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Adjunctive role of Orthodontic Therapy in Periodontology

Concept of Perio Ortho, its role in prevention and treatment of periodontal diseases

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Adjunctive role of Orthodontic Therapy in Periodontology

  2. 2. INTRODUCTION  Orthodontic treatment is based on the principles that if prolonged pressure is applied to a tooth, tooth movement will occur as the bone around the tooth remodels.  Orthodontic tooth movement may be a substantial benefit to the adult periorestorative patient. Many adults who seek routine restorative dentistry have problems with tooth malposition that compromise their ability to clean and maintain their dentitions.  If these individuals also are susceptible to periodontal disease, tooth malposition may be an exacerbating factor that could cause premature loss of specific teeth.  The loss of periodontal support or teeth may result in elongation, spacing and proclination of incisors, rotation and tipping of premolars and molars with collapse of the posterior occlusion, and decreasing vertical dimension.
  3. 3. PHYSIOLOGICAL RESPONSE TOHEAVY PRESSURE AGAINST A TOOTH:- TIME (SECONDS) EVENT <1 PDL fluid incompressible, alveolar bone bends, piezoelectric signal generated 1-2 PDL fluid expressed, tooth moves within PDL space 3-5 PDL fluid squeezed out, tissues compressed; immediate pain if pressure is heavy Orthodontic tooth movement is made possible by the application of prolonged forces. In addition, light prolonged forces in the natural environment- forces from the lips, cheeks, or tongue resting against the teeth- have the same potential as orthodontic forces to cause the teeth to move to a different location.
  4. 4. PERIODONTALLIGAMENTANDBONERESPONSETO SUSTAINEDORTHODONTIC FORCE  The response to sustained force against the teeth is a function of force magnitude: heavy forces lead to rapidly developing pain, necrosis of cellular elements within the PDL, and the phenomenon of “undermining resorption” of alveolar bone near the affected tooth.  Lighter forces are compatible with survival of cells within the PDL and a remodeling of the tooth socket by a painless “frontal resorption” of the tooth socket.  In orthodontic practice, the objective is to produce tooth movement as much as possible by frontal resorption, recognizing that some areas of PDL necrosis and undermining resorption will probably occur despite efforts to prevent this.
  5. 5. BIOLOGIC CONTROL OF TOOTH MOVEMENT  It is necessary to consider the biologic control mechanism that leads from the stimulus of sustained force application to the response of orthodontic tooth movement. Two control mechanisms have been proposed :  Biologic electricity.  Pressure- tension theory PRESSURE- TENSION THEORY Alteration in blood flow associated with pressure within PDL Formation & release of chemical messengers Activation of PDL cells & Bone remodeling Cellular differentiation & activity leads to bone remodeling by: bone resorption (-) on compression side. *Bone deposition (+) on tension side.
  6. 6. EFFECT OF ORTHODONTIC FORCES ON PERIODONTIUM  When a removable appliance is worn less than 4 to 6 hours per day, it will produce no orthodontic effects, but above this duration threshold, tooth movement does occur.  Experiments have shown increase levels of PG and IL-1ß in PDL within short time after pressure application. Also, evidence shows PG release when cells are mechanically deformed. Other chemical messengers- cytokines and NO and other regulators of cellular activity also involved.  For tooth movement to occur osteoclasts must be formed to remove bone from the area adjacent to compressed PDL. Osteoblasts are needed for formation of bone on tension side and remodel resorbed areas on pressure side.  PG E stimulates both osteoclastic and osteoblastic activity
  7. 7.  In clinical orthodontic it is difficult to avoid pressure that produces at least some avascular area in the PDL, and it has been suggested that releasing pressure against a tooth at intervals while maintaining the pressure for enough hours to produce the biologic response, could help in maintaining tissue vitality
  8. 8. Interrelationship of orthodontic tooth movement with periodontal health: 1.Loss of periodontal attachment and bone relative to orthodontic therapy  In patients with active periodontitis (that is, plaque infected deep pockets evidenced by bleeding on probing), orthodontic tooth movement may accelerate the disease process, even when good oral hygiene is practiced.  Orthodontic bodily movement into plaque induced infra bony defects can be successfully performed, provided that the periodontal lesion is eliminated before tooth movement is began, and excellent oral hygiene is maintained.
