Orthodontic intrusion of periodontally-compromised maxillary incisors: 3-dimensional finite element method analysis

Abstract

Background. Loading of the compromised periodontium with orthodontic forces produces different results than those achieved in patients with healthy periodontal support. Determining the force value at a level preventing further deterioration of the patient's periodontal status, thus delivering the most precisely individualized "dose" of loading, seems to be crucial for the successful intrusion of teeth with reduced periodontal support.

Assessment of the Best FEA Failure Criteria (Part II): Investigation of the Biomechanical Behavior of Dental Pulp and Apical-Neuro-Vascular Bundle in Intact and Reduced Periodontium

“…Orthodontic therapy and its effects over the apical neurovascular bundle (NVB), dental pulp and periodontal ligament (PDL) in a reduced periodontium has been insufficiently studied [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Even a low orthodontic force, considered to be safe when applied in the intact periodontium, could alter the circulatory pressure balance from these tissues in a reduced periodontium (by exceeding the maximum physiological hydrostatic pressure [MHP] of 2–16 KPa that prevents capillary occlusion) due to different types of localized stresses (i.e., tensile, compressive, shear, overall and hydrostatic pressure) [ 1 , 2 , 3 , 4 , 5 ].…”

“…Even a low orthodontic force, considered to be safe when applied in the intact periodontium, could alter the circulatory pressure balance from these tissues in a reduced periodontium (by exceeding the maximum physiological hydrostatic pressure [MHP] of 2–16 KPa that prevents capillary occlusion) due to different types of localized stresses (i.e., tensile, compressive, shear, overall and hydrostatic pressure) [ 1 , 2 , 3 , 4 , 5 ]. As consequence, ischemia, pulpal necrosis, further periodontal loss, and orthodontic root resorption could shortly follow t orthodontic therapy due to the anatomical and functional interconnectivity of the periodontium’s anatomical components [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The optimal amount of orthodontic force (i.e., acknowledged to be light and producing the desired movement without tissue damage) for an intact periodontium remains a subject of debate [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Einstellung der Zahn-Lippen-Relation im parodontal geschwächten Gebiss mittels Intrusion der Front

“…Erst durch eine vollständige Korrektur der Zahnfehlstellung mit Einstellung einer physiologischen Okklusion und optimalen Belastungsverhältnissen im Parodontalligament kann zusammen mit der Therapie der parodontalen Erkrankung eine gute Mundgesundheit wieder hergestellt werden [17]. Dabei ist insbesondere ein Augenmerk auf die Intrusionsbewegung der Zähne zu richten [18][19][20][21]. Sie wird vor allem genutzt, um aufgefächerte, labial gekippte und extrudierte Frontzähne in ihre natürliche Position zurückzuführen.…”

“…Als allgemeine Leitlinie kann der Einsatz von leichten Kräften mit 10-15 g pro Zahn für die Intrusion dienen [18]. Dieser Wert von 0,1 N scheint als Kraft-Dosis-Wirkung effektiv für eine optimale Intrusionen und Regenerationen von Knoch endefekten zu sein [21].…”

Analytical Methods and Finite Element Method Computation The dental - periodontal tissues response

“…Under such circumstances, the resistance and rotation centre of the tooth, as well as the orthodontic movement mechanisms, change. Therefore, a correct decision regarding an orthodontic treatment in such conditions, without the emergence of iatrogenic effects, requires an extremely thorough biomechanical analysis [5][6][7][8][9].…”