|Year : 2012 | Volume
| Issue : 3 | Page : 179-184
Periodontally accelerated osteogenic orthodontics: Review on a surgical technique and a case report
Sharath Karanth, Amitha Ramesh, Biju Thomas, Anju Mary John
Department of Periodontics, A B Shetty Memorial Institute of Dental Sciences, Mangalore, India
|Date of Web Publication||11-Jun-2013|
Anju Mary John
Department of Periodontics, A B Shetty Memorial Institute of Dental Sciences, Mangalore
| Abstract|| |
Modifying the balance between resorption and apposition through selectively injuring the cortical plate of the alveolus has been an approach to accelerate tooth movement and is referred to as periodontally accelerated osteogenic orthodontics. It has gradually gained popularity as an adjunct treatment option for adults, as routine orthodontic tooth movement is difficult and time consuming once the mineralization and maturation of the maxilla and mandible are complete. Case selection is a very important step in which both the orthodontist and the periodontist should agree upon the need for corticotomy. The periodontally accelerated osteogenic orthodontic technique described by Wilcko (2001) involves full thickness flap reflection labially and lingually. Selective alveolar decortications are performed in the form of vertical decortications cuts up to 0.5 mm in depth, interdentally as well as horizontal cuts beyond the apex connecting the vertical decortications cuts. Adequate bio-absorbable grafting material is placed over the decortications site and sutured. Orthodontic tooth movement should start 1 or 2 weeks after the surgery. The present article reviews on contemporary clinical techniques in accelerated osteogenic orthodontics and a case report in which this technique has been implicated.
Clinical Relevance to Interdisciplinary Dentistry
- The term interdisciplinary dentistry depicts the importance of team work.
- The combined effort of the specialists of the various branches of dentistry will help to deliver the best treatment to the patient by providing a well functioning dentition in a healthy periodontal environment.
- The present article highlights the importance of an interdisciplinary approach for the purpose of periodontally accelerated osteogenic orthodontics, in the treatment of adult orthodontic patients.
Keywords: Adult orthodontics, alveolar osteopenia, corticotomy, decortication, orthodontic treatment time, regional acceleratory phenomenon
|How to cite this article:|
Karanth S, Ramesh A, Thomas B, John AM. Periodontally accelerated osteogenic orthodontics: Review on a surgical technique and a case report. J Interdiscip Dentistry 2012;2:179-84
|How to cite this URL:|
Karanth S, Ramesh A, Thomas B, John AM. Periodontally accelerated osteogenic orthodontics: Review on a surgical technique and a case report. J Interdiscip Dentistry [serial online] 2012 [cited 2014 Mar 7];2:179-84. Available from: http://www.jidonline.com/text.asp?2012/2/3/179/113250
| Introduction|| |
The number of adult patients seeking orthodontic treatment has been increasing in the recent years. The efficiency of orthodontic tooth movement in these patients can be increased when well-planned force systems are applied to bony tissues that offer less resistance against the desired movement which results in faster orthodontic movement, and treatment goals can be achieved in a shorter period, without compromising the results.  There are several differences between orthodontic treatment of adults and adolescents, being it psychological, biological and clinical differences. Adults have more specific objectives and concerns related to dentofacial aesthetics, the type of orthodontic appliance and the duration of treatment. An important factor of consideration in adult patients is that they are more prone to periodontal complications since their teeth are confined to thick mineralised alveolar bone.
Growth is almost an insignificant factor in adults compared with children. In addition, there is an increased chance of hyalinization that can occur in adults when compared with adolescents.  All these factors make adult orthodontic treatment a challenging therapeutic modality in dentistry, which necessitates the need for improvised concepts and procedures for the purpose of creating a functional dentition in a healthy periodontal environment. Corticotomy-assisted orthodontic treatment may be considered as an intermediate therapy between orthognathic surgery and conventional orthodontics. 
It can offer solutions to many limitations in adult orthodontic treatment with a wide array of advantages including reduced treatment time, enhanced expansion, differential tooth movement, and increased traction of impacted teeth as well as increased post-orthodontic stability.  The success of incorporating corticotomy as an adjunct to orthodontic treatment has not been well documented. The present article reviews on contemporary clinical techniques in accelerated osteogenic orthodontics (AOO) and a case report in which periodontally accelerated osteogenic orthodontics (PAOO) has been implicated as an adult orthodontic therapeutic modality.