  9. 9. 2. Gingival recession relative to orthodontic therapy  Orthodontic tooth movement per se does not cause gingival recession".  In areas of thin labial tissue, labial orthodontic tooth movement can result in bony dehiscence, creating an environment in which plaque / or toothbrush trauma may cause sudden recession.  Many researchers and clinicians agree that this thin labial tissue should be augmented before labial orthodontic tooth movement is begun. It is interesting to note that in areas of a labially positioned tooth with dehiscence, bone may reform and gingival thickness may increase when the tooth is moves lingually
  10. 10.  In regard to relationship between rapid maxillary expansion procedures and gingival recession Grabe r and Vanarsdall stated that if the maxillary expansion is performed after the mid palatine suture begin to fuse (after approximately 14-16years of age), there is a greater risk of recession of the buccal gingival tissue of the maxillary premolars and molars later in life.  Periodontal evaluation of a potential adult orthodontic patient must include not only the response to periodontal probing but also level and condition of attached gingiva.  We nnstro m e t al (1 9 8 7 ) found no relationship between initial width of keratinized gingiva and tendency for development of gingival recession during orthodontic tooth movement in monkeys.  Instead it is the buccolingual thickness which maybe the determining factor for development of gingival recession and attachment loss at sites with gingivitis during orthodontic treatment.
  11. 11. ORTHODONTIC TOOTHMOVEMENT IN ADULTS WITHPERIODONTAL TISSUE BREAKDOWN  With properly performed treatment, extensive orthodontic tooth movement can be made in adults with a reduced but healthy periodontium without further periodontal deterioration.
  12. 12.  More recent studies on much larger groups (350-400 patients) of consecutively treated adult patients from different practice s (Ne lso n & Artun 1 9 9 7 , Re e t al. 20 0 0 ) have confirmed that  (1) pretreatment evidence of periodontal tissue destruction is no contraindication for orthodontics,  (2) orthodontic therapy improves the possibilities of saving and restoring a deteriorated dentition, &  (3) the risk of recurrence of an active disease process is not increased during appliance therapy
  13. 13. Esthetic finishing of treatment results  The presence of papillae between the maxillary incisors is a key esthetic factor after orthodontic treatment.  Normally, when a long-standing crowding with incisor overlap is corrected orthodontically in adults, it is generally not possible to have an intact papilla.  This is because the contact point becomes located too far incisally on the triangular crowns that have not had a normal interdental wear pattern.  Similarly, in patients with advanced periodontal disease and destruction of the crestal bone between the incisors, the papillae may be absent.  This produces unaesthetic gaps between the teeth after orthodontics.  The best method of correcting this problem is to recontour the mesiodistal surfaces of the incisors during the orthodontic finishing stage (Tuverson 1980).  When the diastema thus created is closed, the roots of the teeth can come closer together.  The contact point is lengthened and moved apically, and the papilla can fill out the interdental space more easily.
  14. 14. Retention - problems and solutions; long-termfollow-up  According to Pro ffit (1 9 7 8 ), two major primary factors are involved in the equilibrium which determines the final position of teeth.  These are the resting pressures of lip or cheek and tongue, and forces produced by metabolic activity within the periodontal membrane.  With an intact periodontium, unbalanced tongue-lip forces are normally counteracted by forces from the periodontal membrane.  However, when the periodontium breaks down, its stabilizing function no longer exists and the incisors begin to move.  A consequence of this concept would be that persons with advanced periodontal disease and tooth migration would need permanent retention after the orthodontic correction.
  15. 15. SPECIFIC FACTORS ASSOCIATEDWITHORTHODONTIC TOOTH MOVEMENT IN ADULTS 1. Tooth movement into infrabony pockets  Orthodontic forces pe r se are unlikely to convert gingivitis into destructive periodontitis.  The plaq ue -induce d le sio n in g ing ivitis is co nfine d to the supra-alve o lar co nne ctive tissue , whe re as tissue re actio ns to o rtho do ntic fo rce s o ccur in the co nne ctive tissue be twe e n the ro o t and the alve o lar bo ne .  Infrabony pockets, i.e. angular bony defects with inflamed connective tissue and epithelium apical to the bone crest, may develop as a result of destructive periodontitis.  Infrabony pockets may also be created by orthodontic tipping and/ or intruding movements of teeth harboring plaque (Ericsson et al. 1977).
  16. 16.  The effect of bodily tooth movement into infrabony defects has been evaluated experimentally in monkeys (Polson et al. 1984) and in dogs (Wennstrom et al. 1993)  Provided elimination of the subgingival infection was performed before the orthodontic tooth movement was started, no detrimental effects on the attachment level were observed.  The angular bony defect was eliminated by the orthodontic treatment, but no coronal gain of attachment was found and a thin epithelial lining covered the root surface corresponding to its pretreatment position.
