Flatten Jana, Gedrange Thomasz, Bourauel Christoph, Keilig Ludger, Konermann Anna
Oral Technology, University Hospital Bonn, 53111 Bonn, Germany.
Department of Orthodontics, University Hospital Dresden, 01307 Dresden, Germany.
Biomedicines. 2024 Aug 28;12(9):1959. doi: 10.3390/biomedicines12091959.
This study was conducted to systematically evaluate the biomechanical impact of varying degrees of root and bone resorption resulting from periodontitis and orthodontic tooth movement (OTM) on the mandibular anterior teeth. The objective was to determine whether these distinct resorption patterns exert a specific influence on tooth displacement and strain patterns.
A finite element (FE) model of an idealized anterior mandible from the first premolar in the third to the fourth quadrant was developed without bone or root resorption and a constant periodontal ligament (PDL) thickness of 0.2 mm. Variations included three root resorption levels (0%, 20%, 50%) and three bone resorption types (circular 50%, circular 80%, vestibular 80%). Models ranged from 200,000 to 440,000 elements and 55,000 to 130,000 nodes. Orthodontic forces, namely root torque (5 Nmm), intrusion (0.2 N), and distalization (0.5 N) were applied for subsequent crown displacement and PDL strain analysis.
A total of 180 simulations were performed. Simulations showed that displacement was similar across different bone resorption conditions, irrespective of modeled root resorptions. Circumferential bone resorption increased tooth displacement, regardless of root resorption status. Vestibular bone resorption exhibited less increase in tooth displacement. However, when accompanied by root resorption, the combination exacerbated tooth displacement. Strains in the PDL clearly increased with a circumferential bone resorption of 80%.
This study highlights the critical role of bone resorption in tooth displacement during OTM, particularly the challenges associated with circumferential resorption. Clinicians must consider both bone and root resorption for personalized medicine treatment of patients with severe periodontitis, in favor of low-force application strategies to optimize outcomes and minimize complications linked to excessive tooth displacement.
本研究旨在系统评估牙周炎和正畸牙齿移动（OTM）导致的不同程度牙根和骨吸收对下颌前牙的生物力学影响。目的是确定这些不同的吸收模式是否对牙齿位移和应变模式产生特定影响。
建立了一个理想化的下颌前牙有限元（FE）模型，该模型从第三象限的第一前磨牙到第四象限，没有骨或牙根吸收，牙周膜（PDL）厚度恒定为0.2mm。变量包括三种牙根吸收水平（0%、20%、50%）和三种骨吸收类型（环形50%、环形80%、前庭80%）。模型的单元数量从200,000到440,000不等，节点数量从55,000到130,000不等。施加正畸力，即牙根扭矩（5Nmm）、内收（0.2N）和远中移动（0.5N），用于后续的牙冠位移和PDL应变分析。
总共进行了180次模拟。模拟结果表明，在不同的骨吸收条件下，位移相似，与模拟的牙根吸收情况无关。无论牙根吸收状态如何，环形骨吸收都会增加牙齿位移。前庭骨吸收导致的牙齿位移增加较少。然而，当伴有牙根吸收时，这种组合会加剧牙齿位移。当环形骨吸收达到80%时，PDL中的应变明显增加。
本研究强调了骨吸收在OTM期间牙齿位移中的关键作用，特别是与环形吸收相关的挑战。临床医生在对重度牙周炎患者进行个性化医学治疗时，必须同时考虑骨吸收和牙根吸收，支持采用低力应用策略，以优化治疗效果并尽量减少与过度牙齿位移相关的并发症。
