Corticotomy Facilitated Orthodontics

1. 1 Corticotomy Corticotomy F Facilitated acilitated O Orthodontics Prepared by Prepared by Dr. Mohammed Alruby Dr. Mohammed Alruby rthodontics Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Corticotomy facilitated Orthodontics Although the art and science of orthodontics have progressed significantly over the past 100 years, relatively little has been done to enhance the rate at which tooth movement occur. Many methods have been done to enhance the rate of tooth movement. These methods include the injection of biologically active peptides, the use of magnets and even the application of electric current and corticotomy. Corticotomy: is slight penetration through the cortical bone and did not be confused with the osteotomy. Or defined as incision made into the cortical bone. This penetration or incision leads to decrease the resistance of the alveolar and diminish physical alveolar bone contact that accelerates the rate of tooth movement. Several authors have described rapid tooth in conjunction with corticotomy surgery as movement by bony (Block). Kole6 was the first describe the corticotomy as a surgical procedure in which one tooth or group of teeth with the adjacent bone is repositioned in one step. But others prefer to call this osteo-corticotomy or intra alveolar segmental osteotomy, reserving the term corticotomy for a technique in which cuts are made in the buccal cortical plate of bone. So that the segment to be moved orthodontically is held only by cancellous trabeculea and palatal cortical bone. Kole in 19596 reported combining orthodontics with corticotomy surgery and complete the active tooth movement in adult orthodontic cases in 6 to 12 weeks. The inter-proximal corticotomy cuts were extended through the entire thickness of the cortical layer, just barely penetrating the medullary bone. The vertical cuts were connected beyond the apices of the teeth with horizontal osteotomy cut extending through the entire thickness of the alveolus, essentially creating blocks of bone in which one or more teeth were embedded, using the crowns of the teeth as a handles. Kole believed that he was able to move the blocks of bone some what independly of each other because they were only connected by less-dense medullary bone. He found no incidence of root resorption, no loss of tooth vitality and no pocket formation. Kole used this surgical technique for correction of some of dento-alveolar problems as: Protruding of lower incisors: this procedure is indicated in most of cases but should be determined whether a mandibular or dento-alveolar retrusion. Buccally the corticotomy is performed between the incisors and canine then horizontal cut is made 1cm. below the incisors, lingual two vertical and one horizontal cut is made---- figure (1). Distal displacement of a single tooth or group of teeth: correction necessitates a long period of treatment in adult patient’s figure (2). The retrusion of all six lower anterior teeth: after buccal and lingual Corticotomy is performed. Alignment of rotated teeth. Correction of spaced teeth: in maxillary and mandibular protrusion with diastemas between the teeth, the Corticotomy is performed on the buccal and lingual as well as on the mesial and distal aspects of each tooth fig (3). Linguversion of posterior teeth with compression of the alveola process, very good results are obtained with corticotomy. Correction of contracted maxilla, by the same method as for the mandible --- figure (4). Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

3. Correction of too wide maxilla: an adequate strip of bone is removed on the palate, the treatment is analogous to the extension of the maxilla but the extension screw is inserted wide open and activated by screwing it tight. Suya reported surgical orthodontic treatment of 39 adult Japanese patient with an improved surgical procedure that referred to as (corticotomy facilitated orthodontics) Suya’surgical technique differ from Kole with the substitution of the supra apical horizontal corticotomy cut in place of the horizontal osteotomy cut beyond the apices of the teeth. Like Kole. Suyra did not report luxation any of the coticotomized blocks of bone. He completed most of cases in less then 12 months and showed examples of cases completed in 6 months. He like Kole. Believed that the tooth movements were made by moving blocks of bone using the crowns of the teeth as a handles. He recommended completing the major active tooth movement in 3 to 4 months, after which time that the edges of blocks of bone would begin to fuse together 11. Gantes et al reported treating five adult patient 21 to 32 years of age using Suyra’ corticotomy facilitated orthodontic procedure. The cases include some difficult space closing. Mean treatment time was 14.8 month for test group and 28.3 for the control group. Some apical root resorption was observed, no loss of tooth vitality, no adverse periodontal effect was clinically noticeable, no attachment loss of clinical significance, inter-dental papilla was preserved resulting in good esthetic results, and only minimal gingival recession3. Hajji studied the effect of eliminating mandibular dental arch crowding by comparing non extraction (30) extraction (34) and corticotomy facilitated orthodontics non extraction (20) cases by using casts and lateral cephalometric radiograph and he concluded that, there is no post treatment differences between non extraction cases and corticotomy facilitated orthodontic. In contrast, mean active treatment time for the corticotomy group was 6.1 months, versus 18 months for the non extraction orthodontics and 26.6 months for the extraction therapy11. Wilcko et al use the Suyra surgical technique to resolve dental arch crowding and achieve decrease treatment, no loss of tooth vitality, no significant apical root resorption, and no periodontal pocketing. Comparison of pretreatment and post treatment computed tomography (CT) scans, however indicated a demineralization of the alveolar bone over the root of moved tooth. CT scan analysis after 2 years of treatment indicated varying degrees of remineralization of the alveolar bone. The demineralization / remineralization finding strongly suggest the rapid tooth movement was because of rapid accelerating phenomena not bony (block) movement. This new orthodontic method includes the advantage of corticotomy and alveolar augmentation. An evaluation of this method in non extraction orthodontics for decrowding with normal orthodontic forces demonstrated dramatic decrease in the treatment time and increases the thickness of bone. This method not only safe but has made it possible to help to maintain and even thicken the layer of pre treatment over the prominence root. Fenestration can be covered; there is still vital root surface. The corticotomy was made in buccal and lingual as vertical cut and horizontal and after that augmentation occur by using resorbable material. This study indicated that, good preservation of the inter dental papillae, no loss of tooth vitality, no significant reduction in the radiographic height of crestal bone, no radiographic evidence of any significant apical root resorption11. Lars Goldson and jack Van Reck used surgical technique to allow correction of malposed cuspids through vertical cut on both sides of the tooth and this cut not pass through the 3 Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

