In patients with advanced periodontal disease, pathological tooth migration may occur, which may require subsequent orthodontic treatment for both aesthetic and functional purposes. When planning orthodontic treatment mechanics, intrusive or extrusive forces are frequently indicated. Understanding tissue reactions during these movements is essential for clinicians when devising a comprehensive orthodontic-periodontal treatment plan. This knowledge enables clinicians to be fully aware of and account for the potential effects on the surrounding tissues. The majority of our understanding regarding the behavior of periodontal tissues in both healthy and compromised periodontal conditions is derived from animal studies. These studies offer the advantage of conducting histological and other assessments that would not be feasible in human research. Human studies are nevertheless invaluable in being able to understand the clinically relevant response elicited by the periodontal tissues following orthodontic tooth movement. Animal and human data show that in dentitions with reduced periodontal support, orthodontic intrusion of the teeth does not induce periodontal damage, provided the periodontal tissues do not have inflammation and plaque control with excellent oral hygiene is maintained. On the contrary, when inflammation is not fully controlled, orthodontic intrusion may accelerate the progression of periodontal destruction, with bacterial plaque remnants being displaced subgingivally, leading to further loss of attachment. Orthodontic extrusion, on the other hand, does not seem to cause further periodontal breakdown in dentitions with reduced periodontal support, even in cases with deficient plaque control. This is attributed to the nature of the tooth movement, which directs any plaque remnants coronally (supragingivally), reducing the risk of adverse effects on the periodontal tissues. This specific type of tooth movement can be leveraged to benefit periodontal conditions by facilitating the regeneration of lost hard and soft periodontal tissues in a coronal direction. As a result, orthodontic extrusion can be employed in implant site development, offering an advantageous alternative to more invasive surgical procedures like bone grafting. Regardless of the tooth movement prescribed, when periodontal involvement is present, it is essential to prioritize periodontal therapy before commencing orthodontic treatment. Adequate plaque control is also imperative for successful outcomes. Additionally, utilizing light orthodontic forces is advisable to achieve efficient tooth movement while minimizing the risk of adverse effects, notably root resorption. By adhering to these principles, a more favorable and effective combined orthodontic-periodontal approach can be ensured. The present article describes indications, mechanisms, side effects, and histological and clinical evidence supporting orthodontic extrusion and intrusion in intact and reduced periodontal conditions.

中文翻译：

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健康和减少的牙周组织正畸侵入和挤压期间的牙周注意事项。


患有晚期牙周病的患者可能会发生病理性牙齿迁移，这可能需要随后的正畸治疗以达到美观和功能的目的。在规划正畸治疗机制时，经常需要指出侵入力或挤压力。了解这些运动过程中的组织反应对于临床医生设计全面的正畸牙周治疗计划至关重要。这些知识使临床医生能够充分了解并解释对周围组织的潜在影响。我们对健康和受损牙周条件下牙周组织行为的大部分了解都来自动物研究。这些研究提供了进行组织学和其他评估的优势，而这在人类研究中是不可行的。然而，人体研究对于了解正畸牙齿移动后牙周组织引起的临床相关反应具有无价的价值。动物和人类数据表明，在牙周支持减少的牙列中，只要牙周组织没有炎症并且牙菌斑控制保持良好的口腔卫生，牙齿的正畸侵入不会引起牙周损伤。相反，当炎症未得到完全控制时，正畸侵入可能会加速牙周破坏的进展，残留的菌斑在龈下移位，导致附着进一步丧失。另一方面，正畸挤压似乎不会导致牙周支持减少的牙列进一步破坏，即使在牙菌斑控制不足的情况下也是如此。 这是由于牙齿移动的性质，它将任何牙菌斑残余物引导到冠状方向（龈上），从而降低对牙周组织产生不利影响的风险。这种特定类型的牙齿移动可以通过促进在冠状方向上丢失的硬牙周组织和软牙周组织的再生来有益于牙周状况。因此，正畸挤压可用于种植位点开发，为骨移植等更具侵入性的外科手术提供有利的替代方案。无论规定的牙齿移动方式如何，当存在牙周受累时，在开始正畸治疗之前必须优先考虑牙周治疗。充分的菌斑控制对于成功的结果也至关重要。此外，建议使用较轻的正畸力，以实现有效的牙齿移动，同时最大限度地减少不良影响（尤其是牙根吸收）的风险。通过遵守这些原则，可以确保更有利、更有效的正畸-牙周联合治疗方法。本文描述了在完整和减少的牙周状况下支持正畸挤压和侵入的适应症、机制、副作用以及组织学和临床证据。