Periodontics-orthodontics interrelationships
Introduction : The interrelations between orthodontics and periodontics are multiple. They concern both screening, prevention and the treatments involved in each of these disciplines.
1-Reminder on dental malpositions : dental malpositions are defined by Rateischak in 1968. They are of two types
-primary malpositions: appear during dental eruption such as open bite and supraclusia.
-secondary malposition: appear following parafunctions, premature loss of teeth or collapse of the bone support during periodontal disease.
2-Definitions of dental movements:
- Version movement: The version movement is achieved by applying a force to the crown of a tooth in the direction in which we want the tooth to move.
- Aggression movement: Aggression movement is achieved by applying a force to a tooth whose line of action passes through the center of resistance of the tooth.
- Ingression movement : the intrusion movement is achieved by applying a force in the gingival direction along the long axis of the tooth.
- Egression movement: egression can be achieved by the removal of the occlusal contacts of the tooth.
- Rotational movement: Rotational movement is achieved by applying a torque of forces to the crown of a tooth.
3-Orthodontic means used in periodontics: we use removable devices such as the Hawley plate
and fixed devices.
4-Goals of orthodontic treatment in periodontics: orthodontics allows to
-restore harmonious bone and gingival morphology
-provide a stable occlusal pattern
-improve crown-root ratios
5-Effects of orthodontic forces on the periodontium : after the implementation of an orthodontic anchor, the periodontal tissues will undergo changes that will allow and follow dental movements. The thickness of the superficial and deep periodontal tissues plays a role in the orthodontic response. Proposals for a typological classification of the periodontium have been given.
Pougatch proposes to distinguish:
– thick and/or normal periodontium involving alveolar bone with a trabecular bone part over almost its entire height, both at the interproximal and vestibular and lingual or palatal levels. This bone is protected by a gingiva of significant height and thickness.
-thin periodontium : the alveolar bone has over a significant part of its height, most often on its external faces, a thin cortex protected by a thin and not very high gum.
-Dentoperiodontal dysharmony (DPD): due to ectopic dental eruption or morphological problems, the alveolar processes present primitive bone dehiscences on many, if not all, vestibular and/or lingual and palatal surfaces. This situation is associated with a generalized insufficiency of gingival height and thickness leading to agingivitis.
Effects of orthodontic forces on the deep periodontium : The effect of orthodontic forces on the deep periodontium can be distinguished according to the intensity of the force (heavy or light) and the direction of the force relative to the alveolar wall (pressure or tension force).
- Depending on the intensity of the force: the use of light forces will be preferred because it allows adaptation of the structures of the deep periodontium and minimizes the creation of anatomical risk factors (bone dehiscence).
- According to the type of orthodontic movements:
-dental intrusion: we have a pressure force in the whole or the apical part of the root, which leads to predominant phenomena of osteolysis.
-dental egression: we have tension forces throughout the desmodont, leading to phenomena of bone apposition and gingival extension.
-translation: there is pressure on one side of the root and tension on the other.
-rotation: in the case of rotation, we have, around the hypomochlion, cervical pressure on the side of the force effect and apical on the other. The tension phenomena are symmetrically opposed.
Periodontics-orthodontics interrelationships
Effects of orthodontic forces on the superficial periodontium : several points should be emphasized at the level of the gingival tissues:
The metabolism of supracrestal collagen fibers would be much slower than that of desmodontal fibers. This would explain a significant percentage of postorthodontic relapses, due to a phenomenon of tension of these fibers.
-this slowness of gingival remodeling also explains the formation of interdental gingival folds after closing the extraction spaces. These folds undergo remodeling and disappear in 80% of cases within 2 years.
-Yamaguuchi et al. demonstrated a decrease in gingival blood flow under orthodontic forces without clinical consequences.
Influence of age on orthodontic tissue remodeling : young subjects, children and adolescents have more desmodontal fibroblasts than adults, which allows for faster tissue remodeling.
Effects of orthodontic forces on the pathological periodontium : in the presence of bacterial plaque, orthodontic treatment is likely to transform gingivitis into periodontitis and/or aggravate pre-existing periodontitis. This depends on the type of anchorage (bacterial retention), the type of forces used and the direction of orthodontic movement (intrusion and version being more pathogenic than egression).
Effects of orthodontic forces on reduced periodontium : Teeth can be moved without iatrogenic effects in a reduced but healthy periodontium , with light forces. This means that malpositions associated with periodontal disease can be treated, for functional and esthetic purposes, after periodontal healing. Reduced bone support secondary to periodontal disease does not contraindicate orthodontic treatment unless there is insufficient bone remaining to support current functional needs. Repositioning teeth within the bone, in order to direct occlusal forces in the vertical axis, increases the longevity of teeth with reduced bone support.