4. palatal side of the root and also supra apical osteotomy is made at least 7 mm. above the apex, and then complete the orthodontic procedure to position the tooth7 fig 5, 6. Chung et al2 conclude that the corticotomy procedures can promote efficient posterior intrusion and rapid anterior retraction: Posterior intrusion: in cases of vertical problems and anterior open bite preferable to intrude the molar teeth with headgear but in adult patient who have completed bone maturity, this approach will be ineffective, and a corticotomy- assisted technique should be considered. The corticotomy is carried out first on the palatal side then two weeks later on the buccal side, the vertical cuts 2mm. away from the inter dental alveolar margin and should be coincident with the desired direction of intrusion of the posterior segment, the horizontal cut is made 2mm. away from the apices of the teeth to be moved. The depth of bone cut should be limited to the cortical bone, and then high pull headgear is applied. Anterior retraction: in patients with severe anterior protrusion need maximum retraction of anterior teeth into the premolar extraction sites. The corticotomy is performed first on the palatal side and two weeks later on the buccal side. In palatal side the cortical bone is removed across both premolar extraction sites, the buccal corticotomy involves a vertical bony cut beginning at the extraction site and extending to the long axis of the canine. A connecting horizontal bony cut is then made; at least 5mm. above the root apices, the depth of bony cut should be limited to cortical bone. Then complete the retraction procedures fig 7,8 Hwang and Lee5 although posterior tooth intrusion in an adult patient is difficult procedure it can be achieved without extending the adjacent teeth by performing corticotomy and using magnets. The corticotomy procedure was performed as: a vertical cut begun 2 to 3mm. below the alveolar crest and extended 2 to 3mm. beyond the apex on both buccal and lingual side, and then horizontal cut was made 2 to 3mm. below the apex to connect the two vertical cuts. This resection was 3 to 4mm. wide to facilitate molar intrusion. To obtain the desired tooth movement before the bone heal completely, it is necessary to apply orthodontic force immediately after corticotomy, otherwise it lose effectiveness. Mostafa et al have suggested that the use of surgery as corticotomy before the application of orthodontic force on the over erupted molars can over come the limitation fore the movement. They made cutting around the tooth from the buccal side only and the incision ended before reaching the crestal bone to preserve the bone and to minimize possible future periodontal problems9. Generson et al, suggested use of corticotomy to allow treatment of anterior open bite by orthodontic approach. Four vertical cuts were made between the roots for the labial and palatal aspect, the vertical cuts were connected by supraapical horizontal cuts on both surfaces. For the mandibular one, there is no vertical cut made in lingual area between the central incisors because of difficult access and possibility to damage the teeth4. Cheng et al, use the corticotomy procedure for treatment of ankylosed tooth1 fig 9 Owen 2001 makes combination treatment, invisaline and corticotomy technique to allow rapid tooth movement and he decided to treat himself first using this technique. He had class 1 occlusion with minor crowding on the mandibular arch with acceptable over jet and over bite 4 Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