  17. 17. CONCLUSION  It was the re fo re co nclude d that o rtho do ntic to o th m o ve m e nt into infrabo ny pe rio do ntal de fe cts had no favo rable e ffe cts o n the le ve lo f co nne ctive tissue attachm e nt.  Ho we ve r, it was po ssible to m o ve te e th with re duce d he althy pe rio do ntium witho ut additio nalattachm e nt lo ss.  If, o n the o the r hand, the o rtho do ntic tre atm e nt invo lve d m o ve m e nt o f te e th into and thro ug h a site with inflam m atio n and ang ular bo ne lo ss, an e nhance d rate o f pe rio do ntal de structio n was no te d. Schematic illustration of persisting junctional epithelium subsequent to orthodontic tooth movement (direction of arrow) into an infrabony pocket.
  18. 18. 2. To o th m o ve m e nt into co m pro m ise d bo ne are as  O rtho do ntic to o th m o ve m e nt m ay so m e tim e s be pe rfo rm e d in adults with partially e de ntulo us de ntitio ns ( due to ag e ne sis o r pre vio us e xtractio ns o f te e th) and such patie nts m ay have a m o re o r le ss co m pro m ise d alve o lar pro ce ss.  Expe rim e ntal re po rts (Lindsko g - Sto kland e t al. 1 9 9 3) and clinical studie s (Ste po vich 1 9 7 9 , Ho rn & Turle y 1 9 8 4, Go ldbe rg & Turle y 1 9 8 9 , Thilande r 1 9 9 6 ) have sho wn that a re ductio n in ve rtical bo ne he ig ht is no t a co ntraindicatio n fo r o rtho do ntic to o th m o ve m e nt to wards, o r into , the co nstricte d are a.  Mandibular se co nd m o lars can be m o ve d m e sially thro ug h re m o de le d e de ntulo us first m o lar are as in adults with o nly a lim ite d re ductio n in ve rticalbo ne he ig ht, ave rag ing -1 . 3 m m (Ho rn & Turle y 1 9 8 4).  Space clo sure is po ssible also in e de ntulo us m axillary first m o lar are as, altho ug h ve rtical bo ne lo ss and so m e space re -o pe ning can be a co m plicatio n.
  19. 19.  Histo lo g ic o bse rvatio ns in anim al e xpe rim e nts have co nfirm e d that whe n lig ht fo rce s we re applie d to m o ve te e th bo dily into an are a with re duce d bo ne he ig ht, a thin bo ne plate was re cre ate d ahe ad o f the m o ving to o th.  The ke y to m o ving te e th with bo ne is dire ct re so rptio n in the dire ctio n o f to o th m o ve m e nt, and avo iding hyalinizatio n. Te e th can be m o ve d with bo ne into the m axillary sinus also (Me lse n 1 9 9 1 ). Note radiographic visualization of the thin bone spicule on the mesial side of the second molar (arrow in d). Although the molar is moved to contact the second premolar, a marked gingival invagination is present in the area (arrow in c).
  20. 20.  Altho ug h the re sults o f clinical e xpe rim e nts and fo llo w- ups are e nco urag ing , pro vide d lig ht fo rce s are use d and e xce lle nt o ral hyg ie ne is m aintaine d, it is pro bably wise no t to stre tch the indicatio ns fo r to o th m o ve m e nt into co nstricte d bo ne are as to o far.  Marke d g ing ivalinvag inatio ns are so m e tim e s se e n in such are as.
  21. 21. 3. To o th m o ve m e nt thro ug h co rticalbo ne  Expe rim e ntal studie s in anim als have de m o nstrate d that whe n a to o th is m o ve d bo dily in a labial dire ctio n to wards and thro ug h the co rtical plate o f the alve o lar bo ne , no bo ne fo rm atio n will take place in fro nt o f the to o th (Ste ine r e t al. 1 9 8 1 , Karring e t al. 1 9 8 2).  Afte r initial thinning o f the bo ne plate , a labial bo ne de hisce nce is the re fo re cre ate d. Fo r e xam ple  (1 ) in the m andibular ante rio r re g io n due to fro ntal e xpansio n o f inciso rs (We hrbe in e t al. 1 9 9 4),  (2) in the m axillary po ste rio r re g io n during late ral e xpansio n o f cro ss- bite s (Gre e nbaum & Zachrisso n 1 9 8 2),  (3) ling ually in the m axilla asso ciate d with re tractio n and ling ual ro o t to rq ue o f m axillary inciso rs in patie nts with larg e o ve rje ts (Te n Ho e ve & Mulie 1 9 7 6 ), and  (4) by pro no unce d traum atic jig g ling o f te e th (Nym an e t al. 1 9 8 2).