6-Periodontal lesions of orthodontic origin:
1-Plaque retention: the insertion of orthodontic appliances in the oral cavity leads (by the reliefs and the crevices created) to additional bacterial retention zones. It has thus been demonstrated that removable appliances increase the number of mycotic agents as well as the increase in anaerobic sulcular bacteria. Orthodontic systems therefore constitute an additional risk factor at the periodontal level. This risk linked to the increase in microorganisms could be exacerbated by the cytotoxicity of certain alloys used for orthodontic appliances.
2-Gingivitis and orthodontics: the insertion of intrasulcular bands, bonding substances and bacterial retention facilitate the development of perorthodontic gingivitis. Lesions of the epithelial attachment by orthodontic anchors have been demonstrated. An increase in the bleeding index on probing and the persistence of its bleeding 3 months after removal of the appliances have been noted. The clinic often shows gingival hyperplasia, mainly papillary, during orthodontic treatments. These hyperplasias most often disappear spontaneously after removal of the orthodontic appliances. Surgical removal may be necessary to facilitate dental movements.
3-Orthodontic periodontal disease: alveolysis has been observed in young or adult subjects following orthodontic treatment. These early periodontitis cases appear to be reversible in young subjects and irreversible in adults. In any case, they are linked to bacterial retention and should stabilize after the removal of the anchors and the establishment of optimal bacterial control. However, these phenomena aggravate irreversible bone lysis in thin or disharmonious periodontiums (dehiscence).
4-Elastosyndesmotomy: it was described, among others, by Caldwell et al. In 1980. It is an involuntary experimental human periodontal disease, triggered by intrasulcular then desmodontal sliding of orthodontic elastics most often intended to close a median diastema. These lesions can result in the expulsion of the two teeth concerned, following the accumulation of elastics in the apical direction. They are currently, we hope, taking on a historical character.
5-Rhizalysis and root resorption: the application of orthodontic forces not only causes periodontal and bone remodeling, but also, with relatively high frequency, or even systematically, phenomena, most often clastic, cementary and dentinal. When it goes beyond the infraclinical stage, these attacks on the root structure result in lateral and, most frequently in orthodontics, apical resorptions. These rhizalyses are of multifactorial etiology and would be affected at the general level by age (more frequent in adults), sex (female predominance), general condition (obesity, allergy, pregnancy, hormonal disorders, diabetes, growth retardation due to hypothyroidism) and general factors related to the human leukocyte antigen (HLA) group.
At the local level, the shape of the apices, wide pulps, endodontic treatments, dental trauma, occlusal parafunctions, the type of malocclusion corrected (class II, supra clusie, open bite) are mentioned. This seems to have to be related to the type of dental movement involved, intrusion and torque movements being the most likely to trigger rhizalysis, as well as to the extent of the movement carried out.
Periodontics-orthodontics interrelationships
6-Orthognathic and periodontal surgery: complications such as periodontal recession and/or rhizalysis appear very rarely following orthognathic surgery. These complications are frequent in patients with thin or dysharmonic periodontium undergoing mandibular advancement. Orthodontic and orthognathic treatments pose a variable risk to periodontal structures depending on the individuals, the forces and the moments considered.
7-pulp mortification caused by significant or continuous forces.
Periodontics-orthodontics interrelationships
7-Contribution of periodontics to orthodontic TRT : periodontal therapies will support orthodontic treatments by facilitating these treatments, by preventing per- and post-orthodontic periodontal complications, by correcting these same complications.
1-facilitate orthodontic treatments: periodontal surgery can improve orthodontic movements by removing certain mucogingival tissue obstacles (fiber, frenum, hyperplasia), by acting at the bone level and/or by creating implant anchors.
a – Supracrestal fibrotomy: the tension of the cementogingival and desmodontal fibers can persist for more than a year after completion of treatment , thus becoming a source of relapse that retention does not always prevent. In order to minimize the risk of relapse, it has been proposed to section the cementogingival fibers by a circumferential intrasulcular incision, reaching the bony crest or even the mucogingival line. Modifications have been made to this technique by adding vertical interdental incisions.
b – Correction of gingival hyperplasia: papillary gingival hyperplasia is a frequent and reversible complication after removal of orthodontic systems. It rarely poses a problem for the proper conduct of treatment. Only an adaptation of plaque control techniques is most often necessary. On the other hand, generalized hyperplasia, of drug or genetic origin, is characterized histologically by a very high collagen density which often hinders first the eruption of teeth, then any orthodontic movement. The periodontist is called upon to intervene in order to remove this tissue obstacle.
c -Frenectomy: this is a surgical procedure which consists of the removal of the median frenulum when it is located high up.
d – Bone facilitation surgery: orthodontic corticotomy, bone distraction: the principle is to facilitate and/or accelerate orthodontic movements by preparing the cortical alveolar bone, or cortical and cancellous bone.
e- implant anchoring in orthodontics
2-prevention of per- and postorthodontic periodontal diseases: periodontal complications and carious lesions are major risks associated with orthodontic treatments . Periodontal complications are of two types: bacterial (this is periodontitis), tissue: these are periodontal recessions that can be associated with periodontitis, but are most often correlated with problems of trauma to the marginal periodontium by orthodontic anchors and dental movements.