5. and after eight weeks later the crowding was corrected and over jet remain the same, radiographically there is no evidence of root resorption10. Liou and Huang reduce the resistance of the socket through decortication of it to allow the rapid canine retraction through distraction of the periodontal ligament. Immediately after 1st premolar extraction, the interseptal bone distal to the canine is undermined and reduced in thickness. Because the 1st premolar socket depth is always less than the canine the bone located distal to canine root apex would resist tooth movement during distraction, therefore the 1st premolar extraction socket must be extended to the same depth as the canine socket using round bur, the bur is held parallel to the long axis of canine, the interseptal bone is reduced to a thickness 1 to 1.5mm. Priapical film is taken to ensure that the socket has been adequately deepened and the interseptal bone sufficiently reduced. Two vertical grooves performed from the inferior to superior aspect of the socket on both mesiobuccal and mesiolingual line angle of the extraction socket, the two grooves are connected at its base then the distraction device is used to allow retraction of the canine8. How can explain the rapid tooth movement The conventional view of orthodontic tooth movement is that of cell-mediated process within the periodontal ligament (PDL). Sustained force on the tooth translates into PDL cell population where in poleomorphic fibroblasts are converted to osteoblasts. And osteoclasts are derived from the blood borne monocytes. The lamina dura undergoes osteoclasis in the area of PDL (pressure) and bone apposition occurs in the area of tension. Brezniak and Wasstern discussed the multitude of factors affecting root resorption, they pointed out that in the older individuals the PDL becomes less vascular a plastic and narrow, the bone become denser, a vascular and a plastic. They speculated that these changes are reflected in a higher susptability to root resorption in adult11. Harold Frost recognized that surgical wounding of osseous hard tissue results in striking recognized activity adjacent to the site of injury in osseous and / or soft tissue surgery. He collectively termed this cascade of physiologic healing events the regional accelerating phenomena (RAP). RAP is a complex physiologic process with dominating features involving accelerated bone turn over and decrease in regional bone densities. RAP does not provide new healing process but rather explain the acceleration of normal healing events, the greater the insult the more accelerated and intense the regional response. RAP begins within a few days of insult and typically peeks at 1 to months, but may take as long as 2 years to subside11. The authors suggested that RAP in human being within a few days of surgery, typically peaks at 1 to 2 months, and may take from 6 to 24 months to subsided, they characterized the initial phase of RAP as an increase in the cortical bone porosity because of increased osteoclastic activity. They surmised that RAP might be contributing factor to increase mobility of the teeth after surgery. The damaged bone manifested by increase cellular activity, initially manifesting with demineralization but resolving with re-mineralization. It was later shown that protein extracts from the decalcified bone matrix are responsible for the new bone formation. A key factor in bone morphogenesis appear to be bone morphogenetic protein (BMP), which influence primitive stem cells to become the more specific cell type that participate in bone formation. More recently, 5 Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

6. recombinant human morphogenetic protein-2 (rh BMP-2) has been shown to induce new bone formation11. Trauma to the cortical bone has been shown to be apotentiating factor in producing a localized osteoporosis, surgery invokes an RAP when both hard and soft tissue reorganization is potentiated, and leading to a transient osteoporosis means increased mobilization of calcium, decrease bone density and increased bone turn over11. All of which would facilitate more rapid tooth movement, so that the dynamics of the physiologic tooth movement described as a demineralization / remineralization process, rather than bony block movement or resorption / apposition. Following cessation of active tooth movement, this growth protein component may assist in stimulating an increase in osteoblastic activity, resulting in remineralization of soft tissue matrix. \ 6 Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby

7. References Cheng C Y, Zen E C, Su C P: Surgical orthodontic treatment of ankylosis. J Clin Orhod, 1997, 31:375-77. Chung K R, Oh M Y, Jin S: Corticotomy assisted orthodontics. J Clin orthod 2001.35:331-9 . Gantes B, Ralhbun W E, Anholm M: Effect on periodontium following corticotomy facilitated orthodontics- case reports. J Periodontol 1991, 61:234-8. Generson R M, Porter J M, Stratigos G T: combined surgical and orthodontic management of anterior open-bite using corticotomy J oral surgery 1978,36 : 216-19 . Hwang H S, Lee K H: Intrusion of over erupted molars by corticotomy and magnets. Am J Dentofacial Orthop 2001, 120: 209- 16. Kole H: surgical operation on the alveolar ridge to correct occlusal abnormalities Oral surgery Oral medicine Oral pathology 1959, 12:515- 29. Lars Goldson, Jack van Reck: Sirgical orthodontic treatment of malposed cuspids J Clin Orthod 2001, 35: 331- 9. Lio FGW, Huang C S: Rapid canine retraction through distraction of periodontal ligament Am J Orthod Dentofacial Ortrhop 1998, 114: 372- 81. Mostafa Y A, Tawfik K M, Elmangoury N H: surgical orthodontic treatment for over erupted maxillary molars J Clin Orthod 1985, 19: 350-1. Owen A h: Accelerated invisaline treatment J Clin Orthod 2001, 35: 381- 5. Wilcko W M, Wilcko T, Ferguson D J: Rapid orthodontics with alveolar reshaping: two case reports of crowding Int J Periodontics Restorative Det 2001, 21:9-19. With my best wishes 7 Facilitated Orthodontics Orthodontics Corticotomy Corticotomy Facilitated Dr. Mohammed Alruby Dr. Mohammed Alruby