Contemporary clinical techniques
Rapid tooth movement following surgery has been demonstrated as a consequence of changes in the physiology and/or composition of alveolar bone. Recently, a technique called "Dental Distraction" has been presented by Dr. Eric Liou in which the mesial aspect of an extracted first premolar tooth was surgically undermined in such a way as to allow "distal distraction" of the adjacent cuspid. By forcible distraction into a new configuration, the alveolus and/or the periodontal ligament were allowed to reorganize and the authors claimed no adverse effects to the periodontal support following the procedure. 
Later on, Dr. Thomas Wilcko and Dr. Bill demonstrated rapid orthodontic tooth movement following selective labial and lingual decortications of alveolar bone using a patented the technique, AOO or PAOO or Wilckodontics. PAOO is similar to conventional corticotomy except that in addition to selective decortications lines and/or points, a resorbable bone graft is placed over the surgical sites to augment the confining bone during tooth movement. After a healing period of 1or 2 weeks orthodontic tooth movement is started. It is then followed up using a faster rate of activation, at short intervals of 2 to 3 weeks. 
Rapid tooth movement has been reported by Wilcko using this technique which can be attributed to a state of reduced mineralization (reversible osteopenia) of the alveolar bone surrounding the involved teeth.  The concept of reversible osteopenia was explained by Wilcko in a study of five patients using computed tomography imaging. Demineralization occurs in the alveolar bone after corticotomy, and the remaining collagenous matrix of bone is transported with the tooth during its movement which will be remineralized following orthodontic movement. 
Case report studies that have been presented so far in support of corticotomy assisted orthodontic treatment, are considered weak evidence to support the advantages and mechanism of action involved in this technique. Recently few animal studies have been conducted which add more evidence to the effect of corticotomy assisted orthodontic treatment. 
The effect of alveolar interseptal corticotomy and extraction on orthodontic tooth movement has been evaluated by Ren et al. in beagle dogs. There was rapid tooth movement on the experimental side without any associated root resorption or irreversible pulpal injury. 
A doubled rate of tooth movement after corticotomy was shown by Mostafa et al. in dogs and they suggested that the resultant accelerated tooth movement can be attributed to the observed increase in bone turnover and the regional acceleratory phenomenon (RAP).  "RAP" was coined by a distinguished orthopaedist, Harold Frost. According to him RAP is a direct correlation between degree of injury and intensity of physiological healing response.  Nishimori et al. conducted study in 12 dogs in which corticotomy-assisted orthodontic therapy has been used. In this study, the second premolar was mesialized significantly faster in the test side than the control side. 
Sebaoun et al. and Lei Wang et al. conducted histological studies to evaluate the tissue response to decortications. , In the study conducted by Sebaoun et al. the response of alveolar bone to a selective decortications was evaluated in a rat model in terms of time and proximity to the site of decortications without attempting any type of tooth movement. Following surgery there was a dramatic increase in bone turnover which decreased to a steady state by the 11 th week after surgery and this effect was localized to the area immediately adjacent to the decortications cuts. 
The other histological study conducted by Wang et al. in rats explained the sequence of events occurring after corticotomy. According to this study, corticotomy-induced bone resorption around the teeth by day 21 after surgery and the area refilled with bone after 60 days following surgery. These findings confirmed the occurrence of reversible osteopenia during corticotomy assisted orthodontic therapy. 
| Case Report|| |
A 38-year-old female patient had a complaint of forwardly placed upper and lower front teeth with spacing between the teeth. The case was diagnosed as Angles Class I malocclusion with proclination and spacing of upper and lower anterior teeth. Appropriate treatment plan was made through an interdisciplinary approach and PAOO was opted for the correction of spacing and proclination, in consideration with all the clinical and biological conditions.
Surgical procedure was described to the patient. Other orthodontic treatment options available were also explained to the patient including orthognathic surgery. The patient consented to the PAOO. Prior to surgical and orthodontic treatment, periodontal health of the patient was restored by phase I periodontal therapy including plaque control measures and scaling and root planning. The results obtained by this phase of therapy were monitored monthly during the treatment period.
