Australasian Dentist Magazine Sept-Oct 2021

Category 56 Australasian Dentist Inter-Relationship of Orthodontics and Periodontics clinical O rthodontic treatment is based on the principle that forces applied to teeth produce stresses on the periodontal ligament, in turn, induce bone remodelling and results in tooth movement. Since the periodontal ligament mediates this response, orthodontic treatment outcomes depend on the health status of the periodontium before, during, and after active orthodontic treatment. Periodontal disease is a manifestation of pathogenic microbial biofilm. The pathology of periodontal disease results in inflammation, which may lead to bone loss, pathologic migration, spacing, flared incisors, and trauma from occlusion. Orthodontic therapy can contribute in many ways to help patients with periodontal problems. Orthodontic tooth movement may be of substantial benefit to the adult perio- restorative patient. Many adults who seek routine restorative dentistry have problems with tooth malposition, which compromises their ability to clean and maintain their dentition. 1. Effects of Orthodontic force on Periodontal tissues Tooth movement induced by orthodontic force is due to the controlled forces on teeth. The applied force causes remodelling changes in the dental and periodontal tissues. Bone surrounding a tooth subjected to a force responds in the following manner: u Bone resorption on the pressure side u Bone formation on the tension side. 2. Orthodontic treatment as an adjunct to periodontal therapy Tooth movement such as extrusion, intrusion, rotation and bodily movement are thought to prevent further periodontal breakdown, reduce plaque retention, improve gingival form and oral function and enhance aesthetics. These procedures should be performed only after biofilm control, initial debridement, and scaling and root planing. During orthodontic therapy all the components of tooth including the osseous structure, periodontal ligament and the soft tissue move together with the tooth. CrowdedTeeth: Patientswithcrowded, malaligned and malpositioned maxillary or mandibular anterior teeth present a difficulty in biofilm control. Aligning the crowded teeth orthodontically will help patients maintain improved biofilm control. Tilted molars: Orthodontic uprighting of mesially tilted molars to correct the pathologically migrated teeth aids in control of further periodontal breakdown, improve oral function and provide acceptable aesthetics. The distal tooth movement allows the mesial deposition of alveolar bone thereby eliminating bony defects, gingival folding and plaque retentive areas, thus reducing periodontal probing depths. Various tooth movements: Bodily movement: In patients with partially edentulous dentitions and reduced vertical bone height, orthodontic bodily tooth movement into constricted bone areas results in healing and regeneration of the attachment apparatus, which may be a possibility for space closure. For tooth movement into areas with considerably reduced alveolar ridges, bone procedures (such as guided bone regeneration) should be considered. Tooth Extrusion: Indicated for shallowing out intraosseous defects and for increasing the clinical crown length. Extrusion results in coronal positioning of intact healthy connective tissue attachment along the tooth and also bone deposition resulting in reduced probing depths and infrabony defects. It is the Dr Geoff Hall By Geoffrey Hall Figure 1b Diagrammatic representation of bone following the tooth extrusion least hazardous type of movement to solve individual tooth defects due to periodontal disease. In case of fractured teeth, the fracture extends beneath the level of the gingival margin and terminates at the level of the alveolar ridge becomes a site of marginal gingival inflammation. Severe fracture of the anteriors, require forced eruptions of the fractured root out of the bone and move the fracture margin coronally so that it can be properly restored. This will allow the crown preparation to have sufficient resistance and retention form. Figure 1a Tooth fracture showing extrusion Tooth Intrusion: Indicated for teeth with horizontal bone defects. Intrusion forces are apically concentrated and can cause root resorption and deepened infrabony pockets of anterior teeth. Application of light orthodontic forces during active intrusion, while maintaining plaque control to prevent further periodontal destruction. The intrusion of