  22. 22. Extrusio n and intrusio n o f sing le te e th - e ffe cts o n pe rio do ntium , clinicalcro wn le ng th and e sthe tics  Extrusion  O rtho do ntic e xtrusio n o f te e th, o r so -calle d "fo rce d e ruptio n", m ay be indicate d fo r  (1 ) shallo wing o ut intrao sse o us de fe cts  (2) fo r incre asing clinicalcro wn le ng th o f sing le te e th.  The fo rce d e ruptio n te chniq ue was o rig inally de scribe d by Ing be r (1 9 7 4) fo r tre atm e nt o f o ne -walland two -wallbo ny po cke ts that we re difficult to handle by co nve ntio nalthe rapy alo ne .  The e xtrusive to o th m o ve m e nt le ads to a co ro nalpo sitio ning o f intact co nne ctive tissue attachm e nt, and the bo ny de fe ct is shallo we d o ut.  This was co nfirm e d in anim ale xpe rim e nts (van Ve nro y & Yukna 1 9 8 5) and clinicaltrials.  Be cause o f the o rtho do ntic e xtrusio n, the to o th willbe in suprao cclusio n. He nce , the cro wn o f the to o th willne e d to be sho rte ne d, in so m e case s fo llo we d by e ndo do ntic tre atm e nt.
  23. 23.  During the e lim inatio n o f an intrao sse o us po cke t by m e ans o f o rtho do ntic e xtrusio n, the re latio nship be twe e n the CEJ and the bo ne cre st is m aintaine d.  This m e ans that the bo ne fo llo ws the to o th during the e xtrusive m o ve m e nt. This m ay o r m ay no t be be ne ficial de pe nding o n the clinical situatio n.  In o the r wo rds, it is so m e tim e s de sirable to have the pe rio do ntium fo llo w the to o th and in o the r situatio ns it is de sirable to m o ve a to o th o ut o f the pe rio do ntalsuppo rt. Extrusionwithperiodontium  O rtho do ntic e xtrusio n o f a sing le to o th that ne e ds to be e xtracte d is an e xce lle nt m e tho d fo r im pro ve m e nt o f the m arg inalbo ne le ve lbe fo re the surg ical place m e nt o f sing le im plants. No t o nly the bo ne , but also the so ft suppo rting tissue s will m o ve ve rtically with the te e th during o rtho do ntic e xtrusio n.
  24. 24. Regenerative procedures and orthodontic tooth movement  The development of barrier membranes to prevent cells of the epithelium and gingival connective tissue from colonizing the decontaminated root surface, as well as the use of Emdogain, would appear to provide a distinct improvement in orthodontic therapy in the periodontally compromised patient.  New supracrestal and periodontal ligament collagen fibers may be gained on the tension side, which can transfer the orthodontic force stimulus to the alveolar bone (Diedrich 1996).  The regenerative techniques would be advantageous associated with both extrusion and intrusion of teeth with infrabony defects, and for uprighting of tipped molars with mesial angular lesions.
  25. 25. Severe intraosseous defect between the right central and lateral incisors (b). Three months after GTR treatment (GoreTex membrane) partial reossification is evident (c), possibly with new attachment. Orthodontic leveling (d) with controlled space closure and intrusion of the lateral incisor.
  26. 26. MINOR SURGERY ASSOCIATED WITH ORTHODONTIC THERAPY  Fiberotomy  The problem of relapse of orthodontically treated teeth in general, and rotated teeth in particular, has been well recognized for years.  Methods, to reduce the occurrence of rotational relapse may include (1) Complete correction, or overcorrection, of rotated teeth, (2) Long-term retention with bonded lingual retainers, and (3) The use of fiberotomy. Two soft-tissue periodontal entities may influence the stability:  The principal fibers of the periodontal ligament, and the supra-alveolar fibers.  
  27. 27.  Whereas the fibers of the periodontal ligament and transseptal groups remodel efficiently and histologically completely in only 2 to 3 months after orthodontic rotation of teeth, the supra-alveolar fibers are apparently more stable, with a slow turnover.  The supracrestal gingival tissues seemingly do contribute to rotational relapse, as evidenced by the effect of the circumferential supracrestal fiberotomy (CSF) technique. First developed by Edwards (1970)  Basically this technique consists of inserting a scalpel into the gingival sulcus and severing the epithelial attachment surrounding the involved teeth.  The blade also transects the transseptal fibers by interdentally entering the periodontal ligament space.
  28. 28. Adult male patient with median diastema, small teeth, and low attaching frenum (a,b), in whom several different types of minor surgeries were performed (d) in order to improve and stabilize the orthodontic treatment result (c). Gingivectomy over four incisors increased crown length. Note healing with intact stippling 2 months later (e,f). The surgical procedure also comprised frenotomy and fiberotomies with interdental vertical cuts
  29. 29. Frenotomy  Bergstrom et al (1973) stated that the probability for diastema in the long run is the same whether or not frenectomy is preformed. Earlier frenectomy extending into palatal surface was advocated. But this leads to loss of inter dental papilla between upper central incisors.  So, the frenotomy by Edwards (1977) was introduced, which represents a more gentle operation, with only partial removal of frenum and with the purpose of relocating the attachment in an apical direction.
