The theoretical step function was replaced by static loading with a total loading time of 1 s. The creep loading with the constant stresses of 0.05, 0.1, and 0.15 MPa was selected and kept unchanged for 1000 s. The instantaneous hyperelastic mechanical behavior and time-dependent nonlinear viscoelastic mechanical behavior of PDL were characterized by coupled instantaneous third-order Ogden hyperelastic and time-dependent nonlinear creep models. RESULTS The results showed that the instantaneous elastic curve of PDL increases in the form of hyperelastic index. The creep strain and creep compliance curves increase rapidly before 200s, and then increase slowly in steady state. The creep strain increased with an increase in the constant stress; conversely, the creep compliance decreased with an increase in the constant stress. The results showed that the experimental data were highly consistent with the hyper-viscoelastic constitutive model (R2>0.97). SIGNIFICANCE We normalize the framework of hyper-viscoelastic coupling modeling (Instantaneous hyperelastic model + time-dependent nonlinear viscoelastic model). Which can be extended to other nonlinear viscoelastic biomaterials.
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Affiliation(s)
- Jinlai Zhou
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin 300384, China
| | - Yang Song
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Xue Shi
- Periodontitis Department, Tianjin Stomatological Hospital, Tianjin 300041, China
| | - Chunqiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin 300384, China
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ZHOU JINLAI, SONG YANG, XU CHENGUANG, ZHANG CHUNQIU, YANG XIUPING, SHI XUE. EXPERIMENTAL RESEARCH ON VISCOELASTICITY PROPERTY OF DIFFERENT LAYERS PERIODONTAL LIGAMENT UNDER COMPRESSION. J MECH MED BIOL 2021. [DOI: 10.1142/s0219519421500500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The periodontal ligament (PDL) exhibits different material mechanical properties along the long axis of the teeth. To explore the creep and the relaxation effects of dissimilar layers of PDL, this paper took the central incisors of porcine mandibular as experimental subjects and divided them perpendicular to the teeth axis into five layers. Creep experiments and relaxation experiments on five layers were conducted to obtain the creep compliance and relaxation modulus at different layers. Linear elastic model, generalized Kelvin model, and generalized Maxwell model were used to describe the major characteristics of the PDL: Instantaneous elasticity, creep and relaxation. Fitting accuracy of three-parameter, five-parameter, and seven-parameter of the model was compared, and the constitutive equations of different layers were established by the least square method. The results presented that the creep strain and the relaxation stress of PDL were exponentially correlated with time under different loading conditions. Different layers showed a significant effect on the creep strain and relaxation stress of PDL. Along the long axis of the teeth, the changing rule of the creep compliance and relaxation modulus of each layer showed quite the contrary, and the instantaneous elastic modulus first decreased to the minimum, then increased to the maximum. Higher instantaneous elastic modulus led to lower creep compliance and higher relaxation modulus. The generalized Kelvin model and the generalized Maxwell model well characterized the creep and relaxation properties of PDL. Fitting accuracy increased with the number of model parameters. The relaxation time of PDL was about one order of magnitude shorter than the creep retardation time, which indicated that the relaxation effect lasted shorter than the creep effect.
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Affiliation(s)
- JINLAI ZHOU
- National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin Key Laboratory for Advanced Mechatronic, System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Binshui West Road No. 391, 300384 Tianjin, P. R. China
| | - YANG SONG
- National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin Key Laboratory for Advanced Mechatronic, System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Binshui West Road No. 391, 300384 Tianjin, P. R. China
| | - CHENGUANG XU
- National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin Key Laboratory for Advanced Mechatronic, System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Binshui West Road No. 391, 300384 Tianjin, P. R. China
| | - CHUNQIU ZHANG
- National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin Key Laboratory for Advanced Mechatronic, System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Binshui West Road No. 391, 300384 Tianjin, P. R. China
| | - XIU PING YANG
- National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin Key Laboratory for Advanced Mechatronic, System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Binshui West Road No. 391, 300384 Tianjin, P. R. China
| | - XUE SHI
- Periodontitis Department, Tianjin Stomatological Hospital, Dagu Road No. 75, 300041 Tianjin, P. R. China
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Zhou J, Song Y, Shi X, Lin J, Zhang C. A new perspective: Periodontal ligament is a viscoelastic fluid biomaterial as evidenced by dynamic shear creep experiment. J Mech Behav Biomed Mater 2020; 113:104131. [PMID: 33125951 DOI: 10.1016/j.jmbbm.2020.104131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 11/17/2022]
Abstract
Currently, Periodontal ligament (PDL) is considered as a viscoelastic solid biomaterial. However, we observed the steady-state rheological behavior of PDL through long time loading experiments, and suggested the theoretical definition of PDL as a viscoelastic fluid biomaterial. PDL specimens were prepared from the middle area of the mandibular central incisors in pigs. Dynamic force loading with frequencies of 0 (static load), 2, 5, and 10 Hz and amplitudes of 0.01, 0.02, and 0.03 MPa was adopted. The shear strain-time curve at the equilibrium position of PDL was obtained by a dynamic shear creep experiment. The results showed that the shear strain increased exponentially at first and then inclined toward an oblique line. The results showed that the PDL has viscoelastic fluid characteristics, independent of frequency and amplitude. The shear strain decreased with an increase in frequency and amplitude. To further analyze the viscoelastic characteristics of PDL, a 50000-s static shear creep experiment was re-designed. PDL exhibited viscoelastic fluid biomaterial characteristics according to the three aspects of the algebraic fitting, geometric characteristics, and physical results. For the first time, a viscoelastic fluid constitutive model was established to characterize the mechanical properties of PDL with high fitting accuracy. Furthermore, the shear viscosity coefficient of the dynamic load was larger than that of the static load, increasing with an increase in frequency and amplitude; compared with the static force, the dynamic force improved the viscosity of PDL, enhancing its function of fixing teeth, and introducing the new medical knowledge of "No tooth extraction after a meal."
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Affiliation(s)
- Jinlai Zhou
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China
| | - Yang Song
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China.
| | - Xue Shi
- Periodontitis Department, Tianjin Stomatological Hospital, China
| | - Jiexiang Lin
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China
| | - Chunqiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China
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