ORTHO –PERIO: A Synergistic Alliance

Introduction : The goal of orthodontic treatment is not only to improve facial esthetics and function but also to address to the health of supporting structures and how teeth are placed in them. Both the short and long term successful outcomes of orthodontic treatment are influenced by the patient’s periodontal status before, during and after active orthodontic therapy. Co-operation between different specialties in dentistry is extremely important in establishing diagnosis as well as in treatment planning. In many cases, periodontal health is improved by orthodontic tooth movement, whereas orthodontic tooth movement is often facilitated by periodontal therapy.
This article reviews the affect of different orthodontic tooth movements on the periodontium and effects of periodontal break down on orthodontic treatment planning.
Orthodontic treatment is based on the premise that when force is applied to a tooth it is transmitted to the adjacent investing tissues and certain structural alterations take place within these tissues which allow for, and contribute to tooth movement.

INTRUSION:
Intrusion alters the cemento-enamel junction and angular crest relationships, and creates only epithelial root attachment: therefore a periodontally susceptible patient is at greater risk of future periodontal breakdown. Tooth movement, when properly executed, improves periodontal condition and is beneficial to periodontal health. Orthodontic forces, when kept within biological limits, do not induce tissue alterations leading to loss of connective tissue attachment and periodontal pocket formation. The gingiva moves in the same direction as that of tooth intrusion but it moves only by about 60%. Gingival sulcus gets deepened by about 40% of tooth intrusion.
Indications:
1. It is indicated for teeth with horizontal bone loss.
2. For increasing the clinical crown length of single teeth.
Although early studies reported that orthodontic intrusion of teeth can shift supragingivally located plaque to a subgingival location, leading to formation of infrabony pockets and loss of connective tissue attachment, it is now clear that periodontal integrity can be maintained with proper oral hygiene maintenance.

EXTRUSION:
Extrusion or eruption of a tooth or several teeth, along with reduction of the clinical crown height is reported to reduce infrabony defects and decrease pocket depth. Extrusion of an individual tooth is used specifically for correction of isolated periodontal osseous lesions. Studies have shown that extrusion in the absence of gingival inflammation reduces bleeding on probing, decreases pocket depth and even causes formation of new bone at the alveolar crest as the tooth erupts, with no occlusal factor present.
FORCED ERUPTION:
It helps to save an isolated tooth in which caries, trauma, or iatrogenesis have destroyed the clinical crown by bringing the fractured, diseased or prepared margins of the neck of the tooth more coronally It is associated with an increase in the width of attached gingiva, mucogingival junction remains unaltered.Fibrotomy, which is done before active eruption, is essential for success of the procedure.
ROTATION:
Relapse tendencies exist in a fairly high percentage of treated malocclusion and it is greatest for rotation corrections. The fibrous elements of the periodontal ligament adapt to tooth movement in possibly 3 mechanisms:
1. Progressive osteogenic and cementogenic activity plays an active role in the shortening of the extended fibers during tooth movement.
2. The stretching of the wavy collagen fibers and reorientation of their directional morphology permits a certain amount of tooth movement.
3. The existence of a type of intermediate plexus might allow an elongation of fiber bundles by slippage of the fibers over one another and a subsequent reorientation of the fibers in a new position.
Circumferential fibrotomy is often used to stabilize rotational corrections.

SPACE CLOSURE:
orthodontic movement of teeth into infrabony pockets may be detrimental for the periodontal attachment when realignment of teeth that have been tipped and/or elongated as a result of periodontal disease is considered. Hence periodontal treatment directed at elimination of the plaque-induced lesion should precede the initiation of orthodontic therapy and proper oral hygiene maintained during the course of orthodontic treatment.
Gingival invaginations occur commonly during orthodontic treatment that involves first premolar extraction and space closure. Although they may decrease in size or even resolve, many invaginations persist for years after treatment.The presence, severity, and complexity of invaginations may impair the patient's ability to maintain adequate gingival health in the extraction area.
PERIODONTAL CONSIDERATIONS IN SURGICAL EXPOSURE:
Management of the periodontal tissues is the most crucial factor influencing the long term prognosis of impacted tooth. The amount of attached gingival available for impacted teeth after surgical exposure dictates the choice of method of exposure. If adequate attached gingiva can be maintained then a simple gingevectomy procedure is preferred. A apically positioned flap can be used to increase the width of attached gingiva. A closed eruption technique is the ideal procedure as it allows more physiological eruption of teeth through the alveolar crest.
Abnormal frenal and muscle attachments
Abnormal frenum and muscle pull has been considered detrimental to periodontal health by pulling away the gingival margin from the tooth contributing to accumulation of plaque and calculus, and leading to inflammation and pocket formation. Adequate depth of the vestibule has been similarly held significant. Several surgical procedures to deepen the vestibule as well as to reduce the height of frenal attachments have been developed as preventive therapeutic measures. In cases with low frenal attachment with incisor diastema, it is advocated to perform the frenotomies/frenectomies after the closure of the diastema as the surgical scar formed after the surgery may inhibit diastema closure.
PERIODONTAL SURGICAL PROCEDURES:
GINGIVAL CURETTAGE:
Curettage means scraping of the gingival wall of a periodontal pocket to remove infected and necrotic tooth substance. It removes the inflamed soft tissue lateral to the pocket wall. The aim of curettage is to reduce pocket depth by enhancing gingival shrinkage and new connective tissue attachment.