  30. 30.  Gingivectomy  If the gingival discrepancy is apparent, however, one of four different techniques may be used.  Gingivectomy  Intrusion and incisal restoration or porcelain laminate veneer  Extrusion + fiberotomy + porcelain crown  Surgical crown lengthening, by flap procedure and ostectomy/osteoplasty of bone (Bragger et al 1992)  Clinical and histologic examination demonstrated that it was possible to permanently increase clinical crown length after orthodontic treatment by making a labial gingivectomy to the bottom of the clinical pocket.  The healing and regeneration of the gingiva was uneventful, provided excellent oral hygiene was maintained in the wound area for 2 months.   
  31. 31. BENEFITS OF ORTHODONTIC THERAPY 1. Aligning crowded or malposed maxillary or mandibular anterior teeth permits the adult patient better access to clean all surfaces of their teeth adequately. This could be a tremendous advantage for patients who are susceptible to periodontal bone loss or do not have the dexterity to maintain their oral hygiene. 2. Vertical orthodontic tooth repositioning can improve certain types of osseous defects in periodontal patients. Often the tooth movement eliminates the need for resective osseous surgery. 3. Orthodontic treatment can improve the esthetic relationship of the maxillary gingival margin levels before restorative dentistry. Aligning the gingival margins orthodontically avoids gingival recontouring, which could require bone removal and exposure of the roots of the teeth. 4. Orthodontic treatment allows open gingival embrasures to be corrected to regain lost papilla.
  32. 32. ORTHODONTIC TREATMENT OF OSSEOUS DEFECTS Hemiseptal Defects  Hemiseptal defects are one-or two-wall osseous defects that often are found around mesially tipped teeth or teeth that have supererupted.  Usually, these defects can be eliminated with the appropriate orthodontic treatment.  In the case of the tipped tooth, uprighting and eruption of the tooth levels the bony defect.  If the tooth is supererupted, intrusion and leveling of the adjacent cementoenamel junctions can help level the osseous defect.
  33. 33. This patient was missing the mandibular left second premolar, and the first molar had tipped mesially (A). Pretreatment periapical radiograph (B) revealed a significant hemiseptal osseous defect on the mesial of the molar. To eliminate the defect, the molar was erupted, and theocclusal surface was equilibrated (C). The eruption was stopped when the bone defect was leveled
  34. 34.  After the completion of orthodontic treatment, these teeth should be stabilized for at least 6 months and reassessed periodontally.  In the periodontally healthy patient, orthodontic brackets are positioned on the posterior teeth relative to the marginal ridges and cusps.  However, some adult patients may have marginal ridge discrepancies caused by uneven tooth eruption.  When marginal ridge discrepancies are encountered, the decision as to where to place the bracket or band is not determined by the anatomy of the tooth.  In these patients, it is important to assess these teeth radiographically to determine the interproximal bone level.
  35. 35. If the bone is flat and a marginal ridge discrepancy is present, the orthodontist should not level the marginal ridges orthodontically. In these situations, it may be necessary to equilibrate the crown of the tooth. (B) showed that the interproximal bone was flat. To avoid creating a hemiseptal defect, the occlusal surface of the first molar was equilibrated and malocclusion was corrected orthodontically
  36. 36. Advanced Horizontal Bone Loss  In a patient with advanced horizontal bone loss, the bone level may have receded several millimeters from the CEJ.  As this occurs, the crown-to-root ratio becomes less favorable. By aligning the crowns of the teeth, the clinician may perpetuate tooth mobility by maintaining an unfavorable crown-to-root ratio.  In addition, by aligning the crowns of the teeth and disregarding the bone level, significant bone discrepancies occur between healthy and periodontally diseased roots. This could require periodontal surgery to ameliorate the discrepancies.  Many of these problems can be corrected by using the bone level as a guide to position the brackets on the teeth.  In these situations the crowns of the teeth may require considerable equilibration. If the tooth is vital, the equilibration should be performed gradually to allow the pulp to form secondary dentin and insulate the tooth during the equilibration process.
  37. 37.  The goal of equilibration and creative bracket placement is to provide a more favorable bony architecture as well as a more favorable crown-to-root ratio.  In some of these patients, the periodontal defects that were apparent initially may not require periodontal surgery after orthodontic treatment.