- Prevention of periodontitis
-screening of at-risk subjects: screening will be based on medical and periodontal questioning by looking for pathologies or problems associated with periodontitis (diabetes, stress, smoking) and family periodontal history.
Clinical and radiographic examination looking for signs of inflammation and bone lysis.
Bacteriological tests and genetic tests which are reserved for cases requiring the practitioner’s vigilance.
– preorthodontic periodontal therapies: any diagnosis of gingivitis and/or periodontitis requires control of this pathology prior to orthodontic treatment. Treatment includes control of bacterial etiologies through mechanical and drug therapeutic approaches. The most severe lesions require surgical therapies according to a chronology depending on the orthodontic treatment.
-perorthodontic supportive periodontal therapies : maintenance or supportive periodontal treatment is an essential step in maintaining the healing of periodontitis. Since orthodontics induces additional periodontal risk factors and therefore relapse, perorthodontic periodontal maintenance on a patient who has suffered from periodontolysis involves a session every 2 months for the entire duration of the orthodontic treatment.
Periodontics-orthodontics interrelationships
- Prevention of periodontal recessions: recessions are relatively common complications of orthodontics. Studies show a correlation between certain orthodontic movements and the appearance of gingival recessions. Orthodontic movement is also the potential cause of creation or aggravation of bone dehiscence which predisposes to the development of gingival recessions. (version towards the mucogingival line, periodontal thickness, the presence of gingival inflammation).
Periodontics-orthodontics interrelationships
Preventive muco-gingival surgery: it consists of surgical intervention to create or strengthen the gingival tissue. Prevention of recessions is done by optimal bacterial control, screening for dento-maxillary disharmonies or performing muco-gingival surgery for tissue supply.
Treatment of per and post orthodontic periodontal recessions : when one or more root denudations occur during or at the end of orthodontic treatment, recourse to muco-gingival coverage surgery is the rule. The choice of surgical protocol depends on the height and width of the recession , their number, and the existence of proximal donor sites or not (their width or thickness).
8-Contribution of orthodontics to periodontal therapies
a-Orthodontics and prevention of periodontal diseases :
– periodontal consequences of orthodontic corrections : certain clinical studies highlight the positive impact of correcting certain positional anomalies.
-Correction of malpositions and crowding : primary or recurrent incisor crowding is regularly correlated, in the absence of appropriate plaque control education, with an increase in bacterial deposits, tartar, and signs of gingivitis. Their correction, by facilitating hygiene, allows better control of inflammation.
b-Orthodontic treatment of periodontal disease manifestations:
– correction of migrations secondary to periodontitis : severe periodontitis often results in dental migrations (vestibuloversion and secondary diastemas in the anterior maxillary sector, mandibular incisor egression) and in the case of tooth loss in the posterior sectors, by mesio or distoversion often leading to a loss of molar wedging. These consequences of periodontal diseases will be corrected orthodontically after control of the infection and will be part of a global therapeutic plan.
Periodontics-orthodontics interrelationships
-Orthodontic treatment of periodontal lesions: a number of periodontal lesions can be corrected by the application of light orthodontic forces that pull the periodontal structures with the displaced teeth. The tension forces trigger bone apposition phenomena and an elongation of the gingival height from the mucogingival line.
1-correction of infraosseous lesions that cannot be treated surgically (hemisepta) by egression.
2-treatment of localized gingival recessions by intrusion
3-recovery of fractured or decayed subgingival teeth: slow egression taking the periodontium with its tooth.
4-creation of implant sites in areas with severe periodontal disease: slow and progressive orthodontic egression of the affected teeth allows bone and gingival augmentation which, after extraction of the tooth, will serve as an implant site.
5-treatment of furcations: mandibular class III furcations can be treated by hemisection in order to transform the two roots of a molar into a premolar equivalent; however, the inter-radicular embrasure does not always allow for optimal prosthetic morphology and a mini orthodontic displacement can improve the situation.
Periodontics-orthodontics interrelationships
6-Reduction of horizontal alveolysis by orthodontic intrusion: this involves intruding the teeth into the lysed alveolar bone in order to increase root support and thus reduce supraosseous pockets. It is essential to use very light forces to minimize the risk of rhizalysis.