GINGIVECTOMY:
Gingivectomy means excision of gingiva. By removing diseased tissue and local irritants, it creates a favorable environment for gingival healing and the restoration of a physiological gingival contour.
The Gingivectomy technique is useful in improving orthodontic results, especially in cases with missing maxillary central or lateral incisors, after premolar auto transplantation or in gummy smiles. It is possible to permanently increase the clinical crown length after orthodontic treatment by labial gingivectomy technique.
GINGIVOPLASTY:
Gingivoplasty is the reshaping of gingiva to create physiologic gingival contours, for the sole purpose of recontouring the gingiva in the absence of pockets. Gingival and periodontal diseases often produce deformities in the gingiva that interferes with normal food excursion, collect plaque and food debris and aggravate the disease process. The relationship of gingival margin of anterior teeth are crucial for an esthetic smile. Any gingival margin discrepancies can be corrected with gingivoplasty ,after orthodontic treatment.

IDEAL GINGIVAL MARGIN  RELATIONSHIP OF ANTERIOR TEETH

FIBROTOMY:
Periodontal fiber bundles that influence post treatment stability are the principal fibers of PDL and the supra alveolar fibers. Fibers of PDL remodel completely only after 2-3 months. The supra alveolar fibers are stable and have a slower turnover. The supra crestal gingival tissues contribute to rotational relapse and hence the technique of ‘Circumferential Supracrestal Fibrotomy’ is used to stabilize rotation corrections. The transseptal fibers are cut interdentally by entering the PDL space. Clinical healing occurs in 7-10 days. The fibrotomy procedure is not indicated during active tooth movement or in the presence of gingival inflammation. When performed in healthy tissues after orthodontics, the attachment loss is minimal.

CIRCUMFERENTIAL SUPRACRESTAL FIBROTOMY

FRENOTOMY:

Hyperplastic types of frenum with fan shaped attachment may obstruct diastema closure and hence surgical intervention is desirable. The complication with frenectomy is that the complete removal of the frenum may result in gingival recession between the central incisors. Hence frenotomy with only partial removal of the frenum with the purpose of relocating the attachment in a more apical direction is currently undertaken. Tissue healing is uneventful although some scarring may occur.


REMOVAL OF GINGIVAL CLEFTS:
Incomplete adaptation of supporting tissues during space closure may result in invaginations or infolding or clefts in the gingiva. A simple removal of only the excess gingiva in the buccal and lingual areas would be sufficient to alleviate the tendency of teeth to separate after space closure.

CHANGES IN PDL DURING ORTHODONTIC TREATMENT
There is formation of degenerating tissues in the periodontal ligament on the pressure side during the tooth movement, termed as hyalinized tissues, because the degenerating tissues is stained eosinophilically with glass-like structures, with hematoxylin-eosin (H-E) stain.
It is postulated that forces of about 25 gm/cm2 ,equal to blood pressure of PLD terminal capillaries, should be optimal for tooth movement, while larger forces would block PDL blood flow, leading to tissue necrosis at compressed areas. Hence necrosis caused is not due to the direct destructive effect of large orthodontic force, but rather to stagnation of blood supply to the area.
Periodontal tissues adapt to teeth that are moved orthodontically along the dental arch. Orthodontic tooth movements along the arch will not result in loss of periodontal support provided the gingival tissue is kept free of inflammation. Dentitions with reduced periodontal support show a marked tendency to return to their pretreatment position following active appliance therapy. Thus, semi-permanent or permanent retention should be considered for patients with periodontally compromised dentitions.
Orthodontic treatment during adolescence has no discernible effect upon later periodontal health. Although a relationship may exist in conversion of gingivitis to periodontitis in orthodontic patients, it is due to difficult oral hygiene maintenance, for example orthodontic bands may increase subgingival plaque retention. Patient motivation becomes an important part of therapy in this regard. Preventive program for orthodontic patients: Before orthodontic treatment: 1. control active periodontal disease and caries 2. Risks of treatment have to be explained to the patient. Awareness of the existing problem and the possible complications that may arise during treatment must be explained. During orthodontic treatment: 1. Emphasis on oral hygiene. 2. brushing instructions. 3. check plaque removal effectiveness 4. periodic periodontal evaluation and check up After orthodontic treatment 1. Patient must be motivated to maintain good oral hygiene. 2. Maintenance of routine dental check ups.

CONCLUSION – Successful orthodontic treatment for the patients will depend on the periodontal preparation before treatment and the maintenance of periodontal health throughout all phases of mechanotherapy. Periodontal disease and its sequelae may lead to severe aesthetic and functional problems. An interdisciplinary approach with orthodontic intervention may be essential to achieve optimal results of periodontal therapy.