  38. 38. Furcation Defects  Furcation defects can be classified as incipie nt (class I), m o de rate (class II), o r advance d (class III).  These lesions require special attention in the patient undergoing orthodontic treatment. Often the molars require bands with tubes and other attachments that impede the patient’s access to the buccal furcation for home care and instrumentation at the time of recall.  Furcation lesions require special consideration because they are the most difficult lesions to maintain and can worsen during orthodontic therapy. These patients need to be maintained on a 2- to 3-month recall schedule. Detailed instrumentation of these furcations helps minimize further periodontal breakdown.
  39. 39.  If a patient with a class III furcation defect will be undergoing orthodontic treatment, a possible method for treating the furcation is to eliminate it by hemisecting the crown and root of the tooth. However, this procedure requires endodontic, periodontal, and restorative treatment.  If the patient will be undergoing orthodontic treatment, it is advisable to perform the orthodontic treatment first. This is especially true if the roots of the teeth will not be moved apart. In these patients the molar to be hemisected remains intact during orthodontics.  This patient would require 2- or 3-month recall visits to ensure that the furcation defect does not lose bone during orthodontic treatment.
  40. 40.  In some patients requiring hemisection of a mandibular molar with a class III furcation, pushing the roots apart during orthodontic treatment may be advantageous. If the hemisected molar will be used as an abutment for a bridge after orthodontics, moving the roots apart orthodontically permits a favorable restoration and splinting across the adjacent edentulous spaces.  In these patients, hemisection, endodontic therapy, and periodontal surgery must be completed before the start of orthodontic treatment. After completion of these procedures, bands or brackets can be placed on the root fragments and coil springs used to separate the roots. The amount of separation is determined by the size of the adjacent edentulous spaces and the occlusion in the opposing arch. About 7 or 8 mm may be created between the roots of the hemisected molar.
  41. 41.  In some molars with class III furcation defects, the tooth may have short roots, advanced bone loss, fused roots, or other problems that prevent hemisection and crowning of the remaining roots. In these patients, extracting the root with a furcation defect and placing an implant may be more advisable.  If this type of plan has been adopted, the timing of the extraction and placement of the implant can occur at any time relative to the orthodontic treatment. In some patients the implant can be used as an anchor to facilitate prerestorative orthodontic treatment.  The implant must remain embedded in bone for 4 to 6 months after placement before it can be loaded as an orthodontic anchor. It must be placed precisely so that it not only provides an anchor for tooth movement, but also may be used an eventual abutment for a crown or fixed bridge.  If the implant will not be used as an anchor for orthodontic movement, it may be placed after the orthodontic treatment has been completed.
  42. 42. This patient was missing several teeth in the mandibular left posterior quadrant (A). The mandibular left third molar had a class III furcation defect and short roots (B). The third molar was extracted, and two implants were placed in the mandibular left posterior quadrant (C). The implants were used as anchors to facilitate orthodontic treatment (D) and help reestablish the left posterior occlusion (E and F).
  43. 43. Root Proximity  When roots of posterior teeth are close together, the ability to maintain periodontal health and accessibility for restoration of adjacent teeth may be compromised. However, for the patient undergoing orthodontic therapy, the roots can be moved apart, and bone will form between the adjacent roots.  This opens the embrasure beneath the tooth contact, provides additional bone support, and enhances the patient’s access to the interproximal region for hygiene.  This approach generally improves the periodontal health of this area.
  44. 44. Fractured Teeth and Forced Eruption Occasionally, children and adolescents may fall and injure their anterior teeth. If the injuries are minor and result in small fractures of enamel, these can be restored with light-cured composite or porcelain veneers.  In some patients, however, the fracture may extend beneath the level of the gingival margin and terminate at the level of the alveolar ridge; restoration of the fractured crown is impossible because the tooth preparation would extend to the level of the bone.  This over-extension of the crown margin could result in an invasion of the biologic width of the tooth and cause persistent inflammation of the marginal gingiva. It may be beneficial in such cases to erupt the fractured root out of the bone and move the fracture margin coronally so that it can be properly restored.  However, if the fracture extends too far apically, it may be better to extract the tooth and replace it with an implant or bridge.
