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Microcracks on the Rat Root Surface Induced by Orthodontic Force, Crack Extension Simulation, and Proteomics Study
Shengzhao Xiao1, Linhao Li2, Jie Yao1
1Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Chinese Education Ministry, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.
Microcracks on tooth roots during orthodontic treatment can cause root resorption. This study reveals that microcrack extension increases calcium ions and activates specific pathways, promoting cementoclast formation and root resorption.
Area of Science:
- Biomaterials Science
- Orthodontics
- Cell Biology
Background:
- Root resorption is a frequent complication of orthodontic therapy.
- The precise mechanisms linking microcracks to root resorption are not fully understood.
- Microcracks on the root surface may initiate or exacerbate root resorption during orthodontic treatment.
Purpose of the Study:
- To investigate the biological mechanisms of microcrack-induced root resorption during orthodontic treatment.
- To elucidate the cellular and molecular pathways involved in root resorption following microcrack formation.
Main Methods:
- Utilized a rat orthodontic model with a 0.5-N force applied to the first molar for 7 days.
- Employed scanning electron microscopy to observe root apex microcracks.
- Developed a finite element model to analyze stress distribution and microcrack mechanics.
- Conducted histological analysis to identify resorption areas and cementoclasts.
- Performed proteomics analysis on the root apex to identify involved signaling pathways.
Main Results:
- Observed microcracks on the root apex after 7 days of orthodontic force application.
- Finite element analysis indicated maximum stress at the root apex contributes to microcrack extension.
- Histological findings confirmed root resorption and cementoclast presence in stress concentration areas.
- Proteomics revealed the involvement of NOX2, Aifm1, and MAPK signaling pathways in root resorption.
- Microcrack extension was associated with increased calcium ion concentration and altered resorption-related proteins.
Conclusions:
- Microcracks induced by orthodontic forces play a significant role in root resorption.
- The NOX2, Aifm1, and MAPK pathways are implicated in the biological response to microcracks.
- Microcrack extension leads to cellular changes that promote cementoclast activity and root resorption.