The surgical procedures were performed under local anaesthesia. First, corticotomy was done for mandibular anterior teeth followed by maxillary anterior teeth [Figure 1]. Vertical releasing incisions were placed extending from gingival margin toward level apical to the apices of mandibular anterior teeth. The vertical incisions were connected by buccal and lingual intracrevicular incisions. Mucoperiosteal flaps were reflected beyond the level of the apices of the teeth [Figure 2]. Vertical buccal and lingual grooves were made through the cortical layer of the exposed bone with a round fissure bur mounted on a micromotor hand piece with concomitant saline irrigation, starting 1.5 mm below the interdental crest. A horizontal groove penetrating the cortical bone connected all vertical grooves 2-3 mm apical to the apices of the teeth [Figure 3] and [Figure 4]. Adequate bio-absorbable grafting material was placed over the decortication site [Figure 5] and [Figure 6]. The surgical sites were vigorously irrigated with saline prior to flap repositioning and sutured [Figure 7]. Analgesics and adjunctive antibiotics were prescribed for 1 week.
After a period of 1 week, procedure was performed on the maxillary arch [Figure 8]. Full thickness mucoperiosteal flaps were reflected beyond the level of the apices of the maxillary anterior teeth [Figure 9] and [Figure 10]. Vertical buccal and palatal grooves were made through the cortical layer of the exposed bone, starting 1.5 mm below the interdental crest. A horizontal groove penetrating the cortical bone connected all vertical grooves 23 mm apical to the apices of the teeth [Figure 11]. Adequate bio-absorbable grafting material was placed over the decortication site [Figure 12] and [Figure 13]. The surgical sites were vigorously irrigated with saline prior to flap repositioning and sutured [Figure 14]. Analgesics and adjunctive antibiotics were prescribed for 1 week. Follow up was done after 1 week. Presently patient is undergoing orthodontic treatment [Figure 15].
| Discussion|| |
Reduction of orthodontic treatment time is considered an important goal in the management of malocclusions in adult patients.  Corticotomy facilitated orthodontic treatment has been found useful in reducing treatment time and allowing for conventional orthodontic measures treating adult patients with severe malocclusion.
Extrapolation of the results of the present case help to explain how selective decortication facilitates clinical orthodontic treatment in adult patient, when applied in conjunction with tooth movement. In addition, gingival recession was minimal in this case and interdental papillas were preserved, insuring a good post-treatment aesthetic result. The vertical mattress suturing technique as well as the papilla preservation flap as an attempt to preserve the inter-proximal soft tissue during surgery seems to be successful in retaining the papilla architecture.
The osteotomy restricted to the cortical layer minimizes the injury of the vital structures. Kole showed the importance of preserving an intact spongiosa using this technique, while a total alveolar osteotomy may impair the intraosseous and intrapulpal blood circulation. , The histological study conducted by Sebaoun et al. showed that selective decortication injury provided an overwhelming activation stimulus for the catabolic resorption response and the anabolic formation response.  And also in the same study, 3 weeks post cortication represented peak in both aspects of bone-modeling behaviour.
At 3 weeks, calcified spongiosa content of the alveolar bone adjacent to the injury had decreased by two-fold and periodontal ligament surface has increased by two-fold. Overall, surgical injury to the alveolus induced a dramatic increase in tissue turn over by 3 weeks, which dissipated to steady state by 11 weeks postoperatively. Another key finding of the same study was that increased bone metabolism was localized to the area immediately adjacent to the injury, which supports the suggestion that RAP is responsible for the observed tissue response to selective alveolar decortications. 
Rapid orthodontic treatment using heavy forces in combination with corticotomy does not affect tooth vitality but induces a transient histological change in the periodontal ligament. These short-term changes seem to be of little clinical importance.  Considering the surgical access of bony structures, this procedure was designed primarily for anterior teeth movement. However, if the anatomical considerations permit it may be possible to apply this technique to posterior segments as well.
This procedure should be avoided on any patients having any form of periodontal pathology or deformity that compromises the periodontal health. Before such treatment, it is advised to review carefully the health history of the patient, routine lab investigations, and a complete set of intra-oral periapical and bite wing radiographs in order to pinpoint and therefore, foresee any anatomical obstacle for the surgical procedure. All the risks and possible after effects, should be explained to the patient prior to the initiation of the treatment.
| Conclusion|| |
PAOO is a promising technique that has several applications in the orthodontic treatment of adults because it helps to overcome many of the current limitations of adult orthodontic treatment, the most important being the lengthy duration and the potential for periodontal complications. This treatment effects and mechanisms were confirmed by recent well-designed histological studies. However, further randomized control trials in humans are needed to confirm the claimed advantages of this technique and to evaluate the long-term effects.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14], [Figure 15]