  45. 45. The following six criteria are used to determine whether the tooth should be forcibly erupted or extracted: 1. Root length: the clinician must know how far to erupt the root. If a tooth fracture extends to the level of the bone, it must be erupted 4 mm. The first 2.5 mm moves the fracture margin far enough away from the bone to prevent a biologic width problem. The other 1.5 mm provides the proper amount of ferrule for adequate resistance form of the crown preparation. The root/crown ratio should be about 1:1. 2. Root form: The shape of the root should be broad and nontapering rather than thin and tapered. A thin, tapered root provides a narrower cervical region after the tooth has been erupted 4 mm. This could compromise the esthetic appearance of the final restoration. 3. Level of the fracture. If the e ntire cro wn is fracture d 2 to 3 m m apical to the le ve lo f the alveolar bone, it is difficult, if not impossible, to attach to the root to erupt it. 4. Relative importance of the tooth. If the patie nt is 7 0 ye ars o f ag e and bo th
  46. 46. 5. Esthetics: If the patie nt has a hig h lip line and displays 2 to 3 m m o f g ing iva whe n sm iling , any type of restoration in this area will be more obvious. Keeping the patient’s own tooth would be much more esthetic than any type of implant or prosthetic replacement. 6. Endodontic/periodontal prognosis. If the to o th has a sig nificant pe rio do ntal de fe ct, it m ay not be possible to retain the root. In addition, if the tooth root has a vertical fracture, the prognosis would be poor, and extraction of the tooth would be the proper course of therapy.  After the tooth root has been erupted, it must be stabilized to prevent it from intruding back into the alveolus. The reason for re intrusio n is the o rie ntatio n o f the principalfibe rs o f the pe rio do ntium . During forced eruption, the periodontal fibers become oriented obliquely and stretched as the root moves coronally. These fibers eventually reorient themselves after about 6 months. Before this occurs, the root can reintrude significantly. Therefore, if this type of treatment is performed, an adequate period of stabilization
  47. 47. To restore the tooth adequately and avoid impinging on the periodontium, the fractured root was extruded 4 mm
  48. 48. Hopeless Teeth Maintained forOrthodontic Anchorage  Patients with advanced periodontal disease may have specific teeth diagnosed as hopeless, which would be extracted before orthodontic therapy. However, these teeth can be useful for orthodontic anchorage if the periodontal inflammation can be controlled. In moderate to advanced cases, some periodontal surgery may be indicated around a hopeless tooth.  Flaps are reflected for debridement of the roots to control inflammation around the hopeless tooth during the orthodontic process. The important factor is to maintain the health of the bone around the adjacent teeth. Periodontal recall is imperative during the process.  After orthodontic treatment, there is a 6-month period of stabilization before reevaluating the periodontal status. Occasionally the hopeless tooth may be so improved after orthodontic treatment that it is retained.
  49. 49. The mandibular right first molar was periodontally hopeless because of an advanced class III furcation defect. The impacted second molar was extracted, but the first molar was maintained as an anchor to help upright the third molar orthodontically (B, C, and D).
  50. 50. ORTHODONTIC TREATMENT OF GINGIVAL DISCREPANCIES Uneven Gingival Margins The relationship of the gingival margins of the six maxillary anterior teeth plays an important role in the esthetic appearance of the crowns. The following four factors contribute to ideal gingival form: 1. The gingival margins of the two central incisors should be at the same level. 2. The gingival margins of the central incisors should be positioned more apically than the lateral incisors and at the same level as the canines. 3. The contour of the labial gingival margins should mimic the CEJs of the teeth. 4. A papilla should exist between each tooth, and the height of the tip of the papilla is usually halfway between the incisal edge and the labial gingival height of contour over the center of each anterior tooth. Therefore the gingival papilla occupies half of the interproximal contact, and the adjacent teeth form the other half of the contact.
  51. 51.  However, some patients may have gingival margin discrepancies between adjacent teeth. These discrepancies may be caused by abrasion of the incisal edges or delayed migration of the gingival margins.  When gingival margin discrepancies are present, the proper solution for the problem must be determined: orthodontic movement to reposition the gingival margins or surgical correction of gingival margin discrepancies.  To make the correct decision, it is necessary to evaluate four criteria. First, the relationship between the gingival margin of the maxillary central incisors and the patient’s lip line should be assessed when the patient smiles. If a gingival margin discrepancy is present but the discrepancy is not exposed, it does not require correction.  If a gingival margin discrepancy is apparent, the second step is to evaluate the labial sulcular depth over the two central incisors. If the shorter tooth has a deeper sulcus, excisional gingivectomy may be appropriate to move the gingival margin of the shorter tooth apically. However, if the sulcular depths of the short and long incisors are equivalent, gingival surgery does not correct the problem.