Periodontics-orthodontics interrelationships
9-Contraindication of orthodontic treatment:
-excessive dental mobility
-terminal periodontal disease
-Aggressive periodontitis
– altered general condition (decalcification, AIDS, immune deficiency)
-uncooperative patient
10-Treatment planning: the choice of orthodontic time in the treatment of a patient with periodontitis requires taking into consideration several factors:
- Control of the periodontal inflammation and infection , which requires the implementation of complete initial therapy which may include flap procedures, known as sanitation procedures.
- Surgical indications for bone treatment: in the event of an indication for bone treatment, the interventions are carried out following orthodontic treatment which, through the changes caused, can modify the morphology of the lesions by reducing their severity or eliminating them.
- Cases of very severe lesions: only cases of very severe lesions that risk compromising the conservation of the teeth concerned are treated prior to orthodontics. In this case, a healing period of 8 weeks for regeneration cases, 4 to 12 months for filling cases depending on the resorbability of the material used, must be respected.
- Bimonthly perorthodontic support therapy: it must be strictly adhered to.
So the therapeutic regimen to follow in our patients, especially in the presence of reduced periodontium, is as follows.
1-periodontal diagnosis: a systemic survey, screening for gingival bleeding and performing a retro-alveolar radiographic status make it possible not to miss unstabilized periodontitis.
2-etiological periodontal treatment aimed at controlling inflammation. By
-plate control
-root planing
– supportive periodontal care
Periodontics-orthodontics interrelationships
Periodontal treatment can then begin under strict periodontal supervision . Supportive periodontal care will be done every two months (plaque control, probing of pockets and furcations, checks for bleeding indices, and professional prophylaxis).
During orthodontic treatment, the easiest sign to detect is the appearance of bleeding when probing. Regular probing of the pockets and taking X-rays can detect any loss of attachment before it takes on alarming proportions.
In case of gingival hyperplasia, prophylaxis is reinforced and the hyperplasia is treated by internal bevel gingivectomy.
If a recession appears during orthodontic treatment, it is necessary to stop the movement for 5 to 6 weeks, graft, wait another 5 to 6 weeks before resuming the movement).
3-a fixed retention: is necessary after orthodontics on reduced periodontium to avoid relapse. After the completion of active orthodontic treatment, the retention will allow the periodontium to reconstitute itself. The repair of the various periodontal support tissues will be clinically objectified by the absence of mobility. The retention according to BUYLE-BODIN and GIRAUD makes it possible to compensate for the temporary inability of the periodontium of displaced teeth, weakened by the orthodontic treatment, to adapt to a normal function. The retention is done in two phases.
Periodontics-orthodontics interrelationships
– passive contention : includes the adaptation of periodontal tissues, especially collagen, to their new environment.
– active contention : essentially consisting of occlusal balancing which will achieve the functional integration of the previously moved teeth.
This balancing will be done as soon as possible after the end of active orthodontic treatment, that is to say as soon as the teeth have acquired relative stability. In practice, the best time to do it is 3 or 4 months after the start of retention in adults, and 3 months after the end of retention in children.
Duration of retention : the duration of retention can vary from 80 days to 1 year. Since recurrence is effective 2 hours after removal of the device, retention will be instituted as soon as possible.
Advantages of orthodontic mini-screws : to move teeth or groups of teeth, it is necessary to rely on an anchor. In classic orthodontic treatments, this anchor is taken from the teeth by means of bonded attachments . However, there is a risk of parasitic movements linked to the mobilization of this anchor. In cases where the anchor is absent, or when the risk of loss of anchorage appears too high (reduced periodontium for example), the use of skeletal anchorage means may prove judicious or even essential. These devices allow the movement of an entire dental segment, which is more complicated with purely dental anchorage.
Conclusion :
We are convinced that in the coming years, the most important advances in orthodontics will be made in collaboration with periodontology and occlusodontology.
Orthodontists and periodontists must help each other and know the techniques of other disciplines to establish the best possible treatment plans.
Bibliography:
-A.SALVADORI F. LOUSE M. REBOUL orthodontics periodontology EMC Paris France, stomatology 23602 E-103- 1986
-BERCY TENENBAUM periodontology from diagnosis to therapy by BOECK- university
-D Boes E. Maujean P POUGATCH H Tarragano interrelation orthodontics-periodontology EMC Elsevier, Paris odontology, 23-448-A-10
-IRVING GLICKMAN clinical periodontology prevention, diagnosis and treatment of periodontal diseases in the context of general dentistry. Edition cdp 57, rue Dulong-75017 Paris.
-Phillipe BOUCHARD periodontology and implantology