  52. 52. The objective was to level the gingival margins during orthodontic therapy. Although gingival surgery was a possibility, the labial sulcular depth of the maxillary right central incisor was only 1 mm, and the cemento enamel junction was located at the bottom of the sulcus. Therefore the best solution involved positioning the orthodontic brackets to facilitate intrusion of the right central incisor
  53. 53.  The third step is to evaluate the relationship between the shortest central incisor and the adjacent lateral incisors.  If the shortest central incisor is still lo ng e r than the late ral inciso rs, the o the r possibility is to extrude the longer central incisor and equilibrate the incisal edge. This moves the gingival margin coronally and eliminates the gingival margin discrepancy. However, if the shortest central incisor is sho rte r than the late ral inciso rs, this te chniq ue wo uld pro duce an une sthe tic relationship between the gingival margins of the central and lateral incisors.  The fourth step is to determine whether the incisal edges have been abraded. This is best accomplished by evaluating the teeth from an incisal perspective. If one incisal edge is thicker labiolingually than the adjacent tooth, this may indicate that it has been abraded and the tooth has overerupted. In such cases, the best method of correcting the gingival margin discrepancy is to intrude the short central incisor.
  54. 54. Significant Abrasion and Overeruption  Occasionally, patients have destructive dental habits, such as a protrusive bruxing habit, that can result in significant wear of the maxillary and mandibular incisors and compensatory overeruption of these teeth.  One option is extensive crown lengthening by elevating a flap, removing sufficient bone, and apically positioning the flap to expose adequate tooth length for crown preparation.  This type of procedure is contraindicated in the patient with short, tapered roots because it could adversely affect the final root/crown ratio and potentially open gingival embrasures between the anterior teeth.  The other option for improving the restorability of these short abraded teeth is to intrude the teeth orthodontically and move the gingival margins apically.  When abraded teeth are significantly intruded, it is necessary to hold these teeth for at least 6 months in the intruded position with orthodontic brackets or archwires (or both), or some type of bonded retainer. The principal fibers of the periodontium must accommodate to the new intruded position, a process that could take a minimum of
  55. 55. The less destructive option was to intrude the four incisors orthodontically, level the gingival margins (C and D), and allow the dentist to restore the abraded incisal edges
  56. 56.  WILCKODONTICS: also known as accelerated osteogenic orthodontics. Introduced by two wilko brothers-william (orthodontist) and Thomas (periodontist).  History: Surgical intervention to affect the alveolar housing and speed tooth movement has been used in various forms for more than a hundred years.  Heinrich Köle’s in 1959 arose the term “bony block” .He believed that it was the continuity and thickness of the denser layer of cortical bone that offered the most resistance to tooth movement. He theorized that by disrupting the continuity of cortical layer of bone using vertical interradicular corticotomy cuts both facially and lingually and these were joined 10 mm supra-apically with an osteotomy cut through the entire thickness of the alveolus..
  57. 57.  Periodontally accelerated osteogenic orthodontics (PAOO) Wilcko et al(2000, 2001, 2003, 2008) : which included the corticotomy surgery with alveolar grafting referred to as Accelerated Osteogenic Orthodontics (AOO) and more recently to as Periodontally Accelerated Osteogenic Orthodontics.  This technique advocated for comprehensive fixed orthodontic appliances in conjunction with full thickness flaps and labial and lingual corticotomies around teeth to be moved.  Bone graft consisting of demineralized freeze-dried bone and bovine bone with clindamycin was applied directly over the bone cuts and the flap was sutured in place. Tooth movement was initiated two weeks after the surgery, and every two weeks thereafter by activation of the orthodontic appliance. With this technique, treatment time reduce to one-third the time of conventional orthodontics.. 
  58. 58. Figure 1: Preoperative Figure 2: Maxillary anterior teeth coticotomy Figure 3: Bone graft placed Figure 4: Bone graft placed in the corticotomy site in the lower anteriors Figure 5: Postoperative
  59. 59.  ADVANTAGES: 1.Reduced treatment time: this technique will reduce treatment time to one-third the time of conventional orthodontics  2. Less root resorption due to decreased resistance of cortical bone  3. More bone support due to the addition of bone graft  4. History of relapse reported to be very low  DISADVANTAGES:  Mildly invasive surgical procedure  Post-surgical crestal bone loss and recession may occur.  Some pain and swelling is expected, and the possibility of infection.  Expensive  Not applicable to all cases, proper case selection is necessary to attain a good result.  
  60. 60. Conclusion  Orthodontic tooth movement is brought about by prolonged application of force on the attachment apparatus. One should consider the fact the two disparate processes occur in the gingiva that alter the transduction of the orthodontic force. First there is an injury to the connective tissue manifested by the torn and ripped collagen fibers, second the genes of both collagen and elastin are activated where a both collagen and elastin are activated where as that of tissue collagenase is inhibited. Thus affecting the ECM of gingiva.  Marked frontal expansion of incisors may lead to gingival recession, loss of attachment and bony dehiscence. Finally some forms of minor periodontal surgery were briefly discussed. Using this information along with a well defined patient management protocol (and a home care commitment from the patient) the inter- disciplinary team of periodontist and orthodontist can manage majority of inter related Ortho – Perio problem with predictably